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// Copyright (C) 2013, Georges-Etienne Legendre <legege@legege.com>
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
var url = require('url');
var http = require('http');
require('buffertools');
function extractBoundary(contentType) {
var startIndex = contentType.indexOf('boundary=');
var endIndex = contentType.indexOf(';', startIndex);
if (endIndex == -1) { //boundary is the last option
// some servers, like mjpeg-streamer puts a '\r' character at the end of each line.
if ((endIndex = contentType.indexOf('\r', startIndex)) == -1) {
endIndex = contentType.length;
}
}
return contentType.substring(startIndex + 9, endIndex).replace(/"/gi,'');
}
var MjpegProxy = exports.MjpegProxy = function(mjpegUrl, still_frames) {
var self = this;
if (!mjpegUrl) throw new Error('Please provide a source MJPEG URL');
self.mjpegOptions = url.parse(mjpegUrl);
self.mjpegOptions.agent = false;
self.still_frames = still_frames;
self.still_frame_idx = 0;
self.consumers = [];
self.boundary = 'ipcamera';
self.on_air = true;
self.frames_missed = 50;
self._handle_data = function(chunk) {
var p = chunk.indexOf('--' + self.boundary);
if (p >= 0)
self.frames_missed = 0;
if (!self.on_air)
return;
for (var i = self.consumers.length; i--;) {
var res = self.consumers[i];
if (res.is_live) {
res.write(chunk);
} else {
if (p >= 0) {
res.write(chunk.slice(p));
res.is_live = true;
}
}
}
};
self._newClient = function(req, res){
res.writeHead(200, {
'Expires': 'Mon, 01 Jul 1980 00:00:00 GMT',
'Cache-Control': 'no-cache, no-store, must-revalidate',
'Pragma': 'no-cache',
'Content-Type': 'multipart/x-mixed-replace;boundary=' + self.boundary
});
res.is_live = false;
self.consumers.push(res);
req.socket.on('close', function() {
self.consumers.splice(self.consumers.indexOf(res), 1);
});
};
self.proxyRequest = function(req, res) {
self._newClient(req, res);
};
self._start_request = function() {
self.producer_response = null;
self.producer_request = http.request(self.mjpegOptions, function(response) {
self.producer_response = response;
self.boundary = extractBoundary(response.headers['content-type']);
response.on('data', self._handle_data);
response.on('end', function() {
/* handle end of camera stream */
});
response.on('close', function() {
/* handle close of producer */
});
});
self.producer_request.on('error', function(e) {
console.log('Error on producer', e);
});
self.producer_request.end()
};
self.frame_ticker_interval = 240;
self._frame_ticker = function() {
self.frames_missed += 1;
if (self.frames_missed > (1000 / self.frame_ticker_interval)) {
self.frames_missed = -(10000 / self.frame_ticker_interval);
console.log("No frames received - restarting producer request.");
if (self.producer_response)
self.producer_response.destroy();
else if (self.producer_request)
self.producer_request.abort();
self.producer_request = null;
self.producer_response = null;
self._start_request();
}
if (self.on_air && self.frames_missed >= 0)
return;
self.still_frame_idx++;
if (self.still_frame_idx >= self.still_frames.length)
self.still_frame_idx = 0;
var frame = self.still_frames[self.still_frame_idx];
var header = '\r\n--' + self.boundary + '\r\n';
header += 'Content-Type: image/jpeg\r\n';
header += 'Content-Length: ' + frame.length + '\r\n\r\n';
var buffer = Buffer.concat([ new Buffer(header), frame ]);
for (var i = self.consumers.length; i--;) {
var res = self.consumers[i];
res.write(buffer);
res.is_live = true;
}
};
self.frame_ticker_id = setInterval(self._frame_ticker, self.frame_ticker_interval);
}
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