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/* -*- Mode: JavaScript; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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
/* dash_detect_stream_switch.sjs
*
* Parses requests for DASH manifests and ensures stream switching takes place
* by verifying the subsegments downloaded and the streams they belong to.
* If unexpected subsegments (byte ranges) are requested, the script will
* will respond with a 404.
*/
var DEBUG = false;
function parseQuery(request, key) {
var params = request.queryString.split("&");
if (DEBUG) {
dump('DASH-SJS: request params = "' + params + '"\n');
}
for (var j = 0; j < params.length; ++j) {
var p = params[j];
if (p == key) {
return true;
}
if (p.indexOf(key + "=") === 0) {
return p.substring(key.length + 1);
}
if (!p.includes("=") && key === "") {
return p;
}
}
return false;
}
function handleRequest(request, response) {
try {
var name = parseQuery(request, "name");
var range = request.hasHeader("Range")
? request.getHeader("Range")
: undefined;
// Should not get request for 1st subsegment from 2nd stream, nor 2nd
// subsegment from 1st stream.
if (
(name == "dash-webm-video-320x180.webm" &&
range == "bytes=25514-32767") ||
(name == "dash-webm-video-428x240.webm" && range == "bytes=228-35852")
) {
throw new Error(
"Should not request " + name + " with byte-range " + range
);
} else {
var rangeSplit = range.split("=");
if (rangeSplit.length != 2) {
throw new Error(
"DASH-SJS: ERROR: invalid number of tokens (" +
rangeSplit.length +
") delimited by '=' in 'Range' header."
);
}
var offsets = rangeSplit[1].split("-");
if (offsets.length != 2) {
throw new Error(
"DASH-SJS: ERROR: invalid number of tokens (" +
offsets.length +
") delimited by '-' in 'Range' header."
);
}
var startOffset = parseInt(offsets[0]);
var endOffset = parseInt(offsets[1]);
var file = Services.dirsvc.get("CurWorkD", Ci.nsIFile);
var fis = Cc["@mozilla.org/network/file-input-stream;1"].createInstance(
Ci.nsIFileInputStream
);
var bis = Cc["@mozilla.org/binaryinputstream;1"].createInstance(
Ci.nsIBinaryInputStream
);
var paths = "tests/dom/media/test/" + name;
var split = paths.split("/");
for (var i = 0; i < split.length; ++i) {
file.append(split[i]);
}
fis.init(file, -1, -1, false);
// Exception: start offset should be within file bounds.
if (startOffset > file.fileSize) {
throw new Error(
"Starting offset [" +
startOffset +
"] is after end of file [" +
file.fileSize +
"]."
);
}
// End offset may be too large in the MPD. Real world HTTP servers just
// return what data they can; do the same here - reduce the end offset.
if (endOffset >= file.fileSize) {
if (DEBUG) {
dump(
"DASH-SJS: reducing endOffset [" +
endOffset +
"] to fileSize [" +
(file.fileSize - 1) +
"]\n"
);
}
endOffset = file.fileSize - 1;
}
fis.seek(Ci.nsISeekableStream.NS_SEEK_SET, startOffset);
bis.setInputStream(fis);
var byteLengthToRead = endOffset + 1 - startOffset;
var totalBytesExpected = byteLengthToRead + startOffset;
if (DEBUG) {
dump(
"DASH-SJS: byteLengthToRead = " +
byteLengthToRead +
" byteLengthToRead+startOffset = " +
totalBytesExpected +
" fileSize = " +
file.fileSize +
"\n"
);
}
var bytes = bis.readBytes(byteLengthToRead);
response.setStatusLine(request.httpVersion, 206, "Partial Content");
response.setHeader("Content-Length", "" + bytes.length, false);
response.setHeader("Content-Type", "application/dash+xml", false);
var contentRange =
"bytes " + startOffset + "-" + endOffset + "/" + file.fileSize;
response.setHeader("Content-Range", contentRange, false);
response.write(bytes, bytes.length);
bis.close();
}
} catch (e) {
dump("DASH-SJS-ERROR: " + e + "\n");
response.setStatusLine(request.httpVersion, 404, "Not found");
}
}