Download legal hold data.

Fixes #3

server/api.go

@@ -1,10 +1,15 @@
 package main
 
 import (
+	"archive/zip"
+	"bufio"
 	"encoding/json"
+	"fmt"
 	"github.com/gorilla/mux"
 	"github.com/pkg/errors"
+	"io"
 	"net/http"
+	"time"
 
 	mattermostModel "github.com/mattermost/mattermost-server/v6/model"
 	"github.com/mattermost/mattermost-server/v6/plugin"
@@ -36,6 +41,7 @@ func (p *Plugin) ServeHTTP(c *plugin.Context, w http.ResponseWriter, r *http.Req
 	router.HandleFunc("/api/v1/legalhold/create", p.createLegalHold)
 	router.HandleFunc("/api/v1/legalhold/{legalhold_id:[A-Za-z0-9]+}/release", p.releaseLegalHold)
 	router.HandleFunc("/api/v1/legalhold/{legalhold_id:[A-Za-z0-9]+}/update", p.updateLegalHold)
+	router.HandleFunc("/api/v1/legalhold/{legalhold_id:[A-Za-z0-9]+}/download", p.downloadLegalHold)
 
 	p.router = router
 	p.router.ServeHTTP(w, r)
@@ -204,6 +210,81 @@ func (p *Plugin) updateLegalHold(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func (p *Plugin) downloadLegalHold(w http.ResponseWriter, r *http.Request) {
+	// Get the LegalHold.
+	legalholdID, err := RequireLegalHoldID(r)
+	if err != nil {
+		http.Error(w, "failed to parse LegalHold ID", http.StatusBadRequest)
+		p.Client.Log.Error(err.Error())
+		return
+	}
+
+	legalHold, err := p.KVStore.GetLegalHoldByID(legalholdID)
+	if err != nil {
+		http.Error(w, "failed to download legal hold", http.StatusInternalServerError)
+		p.Client.Log.Error(err.Error())
+		return
+	}
+
+	// Get the list of files to include in the download.
+	files, err := p.FileBackend.ListDirectoryRecursively(legalHold.BasePath())
+	if err != nil {
+		http.Error(w, "failed to download legal hold", http.StatusInternalServerError)
+		p.Client.Log.Error(err.Error())
+		return
+	}
+
+	// Write headers for the zip file.
+	w.Header().Set("Content-Type", "application/zip")
+	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s\"", "legalholddata.zip"))
+	w.WriteHeader(http.StatusOK)
+
+	// Write the files to the download on-the-fly.
+	zipWriter := zip.NewWriter(w)
+	for _, entry := range files {
+		header := &zip.FileHeader{
+			Name:     entry,
+			Method:   zip.Deflate, // deflate also works, but at a cost
+			Modified: time.Now(),
+		}
+
+		entryWriter, err := zipWriter.CreateHeader(header)
+		if err != nil {
+			http.Error(w, "failed to download legal hold", http.StatusInternalServerError)
+			p.Client.Log.Error(err.Error())
+			return
+		}
+
+		backendReader, err := p.FileBackend.Reader(entry)
+		if err != nil {
+			http.Error(w, "failed to download legal hold", http.StatusInternalServerError)
+			p.Client.Log.Error(err.Error())
+			return
+		}
+
+		fileReader := bufio.NewReader(backendReader)
+
+		_, err = io.Copy(entryWriter, fileReader)
+		if err != nil {
+			http.Error(w, "failed to download legal hold", http.StatusInternalServerError)
+			p.Client.Log.Error(err.Error())
+			return
+		}
+
+		if err = zipWriter.Flush(); err != nil {
+			http.Error(w, "failed to download legal hold", http.StatusInternalServerError)
+			p.Client.Log.Error(err.Error())
+			return
+		}
+	}
+
+	if err := zipWriter.Close(); err != nil {
+		http.Error(w, "failed to download legal hold", http.StatusInternalServerError)
+		p.Client.Log.Error(err.Error())
+		return
+	}
+}
+
 func RequireLegalHoldID(r *http.Request) (string, error) {
 	props := mux.Vars(r)
 

webapp/src/client.ts

@@ -8,6 +8,10 @@ class APIClient {
     private readonly url = `/plugins/${manifest.id}/api/v1`;
     private readonly client4 = new Client4();
 
+    downloadUrl = (id: string) => {
+        return `${this.url}/legalhold/${id}/download`;
+    }
+
     getLegalHolds = () => {
         const url = `${this.url}/legalhold/list`;
         return this.doGet(url);

webapp/src/components/legal_hold_table/legal_hold_row/legal_hold_row.tsx

@@ -2,6 +2,7 @@ import React from 'react';
 import {UserProfile} from 'mattermost-redux/types/users';
 
 import {LegalHold} from '@/types';
+import Client from "@/client";
 
 interface LegalHoldRowProps {
     legalHold: LegalHold;
@@ -26,6 +27,8 @@ const LegalHoldRow = (props: LegalHoldRowProps) => {
         return 'loading...';
     });
 
+    const downloadUrl = Client.downloadUrl(lh.id);
+
     return (
         <React.Fragment>
             <div>{lh.display_name}</div>
@@ -40,7 +43,7 @@ const LegalHoldRow = (props: LegalHoldRowProps) => {
                     {'Edit'}
                 </a>
                 {' '}
-                <a href='#'>{'Download'}</a>
+                <a href={downloadUrl}>{'Download'}</a>
                 {' '}
                 <a
                     href='#'