Hi Oudin,

It looks like this needs to be cast to a hashtable since the included JSONObject is not optimized for FiddlerScript. See the following steps to test this.

Testing

First, in the Custom Rules OnBeforeResponse event handler try the following code snippet.

public static void OnBeforeResponse(Session oSession)
    if (m_Hide304s && oSession.responseCode == 304)
        oSession["ui-hide"] = "true";
    if(oSession.HostnameIs("www.httpbin.org") && oSession.uriContains("post"))
        oSession["ui-backcolot"] = "yellow";				
    string sInput = oSession.GetResponseBodyAsString();
    JSON.JSONParseResult json = (JSON.JSONParseResult)JSON.JsonDecode(sInput);
    Hashtable oObj = (Hashtable)json.JSONObject;
    string value = (oObj != null) ? (string)oObj["url"] : "null";       
    FiddlerApplication.Log.LogString(value);
}

Then, use the Composer and POST a custom request to httpbin.org which will respond with JSON. See the below screenshot.

Finally, in the log this will output the url value submitted through the composer. See the below screenshot.

Note that this will only work with the httpbin.org because it returns a url value in the JSON Response.

Wrapping Up

For additional reference, see Eric's response in the How to call JSON methods inside FiddlerScript feature request.

Please give this a try and let me know if you need any additional information. Thank you for using the Fiddler Forums.

Regards,

Eric R | Senior Technical Support Engineer
Progress Telerik

Hello Eric,

apologies for the late answer ... it's holiday time here ...

I sticked to Jscript because I find it easier to read afterwards ...

I tried your code snippet, and I still get this in the log window :

Jscript Code :

And here's the output log :

I got this on httbin.org, with both requests using ID or not :

http://www.httpbin.org/post?id=123&ware=were

http://www.httpbin.org/post

At least, we confirmed that the problem is not linked to the website I'm working on, but to the way fiddler is handling Json objects ...

I'm almost sure that If it works on httpbin.org, it will work anywere ...

Can you see any reason for fiddler to badly reading the Jsons ?

I tried activating session decoding :

but it doesn't work, with it or without ... any ideas ?

Hi Oudin,

Line 2 of your code snippet needs top be changed to the following:

var json:JSON.JSONParseResult = JSON.JsonDecode(sInput);

In my testing the above line was required to convert the JsonDecode to a JSONParseResult. Doing this allowed viewing the JSONObject's properties.

The reason for this is described in Eric's comment on the How to Call JSON Methods inside Fiddler Script which is that Fiddler's JSON Object's are not optimized for Fiddler Script.

Please give this a try and let me know the results. Thank you and I look forward to your reply.

Regards,

Eric R | Senior Technical Support Engineer
Progress Telerik

I'm guessing a missing include/import at the beginning of the script ... Bit I don't know the Jscript modules very well ...

As a reminder, this line works well ASIS :

import Fiddler.WebFormats;
// Code Removed for Brevity //
static function OnBeforeResponse(oSession: Session) {
    if (m_Hide304s && oSession.responseCode == 304) {
        oSession["ui-hide"] = "true";
    var sInput = oSession.GetResponseBodyAsString();
    var json:JSON.JSONParseResult = Fiddler.WebFormats.JSON.JsonDecode(sInput);
    var oObj = json.JSONObject;
    FiddlerApplication.Log.LogString(oObj["url"]);		
}