Use Websockets on all browsers other than iOS <= 5

packages/livedata/stream_client_sockjs.js

@@ -126,6 +126,27 @@ _.extend(Meteor._DdpClientStream.prototype, {
       self.HEARTBEAT_TIMEOUT);
   },
 
+  _sockjsProtocolsWhitelist: function () {
+    // only allow polling protocols. no streaming.  streaming
+    // makes safari spin.
+    var protocolsWhitelist = [
+      'xdr-polling', 'xhr-polling', 'iframe-xhr-polling', 'jsonp-polling'];
+
+    // iOS 4 and 5 and below crash when using websockets over certain
+    // proxies. this seems to be resolved with iOS 6. eg
+    // https://github.com/LearnBoost/socket.io/issues/193#issuecomment-7308865.
+    //
+    // iOS <4 doesn't support websockets at all so sockjs will just
+    // immediately fall back to http
+    var noWebsockets = navigator &&
+          /iPhone|iPad|iPod/.test(navigator.userAgent) &&
+          /OS 4_|OS 5_/.test(navigator.userAgent);
+
+    if (!noWebsockets)
+      protocolsWhitelist = ['websocket'].concat(protocolsWhitelist);
+
+    return protocolsWhitelist;
+  },
 
   _launchConnection: function () {
     var self = this;
@@ -137,11 +158,8 @@ _.extend(Meteor._DdpClientStream.prototype, {
     self.socket = new SockJS(
       Meteor._DdpClientStream._toSockjsUrl(self.rawUrl),
       undefined, {
-        debug: false, protocols_whitelist: [
-          // only allow polling protocols. no websockets or streaming.
-          // streaming makes safari spin, and websockets hurt chrome.
-          'xdr-polling', 'xhr-polling', 'iframe-xhr-polling', 'jsonp-polling'
-        ]});
+        debug: false, protocols_whitelist: self._sockjsProtocolsWhitelist()
+      });
     self.socket.onmessage = function (data) {
       self._heartbeat_received();