No transport error while consuming WCF service in a REST way

Question

Hi,
Here is a small article on when we usually face No Transport error and how to get rid of it.
I recently worked on a sample application using “app for Office” (New in Visual Studio 11.0)
What is “app for Office”?
An app for Office is basically a webpage that is hosted inside an Office client application. You can use apps to extend the functionality of a document, email message, meeting request, or appointment. Apps
can run in multiple environments and clients, including rich Office desktop clients, Office Web Apps, mobile browsers, and also on-premises and in the cloud.
What can an app for Office do?
An app for Office can do pretty much anything a webpage can do inside the browser, such as the following:
Provide an interactive UI and custom logic through      JavaScript. (Develop UI using HTML and JavaScript)
Use JavaScript frameworks such as jQuery.
Connect to REST endpoints and web services via      HTTP and AJAX.
Run server-side code or logic, if the page is      implemented using a server-side scripting language such as ASP or PHP.
As “app for Office” doesn’t have an option to write server side scripting (unlike code behind or in-line coding feature in ASP.NET/MVC) we will have to go for web service or WCF service and consume the service
using any JavaScript framework like Jquery.
I wrote a simple WCF service to hook up with server side code and consumed the service using Jquery as follows
$(document).ready(function () {
$.ajax({
type: "GET",
url: "http://localhost/MyService.svc/rh/data?id=" + $('#sampleType').val(),
processData: false,
contentType: "application/json; charset=utf-8",
dataType: "json",
crossDomain: true,
success: function (data) {
alert(data)
error: function (xhr, status, error) {
alert(error);
I encountered an error saying “No Transport” when I executed the client application.
 I did some investigation on this and found out the root cause that cross-domain request was disabled. But I was really not sure whether it was at my WCF service end or “app for Office” client end. I added
Client Access policy and Cross-domain-policy xml files to WCF service in order to enable cross-domain request 
so that service will accept any type requests sent form different domains.
Client Access policy
<?xml version="1.0" encoding="utf-8" ?>
<access-policy>
<cross-domain-access>
<policy>
<allow-from http-request-headers="*">
<domain uri="*"/>
</allow-from>
<grant-to>
<resource include-subpaths="true" path="/"/>
</grant-to>
</policy>
</cross-domain-access>
</access-policy>
Cross-domain-policy
<?xml version="1.0"?>
<!DOCTYPE cross-domain-policy SYSTEM "http://www.macromedia.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
<allow-http-request-headers-from domain="*" headers="*"/>
</cross-domain-policy>
Both the policies should be in different XML files
But this didn’t solve my problem. After a little bit more investigation I found exactly where and how to enable-cross domain requests.
Solution
We need to enable cross-domain requests in environments that do not support cross-domain requests.
“Cors is equal to true if a browser can create an XMLHttpRequest object and if thatXMLHttpRequest
object has a withCredentials property. To enable cross-domain requests in environments that do not support cors yet but do allow cross-domain XHRrequests (windows gadget, etc), set $.support.cors = true;”
You just have to add jQuery.support.cors = true; in your client scripting and it works perfectly fine.
[Cors- Cross-Origin Resource Sharing]
A simple example:
$.support.cors = true;
$(document).ready(function () {
$.ajax({
type: "GET",
url: "http://localhost/MyService.svc/rh/data?id=" + $('#sampleType').val(),
processData: false,
contentType: "application/json; charset=utf-8",
dataType: "json",
crossDomain: true,
success: function (data) {
alert(data)
error: function (xhr, status, error) {
alert(error);
Hope this will be helpful.
Thanks

Answer 1

This is very good technich to resolve the problem. but this is not working in Google chrome or Firfox . can any one help me.