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Customize Web Sessions List

To customize Fiddler's Web Sessions List, add rules using FiddlerScript to the OnBeforeRequest function (except where noted). For example:

Display in the "Custom Column" the time of the original request

    oSession["ui-customcolumn"] += DateTime.Now.ToString("h:mm:ss.ffff ");

Show any Set-Cookie headers in Custom column in Session list. (in OnBeforeResponse)

    oSession["ui-customcolumn"] = oSession.oResponse["Set-Cookie"];

Mark any requests which send cookies in red, and show the value in the Custom column. Otherwise, mark request in green.

    if (oSession.oRequest.headers.Exists("Cookie")) 
    oSession["ui-customcolumn"] = oSession.oRequest["Cookie"];

Hide requests for .GIFs from the session list

    if (oSession.url.EndsWith(".gif")){
        oSession["ui-hide"]="hiding image requests";  //String value not important

Hide completed responses which returned images (in OnBeforeResponse)

    if (oSession.oResponse.headers.ExistsAndContains("Content-Type", "image/")) {
        oSession["ui-hide"] = "hiding images"; // String value not important

Hide requests to domains except those I care about

    if (!oSession.HostnameIs("domainIcareabout.com")){
        oSession["ui-hide"] = "hiding boring domains"; // String value not important

Unhide any response which returned a 404 (in OnBeforeResponse)

    if (oSession.responseCode == 404){

Flag all pages in which the server sends a cookie (in OnBeforeResponse)

    if (oSession.oResponse.headers.Exists("Set-Cookie") ||
      oSession.utilFindInResponse("document.cookie", false)>-1 ||
      oSession.utilFindInResponse('HTTP-EQUIV="Set-Cookie"', false)>-1){

Show redirection target Location in Session List (In OnBeforeResponse)

    if ((oSession.responseCode > 299) && (oSession.responseCode < 308)){ 
        oSession["ui-customcolumn"] = oSession.oResponse["Location"];

Add image size information in a column. (Global scope) Note: you must add System.drawing.dll inside Tools > Fiddler Options > Extensions > References.

    public static BindUIColumn("ImageSize", 60)
    function FillImageSizeColumn(oS: Session){
     if ((oS.oResponse != null) && (oS.oResponse.headers != null))
          if (!oS.oResponse.headers.ExistsAndContains("Content-Type", "image/")) return "NotAnImage";

          var oMS: System.IO.MemoryStream = new System.IO.MemoryStream(oS.responseBodyBytes);
          var i:System.Drawing.Bitmap = new System.Drawing.Bitmap(oMS);
          return (i.Width + " x " + i.Height);
          catch(e) { return "err"; }
     return String.Empty;

Search all text responses for a list of strings and flag sessions (in OnBeforeRequest)


    // Create a array of strings we're looking for.
    var oFindStrings = new Array( "XMLHttp", "onreadystatechange", "readyState", "responseBody", "responseText", "responseXML", "statusText", "abort", "getAllResponseHeaders", "getResponseHeader", "setRequestHeader");

    // For each target string, check the response to see if it's present.
    var iEach=0;


    for (iEach; iEach<oFindStrings.length; iEach++){
        if (oSession.utilFindInResponse(oFindStrings[iEach], false)>0) { 
          oSession["ui-customcolumn"] += oFindStrings[iEach]+"; "; 
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