diff -r 000000000000 -r 6474c204b198 services/sync/modules/rest.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/services/sync/modules/rest.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,90 @@
+/* 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/. */
+
+const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
+
+Cu.import("resource://gre/modules/Log.jsm");
+Cu.import("resource://services-common/rest.js");
+Cu.import("resource://services-sync/util.js");
+Cu.import("resource://services-sync/constants.js");
+
+this.EXPORTED_SYMBOLS = ["SyncStorageRequest"];
+
+const STORAGE_REQUEST_TIMEOUT = 5 * 60; // 5 minutes
+
+/**
+ * RESTRequest variant for use against a Sync storage server.
+ */
+this.SyncStorageRequest = function SyncStorageRequest(uri) {
+  RESTRequest.call(this, uri);
+
+  this.authenticator = null;
+}
+SyncStorageRequest.prototype = {
+
+  __proto__: RESTRequest.prototype,
+
+  _logName: "Sync.StorageRequest",
+
+  /**
+   * The string to use as the base User-Agent in Sync requests.
+   * These strings will look something like
+   * 
+   *   Firefox/4.0 FxSync/1.8.0.20100101.mobile
+   * 
+   * or
+   * 
+   *   Firefox Aurora/5.0a1 FxSync/1.9.0.20110409.desktop
+   */
+  userAgent:
+    Services.appinfo.name + "/" + Services.appinfo.version +  // Product.
+    " FxSync/" + WEAVE_VERSION + "." +                        // Sync.
+    Services.appinfo.appBuildID + ".",                        // Build.
+
+  /**
+   * Wait 5 minutes before killing a request.
+   */
+  timeout: STORAGE_REQUEST_TIMEOUT,
+
+  dispatch: function dispatch(method, data, onComplete, onProgress) {
+    // Compose a UA string fragment from the various available identifiers.
+    if (Svc.Prefs.get("sendVersionInfo", true)) {
+      let ua = this.userAgent + Svc.Prefs.get("client.type", "desktop");
+      this.setHeader("user-agent", ua);
+    }
+
+    if (this.authenticator) {
+      this.authenticator(this);
+    } else {
+      this._log.debug("No authenticator found.");
+    }
+
+    return RESTRequest.prototype.dispatch.apply(this, arguments);
+  },
+
+  onStartRequest: function onStartRequest(channel) {
+    RESTRequest.prototype.onStartRequest.call(this, channel);
+    if (this.status == this.ABORTED) {
+      return;
+    }
+
+    let headers = this.response.headers;
+    // Save the latest server timestamp when possible.
+    if (headers["x-weave-timestamp"]) {
+      SyncStorageRequest.serverTime = parseFloat(headers["x-weave-timestamp"]);
+    }
+
+    // This is a server-side safety valve to allow slowing down
+    // clients without hurting performance.
+    if (headers["x-weave-backoff"]) {
+      Svc.Obs.notify("weave:service:backoff:interval",
+                     parseInt(headers["x-weave-backoff"], 10));
+    }
+
+    if (this.response.success && headers["x-weave-quota-remaining"]) {
+      Svc.Obs.notify("weave:service:quota:remaining",
+                     parseInt(headers["x-weave-quota-remaining"], 10));
+    }
+  }
+};