/
Parser.js
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/
Parser.js
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/**
* @fileoverview SIP Message Parser
*/
/**
* Extract and parse every header of a SIP message.
* @augments JsSIP
* @namespace
*/
(function(JsSIP) {
var Parser,
LOG_PREFIX = JsSIP.name +' | '+ 'PARSER' +' | ';
function getHeader(data, headerStart) {
var
// 'start' position of the header.
start = headerStart,
// 'end' position of the header.
end = 0,
// 'partial end' position of the header.
partialEnd = 0;
//End of message.
if (data.substring(start, start + 2).match(/(^\r\n)/)) {
return -2;
}
while(end === 0) {
// Partial End of Header.
partialEnd = data.indexOf('\r\n', start);
// 'indexOf' returns -1 if the value to be found never occurs.
if (partialEnd === -1) {
return partialEnd;
}
if(!data.substring(partialEnd + 2, partialEnd + 4).match(/(^\r\n)/) && data.charAt(partialEnd + 2).match(/(^\s+)/)) {
// Not the end of the message. Continue from the next position.
start = partialEnd + 2;
} else {
end = partialEnd;
}
}
return end;
}
function parseHeader(message, data, headerStart, headerEnd) {
var header, idx, length, parsed,
hcolonIndex = data.indexOf(':', headerStart),
headerName = data.substring(headerStart, hcolonIndex).trim(),
headerValue = data.substring(hcolonIndex + 1, headerEnd).trim();
// If header-field is well-known, parse it.
switch(headerName.toLowerCase()) {
case 'via':
case 'v':
message.addHeader('via', headerValue);
if(message.countHeader('via') === 1) {
parsed = message.parseHeader('Via');
if(parsed) {
message.via = parsed;
message.via_branch = parsed.branch;
}
} else {
parsed = 0;
}
break;
case 'from':
case 'f':
message.setHeader('from', headerValue);
parsed = message.parseHeader('from');
if(parsed) {
message.from = parsed;
message.from_tag = parsed.getParam('tag');
}
break;
case 'to':
case 't':
message.setHeader('to', headerValue);
parsed = message.parseHeader('to');
if(parsed) {
message.to = parsed;
message.to_tag = parsed.getParam('tag');
}
break;
case 'record-route':
parsed = JsSIP.Grammar.parse(headerValue, 'Record_Route');
if (parsed === -1) {
parsed = undefined;
}
length = parsed.length;
for (idx = 0; idx < length; idx++) {
header = parsed[idx];
message.addHeader('record-route', headerValue.substring(header.possition, header.offset));
message.headers['Record-Route'][message.countHeader('record-route')-1].parsed = header.parsed;
}
break;
case 'call-id':
case 'i':
message.setHeader('call-id', headerValue);
parsed = message.parseHeader('call-id');
if(parsed) {
message.call_id = headerValue;
}
break;
case 'contact':
case 'm':
parsed = JsSIP.Grammar.parse(headerValue, 'Contact');
if (parsed === -1) {
parsed = undefined;
}
length = parsed.length;
for (idx = 0; idx < length; idx++) {
header = parsed[idx];
message.addHeader('contact', headerValue.substring(header.possition, header.offset));
message.headers['Contact'][message.countHeader('contact')-1].parsed = header.parsed;
}
break;
case 'content-length':
case 'l':
message.setHeader('content-length', headerValue);
parsed = message.parseHeader('content-length');
break;
case 'content-type':
case 'c':
message.setHeader('content-type', headerValue);
parsed = message.parseHeader('content-type');
break;
case 'cseq':
message.setHeader('cseq', headerValue);
parsed = message.parseHeader('cseq');
if(parsed) {
message.cseq = parsed.value;
}
if(message instanceof JsSIP.IncomingResponse) {
message.method = parsed.method;
}
break;
case 'max-forwards':
message.setHeader('max-forwards', headerValue);
parsed = message.parseHeader('max-forwards');
break;
case 'www-authenticate':
message.setHeader('www-authenticate', headerValue);
parsed = message.parseHeader('www-authenticate');
break;
case 'proxy-authenticate':
message.setHeader('proxy-authenticate', headerValue);
parsed = message.parseHeader('proxy-authenticate');
break;
default:
// Do not parse this header.
message.setHeader(headerName, headerValue);
parsed = 0;
}
if (parsed === undefined) {
return false;
} else {
return true;
}
}
/** Parse SIP Message
* @function
* @param {String} message SIP message.
* @returns {JsSIP.IncomingRequest|JsSIP.IncomingResponse|undefined}
*/
Parser = {};
Parser.parseMessage = function(data) {
var message, firstLine, contentLength, bodyStart, parsed,
headerStart = 0,
headerEnd = data.indexOf('\r\n');
if(headerEnd === -1) {
console.warn(LOG_PREFIX +'no CRLF found, not a SIP message, discarded');
return;
}
// Parse first line. Check if it is a Request or a Reply.
firstLine = data.substring(0, headerEnd);
parsed = JsSIP.Grammar.parse(firstLine, 'Request_Response');
if(parsed === -1) {
console.warn(LOG_PREFIX +'error parsing first line of SIP message: "' + firstLine + '"');
return;
} else if(!parsed.status_code) {
message = new JsSIP.IncomingRequest();
message.method = parsed.method;
message.ruri = parsed.uri;
} else {
message = new JsSIP.IncomingResponse();
message.status_code = parsed.status_code;
message.reason_phrase = parsed.reason_phrase;
}
message.data = data;
headerStart = headerEnd + 2;
/* Loop over every line in data. Detect the end of each header and parse
* it or simply add to the headers collection.
*/
while(true) {
headerEnd = getHeader(data, headerStart);
// The SIP message has normally finished.
if(headerEnd === -2) {
bodyStart = headerStart + 2;
break;
}
// data.indexOf returned -1 due to a malformed message.
else if(headerEnd === -1) {
return;
}
parsed = parseHeader(message, data, headerStart, headerEnd);
if(!parsed) {
return;
}
headerStart = headerEnd + 2;
}
/* RFC3261 18.3.
* If there are additional bytes in the transport packet
* beyond the end of the body, they MUST be discarded.
*/
if(message.hasHeader('content-length')) {
contentLength = message.getHeader('content-length');
message.body = data.substr(bodyStart, contentLength);
} else {
message.body = data.substring(bodyStart);
}
return message;
};
JsSIP.Parser = Parser;
}(JsSIP));