Fetch with direct cross-origin XMLHttpRequests

I swear I tried this before and it didn't work.

diff --git a/server/server.go b/server/server.go
index f19cefc1dde45eae5ad7fa4efb3c949178f532ec..9ca5e619c1a9d18cd53981af2157458e7caa5cac 100644 (file)
--- a/server/server.go
+++ b/server/server.go
@@ -161,6 +161,7 @@ func start_server(store Store) {
                        return
                }
                w.Header().Add("Content-Type", "application/json")
+               w.Header().Add("Access-Control-Allow-Origin", "*")
                w.Write(json_encoded)
        })
 

diff --git a/webclient/rc.html b/webclient/rc.html
index 591bd212345b9b21617117f3b7e2b393f9f46949..8aeae37ce3d43d4de54b0cfcb65bca39488afc50 100644 (file)
--- a/webclient/rc.html
+++ b/webclient/rc.html
@@ -19,6 +19,7 @@
        var servers = ['chkno.net', 'rc2.chkno.net', 'echto.net', 'the-wes.com', 'vibrantlogic.com'];
 
        var session = Math.random();
+       var since = {};
        var seen = {};
 
        function rcnick() {
@@ -65,41 +66,53 @@
                return id.replace(/@/g, "@@") + "_@_" + text.replace(/@/g, "@@");
        }
 
-       function receiveMessage(server, time, id, text) {
-               var seen_key = make_seen_key(id, text);
-               if (!(seen_key in seen)) {
-                       seen[seen_key] = true;
-                       rcaddmessagetohistory(text);
-                       for (var i in servers) {
-                               rcchangeserverstatus(servers[i], "sad");
+       function rcreceivemessages(server, messages) {
+               for (var i in messages) {
+                       var seen_key = make_seen_key(messages[i]['ID'], messages[i]['Text']);
+                       if (!(seen_key in seen)) {
+                               seen[seen_key] = true;
+                               rcaddmessagetohistory(messages[i]['Text']);
+                               for (var i in servers) {
+                                       rcchangeserverstatus(servers[i], "sad");
+                               }
                        }
+                       rcchangeserverstatus(server, "happy");
                }
-               rcchangeserverstatus(server, "happy");
        }
 
-       function receiveMessageEvent(event)  
-       {  
-               for (var i in servers) {
-                       if (event.origin === rcserverbase(servers[i])) {
-                               messages = JSON.parse(event.data);
-                               for (var j in messages) {
-                                       if ('Time' in messages[j] &&
-                                           'ID'   in messages[j] &&
-                                           'Text' in messages[j]) {
-                                               receiveMessage(servers[i], messages[j]['Time'], messages[j]['ID'], messages[j]['Text']);
+       function rcfetch(server) {
+               var delay = 10000;  // TODO: Exponential backoff
+               var xhr = new XMLHttpRequest();
+               xhr.onreadystatechange = function() {
+                       if (this.readyState == this.DONE) {
+                               if (this.status == 200) {
+                                       var rtxt = this.responseText;
+                                       if (rtxt != null) {
+                                               var messages = JSON.parse(rtxt);
+                                               if (messages != null) {
+                                                       rcreceivemessages(server, messages);
+                                                       window.parent.postMessage(rtxt, "*");
+                                                       delay = 40;
+                                                       if (messages.length >= 1 && "Time" in messages[messages.length-1]) {
+                                                               since[server] = messages[messages.length-1]["Time"];
+                                                       }
+                                               }
                                        }
                                }
+                               window.setTimeout(rcfetch, delay, server);
                        }
                }
+               var uri = rcserverbase(server) + "/fetch";
+               if (server in since) {
+                       uri += '?since="' + since[server] + '"';
+               }
+               xhr.open("GET", uri);
+               xhr.send();
        }
 
        function rcconnect() {
-               window.addEventListener("message", receiveMessageEvent, false);  
                for (var i in servers) {
-                       // Create a hidden iframe for same-origin workaround
-                       var iframe = document.createElement("iframe");
-                       iframe.setAttribute("src", rcserverbase(servers[i]) + "/frame");
-                       document.body.insertBefore(iframe, document.body.firstChild);
+                       rcfetch(servers[i]);
                        // Status bar entry
                        var status_indicator = document.createElement("span");
                        status_indicator.appendChild(document.createTextNode(servers[i]));