parser.js

var sys = require('sys');
var events = require('events');
var StompFrame = require('./frame').StompFrame;

var ParserStates = {
    COMMAND: 0,
    HEADERS: 1,
    BODY: 2,
    ERROR: 3,
};

function StompFrameEmitter(commands) {
    events.EventEmitter.call(this);
    this.state = ParserStates.COMMAND;
    this.frame = new StompFrame();
    this.frames = [];
    this.buffer = '';
    this.commands = commands;
};

sys.inherits(StompFrameEmitter, events.EventEmitter);

StompFrameEmitter.prototype.incrementState = function() {
    if (this.state == ParserStates.BODY || this.state == ParserStates.ERROR){
        this.state = ParserStates.COMMAND;
    }
    else {
        this.state++;
    }
};

StompFrameEmitter.prototype.handleData = function(data) {
    this.buffer += data;
    do {
        if (this.state == ParserStates.COMMAND) {
            this.parseCommand();
        }
        if (this.state == ParserStates.HEADERS) {
            this.parseHeaders();
        }
        if (this.state == ParserStates.BODY) {
            this.parseBody();
        }
        if (this.state == ParserStates.ERROR) {
            this.parseError();
        }
    } while (this.state == ParserStates.COMMAND && this.hasLine());
};

StompFrameEmitter.prototype.hasLine = function() {
    return (this.buffer.indexOf('\n') > -1);
};

StompFrameEmitter.prototype.popLine = function () {
    var index = this.buffer.indexOf('\n');
    var line = this.buffer.slice(0, index);
    this.buffer = this.buffer.substr(index + 1);
    return line;
};

StompFrameEmitter.prototype.error = function (err) {
    this.emit('error', err);
    this.state = ParserStates.ERROR;
};

StompFrameEmitter.prototype.parseCommand = function() {
    while (this.hasLine()) {
        var line = this.popLine();
        if (line != '') {
            if (this.commands.indexOf(line) == -1) {
                this.error({
                    message: 'No such command',
                    details: 'Unrecognized Command \'' + line + '\'',
                });
                break;
            }
            this.frame.setCommand(line);
            this.incrementState();
            break;
        }
    }
};

StompFrameEmitter.prototype.parseHeaders = function() {
    while (this.hasLine()) {
        var line = this.popLine();
        if (line == '') {
            this.incrementState();
            break;
        }
        else {
            var kv = line.split(':', 2);
            if (kv.length != 2) {
                this.error({
                    message: 'Error parsing header',
                    details: 'No ":" in line "' + line + '"',
                });
                break;
            }
            this.frame.setHeader(kv[0], kv[1]);
        }
    }
};

StompFrameEmitter.prototype.parseBody = function() {
    if (this.frame.contentLength > -1) {
        var remainingLength = this.frame.contentLength - this.frame.body.length;
        this.frame.appendToBody(this.buffer.slice(0, remainingLength));
        this.buffer = this.buffer.substr(remainingLength);
        if (this.frame.contentLength == this.frame.body.length) {
            this.frame.contentLength = -1;
        }
        else {
            return;
        }
    }
    var index = this.buffer.indexOf('\0');
    if (index == -1) {
       this.frame.appendToBody(this.buffer);
       this.buffer = '';
    }
    else {
        // The end of the frame has been identified, finish creating it
        this.frame.appendToBody(this.buffer.slice(0, index));
        // Emit the frame and reset
        this.emit('frame', this.frame);
        this.frame = new StompFrame();
        this.incrementState();
        this.buffer = this.buffer.substr(index + 1);
    }
};

StompFrameEmitter.prototype.parseError = function () {
    var index = this.buffer.indexOf('\0');
    if (index > -1) {
        this.buffer = this.buffer.substr(index + 1);
        this.incrementState();
    }
    else {
        this.buffer = "";
    }
};

new StompFrameEmitter();

exports.StompFrameEmitter = StompFrameEmitter;