FiddlerScript customization throws and error in Scriptbase.cs:919

[Alexey]

Hi, I'm trying to proxy and cache some responses that are being redownloaded over and over.

To do that I wrote this simple customization in FiddlerScript:

    static function OnBeforeResponse(oSession: Session) {


        var captureRequests = false;
        var targetHost = "api.nuget.org";
        var captureFolder = "c:\\Projects\\Fiddler\\api.nuget.org";

        // Capture traffic
        if (captureRequests && oSession.host.toLowerCase() == targetHost)
        {
            var targetFile = captureFolder + oSession.PathAndQuery.Split('?')[0].Replace('/','\\');
            oSession.oResponse["X-oSession-PathAndQuery"] = targetFile;
            var fi = new FileInfo(targetFile);
            Directory.CreateDirectory(fi.DirectoryName)
            if(!File.Exists(fi.FullName))
            {
                File.WriteAllBytes(fi.FullName, oSession.ResponseBody);
            }
        }

//      // Replay captured
        var replayRequests = true;
        if (replayRequests&& oSession.host.toLowerCase() == targetHost)
        {
            var targetFile = captureFolder +"\\" + oSession.PathAndQuery.Split('?')[0].Replace('/','\\');
            var fi = new FileInfo(targetFile);
            if(!File.Exists(fi.FullName))
            {
                oSession["x-replywithfile"] = fi.FullName;
            }

        }
    }

 

And presumably it should work - when captureRequests=true - fiddler captures requests from a particular domain into a folder, preserving path and file name

When replayRequests = true - it simply replays existing files.

The problem here that even if I just capturing the data (I suspect I may be replaying too late - fiddler would call http already by that time...) - fiddler throws a lot of errors with this text: 

---------------------------
FiddlerScript OnBeforeResponse() failed.
---------------------------
There was a problem with your FiddlerScript.

The given path's format is not supported.
   at System.Security.Permissions.FileIOPermission.EmulateFileIOPermissionChecks(String fullPath)

   at System.Security.Permissions.FileIOPermission.QuickDemand(FileIOPermissionAccess access, String fullPath, Boolean checkForDuplicates, Boolean needFullPath)

   at System.IO.FileInfo.Init(String fileName, Boolean checkHost)

   at Fiddler.ScriptNamespace.Handlers.OnBeforeResponse(Session oSession)

   at Fiddler.ScriptBase.€(Session ) in C:\JenkinsHome\jobs\FiddlerReleaseBuild\workspace\Fiddler2\Common\Application\Scripting\ScriptBase.cs:line 919
---------------------------
OK
---------------------------

 

I tried to investigate it by playing with code and identified that for some reason a typical file path like `c:\Projects\Fiddler\api.nuget.org\v3\registration1-gz\analytics\index.json` causes an error. Or that code is somehow not thread safe and competing requests simply break it (and visual studio starts them in parallel so there is a high chance of some kind of race).

Can anyone suggest what am I doing wrong here or maybe advice on better solution to the problem.

 

 

 

 

 

 

 

[Alexey]

there is a bug in the code above - 

"if file doesn't exist":

if( !File.Exists(fi.FullName) )
{
  oSession["x-replywithfile"] = fi.FullName;
}

should be "if file exists"

if( File.Exists(fi.FullName) )

I fixed it but it's not related to the problem descibed above