[fix] Fix UTF-8 encoding in Firefox WebWorker (#596)

Cherry-picked from master

Author: devoidfury

lib/transports/polling-xhr.js

@@ -220,10 +220,6 @@ Request.prototype.create = function () {
       xhr.setRequestHeader('Accept', '*/*');
     } catch (e) {}
 
-    if (this.supportsBinary) {
-      xhr.responseType = 'arraybuffer';
-    }
-
     // ie6 check
     if ('withCredentials' in xhr) {
       xhr.withCredentials = true;
@@ -245,8 +241,8 @@ Request.prototype.create = function () {
         if (xhr.readyState === 2) {
           try {
             var contentType = xhr.getResponseHeader('Content-Type');
-            if (contentType !== 'application/octet-stream') {
-              xhr.responseType = 'text';
+            if (self.supportsBinary && contentType === 'application/octet-stream') {
+              xhr.responseType = 'arraybuffer';
             }
           } catch (e) {}
         }
@@ -358,11 +354,7 @@ Request.prototype.onLoad = function () {
       contentType = this.xhr.getResponseHeader('Content-Type');
     } catch (e) {}
     if (contentType === 'application/octet-stream') {
-      if (this.xhr.responseType === 'arraybuffer') {
-        data = this.xhr.response || this.xhr.responseText;
-      } else {
-        data = String.fromCharCode.apply(null, new Uint8Array(this.xhr.response));
-      }
+      data = this.xhr.response || this.xhr.responseText;
     } else {
       data = this.xhr.responseText;
     }

test/connection.js

@@ -62,10 +62,28 @@ describe('connection', function () {
   if (global.Worker) {
     it('should work in a worker', function (done) {
       var worker = new Worker('/test/support/worker.js');
+      var msg = 0;
+      var utf8yay = 'пойду сать всем мпокойной ночи';
       worker.onmessage = function (e) {
-        expect(e.data);
-        done();
+        msg++;
+        if (msg === 1) {
+          expect(e.data).to.be('hi');
+        } else if (msg < 11) {
+          expect(e.data).to.be(utf8yay);
+        } else if (msg < 20) {
+          testBinary(e.data);
+        } else {
+          testBinary(e.data);
+          done();
+        }
       };
+
+      function testBinary (data) {
+        var byteArray = new Uint8Array(data);
+        for (var i = 0; i < byteArray.byteLength; i++) {
+          expect(byteArray[i]).to.be(i);
+        }
+      }
     });
   }
 

test/support/public/worker.js

@@ -3,6 +3,14 @@
 importScripts('/test/support/engine.io.js');
 
 var socket = new eio.Socket();
+
+var count = 0;
 socket.on('message', function (msg) {
+  count++;
+  if (count < 10) {
+    socket.send('give utf8');
+  } else if (count < 20) {
+    socket.send('give binary');
+  }
   postMessage(msg);
 });

test/support/server.js

@@ -32,6 +32,9 @@ server.on('connection', function (socket) {
       }
       socket.send(abv);
       return;
+    } else if (data === 'give utf8') {
+      socket.send('пойду сать всем мпокойной ночи');
+      return;
     }
 
     socket.send(data);