Bug 777633 - Cannot view a video on mobile youtube on Firefox OS - vnd.youtube is not a registered protocol [r=dougt]

b2g/components/B2GComponents.manifest

@@ -41,3 +41,7 @@ contract @mozilla.org/uriloader/content-handler;1?type=application/pdf {d18d0216
 # PaymentGlue.js
 component {8b83eabc-7929-47f4-8b48-4dea8d887e4b} PaymentGlue.js
 contract @mozilla.org/payment/ui-glue;1 {8b83eabc-7929-47f4-8b48-4dea8d887e4b}
+
+# YoutubeProtocolHandler.js
+component {c3f1b945-7e71-49c8-95c7-5ae9cc9e2bad} YoutubeProtocolHandler.js
+contract @mozilla.org/network/protocol;1?name=vnd.youtube {c3f1b945-7e71-49c8-95c7-5ae9cc9e2bad}

b2g/components/Makefile.in

@@ -26,6 +26,7 @@ EXTRA_PP_COMPONENTS = \
         MozKeyboard.js \
         ProcessGlobal.js \
         PaymentGlue.js \
+        YoutubeProtocolHandler.js \
         $(NULL)
 
 ifdef MOZ_UPDATER

b2g/components/YoutubeProtocolHandler.js

@@ -0,0 +1,117 @@
+/* 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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const Cu = Components.utils;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+
+XPCOMUtils.defineLazyGetter(this, "cpmm", function() {
+  return Cc["@mozilla.org/childprocessmessagemanager;1"]
+           .getService(Ci.nsIMessageSender);
+});
+
+// Splits parameters in a query string.
+function extractParameters(aQuery) {
+  let params = aQuery.split("&");
+  let res = {};
+  params.forEach(function(aParam) {
+    let obj = aParam.split("=");
+    res[obj[0]] = decodeURIComponent(obj[1]);
+  });
+  return res;
+}
+
+function YoutubeProtocolHandler() {
+}
+
+YoutubeProtocolHandler.prototype = {
+  classID: Components.ID("{c3f1b945-7e71-49c8-95c7-5ae9cc9e2bad}"),
+  QueryInterface: XPCOMUtils.generateQI([Ci.nsIProtocolHandler]),
+
+  scheme: "vnd.youtube",
+  defaultPort: -1,
+  protocolFlags: Ci.nsIProtocolHandler.URI_NORELATIVE |
+                 Ci.nsIProtocolHandler.URI_NOAUTH |
+                 Ci.nsIProtocolHandler.URI_LOADABLE_BY_ANYONE,
+
+  // Sample URL:
+  // vnd.youtube:iNuKL2Gy_QM?vndapp=youtube_mobile&vndclient=mv-google&vndel=watch&vnddnc=1
+  newURI: function yt_phNewURI(aSpec, aOriginCharset, aBaseURI) {
+    let uri = Cc["@mozilla.org/network/standard-url;1"]
+              .createInstance(Ci.nsIStandardURL);
+    let id = aSpec.substring(this.scheme.length + 1);
+    id = id.substring(0, id.indexOf('?'));
+    uri.init(Ci.nsIStandardURL.URLTYPE_STANDARD, -1, this.scheme + "://dummy_host/" + id, aOriginCharset,
+             aBaseURI);
+    return uri.QueryInterface(Ci.nsIURI);
+  },
+
+  newChannel: function yt_phNewChannel(aURI) {
+    // Get a list of streams for this video id.
+    let infoURI = "http://www.youtube.com/get_video_info?&video_id=" +
+                  aURI.path.substring(1);
+
+    let xhr = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"]
+                .createInstance(Ci.nsIXMLHttpRequest);
+    xhr.open("GET", infoURI, true);
+    xhr.addEventListener("load", function() {
+      // Youtube sends the response as a double wrapped url answer:
+      // we first extract the url_encoded_fmt_stream_map parameter,
+      // and from each comma-separated entry in this value, we extract
+      // other parameters (url and type).
+      let key = "url_encoded_fmt_stream_map=";
+      let pos = xhr.responseText.indexOf(key);
+      if (pos == -1) {
+        return;
+      }
+      let streams = decodeURIComponent(xhr.responseText
+                                       .substring(pos + key.length)).split(",");
+      let uri;
+      let mimeType;
+
+      // Recognized mime types, ordered from the less usable to the most usable.
+      let recognizedTypes = ["video/webm"];
+#ifdef MOZ_WIDGET_GONK
+      recognizedTypes.push("video/mp4");
+#endif
+
+      let bestType = -1;
+
+      streams.forEach(function(aStream) {
+        let params = extractParameters(aStream);
+        let url = params["url"];
+        let type = params["type"] ? params["type"].split(";")[0] : null;
+
+        let index;
+        if (url && type && ((index = recognizedTypes.indexOf(type)) != -1) &&
+            index > bestType) {
+          uri = url;
+          mimeType = type;
+          bestType = index;
+        }
+      });
+
+      if (uri && mimeType) {
+        cpmm.sendAsyncMessage("content-handler", {
+          url: uri,
+          type: mimeType
+        });
+      }
+    });
+    xhr.send(null);
+
+    throw Components.results.NS_ERROR_ILLEGAL_VALUE;
+  },
+
+  allowPort: function yt_phAllowPort(aPort, aScheme) {
+    return false;
+  }
+};
+
+const NSGetFactory = XPCOMUtils.generateNSGetFactory([YoutubeProtocolHandler]);