ClientSession.cpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

#include <config.h>

#include "ClientSession.hpp"

#include <fstream>
#include <ios>
#include <sstream>
#include <memory>
#include <unordered_map>

#include <Poco/Base64Decoder.h>
#include <Poco/Net/HTTPResponse.h>
#include <Poco/StreamCopier.h>
#include <Poco/URI.h>
#include <Poco/JSON/Object.h>

#include "DocumentBroker.hpp"
#include "COOLWSD.hpp"
#include <common/Common.hpp>
#include <common/JsonUtil.hpp>
#include <common/Log.hpp>
#include <common/Protocol.hpp>
#include <common/Clipboard.hpp>
#include <common/Session.hpp>
#include <common/TraceEvent.hpp>
#include <common/Util.hpp>
#include <common/CommandControl.hpp>

#if !MOBILEAPP
#include <net/HttpHelper.hpp>
#endif

using namespace COOLProtocol;

static constexpr int SYNTHETIC_COOL_PID_OFFSET = 10000000;

using Poco::Path;

// rotates regularly
const int ClipboardTokenLengthBytes = 16;
// home-use, disabled by default.
const int ProxyAccessTokenLengthBytes = 32;

static std::mutex GlobalSessionMapMutex;
static std::unordered_map<std::string, std::weak_ptr<ClientSession>> GlobalSessionMap;

ClientSession::ClientSession(
    const std::shared_ptr<ProtocolHandlerInterface>& ws,
    const std::string& id,
    const std::shared_ptr<DocumentBroker>& docBroker,
    const Poco::URI& uriPublic,
    const bool readOnly,
    const RequestDetails &requestDetails) :
    Session(ws, "ToClient-" + id, id, readOnly),
    _docBroker(docBroker),
    _uriPublic(uriPublic),
    _auth(Authorization::create(uriPublic)),
    _isDocumentOwner(false),
    _state(SessionState::DETACHED),
    _lastStateTime(std::chrono::steady_clock::now()),
    _keyEvents(1),
    _clientVisibleArea(0, 0, 0, 0),
    _splitX(0),
    _splitY(0),
    _clientSelectedPart(-1),
    _clientSelectedMode(0),
    _tileWidthPixel(0),
    _tileHeightPixel(0),
    _tileWidthTwips(0),
    _tileHeightTwips(0),
    _kitViewId(-1),
    _serverURL(requestDetails),
    _isTextDocument(false),
    _thumbnailSession(false)
{
    const std::size_t curConnections = ++COOLWSD::NumConnections;
    LOG_INF("ClientSession ctor [" << getName() << "] for URI: [" << _uriPublic.toString()
                                   << "], current number of connections: " << curConnections);

    // populate with random values.
    for (auto it : _clipboardKeys)
        rotateClipboardKey(false);

    // Emit metadata Trace Events for the synthetic pid used for the Trace Events coming in from the
    // client's cool, and for its dummy thread.
    TraceEvent::emitOneRecordingIfEnabled("{\"name\":\"process_name\",\"ph\":\"M\",\"args\":{\"name\":\""
                                          "cool-" + id
                                          + "\"},\"pid\":"
                                          + std::to_string(getpid() + SYNTHETIC_COOL_PID_OFFSET)
                                          + ",\"tid\":1},\n");
    TraceEvent::emitOneRecordingIfEnabled("{\"name\":\"thread_name\",\"ph\":\"M\",\"args\":{\"name\":\"JS\"},\"pid\":"
                                          + std::to_string(getpid() + SYNTHETIC_COOL_PID_OFFSET)
                                          + ",\"tid\":1},\n");
}

// Can't take a reference in the constructor.
void ClientSession::construct()
{
    std::unique_lock<std::mutex> lock(GlobalSessionMapMutex);
    MessageHandlerInterface::initialize();
    GlobalSessionMap[getId()] = client_from_this();
}

ClientSession::~ClientSession()
{
    const std::size_t curConnections = --COOLWSD::NumConnections;
    LOG_INF("~ClientSession dtor [" << getName() << "], current number of connections: " << curConnections);

    std::unique_lock<std::mutex> lock(GlobalSessionMapMutex);
    GlobalSessionMap.erase(getId());
}

void ClientSession::setState(SessionState newState)
{
    LOG_TRC("transition from " << name(_state) << " to " << name(newState));

    // we can get incoming messages while our disconnection is in transit.
    if (_state == SessionState::WAIT_DISCONNECT)
    {
        if (newState != SessionState::WAIT_DISCONNECT)
            LOG_WRN("Unusual race - attempts to transition from " << name(_state) << " to "
                                                                  << name(newState));
        return;
    }

    switch (newState)
    {
    case SessionState::DETACHED:
        assert(_state == SessionState::DETACHED);
        break;
    case SessionState::LOADING:
        assert(_state == SessionState::DETACHED);
        break;
    case SessionState::LIVE:
        assert(_state == SessionState::LIVE ||
               _state == SessionState::LOADING);
        break;
    case SessionState::WAIT_DISCONNECT:
        assert(_state == SessionState::LOADING ||
               _state == SessionState::LIVE);
        break;
    }
    _state = newState;
    _lastStateTime = std::chrono::steady_clock::now();
}

bool ClientSession::disconnectFromKit()
{
    assert(_state != SessionState::WAIT_DISCONNECT);
    auto docBroker = getDocumentBroker();
    if (_state == SessionState::LIVE && docBroker)
    {
        setState(SessionState::WAIT_DISCONNECT);

#ifndef IOS
        LOG_TRC("request/rescue clipboard on disconnect for " << getId());
        // rescue clipboard before shutdown.
        docBroker->forwardToChild(client_from_this(), "getclipboard");
#endif
        // handshake nicely; so wait for 'disconnected'
        LOG_TRC("Sending 'disconnect' command to session " << getId());
        docBroker->forwardToChild(client_from_this(), "disconnect");

        return false;
    }

    return true; // just get on with it
}

// Allow 20secs for the clipboard and disconnection to come.
bool ClientSession::staleWaitDisconnect(const std::chrono::steady_clock::time_point &now)
{
    if (_state != SessionState::WAIT_DISCONNECT)
        return false;
    return std::chrono::duration_cast<std::chrono::seconds>(now - _lastStateTime).count() >= 20;
}

void ClientSession::rotateClipboardKey(bool notifyClient)
{
    if (_state == SessionState::WAIT_DISCONNECT)
        return;

    _clipboardKeys[1] = _clipboardKeys[0];
    _clipboardKeys[0] = Util::rng::getHardRandomHexString(
        ClipboardTokenLengthBytes);
    LOG_TRC("Clipboard key on [" << getId() << "] set to " << _clipboardKeys[0] <<
            " last was " << _clipboardKeys[1]);
    if (notifyClient)
        sendTextFrame("clipboardkey: " + _clipboardKeys[0]);
}

std::string ClientSession::getClipboardURI(bool encode)
{
    if (_wopiFileInfo && _wopiFileInfo->getDisableCopy())
        return std::string();

    return createPublicURI("clipboard", _clipboardKeys[0], encode);
}

std::string ClientSession::createPublicURI(const std::string& subPath, const std::string& tag, bool encode)
{
    Poco::URI wopiSrc = getDocumentBroker()->getPublicUri();
    wopiSrc.setQueryParameters(Poco::URI::QueryParameters());

    const std::string encodedFrom = Util::encodeURIComponent(wopiSrc.toString());

    std::string meta = _serverURL.getSubURLForEndpoint(
        "/cool/" + subPath + "?WOPISrc=" + encodedFrom +
        "&ServerId=" + Util::getProcessIdentifier() +
        "&ViewId=" + std::to_string(getKitViewId()) +
        "&Tag=" + tag);

#if !MOBILEAPP
    if (!COOLWSD::RouteToken.empty())
        meta += "&RouteToken=" + COOLWSD::RouteToken;
#endif

    if (!encode)
        return meta;

    return Util::encodeURIComponent(meta);
}

bool ClientSession::matchesClipboardKeys(const std::string &/*viewId*/, const std::string &tag)
{
    if (tag.empty())
    {
        LOG_ERR("Invalid, empty clipboard tag");
        return false;
    }

    // FIXME: check viewId for paranoia if we can.
    return std::any_of(std::begin(_clipboardKeys), std::end(_clipboardKeys),
                       [&tag](const std::string& it) { return it == tag; });
}


void ClientSession::handleClipboardRequest(DocumentBroker::ClipboardRequest     type,
                                           const std::shared_ptr<StreamSocket> &socket,
                                           const std::string                   &tag,
                                           const std::shared_ptr<std::string>  &data)
{
    // Move the socket into our DocBroker.
    auto docBroker = getDocumentBroker();
    docBroker->addSocketToPoll(socket);

    if (_state == SessionState::WAIT_DISCONNECT)
    {
        LOG_TRC("Clipboard request " << tag << " for disconnecting session");
        if (docBroker->lookupSendClipboardTag(socket, tag, false))
            return; // the getclipboard already completed.
        if (type == DocumentBroker::CLIP_REQUEST_SET)
        {
            #if !MOBILEAPP
            HttpHelper::sendErrorAndShutdown(400, socket);
            #endif
        }
        else // will be handled during shutdown
        {
            LOG_TRC("Clipboard request " << tag << " queued for shutdown");
            _clipSockets.push_back(socket);
        }
    }

    std::string specific;
    if (type == DocumentBroker::CLIP_REQUEST_GET_RICH_HTML_ONLY)
        specific = " text/html";

    if (type != DocumentBroker::CLIP_REQUEST_SET)
    {
        if (_wopiFileInfo && _wopiFileInfo->getDisableCopy())
        {
            // Unsupported clipboard request.
            LOG_ERR("Unsupported Clipboard Request from socket #" << socket->getFD()
                                                                  << ". Terminating connection.");
            std::ostringstream oss;
            oss << "HTTP/1.1 403 Forbidden\r\n"
                << "Date: " << Util::getHttpTimeNow() << "\r\n"
                << "User-Agent: " << WOPI_AGENT_STRING << "\r\n"
                << "Content-Length: 0\r\n"
                << "Connection: close\r\n"
                << "\r\n";
            socket->send(oss.str());
            socket->closeConnection(); // Shutdown socket.
            socket->ignoreInput();
            return;
        }

        LOG_TRC("Session [" << getId() << "] sending getclipboard" + specific);
        docBroker->forwardToChild(client_from_this(), "getclipboard" + specific);
        _clipSockets.push_back(socket);
    }
    else // REQUEST_SET
    {
        // FIXME: manage memory more efficiently.
        LOG_TRC("Session [" << getId() << "] sending setclipboard");
        if (data.get())
        {
            preProcessSetClipboardPayload(*data);
            docBroker->forwardToChild(client_from_this(), "setclipboard\n" + *data, true);

            // FIXME: work harder for error detection ?
            std::ostringstream oss;
            oss << "HTTP/1.1 200 OK\r\n"
                << "Date: " << Util::getHttpTimeNow() << "\r\n"
                << "User-Agent: " << WOPI_AGENT_STRING << "\r\n"
                << "Content-Length: 0\r\n"
                << "Connection: close\r\n"
                << "\r\n";
            socket->send(oss.str());
            socket->shutdown();
        }
        else
        {
            #if !MOBILEAPP
            HttpHelper::sendErrorAndShutdown(400, socket);
            #endif
        }
    }
}

bool ClientSession::_handleInput(const char *buffer, int length)
{
    LOG_TRC("handling incoming [" << getAbbreviatedMessage(buffer, length) << ']');
    const std::string firstLine = getFirstLine(buffer, length);
    const StringVector tokens = StringVector::tokenize(firstLine.data(), firstLine.size());

    std::shared_ptr<DocumentBroker> docBroker = getDocumentBroker();
    if (!docBroker || docBroker->isMarkedToDestroy())
    {
        LOG_ERR("No DocBroker found, or DocBroker marked to be destroyed. Terminating session " << getName());
        return false;
    }

    if (tokens.size() < 1)
    {
        sendTextFrameAndLogError("error: cmd=empty kind=unknown");
        return false;
    }

    if (tokens.equals(0, "DEBUG"))
    {
        LOG_DBG("From client: " << std::string(buffer, length).substr(strlen("DEBUG") + 1));
        return false;
    }
    else if (tokens.equals(0, "ERROR"))
    {
        LOG_ERR("From client: " << std::string(buffer, length).substr(strlen("ERROR") + 1));
        return false;
    }
    else if (tokens.equals(0, "TRACEEVENT"))
    {
        if (COOLWSD::EnableTraceEventLogging)
        {
            if (_performanceCounterEpoch == 0)
            {
                static bool warnedOnce = false;
                if (!warnedOnce)
                {
                    LOG_WRN("For some reason the _performanceCounterEpoch is still zero, ignoring TRACEEVENT from cool as the timestamp would be garbage");
                    warnedOnce = true;
                }
                return false;
            } else if (_performanceCounterEpoch < 1620000000000000ull || _performanceCounterEpoch > 2000000000000000ull)
            {
                static bool warnedOnce = false;
                if (!warnedOnce)
                {
                    LOG_WRN("For some reason the _performanceCounterEpoch is bogus, ignoring TRACEEVENT from cool as the timestamp would be garbage");
                    warnedOnce = true;
                }
                return false;
            }

            if (tokens.size() >= 4)
            {
                // The intent is that when doing Trace Event generation, the web browser client and
                // the server run on the same machine, so there is no clock skew problem.
                std::string name;
                std::string ph;
                uint64_t ts;
                if (getTokenString(tokens[1], "name", name) &&
                    getTokenString(tokens[2], "ph", ph) &&
                    getTokenUInt64(tokens[3], "ts", ts))
                {
                    std::string args;
                    if (tokens.size() >= 5 && getTokenString(tokens, "args", args))
                        args = ",\"args\":" + args;

                    uint64_t id, tid;
                    uint64_t dur;
                    if (ph == "i")
                    {
                        COOLWSD::writeTraceEventRecording("{\"name\":\""
                                                          + name
                                                          + "\",\"ph\":\"i\""
                                                          + args
                                                          + ",\"ts\":"
                                                          + std::to_string(ts + _performanceCounterEpoch)
                                                          + ",\"pid\":"
                                                          + std::to_string(getpid() + SYNTHETIC_COOL_PID_OFFSET)
                                                          + ",\"tid\":1},\n");
                    }
                    else if ((ph == "S" || ph == "F") &&
                             getTokenUInt64(tokens[4], "id", id),
                             getTokenUInt64(tokens[5], "tid", tid))
                    {
                        COOLWSD::writeTraceEventRecording("{\"name\":\""
                                                          + name
                                                          + "\",\"ph\":\""
                                                          + ph
                                                          + "\""
                                                          + args
                                                          + ",\"ts\":"
                                                          + std::to_string(ts + _performanceCounterEpoch)
                                                          + ",\"pid\":"
                                                          + std::to_string(getpid() + SYNTHETIC_COOL_PID_OFFSET)
                                                          + ",\"tid\":"
                                                          + std::to_string(tid)
                                                          + ",\"id\":"
                                                          + std::to_string(id)
                                                          + "},\n");
                    }
                    else if (ph == "X" &&
                             getTokenUInt64(tokens[4], "dur", dur))
                    {
                        COOLWSD::writeTraceEventRecording("{\"name\":\""
                                                          + name
                                                          + "\",\"ph\":\"X\""
                                                          + args
                                                          + ",\"ts\":"
                                                          + std::to_string(ts + _performanceCounterEpoch)
                                                          + ",\"pid\":"
                                                          + std::to_string(getpid() + SYNTHETIC_COOL_PID_OFFSET)
                                                          + ",\"tid\":1"
                                                            ",\"dur\":"
                                                          + std::to_string(dur)
                                                          + "},\n");
                    }
                    else
                    {
                        LOG_WRN("Unrecognized TRACEEVENT message");
                    }
                }
            }
            else
                LOG_WRN("Unrecognized TRACEEVENT message");
        }
        return false;
    }

    COOLWSD::dumpIncomingTrace(docBroker->getJailId(), getId(), firstLine);

    if (COOLProtocol::tokenIndicatesUserInteraction(tokens[0]))
    {
        // Keep track of timestamps of incoming client messages that indicate user activity.
        updateLastActivityTime();
        docBroker->updateLastActivityTime();

        if (isEditable() && isViewLoaded())
        {
            assert(!inWaitDisconnected() && "A writable view can't be waiting disconnection.");
            docBroker->updateEditingSessionId(getId());
        }
    }

    if (tokens.equals(0, "coolclient"))
    {
        if (tokens.size() < 2)
        {
            sendTextFrameAndLogError("error: cmd=coolclient kind=badprotocolversion");
            return false;
        }

        const std::tuple<int, int, std::string> versionTuple = ParseVersion(tokens[1]);
        if (std::get<0>(versionTuple) != ProtocolMajorVersionNumber ||
            std::get<1>(versionTuple) != ProtocolMinorVersionNumber)
        {
            sendTextFrameAndLogError("error: cmd=coolclient kind=badprotocolversion");
            return false;
        }

        _performanceCounterEpoch = 0;
        if (tokens.size() >= 4)
        {
            const std::string timestamp = tokens[2];
            const char* str = timestamp.c_str();
            char* endptr = nullptr;
            uint64_t ts = strtoull(str, &endptr, 10);
            if (*endptr == '\0')
            {
                const std::string perfcounter = tokens[3];
                str = perfcounter.data();
                endptr = nullptr;
                double counter = strtod(str, &endptr);
                if (*endptr == '\0' && counter > 0 &&
                    (counter < (double)(std::numeric_limits<uint64_t>::max() / 1000)))
                {
                    // Now we know how to translate from the client's performance.now() values to
                    // microseconds since the epoch.
                    _performanceCounterEpoch = ts * 1000 - (uint64_t)(counter * 1000);
                    LOG_INF("Client timestamps: Date.now():" << ts <<
                            ", performance.now():" << counter
                            << " => " << _performanceCounterEpoch);
                }
            }
        }

        // Send COOL version information
        sendTextFrame("coolserver " + Util::getVersionJSON(EnableExperimental));
        // Send LOKit version information
        sendTextFrame("lokitversion " + COOLWSD::LOKitVersion);

        // If Trace Event generation and logging is enabled (whether it can be turned on), tell it
        // to cool
        if (COOLWSD::EnableTraceEventLogging)
            sendTextFrame("enabletraceeventlogging yes");

        #if !MOBILEAPP
            // If it is not mobile, it must be Linux (for now).
            sendTextFrame(std::string("osinfo ") + Util::getLinuxVersion());
        #endif

        // Send clipboard key
        rotateClipboardKey(true);

        return true;
    }

    if (tokens.equals(0, "versionbar"))
    {
#if !MOBILEAPP
        std::string versionBar;
        {
            std::lock_guard<std::mutex> lock(COOLWSD::FetchUpdateMutex);
            versionBar = COOLWSD::LatestVersion;
        }

        if (!versionBar.empty())
            sendTextFrame("versionbar: " + versionBar);
#endif
    }
    else if (tokens.equals(0, "jserror") || tokens.equals(0, "jsexception"))
    {
        LOG_ERR(std::string(buffer, length));
        return true;
    }
    else if (tokens.equals(0, "load"))
    {
        if (getDocURL() != "")
        {
            sendTextFrameAndLogError("error: cmd=load kind=docalreadyloaded");
            return false;
        }

        return loadDocument(buffer, length, tokens, docBroker);
    }
    else if (tokens.equals(0, "loadwithpassword"))
    {
        std::string docPassword;
        if (tokens.size() > 1 && getTokenString(tokens[1], "password", docPassword))
        {
            if (!docPassword.empty())
            {
                setHaveDocPassword(true);
                setDocPassword(docPassword);
            }
        }
        return loadDocument(buffer, length, tokens, docBroker);
    }
    else if (getDocURL().empty())
    {
        sendTextFrameAndLogError("error: cmd=" + tokens[0] + " kind=nodocloaded");
        return false;
    }
    else if (tokens.equals(0, "canceltiles"))
    {
        docBroker->cancelTileRequests(client_from_this());
        return true;
    }
    else if (tokens.equals(0, "commandvalues"))
    {
        return getCommandValues(buffer, length, tokens, docBroker);
    }
    else if (tokens.equals(0, "closedocument"))
    {
        // If this session is the owner of the file & 'EnableOwnerTermination' feature
        // is turned on by WOPI, let it close all sessions
        if (isDocumentOwner() && _wopiFileInfo && _wopiFileInfo->getEnableOwnerTermination())
        {
            LOG_DBG("Session [" << getId() << "] requested owner termination");
            docBroker->closeDocument("ownertermination");
        }
        else if (docBroker->isDocumentChangedInStorage())
        {
            LOG_DBG("Document marked as changed in storage and user ["
                    << getUserId() << ", " << getUserName()
                    << "] wants to refresh the document for all.");
            docBroker->stop("documentconflict " + getUserName());
        }

        return true;
    }
    else if (tokens.equals(0, "versionrestore"))
    {
        if (tokens.size() > 1 && tokens.equals(1, "prerestore"))
        {
            // green signal to WOPI host to restore the version *after* saving
            // any unsaved changes, if any, to the storage
            docBroker->closeDocument("versionrestore: prerestore_ack");
        }
    }
    else if (tokens.equals(0, "partpagerectangles"))
    {
        // We don't support partpagerectangles any more, will be removed in the
        // next version
        sendTextFrame("partpagerectangles: ");
        return true;
    }
    else if (tokens.equals(0, "ping"))
    {
        std::string count = std::to_string(docBroker->getRenderedTileCount());
        sendTextFrame("pong rendercount=" + count);
        return true;
    }
    else if (tokens.equals(0, "renderfont"))
    {
        return sendFontRendering(buffer, length, tokens, docBroker);
    }
    else if (tokens.equals(0, "status") || tokens.equals(0, "statusupdate"))
    {
        assert(firstLine.size() == static_cast<std::size_t>(length));
        return forwardToChild(firstLine, docBroker);
    }
    else if (tokens.equals(0, "tile"))
    {
        return sendTile(buffer, length, tokens, docBroker);
    }
    else if (tokens.equals(0, "tilecombine"))
    {
        return sendCombinedTiles(buffer, length, tokens, docBroker);
    }
    else if (tokens.equals(0, "save"))
    {
        // If we can't write to Storage, there is no point in saving.
        if (!isWritable())
        {
            LOG_WRN("Session [" << getId() << "] on document [" << docBroker->getDocKey()
                                << "] has no write permissions in Storage and cannot save.");
            sendTextFrameAndLogError("error: cmd=save kind=savefailed");
        }
        else
        {
            // Don't save unmodified docs by default.
            int dontSaveIfUnmodified = 1;
            int dontTerminateEdit = 1;
            std::string extendedData;

            // We expect at most 3 arguments.
            for (int i = 0; i < 3; ++i)
            {
                // +1 to skip the command token.
                const StringVector attr = StringVector::tokenize(tokens[i + 1], '=');
                if (attr.size() == 2)
                {
                    if (attr[0] == "dontTerminateEdit")
                        COOLProtocol::stringToInteger(attr[1], dontTerminateEdit);
                    else if (attr[0] == "dontSaveIfUnmodified")
                        COOLProtocol::stringToInteger(attr[1], dontSaveIfUnmodified);
                    else if (attr[0] == "extendedData")
                    {
                        std::string decoded;
                        Poco::URI::decode(attr[1], decoded);
                        extendedData = decoded;
                    }
                }
            }

            constexpr bool isAutosave = false;
            docBroker->sendUnoSave(client_from_this(), dontTerminateEdit != 0,
                                   dontSaveIfUnmodified != 0, isAutosave, extendedData);
        }
    }
    else if (tokens.equals(0, "savetostorage"))
    {
        // By default savetostorage implies forcing.
        int force = 1;
        if (tokens.size() > 1)
            getTokenInteger(tokens[1], "force", force);

        // The savetostorage command is really only used to resolve save conflicts
        // and it seems to always have force=1. However, we should still honor the
        // contract and do as told, not as we expect the API to be used. Use force if provided.
        docBroker->uploadToStorage(client_from_this(), force);
    }
    else if (tokens.equals(0, "clientvisiblearea"))
    {
        int x;
        int y;
        int width;
        int height;
        if ((tokens.size() != 5 && tokens.size() != 7) ||
            !getTokenInteger(tokens[1], "x", x) ||
            !getTokenInteger(tokens[2], "y", y) ||
            !getTokenInteger(tokens[3], "width", width) ||
            !getTokenInteger(tokens[4], "height", height))
        {
            // Be forgiving and log instead of disconnecting.
            // sendTextFrameAndLogError("error: cmd=clientvisiblearea kind=syntax");
            LOG_WRN("Invalid syntax for '" << tokens[0] << "' message: [" << firstLine << ']');
            return true;
        }
        else
        {
            if (tokens.size() == 7)
            {
                int splitX, splitY;
                if (!getTokenInteger(tokens[5], "splitx", splitX) ||
                    !getTokenInteger(tokens[6], "splity", splitY))
                {
                    LOG_WRN("Invalid syntax for '" << tokens[0] << "' message: [" << firstLine << ']');
                    return true;
                }

                _splitX = splitX;
                _splitY = splitY;
            }

            _clientVisibleArea = Util::Rectangle(x, y, width, height);
            resetWireIdMap();
            return forwardToChild(std::string(buffer, length), docBroker);
        }
    }
    else if (tokens.equals(0, "setclientpart"))
    {
        if(!_isTextDocument)
        {
            int temp;
            if (tokens.size() != 2 ||
                !getTokenInteger(tokens[1], "part", temp))
            {
                sendTextFrameAndLogError("error: cmd=setclientpart kind=syntax");
                return false;
            }
            else
            {
                _clientSelectedPart = temp;
                resetWireIdMap();
                return forwardToChild(std::string(buffer, length), docBroker);
            }
        }
    }
    else if (tokens.equals(0, "selectclientpart"))
    {
        if(!_isTextDocument)
        {
            int part;
            int how;
            if (tokens.size() != 3 ||
                !getTokenInteger(tokens[1], "part", part) ||
                !getTokenInteger(tokens[2], "how", how))
            {
                sendTextFrameAndLogError("error: cmd=selectclientpart kind=syntax");
                return false;
            }
            else
            {
                return forwardToChild(std::string(buffer, length), docBroker);
            }
        }
    }
    else if (tokens.equals(0, "moveselectedclientparts"))
    {
        if(!_isTextDocument)
        {
            int nPosition;
            if (tokens.size() != 2 ||
                !getTokenInteger(tokens[1], "position", nPosition))
            {
                sendTextFrameAndLogError("error: cmd=moveselectedclientparts kind=syntax");
                return false;
            }
            else
            {
                docBroker->updateLastModifyingActivityTime();
                return forwardToChild(std::string(buffer, length), docBroker);
            }
        }
    }
    else if (tokens.equals(0, "clientzoom"))
    {
        int tilePixelWidth, tilePixelHeight, tileTwipWidth, tileTwipHeight;
        if (tokens.size() != 5 ||
            !getTokenInteger(tokens[1], "tilepixelwidth", tilePixelWidth) ||
            !getTokenInteger(tokens[2], "tilepixelheight", tilePixelHeight) ||
            !getTokenInteger(tokens[3], "tiletwipwidth", tileTwipWidth) ||
            !getTokenInteger(tokens[4], "tiletwipheight", tileTwipHeight))
        {
            // Be forgiving and log instead of disconnecting.
            // sendTextFrameAndLogError("error: cmd=clientzoom kind=syntax");
            LOG_WRN("Invalid syntax for '" << tokens[0] << "' message: [" << firstLine << ']');
            return true;
        }
        else
        {
            _tileWidthPixel = tilePixelWidth;
            _tileHeightPixel = tilePixelHeight;
            _tileWidthTwips = tileTwipWidth;
            _tileHeightTwips = tileTwipHeight;
            resetWireIdMap();
            return forwardToChild(std::string(buffer, length), docBroker);
        }
    }
    else if (tokens.equals(0, "tileprocessed"))
    {
        std::string tileID;
        if (tokens.size() != 2 ||
            !getTokenString(tokens[1], "tile", tileID))
        {
            // Be forgiving and log instead of disconnecting.
            // sendTextFrameAndLogError("error: cmd=tileprocessed kind=syntax");
            LOG_WRN("Invalid syntax for '" << tokens[0] << "' message: [" << firstLine << ']');
            return true;
        }

        auto iter = std::find_if(_tilesOnFly.begin(), _tilesOnFly.end(),
        [&tileID](const std::pair<std::string, std::chrono::steady_clock::time_point>& curTile)
        {
            return curTile.first == tileID;
        });

        if(iter != _tilesOnFly.end())
            _tilesOnFly.erase(iter);
        else
            LOG_INF("Tileprocessed message with an unknown tile ID '" << tileID << "' from session " << getId());

        docBroker->sendRequestedTiles(client_from_this());
        return true;
    }
    else if (tokens.equals(0, "removesession"))
    {
        if (tokens.size() > 1 && (_isDocumentOwner || !isReadOnly()))
        {
            std::string sessionId = Util::encodeId(std::stoi(tokens[1]), 4);
            docBroker->broadcastMessage(firstLine);
            docBroker->removeSession(client_from_this());
        }
        else
            LOG_WRN("Readonly session '" << getId() << "' trying to kill another view");
    }
    else if (tokens.equals(0, "renamefile"))
    {
        std::string encodedWopiFilename;
        if (tokens.size() < 2 || !getTokenString(tokens[1], "filename", encodedWopiFilename))
        {
            LOG_ERR("Bad syntax for: " << firstLine);
            sendTextFrameAndLogError("error: cmd=renamefile kind=syntax");
            return false;
        }

        std::string wopiFilename;
        Poco::URI::decode(encodedWopiFilename, wopiFilename);
        const std::string error =
            docBroker->handleRenameFileCommand(getId(), std::move(wopiFilename));
        if (!error.empty())
        {
            sendTextFrameAndLogError(error);
            return false;
        }

        return true;
    }
    else if (tokens.equals(0, "dialogevent") ||
             tokens.equals(0, "formfieldevent") ||
             tokens.equals(0, "sallogoverride") ||
             tokens.equals(0, "contentcontrolevent"))
    {
        return forwardToChild(firstLine, docBroker);
    }
    else if (tokens.equals(0, "loggingleveloverride"))
    {
        if (tokens.size() > 0)
        {
            // Note that these LOG_INF() messages won't necessarily show up if the current logging
            // level is higher, of course.
            if (tokens.equals(1, "default"))
            {
                LOG_INF("Thread-local logging level being set to default ["
                        << Log::getLevel()
                        << "]");
                Log::setThreadLocalLogLevel(Log::getLevel());
            }
            else
            {
                try
                {
                    auto leastVerboseAllowed = Poco::Logger::parseLevel(COOLWSD::LeastVerboseLogLevelSettableFromClient);
                    auto mostVerboseAllowed = Poco::Logger::parseLevel(COOLWSD::MostVerboseLogLevelSettableFromClient);

                    if (tokens.equals(1, "verbose"))
                    {
                        LOG_INF("Client sets thread-local logging level to the most verbose allowed ["
                                << COOLWSD::MostVerboseLogLevelSettableFromClient
                                << "]");
                        Log::setThreadLocalLogLevel(COOLWSD::MostVerboseLogLevelSettableFromClient);
                        LOG_INF("Thread-local logging level was set to ["
                                << COOLWSD::MostVerboseLogLevelSettableFromClient
                                << "]");
                    }
                    else if (tokens.equals(1, "terse"))
                    {
                        LOG_INF("Client sets thread-local logging level to the least verbose allowed ["
                                << COOLWSD::LeastVerboseLogLevelSettableFromClient
                                << "]");
                        Log::setThreadLocalLogLevel(COOLWSD::LeastVerboseLogLevelSettableFromClient);
                        LOG_INF("Thread-local logging level was set to ["
                                << COOLWSD::LeastVerboseLogLevelSettableFromClient
                                << "]");
                    }
                    else
                    {
                        auto level = Poco::Logger::parseLevel(tokens[1]);
                        // Note that numerically the higher priority levels are lower in value.
                        if (level >= leastVerboseAllowed && level <= mostVerboseAllowed)
                        {
                            LOG_INF("Thread-local logging level being set to ["
                                    << tokens[1]
                                    << "]");
                            Log::setThreadLocalLogLevel(tokens[1]);
                        }
                        else
                        {
                            LOG_WRN("Client tries to set logging level to ["
                                    << tokens[1]
                                    << "] which is outside of bounds ["
                                    << COOLWSD::LeastVerboseLogLevelSettableFromClient << ","
                                    << COOLWSD::MostVerboseLogLevelSettableFromClient << "]");
                        }
                    }
                }
                catch (const Poco::Exception &e)
                {
                    LOG_WRN("Exception while handling loggingleveloverride message: " << e.message());
                }
            }
        }
    }
    else if (tokens.equals(0, "traceeventrecording"))
    {
        if (COOLWSD::getConfigValue<bool>("trace_event[@enable]", false))
        {
            if (tokens.size() > 0)
            {
                if (tokens.equals(1, "start"))
                {
                    TraceEvent::startRecording();
                    LOG_INF("Trace Event recording in this WSD process turned on (might have been on already)");
                }
                else if (tokens.equals(1, "stop"))
                {
                    TraceEvent::stopRecording();
                    LOG_INF("Trace Event recording in this WSD process turned off (might have been off already)");
                }
            }
            forwardToChild(firstLine, docBroker);
        }
        return true;
    }
    else if (tokens.equals(0, "completefunction"))
    {
        return forwardToChild(std::string(buffer, length), docBroker);
    }
    else if (tokens.equals(0, "resetaccesstoken"))
    {
        if (tokens.size() != 2)
        {
            LOG_ERR("Bad syntax for: " << tokens[0]);
            sendTextFrameAndLogError("error: cmd=resetaccesstoken kind=syntax");
            return false;
        }

        _auth.resetAccessToken(tokens[1]);
        return true;
    }
    else if (tokens.equals(0, "outlinestate") ||
             tokens.equals(0, "downloadas") ||
             tokens.equals(0, "getchildid") ||
             tokens.equals(0, "gettextselection") ||
             tokens.equals(0, "paste") ||
             tokens.equals(0, "insertfile") ||
             tokens.equals(0, "key") ||
             tokens.equals(0, "textinput") ||
             tokens.equals(0, "windowkey") ||
             tokens.equals(0, "mouse") ||
             tokens.equals(0, "windowmouse") ||
             tokens.equals(0, "windowgesture") ||
             tokens.equals(0, "requestloksession") ||
             tokens.equals(0, "resetselection") ||
             tokens.equals(0, "saveas") ||
             tokens.equals(0, "exportas") ||
             tokens.equals(0, "selectgraphic") ||
             tokens.equals(0, "selecttext") ||
             tokens.equals(0, "windowselecttext") ||
             tokens.equals(0, "setpage") ||
             tokens.equals(0, "uno") ||
             tokens.equals(0, "useractive") ||
             tokens.equals(0, "userinactive") ||
             tokens.equals(0, "paintwindow") ||
             tokens.equals(0, "windowcommand") ||
             tokens.equals(0, "signdocument") ||
             tokens.equals(0, "asksignaturestatus") ||
             tokens.equals(0, "uploadsigneddocument") ||
             tokens.equals(0, "exportsignanduploaddocument") ||
             tokens.equals(0, "rendershapeselection") ||
             tokens.equals(0, "resizewindow") ||
             tokens.equals(0, "removetextcontext") ||
             tokens.equals(0, "rendersearchresult"))
    {
        if (tokens.equals(0, "key"))
            _keyEvents++;

        if (COOLProtocol::tokenIndicatesDocumentModification(tokens))
        {
            docBroker->updateLastModifyingActivityTime();
        }

        if (!filterMessage(firstLine))
        {
            const std::string dummyFrame = "dummymsg";
            return forwardToChild(dummyFrame, docBroker);
        }
        else if (tokens[0] != "requestloksession")
        {
            return forwardToChild(std::string(buffer, length), docBroker);
        }
        else
        {
            assert(tokens.equals(0, "requestloksession"));
            return true;
        }
    }
    else if (tokens.equals(0, "attemptlock"))
    {
        return attemptLock(docBroker);
    }
    else if (tokens.equals(0, "blockingcommandstatus"))
    {
        return forwardToChild(std::string(buffer, length), docBroker);
    }
    else
    {
        LOG_ERR("Session [" << getId() << "] got unknown command [" << tokens[0] << ']');
        sendTextFrameAndLogError("error: cmd=" + tokens[0] + " kind=unknown");
    }

    return false;
}

bool ClientSession::loadDocument(const char* /*buffer*/, int /*length*/,
                                 const StringVector& tokens,
                                 const std::shared_ptr<DocumentBroker>& docBroker)
{
    if (tokens.size() < 2)
    {
        // Failed loading ends connection.
        sendTextFrameAndLogError("error: cmd=load kind=syntax");
        return false;
    }

    _viewLoadStart = std::chrono::steady_clock::now();
    LOG_INF("Requesting document load from child.");
    try
    {
        std::string timestamp, doctemplate;
        int loadPart = -1;
        parseDocOptions(tokens, loadPart, timestamp, doctemplate);

        std::ostringstream oss;
        oss << "load url=" << docBroker->getPublicUri().toString();

        if (!getUserId().empty() && !getUserName().empty())
        {
            std::string encodedUserId;
            Poco::URI::encode(getUserId(), "", encodedUserId);
            oss << " authorid=" << encodedUserId;
            encodedUserId = "";
            Poco::URI::encode(COOLWSD::anonymizeUsername(getUserId()), "", encodedUserId);
            oss << " xauthorid=" << encodedUserId;

            std::string encodedUserName;
            Poco::URI::encode(getUserName(), "", encodedUserName);
            oss << " author=" << encodedUserName;
            encodedUserName = "";
            Poco::URI::encode(COOLWSD::anonymizeUsername(getUserName()), "", encodedUserName);
            oss << " xauthor=" << encodedUserName;
        }

        if (!getUserExtraInfo().empty())
        {
            std::string encodedUserExtraInfo;
            Poco::URI::encode(getUserExtraInfo(), "", encodedUserExtraInfo);
            oss << " authorextrainfo=" << encodedUserExtraInfo; //TODO: could this include PII?
        }

        if (!getUserPrivateInfo().empty())
        {
            std::string encodedUserPrivateInfo;
            Poco::URI::encode(getUserPrivateInfo(), "", encodedUserPrivateInfo);
            oss << " authorprivateinfo=" << encodedUserPrivateInfo;
        }

        oss << " readonly=" << isReadOnly();

        if (loadPart >= 0)
        {
            oss << " part=" << loadPart;
        }

        if (getHaveDocPassword())
        {
            oss << " password=" << getDocPassword();
        }

        if (!getLang().empty())
        {
            oss << " lang=" << getLang();
        }

        if (!getDeviceFormFactor().empty())
        {
            oss << " deviceFormFactor=" << getDeviceFormFactor();
        }

        if (!getTimezone().empty())
        {
            oss << " timezone=" << getTimezone();
        }

        if (!getSpellOnline().empty())
        {
            oss << " spellOnline=" << getSpellOnline();
        }

        if (!getWatermarkText().empty())
        {
            std::string encodedWatermarkText;
            Poco::URI::encode(getWatermarkText(), "", encodedWatermarkText);
            oss << " watermarkText=" << encodedWatermarkText;
            oss << " watermarkOpacity=" << COOLWSD::getConfigValue<double>("watermark.opacity", 0.2);
        }

        if (COOLWSD::hasProperty("security.enable_macros_execution"))
        {
            oss << " enableMacrosExecution=" << std::boolalpha
                << COOLWSD::getConfigValue<bool>("security.enable_macros_execution", false);
        }

        if (COOLWSD::hasProperty("security.macro_security_level"))
        {
            oss << " macroSecurityLevel=" << COOLWSD::getConfigValue<int>("security.macro_security_level", 1);
        }

        if (!getDocOptions().empty())
        {
            oss << " options=" << getDocOptions();
        }

        if (_wopiFileInfo && !_wopiFileInfo->getTemplateSource().empty())
        {
            oss << " template=" << _wopiFileInfo->getTemplateSource();
        }

        if (!getBatchMode().empty())
        {
            oss << " batch=" << getBatchMode();
        }
#if ENABLE_FEATURE_LOCK
        sendLockedInfo();
#endif
        return forwardToChild(oss.str(), docBroker);
    }
    catch (const Poco::SyntaxException&)
    {
        sendTextFrameAndLogError("error: cmd=load kind=uriinvalid");
    }

    return false;
}

#if ENABLE_FEATURE_LOCK
void ClientSession::sendLockedInfo()
{
    Poco::JSON::Object::Ptr lockInfo = new Poco::JSON::Object();
    CommandControl::LockManager::setTranslationPath(getLang());
    lockInfo->set("IsLockedUser", CommandControl::LockManager::isLockedUser());
    lockInfo->set("IsLockReadOnly", CommandControl::LockManager::isLockReadOnly());

    // Poco:Dynamic:Var does not support std::unordred_set so converted to std::vector
    std::vector<std::string> lockedCommandList(
        CommandControl::LockManager::getLockedCommandList().begin(),
        CommandControl::LockManager::getLockedCommandList().end());
    lockInfo->set("LockedCommandList", lockedCommandList);
    lockInfo->set("UnlockTitle", CommandControl::LockManager::getUnlockTitle());
    lockInfo->set("UnlockLink", CommandControl::LockManager::getUnlockLink());
    lockInfo->set("UnlockDescription", CommandControl::LockManager::getUnlockDescription());
    lockInfo->set("WriterHighlights", CommandControl::LockManager::getWriterHighlights());
    lockInfo->set("CalcHighlights", CommandControl::LockManager::getCalcHighlights());
    lockInfo->set("ImpressHighlights", CommandControl::LockManager::getImpressHighlights());
    lockInfo->set("DrawHighlights", CommandControl::LockManager::getDrawHighlights());

    const Poco::URI unlockImageUri = CommandControl::LockManager::getUnlockImageUri();
    if (!unlockImageUri.empty())
        lockInfo->set("UnlockImageUrlPath", unlockImageUri.getPath());
    CommandControl::LockManager::resetTransalatioPath();
    std::ostringstream ossLockInfo;
    lockInfo->stringify(ossLockInfo);
    const std::string lockInfoString = ossLockInfo.str();
    LOG_TRC("Sending feature locking info to client: " << lockInfoString);
    sendTextFrame("featurelock: " + lockInfoString);
}
#endif

bool ClientSession::getCommandValues(const char *buffer, int length, const StringVector& tokens,
                                     const std::shared_ptr<DocumentBroker>& docBroker)
{
    std::string command;
    if (tokens.size() != 2 || !getTokenString(tokens[1], "command", command))
        return sendTextFrameAndLogError("error: cmd=commandvalues kind=syntax");

    std::string cmdValues;
    if (docBroker->hasTileCache() && docBroker->tileCache().getTextStream(TileCache::StreamType::CmdValues, command, cmdValues))
        return sendTextFrame(cmdValues);

    return forwardToChild(std::string(buffer, length), docBroker);
}

bool ClientSession::sendFontRendering(const char *buffer, int length, const StringVector& tokens,
                                      const std::shared_ptr<DocumentBroker>& docBroker)
{
    std::string font, text;
    if (tokens.size() < 2 ||
        !getTokenString(tokens[1], "font", font))
    {
        return sendTextFrameAndLogError("error: cmd=renderfont kind=syntax");
    }

    getTokenString(tokens[2], "char", text);

    if (docBroker->hasTileCache())
    {
        Blob cachedStream = docBroker->tileCache().lookupCachedStream(TileCache::StreamType::Font, font+text);
        if (cachedStream)
        {
            const std::string response = "renderfont: " + tokens.cat(' ', 1) + '\n';
            return sendBlob(response, cachedStream);
        }
    }

    return forwardToChild(std::string(buffer, length), docBroker);
}

bool ClientSession::sendTile(const char * /*buffer*/, int /*length*/, const StringVector& tokens,
                             const std::shared_ptr<DocumentBroker>& docBroker)
{
    try
    {
        docBroker->handleTileRequest(tokens, true, client_from_this());
    }
    catch (const std::exception& exc)
    {
        LOG_ERR("Failed to process tile command: " << exc.what());
        return sendTextFrameAndLogError("error: cmd=tile kind=invalid");
    }

    return true;
}

bool ClientSession::sendCombinedTiles(const char* /*buffer*/, int /*length*/, const StringVector& tokens,
                                      const std::shared_ptr<DocumentBroker>& docBroker)
{
    try
    {
        TileCombined tileCombined = TileCombined::parse(tokens);
        tileCombined.setNormalizedViewId(getCanonicalViewId());
        if (tileCombined.hasDuplicates())
        {
            LOG_ERR("Dangerous, tilecombine with duplicates is not acceptable");
            return sendTextFrameAndLogError("error: cmd=tile kind=invalid");
        }
        docBroker->handleTileCombinedRequest(tileCombined, true, client_from_this());
    }
    catch (const std::exception& exc)
    {
        LOG_ERR("Failed to process tilecombine command: " << exc.what());
        // Be forgiving and log instead of disconnecting.
        // return sendTextFrameAndLogError("error: cmd=tile kind=invalid");
    }

    return true;
}

bool ClientSession::forwardToChild(const std::string& message,
                                   const std::shared_ptr<DocumentBroker>& docBroker)
{
    return docBroker->forwardToChild(client_from_this(), message);
}

bool ClientSession::filterMessage(const std::string& message) const
{
    bool allowed = true;
    StringVector tokens(StringVector::tokenize(message, ' '));

    // Set allowed flag to false depending on if particular WOPI properties are set
    if (tokens.equals(0, "downloadas"))
    {
        std::string id;
        if (tokens.size() >= 3 && getTokenString(tokens[2], "id", id))
        {
            if (id == "print" && _wopiFileInfo && _wopiFileInfo->getDisablePrint())
            {
                allowed = false;
                LOG_WRN("WOPI host has disabled print for this session");
            }
            else if (id == "export" && _wopiFileInfo && _wopiFileInfo->getDisableExport())
            {
                allowed = false;
                LOG_WRN("WOPI host has disabled export for this session");
            }
        }
        else
        {
            allowed = false;
            LOG_WRN("No value of id in downloadas message");
        }
    }
    else if (tokens.equals(0, "gettextselection"))
    {
        // Copying/pasting *within* the document is fine,
        // so keep .uno:Copy and .uno:Paste, but exporting is not.
        if (_wopiFileInfo && _wopiFileInfo->getDisableCopy())
        {
            allowed = false;
            LOG_WRN("WOPI host has disabled copying from the document");
        }
    }
    else if (isReadOnly())
    {
        // By default, don't allow anything
        allowed = false;
        if (tokens.equals(0, "userinactive") || tokens.equals(0, "useractive") || tokens.equals(0, "saveas")
            || tokens.equals(0, "rendersearchresult") || tokens.equals(0, "exportas"))
        {
            allowed = true;
        }
        else if (tokens.equals(0, "uno"))
        {
            if (tokens.size() > 1 && (tokens.equals(1, ".uno:ExecuteSearch") || tokens.equals(1, ".uno:Signature")))
            {
                allowed = true;
            }

            if (isAllowChangeComments()
                && tokens.size() > 1
                && (tokens.equals(1, ".uno:EditAnnotation")
                    || tokens.equals(1, ".uno:InsertAnnotation")
                    || tokens.equals(1, ".uno:DeleteAnnotation")))
            {
                allowed = true;
            }
        }
    }

    return allowed;
}

void ClientSession::setReadOnly(bool bVal)
{
    Session::setReadOnly(bVal);
    // Also inform the client
    const std::string sPerm = bVal ? "readonly" : "edit";
    sendTextFrame("perm: " + sPerm);
}

void ClientSession::sendFileMode(const bool readOnly, const bool editComments)
{
    std::string result = "filemode:{\"readOnly\": ";
    result += readOnly ? "true": "false";
    result += ", \"editComment\": ";
    result += editComments ? "true": "false";
    result += "}";
    sendTextFrame(result);
}

void ClientSession::setLockFailed(const std::string& sReason)
{
    // TODO: make this "read-only" a special one with a notification (infobar? balloon tip?)
    //       and a button to unlock
    _isLockFailed = true;
    setReadOnly(true);
    sendTextFrame("lockfailed:" + sReason);
}

bool ClientSession::attemptLock(const std::shared_ptr<DocumentBroker>& docBroker)
{
    if (!isReadOnly())
        return true;
    // We are only allowed to change into edit mode if the read-only mode is because of failed lock
    if (!_isLockFailed)
        return false;

    std::string failReason;
    const bool bResult = docBroker->attemptLock(*this, failReason);
    if (bResult)
        setReadOnly(false);
    else
        sendTextFrame("lockfailed:" + failReason);

    return bResult;
}

bool ClientSession::hasQueuedMessages() const
{
    return _senderQueue.size() > 0;
}

void ClientSession::writeQueuedMessages(std::size_t capacity)
{
    LOG_TRC("performing writes, up to " << capacity << " bytes");

    std::shared_ptr<Message> item;
    std::size_t wrote = 0;
    try
    {
        // Drain the queue, for efficient communication.
        while (capacity > wrote && _senderQueue.dequeue(item) && item)
        {
            const std::vector<char>& data = item->data();
            const auto size = data.size();
            assert(size && "Zero-sized messages must never be queued for sending.");

            if (item->isBinary())
            {
                Session::sendBinaryFrame(data.data(), size);
            }
            else
            {
                Session::sendTextFrame(data.data(), size);
            }

            wrote += size;
            LOG_TRC("wrote " << size << ", total " << wrote << " bytes");
        }
    }
    catch (const std::exception& ex)
    {
        LOG_ERR("Failed to send message " << (item ? item->abbr() : "<empty-item>")
                                          << " to client: " << ex.what());
    }

    LOG_TRC("performed write, wrote " << wrote << " bytes");
}

// NB. also see browser/src/map/Clipboard.js that does this in JS for stubs.
// See also ClientSession::preProcessSetClipboardPayload() which removes the
// <meta name="origin"...>  tag added here.
void ClientSession::postProcessCopyPayload(const std::shared_ptr<Message>& payload)
{
    // Insert our meta origin if we can
    payload->rewriteDataBody([=](std::vector<char>& data) {
            std::size_t pos = Util::findInVector(data, "<meta name=\"generator\" content=\"");

            if (pos == std::string::npos)
                pos = Util::findInVector(data, "<meta http-equiv=\"content-type\" content=\"text/html;");

            // cf. TileLayer.js /_dataTransferToDocument/
            if (pos != std::string::npos) // assume text/html
            {
                const std::string meta = getClipboardURI();
                LOG_TRC("Inject clipboard meta origin of '" << meta << '\'');
                const std::string origin = "<meta name=\"origin\" content=\"" + meta + "\"/>\n";
                data.insert(data.begin() + pos, origin.begin(), origin.end());
                return true;
            }
            else
            {
                LOG_DBG("Missing generator in textselectioncontent/clipboardcontent payload.");
                return false;
            }
        });
}

bool ClientSession::handleKitToClientMessage(const std::shared_ptr<Message>& payload)
{
    LOG_TRC("handling kit-to-client [" << payload->abbr() << ']');
    const std::string& firstLine = payload->firstLine();

    const std::shared_ptr<DocumentBroker> docBroker = _docBroker.lock();
    if (!docBroker)
    {
        LOG_ERR("No DocBroker to handle kit-to-client message: " << firstLine);
        return false;
    }

    const bool isConvertTo = static_cast<bool>(_saveAsSocket);

#if !MOBILEAPP
    COOLWSD::dumpOutgoingTrace(docBroker->getJailId(), getId(), firstLine);
#endif

    const auto& tokens = payload->tokens();
    if (tokens.equals(0, "unocommandresult:"))
    {
        LOG_INF("Command: " << firstLine);
        const std::string stringJSON = payload->jsonString();
        if (!stringJSON.empty())
        {
            try
            {
                Poco::JSON::Parser parser;
                const Poco::Dynamic::Var parsedJSON = parser.parse(stringJSON);
                const auto& object = parsedJSON.extract<Poco::JSON::Object::Ptr>();
                if (object->get("commandName").toString() == ".uno:Save")
                {
                    const bool success = object->get("success").toString() == "true";
                    std::string result;
                    if (object->has("result"))
                    {
                        const Poco::Dynamic::Var parsedResultJSON = object->get("result");
                        const auto& resultObj = parsedResultJSON.extract<Poco::JSON::Object::Ptr>();
                        if (resultObj->get("type").toString() == "string")
                            result = resultObj->get("value").toString();
                    }

                    // Save to Storage and log result.
                    docBroker->handleSaveResponse(client_from_this(), success, result);

                    if (!isCloseFrame())
                        forwardToClient(payload);

                    return true;
                }
            }
            catch (const std::exception& exception)
            {
                LOG_ERR("unocommandresult parsing failure: " << exception.what());
            }
        }
        else
        {
            LOG_WRN("Expected json unocommandresult. Ignoring: " << firstLine);
        }
    }
    else if (tokens.equals(0, "error:"))
    {
        std::string errorCommand;
        std::string errorKind;
        if (getTokenString(tokens[1], "cmd", errorCommand) &&
            getTokenString(tokens[2], "kind", errorKind) )
        {
            if (errorCommand == "load")
            {
                LOG_ERR("Document load failed: " << errorKind);
                if (errorKind == "passwordrequired:to-view" ||
                    errorKind == "passwordrequired:to-modify" ||
                    errorKind == "wrongpassword")
                {
                    if (isConvertTo)
                    {
                        Poco::Net::HTTPResponse response;
                        response.setStatusAndReason(Poco::Net::HTTPResponse::HTTP_UNAUTHORIZED);
                        response.set("X-ERROR-KIND", errorKind);
                        _saveAsSocket->send(response);

                        // Conversion failed, cleanup fake session.
                        LOG_TRC("Removing save-as ClientSession after conversion error.");
                        // Remove us.
                        docBroker->removeSession(client_from_this());
                        // Now terminate.
                        docBroker->stop("Aborting saveas handler.");
                    }
                    else
                    {
                        forwardToClient(payload);
                    }
                    return false;
                }
            }
            else
            {
                LOG_ERR(errorCommand << " error failure: " << errorKind);
            }
        }
    }
    else if (tokens.equals(0, "curpart:") && tokens.size() == 2)
    {
        //TODO: Should forward to client?
        int curPart;
        return getTokenInteger(tokens[1], "part", curPart);
    }
    else if (tokens.equals(0, "setpart:") && tokens.size() == 2)
    {
        if(!_isTextDocument)
        {
            int setPart;
            if(getTokenInteger(tokens[1], "part", setPart))
            {
                _clientSelectedPart = setPart;
                resetWireIdMap();
            }
            else if (stringToInteger(tokens[1], setPart))
            {
                _clientSelectedPart = setPart;
                resetWireIdMap();
            }
            else
                return false;
         }
    }
#if !MOBILEAPP
    else if (tokens.size() == 3 && (tokens.equals(0, "saveas:") || tokens.equals(0, "exportas:")))
    {
        bool isExportAs = tokens.equals(0, "exportas:");

        std::string encodedURL;
        if (!getTokenString(tokens[1], "url", encodedURL))
        {
            LOG_ERR("Bad syntax for: " << firstLine);
            // we must not return early with convert-to so that we clean up
            // the session
            if (!isConvertTo)
            {
                sendTextFrameAndLogError("error: cmd=saveas kind=syntax");
                return false;
            }
        }

        std::string encodedWopiFilename;
        if (!isConvertTo && !getTokenString(tokens[2], "filename", encodedWopiFilename))
        {
            LOG_ERR("Bad syntax for: " << firstLine);
            sendTextFrameAndLogError("error: cmd=saveas kind=syntax");
            return false;
        }

        // Save-as completed, inform the ClientSession.
        std::string wopiFilename;
        Poco::URI::decode(encodedWopiFilename, wopiFilename);

        // URI constructor implicitly decodes when it gets std::string as param
        Poco::URI resultURL(encodedURL);

        // Prepend the jail path in the normal (non-nocaps) case
        if (resultURL.getScheme() == "file" && !COOLWSD::NoCapsForKit)
        {
            std::string relative;
            if (isConvertTo)
                Poco::URI::decode(resultURL.getPath(), relative);
            else
                relative = resultURL.getPath();

            if (relative.size() > 0 && relative[0] == '/')
                relative = relative.substr(1);

            // Rewrite file:// URLs to be visible to the outside world.
            const Path path(docBroker->getJailRoot(), relative);
            if (Poco::File(path).exists())
            {
                if (!isConvertTo)
                {
                    // Encode path for special characters (i.e '%') since Poco::URI::setPath implicitly decodes the input param
                    std::string encodedPath;
                    Poco::URI::encode(path.toString(), "", encodedPath);

                    resultURL.setPath(encodedPath);
                }
                else
                {
                    resultURL.setPath(path.toString());
                }
            }
            else
            {
                // Blank for failure.
                LOG_DBG("SaveAs produced no output in '" << path.toString() << "', producing blank url.");
                resultURL.clear();
            }
        }

        LOG_TRC("Save-as URL: " << resultURL.toString());

        if (!isConvertTo)
        {
            // Normal SaveAs - save to Storage and log result.
            if (resultURL.getScheme() == "file" && !resultURL.getPath().empty())
            {
                // this also sends the saveas: result
                LOG_TRC("Save-as path: " << resultURL.getPath());
                docBroker->uploadAsToStorage(client_from_this(), resultURL.getPath(), wopiFilename,
                                             false, isExportAs);
            }
            else
                sendTextFrameAndLogError("error: cmd=storage kind=savefailed");
        }
        else
        {
            // using the convert-to REST API
            // TODO: Send back error when there is no output.
            if (!resultURL.getPath().empty())
            {
                const std::string mimeType = "application/octet-stream";
                LOG_TRC("Sending file: " << resultURL.getPath());

                const std::string fileName = Poco::Path(resultURL.getPath()).getFileName();
                Poco::Net::HTTPResponse response;
                if (!fileName.empty())
                    response.set("Content-Disposition", "attachment; filename=\"" + fileName + '"');

                HttpHelper::sendFileAndShutdown(_saveAsSocket, resultURL.getPath(), mimeType, &response);
            }

            // Conversion is done, cleanup this fake session.
            LOG_TRC("Removing save-as ClientSession after conversion.");

            // Remove us.
            docBroker->removeSession(client_from_this());

            // Now terminate.
            docBroker->stop("Finished saveas handler.");
        }

        return true;
    }
#endif
    else if (tokens.size() == 2 && tokens.equals(0, "statechanged:"))
    {
        StringVector stateTokens(StringVector::tokenize(tokens[1], '='));
        if (stateTokens.size() == 2 && stateTokens.equals(0, ".uno:ModifiedStatus"))
        {
            // Always update the modified flag in the DocBroker faithfully.
            // Let it deal with the upload failure scenario and the admin console.
            docBroker->setModified(stateTokens.equals(1, "true"));
        }
        else
        {
            // Set the initial settings per the user's request.
            const std::pair<std::string, std::string> unoStatePair = Util::split(tokens[1], '=');

            if (!docBroker->isInitialSettingSet(unoStatePair.first))
            {
                docBroker->setInitialSetting(unoStatePair.first);
                if (unoStatePair.first == ".uno:TrackChanges")
                {
                    if ((unoStatePair.second == "true" &&
                         _wopiFileInfo && _wopiFileInfo->getDisableChangeTrackingRecord() == WopiStorage::WOPIFileInfo::TriState::True) ||
                        (unoStatePair.second == "false" &&
                         _wopiFileInfo && _wopiFileInfo->getDisableChangeTrackingRecord() == WopiStorage::WOPIFileInfo::TriState::False))
                    {
                        // Toggle the TrackChanges state.
                        LOG_DBG("Forcing " << unoStatePair.first << " toggle per user settings.");
                        forwardToChild("uno .uno:TrackChanges", docBroker);
                    }
                }
                else if (unoStatePair.first == ".uno:ShowTrackedChanges")
                {
                    if ((unoStatePair.second == "true" &&
                         _wopiFileInfo && _wopiFileInfo->getDisableChangeTrackingShow() == WopiStorage::WOPIFileInfo::TriState::True) ||
                        (unoStatePair.second == "false" &&
                         _wopiFileInfo && _wopiFileInfo->getDisableChangeTrackingShow() == WopiStorage::WOPIFileInfo::TriState::False))
                    {
                        // Toggle the ShowTrackChanges state.
                        LOG_DBG("Forcing " << unoStatePair.first << " toggle per user settings.");
                        forwardToChild("uno .uno:ShowTrackedChanges", docBroker);
                    }
                }
            }
        }
    } else if (tokens.equals(0, "textselectioncontent:")) {

        postProcessCopyPayload(payload);
        return forwardToClient(payload);

    } else if (tokens.equals(0, "clipboardcontent:")) {

#if !MOBILEAPP // Most likely nothing of this makes sense in a mobile app

        // FIXME: Ash: we need to return different content depending
        // on whether this is a download-everything, or an individual
        // 'download' and/or providing our helpful / user page.

        // for now just for remote sockets.
        LOG_TRC("Got clipboard content of size " << payload->size() << " to send to "
                                                 << _clipSockets.size() << " sockets in state "
                                                 << name(_state));

        postProcessCopyPayload(payload);

        std::size_t header;
        for (header = 0; header < payload->size();)
            if (payload->data()[header++] == '\n')
                break;
        const bool empty = header >= payload->size();

        // final cleanup ...
        if (!empty && _state == SessionState::WAIT_DISCONNECT &&
            (!_wopiFileInfo || !_wopiFileInfo->getDisableCopy()))
            COOLWSD::SavedClipboards->insertClipboard(
                _clipboardKeys, &payload->data()[header], payload->size() - header);

        for (const auto& it : _clipSockets)
        {
            auto socket = it.lock();
            if (!socket)
                continue;

            std::ostringstream oss;
            oss << "HTTP/1.1 200 OK\r\n"
                << "Last-Modified: " << Util::getHttpTimeNow() << "\r\n"
                << "User-Agent: " << WOPI_AGENT_STRING << "\r\n"
                << "Content-Length: " << (empty ? 0 : (payload->size() - header)) << "\r\n"
                << "Content-Type: application/octet-stream\r\n"
                << "X-Content-Type-Options: nosniff\r\n"
                << "Connection: close\r\n"
                << "\r\n";

            if (!empty)
            {
                oss.write(&payload->data()[header], payload->size() - header);
                socket->setSocketBufferSize(
                    std::min(payload->size() + 256, std::size_t(Socket::MaximumSendBufferSize)));
            }

            socket->send(oss.str());
            socket->shutdown();
            LOG_INF("Queued " << (empty?"empty":"clipboard") << " response for send.");
        }
#endif
        _clipSockets.clear();
        return true;
    } else if (tokens.equals(0, "disconnected:")) {

        LOG_INF("End of disconnection handshake for " << getId());
        docBroker->finalRemoveSession(client_from_this());
        return true;
    }
    else if (tokens.equals(0, "graphicselection:") || tokens.equals(0, "graphicviewselection:"))
    {
        if (_thumbnailSession)
        {
            int x, y;
            if (stringToInteger(tokens[1], x) &&
                stringToInteger(tokens[2], y))
            {
                std::ostringstream renderThumbnailCmd;
                renderThumbnailCmd << "getthumbnail x=" << x << " y=" << y;
                docBroker->forwardToChild(client_from_this(), renderThumbnailCmd.str());
            }
        }

        if (payload->find("url", 3) >= 0)
        {
            std::string json(payload->data().data(), payload->size());
            const auto it = json.find('{');
            const std::string prefix = json.substr(0, it);
            json.erase(0, it); // Remove the prefix to parse the purse JSON part.

            Poco::JSON::Object::Ptr object;
            if (JsonUtil::parseJSON(json, object))
            {
                const std::string url = JsonUtil::getJSONValue<std::string>(object, "url");
                if (!url.empty())
                {
                    const std::string id = JsonUtil::getJSONValue<std::string>(object, "id");
                    if (!id.empty())
                    {
                        docBroker->addEmbeddedMedia(
                            id, json); // Capture the original message with internal URL.

                        const std::string mediaUrl = Util::encodeURIComponent(
                            createPublicURI("media", id, /*encode=*/false), "&");
                        object->set("url", mediaUrl); // Replace the url with the public one.
                        object->set("mimeType", "video/mp4"); //FIXME: get this from the source json

                        std::ostringstream mediaStr;
                        object->stringify(mediaStr);
                        const std::string msg = prefix + mediaStr.str();
                        forwardToClient(std::make_shared<Message>(msg, Message::Dir::Out));
                        return true;
                    }
                    else
                    {
                        LOG_ERR("Invalid embeddedmedia json without id: " << json);
                    }
                }
            }
        }

        // Non-Media graphic selsection.
        forwardToClient(payload);
        return true;
    }
    else if (tokens.equals(0, "formfieldbutton:")) {
        // Do not send redundant messages
        if (_lastSentFormFielButtonMessage == firstLine)
            return true;
        _lastSentFormFielButtonMessage = firstLine;
    }
    else if (tokens.equals(0, "canonicalidchange:")) {
        int viewId, canonicalId;
        if (getTokenInteger(tokens[1], "viewid", viewId) &&
            getTokenInteger(tokens[2], "canonicalid", canonicalId))
        {
            _canonicalViewId = canonicalId;
        }
    }

    if (!isDocPasswordProtected())
    {
        if (tokens.equals(0, "tile:"))
        {
            assert(false && "Tile traffic should go through the DocumentBroker-LoKit WS.");
        }
        else if (tokens.equals(0, "jsdialog:") && _state == ClientSession::SessionState::LOADING)
        {
            docBroker->setInteractive(true);
        }
        else if (tokens.equals(0, "status:"))
        {
            setState(ClientSession::SessionState::LIVE);
            docBroker->setInteractive(false);
            docBroker->setLoaded();

            if (UnitWSD::isUnitTesting())
            {
                UnitWSD::get().onDocBrokerViewLoaded(docBroker->getDocKey(), client_from_this());
            }

#if !MOBILEAPP
            Admin::instance().setViewLoadDuration(docBroker->getDocKey(), getId(), std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::steady_clock::now() - _viewLoadStart));
#endif

            // position cursor for thumbnail rendering
            if (_thumbnailSession)
            {
                //check whether we have a target!
                std::ostringstream cmd;
                cmd << "{";
                cmd << "\"Name\":"
                        "{"
                        "\"type\":\"string\","
                        "\"value\":\"URL\""
                        "},"
                        "\"URL\":"
                        "{"
                        "\"type\":\"string\","
                        "\"value\":\"#";
                cmd << getThumbnailTarget();
                cmd << "\"}}";

                const std::string renderThumbnailCmd = "uno .uno:OpenHyperLink " + cmd.str();
                docBroker->forwardToChild(client_from_this(), renderThumbnailCmd);
            }

            // Wopi post load actions
            if (_wopiFileInfo && !_wopiFileInfo->getTemplateSource().empty())
            {
                LOG_DBG("Uploading template [" << _wopiFileInfo->getTemplateSource()
                                               << "] to storage after loading.");
                docBroker->uploadAfterLoadingTemplate(client_from_this());
            }

            for(auto &token : tokens)
            {
                // Need to get the initial part id from status message
                int part = -1;
                if(getTokenInteger(tokens.getParam(token), "current", part))
                {
                    _clientSelectedPart = part;
                    resetWireIdMap();
                }

                int mode = 0;
                if(getTokenInteger(tokens.getParam(token), "mode", mode))
                    _clientSelectedMode = mode;

                // Get document type too
                std::string docType;
                if(getTokenString(tokens.getParam(token), "type", docType))
                {
                    _isTextDocument = docType.find("text") != std::string::npos;
                }

                // Store our Kit ViewId
                int viewId = -1;
                if(getTokenInteger(tokens.getParam(token), "viewid", viewId))
                    _kitViewId = viewId;
            }

            // Forward the status response to the client.
            return forwardToClient(payload);
        }
        else if (tokens.equals(0, "commandvalues:"))
        {
            const std::string stringJSON = payload->jsonString();
            if (!stringJSON.empty())
            {
                try
                {
                    Poco::JSON::Parser parser;
                    const Poco::Dynamic::Var result = parser.parse(stringJSON);
                    const auto& object = result.extract<Poco::JSON::Object::Ptr>();
                    const std::string commandName = object->has("commandName") ? object->get("commandName").toString() : "";
                    if (commandName == ".uno:CharFontName" ||
                        commandName == ".uno:StyleApply")
                    {
                        // other commands should not be cached
                        docBroker->tileCache().saveTextStream(TileCache::StreamType::CmdValues,
                                                              commandName, payload->data());
                    }
                }
                catch (const std::exception& exception)
                {
                    LOG_ERR("commandvalues parsing failure: " << exception.what());
                }
            }
        }
        else if (tokens.equals(0, "invalidatetiles:"))
        {
            assert(firstLine.size() == payload->size() &&
                   "Unexpected multiline data in invalidatetiles");

            // First forward invalidation
            bool ret = forwardToClient(payload);

            handleTileInvalidation(firstLine, docBroker);
            return ret;
        }
        else if (tokens.equals(0, "invalidatecursor:"))
        {
            assert(firstLine.size() == payload->size() &&
                   "Unexpected multiline data in invalidatecursor");

            const std::string stringJSON = payload->jsonString();
            Poco::JSON::Parser parser;
            try
            {
                const Poco::Dynamic::Var result = parser.parse(stringJSON);
                const auto& object = result.extract<Poco::JSON::Object::Ptr>();
                const std::string rectangle = object->get("rectangle").toString();
                StringVector rectangleTokens(StringVector::tokenize(rectangle, ','));
                int x = 0, y = 0, w = 0, h = 0;
                if (rectangleTokens.size() > 2 &&
                    stringToInteger(rectangleTokens[0], x) &&
                    stringToInteger(rectangleTokens[1], y))
                {
                    if (rectangleTokens.size() > 3)
                    {
                        stringToInteger(rectangleTokens[2], w);
                        stringToInteger(rectangleTokens[3], h);
                    }

                    docBroker->invalidateCursor(x, y, w, h);

                    // session used for thumbnailing and target already was set
                    if (_thumbnailSession)
                    {
                        bool cursorAlreadyAtTargetPosition = getThumbnailTarget().empty();
                        if (cursorAlreadyAtTargetPosition)
                        {
                            std::ostringstream renderThumbnailCmd;
                            renderThumbnailCmd << "getthumbnail x=" << x << " y=" << y;
                            docBroker->forwardToChild(client_from_this(), renderThumbnailCmd.str());
                        }
                        else
                        {
                            // this is initial cursor position message
                            // wait for second invalidatecursor message
                            // reset target so we will proceed next time
                            setThumbnailTarget(std::string());
                        }
                    }
                }
                else
                {
                    LOG_ERR("Unable to parse " << firstLine);
                }
            }
            catch (const std::exception& exception)
            {
                LOG_ERR("invalidatecursor parsing failure: " << exception.what());
            }
        }
        else if (tokens.equals(0, "renderfont:"))
        {
            std::string font, text;
            if (tokens.size() < 3 ||
                !getTokenString(tokens[1], "font", font))
            {
                LOG_ERR("Bad syntax for: " << firstLine);
                return false;
            }

            getTokenString(tokens[2], "char", text);
            assert(firstLine.size() < payload->size() && "Missing multiline data in renderfont");
            docBroker->tileCache().saveStream(TileCache::StreamType::Font, font + text,
                                              payload->data().data() + firstLine.size() + 1,
                                              payload->data().size() - firstLine.size() - 1);
            return forwardToClient(payload);
        }
        else if (tokens.equals(0, "extractedlinktargets:"))
        {
            LOG_TRC("Sending extracted link targets response.");

            const std::string stringJSON = payload->jsonString();

            http::Response httpResponse(http::StatusCode::OK);
            httpResponse.set("Last-Modified", Util::getHttpTimeNow());
            httpResponse.set("X-Content-Type-Options", "nosniff");
            httpResponse.setBody(stringJSON, "application/json");
            _saveAsSocket->sendAndShutdown(httpResponse);

            // Now terminate.
            docBroker->closeDocument("extractedlinktargets");
            return true;
        }
        else if (tokens.equals(0, "sendthumbnail:"))
        {
            LOG_TRC("Sending get-thumbnail response.");
            bool error = false;

            if (firstLine.find("error") != std::string::npos)
                error = true;

            if (!error)
            {
                int firstLineSize = firstLine.size() + 1;
                std::string thumbnail(payload->data().data() + firstLineSize, payload->data().size() - firstLineSize);

                http::Response httpResponse(http::StatusCode::OK);
                httpResponse.set("Last-Modified", Util::getHttpTimeNow());
                httpResponse.set("X-Content-Type-Options", "nosniff");
                httpResponse.setBody(thumbnail, "image/png");
                _saveAsSocket->sendAndShutdown(httpResponse);
            }

            if (error)
            {
                http::Response httpResponse(http::StatusCode::InternalServerError);
                httpResponse.set("Content-Length", "0");
                _saveAsSocket->sendAndShutdown(httpResponse);
            }

            docBroker->closeDocument("thumbnailgenerated");
        }
    }
    else
    {
        LOG_INF("Ignoring notification on password protected document: " << firstLine);
    }

    // Forward everything else.
    return forwardToClient(payload);
}

bool ClientSession::forwardToClient(const std::shared_ptr<Message>& payload)
{
    if (isCloseFrame())
    {
        LOG_TRC("peer began the closing handshake. Dropping forward message [" << payload->abbr()
                                                                               << ']');
        return true;
    }

    enqueueSendMessage(payload);
    return true;
}

void ClientSession::enqueueSendMessage(const std::shared_ptr<Message>& data)
{
    if (isCloseFrame())
    {
        LOG_TRC("Connection closed, dropping message " << data->id());
        return;
    }

    const std::shared_ptr<DocumentBroker> docBroker = _docBroker.lock();
    LOG_CHECK_RET(docBroker && "Null DocumentBroker instance", );
    docBroker->assertCorrectThread();

    std::unique_ptr<TileDesc> tile;
    if (data->firstTokenMatches("tile:"))
    {
        // Avoid sending tile if it has the same wireID as the previously sent tile
        tile = Util::make_unique<TileDesc>(TileDesc::parse(data->firstLine()));
        auto iter = _oldWireIds.find(tile->generateID());
        if(iter != _oldWireIds.end() && tile->getWireId() != 0 && tile->getWireId() == iter->second)
        {
            LOG_INF("WSD filters out a tile with the same wireID: " << tile->serialize("tile:"));
            return;
        }
    }

    LOG_TRC("Enqueueing client message " << data->id());
    std::size_t sizeBefore = _senderQueue.size();
    std::size_t newSize = _senderQueue.enqueue(data);

    // Track sent tile
    if (tile)
    {
        traceTileBySend(*tile, sizeBefore == newSize);
    }
}

void ClientSession::addTileOnFly(const TileDesc& tile)
{
    _tilesOnFly.emplace_back(tile.generateID(), std::chrono::steady_clock::now());
}

void ClientSession::clearTilesOnFly()
{
    _tilesOnFly.clear();
}

void ClientSession::removeOutdatedTilesOnFly()
{
    // Check only the beginning of the list, tiles are ordered by timestamp
    bool continueLoop = true;
    while(!_tilesOnFly.empty() && continueLoop)
    {
        auto tileIter = _tilesOnFly.begin();
        const auto elapsedTimeMs = std::chrono::duration_cast<std::chrono::milliseconds>(
            std::chrono::steady_clock::now() - tileIter->second);
        if (elapsedTimeMs > std::chrono::milliseconds(TILE_ROUNDTRIP_TIMEOUT_MS))
        {
            LOG_WRN("Tracker tileID " << tileIter->first << " was dropped because of time out ("
                                      << elapsedTimeMs
                                      << "). Tileprocessed message did not arrive in time.");
            _tilesOnFly.erase(tileIter);
        }
        else
            continueLoop = false;
    }
}

std::size_t ClientSession::countIdenticalTilesOnFly(const TileDesc& tile) const
{
    std::size_t count = 0;
    const std::string tileID = tile.generateID();
    for (const auto& tileItem : _tilesOnFly)
    {
        if (tileItem.first == tileID)
            ++count;
    }
    return count;
}

Util::Rectangle ClientSession::getNormalizedVisibleArea() const
{
    Util::Rectangle normalizedVisArea;
    normalizedVisArea.setLeft(std::max(_clientVisibleArea.getLeft(), 0));
    normalizedVisArea.setTop(std::max(_clientVisibleArea.getTop(), 0));
    normalizedVisArea.setRight(_clientVisibleArea.getRight());
    normalizedVisArea.setBottom(_clientVisibleArea.getBottom());
    return normalizedVisArea;
}

void ClientSession::onDisconnect()
{
    LOG_INF("Disconnected, current global number of connections (inclusive): "
            << COOLWSD::NumConnections);

    const std::shared_ptr<DocumentBroker> docBroker = getDocumentBroker();
    LOG_CHECK_RET(docBroker && "Null DocumentBroker instance", );
    docBroker->assertCorrectThread();
    const std::string docKey = docBroker->getDocKey();

    // Keep self alive, so that our own dtor runs only at the end of this function. Without this,
    // removeSession() may destroy us and then we can't call our own member functions anymore.
    std::shared_ptr<ClientSession> session = client_from_this();
    try
    {
        // Connection terminated. Destroy session.
        LOG_DBG("on docKey [" << docKey << "] terminated. Cleaning up");

        docBroker->removeSession(session);
    }
    catch (const UnauthorizedRequestException& exc)
    {
        LOG_ERR("Error in client request handler: " << exc.toString());
        const std::string status = "error: cmd=internal kind=unauthorized";
        LOG_TRC("Sending to Client [" << status << ']');
        sendMessage(status);
        // We are disconnecting, no need to close the socket here.
    }
    catch (const std::exception& exc)
    {
        LOG_ERR("Error in client request handler: " << exc.what());
    }

    try
    {
        if (isCloseFrame())
        {
            LOG_TRC("Normal close handshake.");
            // Client initiated close handshake
            // respond with close frame
            shutdownNormal();
        }
        else if (!SigUtil::getShutdownRequestFlag())
        {
            // something wrong, with internal exceptions
            LOG_TRC("Abnormal close handshake.");
            closeFrame();
            shutdownGoingAway();
        }
        else
        {
            LOG_TRC("Server recycling.");
            closeFrame();
            shutdownGoingAway();
        }
    }
    catch (const std::exception& exc)
    {
        LOG_ERR("Exception while closing socket for docKey [" << docKey << "]: " << exc.what());
    }
}

void ClientSession::dumpState(std::ostream& os)
{
    Session::dumpState(os);

    os << "\t\tisLive: " << isLive()
       << "\n\t\tisViewLoaded: " << isViewLoaded()
       << "\n\t\tisDocumentOwner: " << isDocumentOwner()
       << "\n\t\tstate: " << name(_state)
       << "\n\t\tkeyEvents: " << _keyEvents
//       << "\n\t\tvisibleArea: " << _clientVisibleArea
       << "\n\t\tclientSelectedPart: " << _clientSelectedPart
       << "\n\t\ttile size Pixel: " << _tileWidthPixel << 'x' << _tileHeightPixel
       << "\n\t\ttile size Twips: " << _tileWidthTwips << 'x' << _tileHeightTwips
       << "\n\t\tkit ViewId: " << _kitViewId
       << "\n\t\tour URL (un-trusted): " << _serverURL.getSubURLForEndpoint("")
       << "\n\t\tisTextDocument: " << _isTextDocument
       << "\n\t\tclipboardKeys[0]: " << _clipboardKeys[0]
       << "\n\t\tclipboardKeys[1]: " << _clipboardKeys[1]
       << "\n\t\tclip sockets: " << _clipSockets.size()
       << "\n\t\tproxy access:: " << _proxyAccess
       << "\n\t\tclientSelectedMode: " << _clientSelectedMode;

    if (_protocol)
    {
        uint64_t sent = 0, recv = 0;
        _protocol->getIOStats(sent, recv);
        os << "\n\t\tsent/keystroke: " << (double)sent/_keyEvents << "bytes";
    }

    os << '\n';
    _senderQueue.dumpState(os);

    // FIXME: need to dump the _tilesOnFly and other bits ...
}

const std::string &ClientSession::getOrCreateProxyAccess()
{
    if (_proxyAccess.size() <= 0)
        _proxyAccess = Util::rng::getHardRandomHexString(
            ProxyAccessTokenLengthBytes);
    return _proxyAccess;
}

void ClientSession::handleTileInvalidation(const std::string& message,
    const std::shared_ptr<DocumentBroker>& docBroker)
{
    docBroker->invalidateTiles(message, getCanonicalViewId());

    // Skip requesting new tiles if we don't have client visible area data yet.
    if(!_clientVisibleArea.hasSurface() ||
       _tileWidthPixel == 0 || _tileHeightPixel == 0 ||
       _tileWidthTwips == 0 || _tileHeightTwips == 0 ||
       (_clientSelectedPart == -1 && !_isTextDocument))
    {
        return;
    }

    // While saving / shutting down we can get big invalidatiions: ignore them
    if (isCloseFrame()) {
        LOG_TRC("Session [" << getId() << "] ignoring invalidation during close: '" << message);
        return;
    }

    std::pair<TileCache::PartModePair, Util::Rectangle> result = TileCache::parseInvalidateMsg(message);
    int part = result.first.first;
    int mode = result.first.second;
    Util::Rectangle& invalidateRect = result.second;

    constexpr SplitPaneName panes[4] = {
        TOPLEFT_PANE,
        TOPRIGHT_PANE,
        BOTTOMLEFT_PANE,
        BOTTOMRIGHT_PANE
    };
    Util::Rectangle paneRects[4];
    int numPanes = 0;
    for(int i = 0; i < 4; ++i)
    {
        if(!isSplitPane(panes[i]))
            continue;

        Util::Rectangle rect = getNormalizedVisiblePaneArea(panes[i]);
        if (rect.intersects(invalidateRect)) {
            paneRects[numPanes++] = rect;
        }
    }

    // We can ignore the invalidation if it's outside of all split-panes.
    if(!numPanes)
        return;

    if( part == -1 ) // If no part is specified we use the part used by the client
        part = _clientSelectedPart;

    int normalizedViewId = getCanonicalViewId();

    std::vector<TileDesc> invalidTiles;
    if((part == _clientSelectedPart && mode == _clientSelectedMode) || _isTextDocument)
    {
        for(int paneIdx = 0; paneIdx < numPanes; ++paneIdx)
        {
            const Util::Rectangle& normalizedVisArea = paneRects[paneIdx];
            // Iterate through visible tiles
            for(int i = std::ceil(normalizedVisArea.getTop() / _tileHeightTwips);
                        i <= std::ceil(normalizedVisArea.getBottom() / _tileHeightTwips); ++i)
            {
                for(int j = std::ceil(normalizedVisArea.getLeft() / _tileWidthTwips);
                    j <= std::ceil(normalizedVisArea.getRight() / _tileWidthTwips); ++j)
                {
                    // Find tiles affected by invalidation
                    Util::Rectangle tileRect (j * _tileWidthTwips, i * _tileHeightTwips, _tileWidthTwips, _tileHeightTwips);
                    if(invalidateRect.intersects(tileRect))
                    {
                        TileDesc desc(normalizedViewId, part, mode,
                                      _tileWidthPixel, _tileHeightPixel,
                                      j * _tileWidthTwips, i * _tileHeightTwips,
                                      _tileWidthTwips, _tileHeightTwips, -1, 0, -1, false);

                        bool dup = false;
                        // Check we don't have duplicates
                        for (const auto &it : invalidTiles)
                        {
                            if (it == desc)
                            {
                                LOG_TRC("Duplicate tile skipped from invalidation " << desc.debugName());
                                dup = true;
                                break;
                            }
                        }

                        if (!dup)
                        {
                            invalidTiles.push_back(desc);

                            TileWireId oldWireId = 0;
                            auto iter = _oldWireIds.find(invalidTiles.back().generateID());
                            if(iter != _oldWireIds.end())
                                oldWireId = iter->second;

                            invalidTiles.back().setOldWireId(oldWireId);
                            invalidTiles.back().setWireId(0);
                        }
                    }
                }
            }
        }
    }

    if(!invalidTiles.empty())
    {
        TileCombined tileCombined = TileCombined::create(invalidTiles);
        tileCombined.setNormalizedViewId(normalizedViewId);
        docBroker->handleTileCombinedRequest(tileCombined, false, client_from_this());
    }
}

bool ClientSession::isSplitPane(const SplitPaneName paneName) const
{
    if (paneName == BOTTOMRIGHT_PANE)
        return true;

    if (paneName == TOPLEFT_PANE)
        return (_splitX && _splitY);

    if (paneName == TOPRIGHT_PANE)
        return _splitY;

    if (paneName == BOTTOMLEFT_PANE)
        return _splitX;

    return false;
}

Util::Rectangle ClientSession::getNormalizedVisiblePaneArea(const SplitPaneName paneName) const
{
    Util::Rectangle normalizedVisArea = getNormalizedVisibleArea();
    if (!_splitX && !_splitY)
        return paneName == BOTTOMRIGHT_PANE ? normalizedVisArea : Util::Rectangle();

    int freeStartX = normalizedVisArea.getLeft() + _splitX;
    int freeStartY = normalizedVisArea.getTop()  + _splitY;
    int freeWidth = normalizedVisArea.getWidth() - _splitX;
    int freeHeight = normalizedVisArea.getHeight() - _splitY;

    switch (paneName)
    {
    case BOTTOMRIGHT_PANE:
        return Util::Rectangle(freeStartX, freeStartY, freeWidth, freeHeight);
    case TOPLEFT_PANE:
        return (_splitX && _splitY) ? Util::Rectangle(0, 0, _splitX, _splitY) : Util::Rectangle();
    case TOPRIGHT_PANE:
        return _splitY ? Util::Rectangle(freeStartX, 0, freeWidth, _splitY) : Util::Rectangle();
    case BOTTOMLEFT_PANE:
        return _splitX ? Util::Rectangle(0, freeStartY, _splitX, freeHeight) : Util::Rectangle();
    default:
        assert(false && "Unknown split-pane name");
    }

    return Util::Rectangle();
}

bool ClientSession::isTileInsideVisibleArea(const TileDesc& tile) const
{
    if (!_splitX && !_splitY)
    {
        return (tile.getTilePosX() >= _clientVisibleArea.getLeft() && tile.getTilePosX() <= _clientVisibleArea.getRight() &&
            tile.getTilePosY() >= _clientVisibleArea.getTop() && tile.getTilePosY() <= _clientVisibleArea.getBottom());
    }

    constexpr SplitPaneName panes[4] = {
        TOPLEFT_PANE,
        TOPRIGHT_PANE,
        BOTTOMLEFT_PANE,
        BOTTOMRIGHT_PANE
    };

    for (int i = 0; i < 4; ++i)
    {
        if (!isSplitPane(panes[i]))
            continue;

        Util::Rectangle paneRect = getNormalizedVisiblePaneArea(panes[i]);
        if (tile.getTilePosX() >= paneRect.getLeft() && tile.getTilePosX() <= paneRect.getRight() &&
            tile.getTilePosY() >= paneRect.getTop() && tile.getTilePosY() <= paneRect.getBottom())
            return true;
    }

    return false;
}

void ClientSession::resetWireIdMap()
{
    _oldWireIds.clear();
}

void ClientSession::traceTileBySend(const TileDesc& tile, bool deduplicated)
{
    const std::string tileID = tile.generateID();

    // Store wireId first
    auto iter = _oldWireIds.find(tileID);
    if(iter != _oldWireIds.end())
    {
        iter->second = tile.getWireId();
    }
    else
    {
        // Track only tile inside the visible area
        if(_clientVisibleArea.hasSurface() && isTileInsideVisibleArea(tile))
        {
            _oldWireIds.insert(std::pair<std::string, TileWireId>(tileID, tile.getWireId()));
        }
    }

    // Record that the tile is sent
    if (!deduplicated)
        addTileOnFly(tile);
}

// This removes the <meta name="origin" ...> tag which was added in
// ClientSession::postProcessCopyPayload(), else the payload parsing
// in ChildSession::setClipboard() will fail.
// To see why, refer
// 1. ChildSession::getClipboard() where the data for various
//    flavours along with flavour-type and length fields are packed into the payload.
// 2. The clipboard payload parsing code in ClipboardData::read().
void ClientSession::preProcessSetClipboardPayload(std::string& payload)
{
    std::size_t start = payload.find("<meta name=\"origin\" content=\"");
    if (start != std::string::npos)
    {
        std::size_t end = payload.find("\"/>\n", start);
        if (end == std::string::npos)
        {
            LOG_DBG("Found unbalanced <meta name=\"origin\".../> tag in setclipboard payload.");
            return;
        }

        std::size_t len = end - start + 4;
        payload.erase(start, len);
    }
}

std::string ClientSession::processSVGContent(const std::string& svg)
{
    const std::shared_ptr<DocumentBroker> docBroker = _docBroker.lock();
    if (!docBroker)
    {
        LOG_ERR("No DocBroker to process SVG content");
        return svg;
    }

    bool broken = false;
    std::ostringstream oss;
    std::string::size_type pos = 0;
    for (;;)
    {
        static const std::string prefix = "src=\"file:///tmp/";
        const auto start = svg.find(prefix, pos);
        if (start == std::string::npos)
        {
            // Copy the rest and finish.
            oss << svg.substr(pos);
            break;
        }

        const auto startFilename = start + prefix.size();
        const auto end = svg.find('"', startFilename);
        if (end == std::string::npos)
        {
            // Broken file; leave it as-is. Better to have no video than no slideshow.
            broken = true;
            break;
        }

        auto dot = svg.find('.', startFilename);
        if (dot == std::string::npos || dot > end)
            dot = end;

        const std::string id = svg.substr(startFilename, dot - startFilename);
        oss << svg.substr(pos, start - pos);

        // Store the original json with the internal, temporary, file URI.
        const std::string fileUrl = svg.substr(start + 5, end - start - 5);
        docBroker->addEmbeddedMedia(id, "{ \"action\":\"update\",\"id\":\"" + id + "\",\"url\":\"" +
                                            fileUrl + "\"}");

        const std::string mediaUrl =
            Util::encodeURIComponent(createPublicURI("media", id, /*encode=*/false), "&");
        oss << "src=\"" << mediaUrl << '"';
        pos = end + 1;
    }

    return broken ? svg : oss.str();
}

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