[JENKINS-15105]

Prefer the postMessage version to retrieve the metadata so that we can leave the existing JSON format as-is for backward compatibility with pre-1.424 Jenkins. (cherry picked from commit f3701da) Conflicts: war/src/main/webapp/scripts/hudson-behavior.js
jenkinsci · Sep 13, 2012 · ad61369 · ad61369
1 parent 682c955
commit ad61369
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Showing 2 changed files with 91 additions and 7 deletions.
diff --git a/core/src/main/java/hudson/model/DownloadService.java b/core/src/main/java/hudson/model/DownloadService.java
@@ -63,7 +63,8 @@ public class DownloadService extends PageDecorator {
      */
     public String generateFragment() {
     	if (neverUpdate) return "";
-
+        if (doesNotSupportPostMessage())  return "";
+
         StringBuilder buf = new StringBuilder();
         if(Jenkins.getInstance().hasPermission(Jenkins.READ)) {
             long now = System.currentTimeMillis();
@@ -90,6 +91,23 @@ public String generateFragment() {
         return buf.toString();
     }
 
+    private boolean doesNotSupportPostMessage() {
+        StaplerRequest req = Stapler.getCurrentRequest();
+        if (req==null)      return false;
+
+        String ua = req.getHeader("User-Agent");
+        if (ua==null)       return false;
+
+        // according to http://caniuse.com/#feat=x-doc-messaging, IE <=7 doesn't support pstMessage
+        // see http://www.useragentstring.com/pages/Internet%20Explorer/ for user agents
+
+        // we want to err on the cautious side here.
+        // Because of JENKINS-15105, we can't serve signed metadata from JSON, which means we need to be
+        // using a modern browser as a vehicle to request these data. This check is here to prevent Jenkins
+        // from using older browsers that are known not to support postMessage as the vehicle.
+        return ua.contains("Windows") && (ua.contains(" MSIE 5.") || ua.contains(" MSIE 6.") || ua.contains(" MSIE 7."));
+    }
+
     private String mapHttps(String url) {
         /*
             HACKISH:

diff --git a/war/src/main/webapp/scripts/hudson-behavior.js b/war/src/main/webapp/scripts/hudson-behavior.js
@@ -2571,12 +2571,69 @@ function loadScript(href,callback) {
     head.insertBefore( script, head.firstChild );
 }
 
+/**
+ * Loads a dynamically created invisible IFRAME.
+ */
+function createIframe(src,callback) {
+    var iframe = document.createElement("iframe");
+    iframe.src = src;
+    iframe.style.display = "none";
+
+    var done = false;
+    iframe.onload = iframe.onreadystatechange = function() {
+        if ( !done && (!this.readyState ||
+                this.readyState === "loaded" || this.readyState === "complete") ) {
+            done = true;
+            callback();
+        }
+    };
+
+    document.body.appendChild(iframe);
+    return iframe;
+}
+
 var downloadService = {
     continuations: {},
 
     download : function(id,url,info, postBack,completionHandler) {
-        this.continuations[id] = {postBack:postBack,completionHandler:completionHandler};
-        loadScript(url+"?"+Hash.toQueryString(info));
+        var tag = {id:id,postBack:postBack,completionHandler:completionHandler,received:false};
+        this.continuations[id] = tag;
+
+        // use JSONP to download the data
+        function fallback() {
+            loadScript(url+"?id="+id+'&'+Hash.toQueryString(info));
+        }
+
+        if (window.postMessage) {
+            // try downloading the postMessage version of the data,
+            // if we don't receive postMessage (which probably means the server isn't ready with these new datasets),
+            // fallback to JSONP
+            tag.iframe = createIframe(url+".html",function() {
+                window.setTimeout(function() {
+                    if (!tag.received)
+                        fallback();
+                },100); // bit of delay in case onload on our side fires first
+            });
+        } else {
+            // this browser doesn't support postMessage
+            fallback();
+        }
+
+        // NOTE:
+        //   the only reason we even try fallback() is in case our server accepts the submission without a signature
+        //   (which it really shouldn't)
+    },
+
+    /**
+     * Call back to postMessage
+     */
+    receiveMessage : function(ev) {
+        var self = this;
+        Object.values(this.continuations).each(function(tag) {
+            if (tag.iframe.contentWindow==ev.source) {
+                self.post(tag.id,JSON.parse(ev.data));
+            }
+        })
     },
 
     post : function(id,data) {
@@ -2585,15 +2642,22 @@ var downloadService = {
             data = id;
             id = data.id;
         }
-        var o = this.continuations[id];
+        var tag = this.continuations[id];
+        if (tag==undefined) {
+            console.log("Submission from update center that we don't know: "+id);
+            console.log("Likely mismatch between the registered ID vs ID in JSON");
+            return;
+        }
+        tag.received = true;
+
         // send the payload back in the body. We used to send this in as a form submission, but that hits the form size check in Jetty.
-        new Ajax.Request(o.postBack, {
+        new Ajax.Request(tag.postBack, {
             contentType:"application/json",
             encoding:"UTF-8",
             postBody:Object.toJSON(data),
             onSuccess: function() {
-                if(o.completionHandler!=null)
-                    o.completionHandler();
+                if(tag.completionHandler!=null)
+                    tag.completionHandler();
                 else if(downloadService.completionHandler!=null)
                     downloadService.completionHandler();
             }
@@ -2604,6 +2668,8 @@ var downloadService = {
 // update center service. to remain compatible with earlier version of Jenkins, aliased.
 var updateCenter = downloadService;
 
+YAHOO.util.Event.addListener(window, "message", function(ev) { downloadService.receiveMessage(ev); })
+
 /*
 redirects to a page once the page is ready.