Fiddler AutoResponder should returns a json response with jQuery session id given in request

Question

I need your help, I develop a javascript code that ask a webservice and get back data in JSON format.

When I ask the webservice like this :

https://Server/ServiceEndPoint?id=12345

MyApplication adds some other parameters to my web service URL like this :

https://Server/ServiceEndPoint?id=12345&callback=jQuery18205735686348496944_1459416484049&_=1459416484892

This jQuery session id is generic.

So, I'm using Fiddler to simulate the webservice response. And I need to add this jQuery session Id in the begining of my response like this :

jQuery18205735686348496944_1459416484049({"data":"JSON data"})

Can any one helps me to do this.

Thank you.

Answer 1

I Used FiddlerScript to do it :

    if (oSession.HostnameIs("ServerName")){

        var body = "";
        var s_qs = (oSession.url + "?").split("?")[1];

        var querystring = HttpUtility.ParseQueryString(s_qs);
        var s_callback = querystring.Get("callback");

        if(oSession.uriContains("EndPointName"))
        {
            body = s_callback + "({'data':'datContent'})";
        }
        oSession.utilSetResponseBody(body);
    }

Answer 2

Fiddler's AutoResponder cannot do this itself (as it cannot modify response bodies based on the request URL). Instead, you'd need to write some simple FiddlerScript to do it. E.g. Rules > Customize Rules > OnBeforeRequest

    if (oSession.uriContains("server/ServiceEndPoint?")) {
        oSession.utilCreateResponseAndBypassServer();
        oSession.oResponse.headers.Add("Content-Type", "application/json");
        oSession.ResponseBody = System.IO.File.ReadAllBytes("C:\\Your\\File.txt");              
        // TODO:Copy the callback value to the front of the response string here.      
    }

Answer 3

Just add this FiddlerScript to OnBeforeResponse and you can continue using AutoResponder. This will fix callback names for you automatically:

    //Autofix all JSONP responses
    if (oSession.uriContains("callback=jQuery")) {

        var s_qs = (oSession.url + "?").split("?")[1];

        var querystring = HttpUtility.ParseQueryString(s_qs);
        var s_callback = querystring.Get("callback");           

        var body = new Regex("jQuery\\d+_\\d+").Replace(oSession.GetResponseBodyAsString(), s_callback);

        oSession.utilSetResponseBody(body);
    }

Answer 4

Assuming you're returning static content (file content or whatever), you really want to take the dynamic jquery callback function name and wrap that around whatever you're statically returning. As such, I modified one of the answers above and took care not to affect JSONP responses you aren't targeting.

In Rules > Customize Rules..., do the following:

1. Add this import at the top of the file if it's not already there: import System.Web;

2. Find the OnBeforeResponse(oSession) method and add the following:

   //Autofix all JSONP responses
   if (oSession.uriContains("callback=jQuery")) {
       var s_qs = (oSession.url + "?").split("?")[1];
   
       var querystring = HttpUtility.ParseQueryString(s_qs);
       var s_callback = querystring.Get("callback"); 
   
       var oldBody = oSession.GetResponseBodyAsString();
       if (oldBody.StartsWith(s_callback)) return;
   
       var body = String.Concat(s_callback, "(", oSession.GetResponseBodyAsString(), ")");
   
       oSession.utilSetResponseBody(body);
   }
   

This will convert a JSON response of { "test": "testValue" } to jQuery9827345872635_982735982375({ "test": "testValue" }) (the jQuery callback here is random BS I generated for demonstrative purposes).