FiddlerCap "Unable to write traffic to file."

[Graeme]

Hi,

I ran FiddlerCap on a customer's machine to try to debug some timeouts between our app and a web service api. It captured 82,256 sessions, of which only 1 is of interest, but I'm not sure which one yet. I went to save the capture to a file in order to inspect in Fiddler on my machine, but when I try that it says "Unable to write traffic to file." in the status bar.

Is this because I captured too many sessions? Is there a way of saving only a subset (I know the rough time of the packet that I want to inspect)?

Cheers

Graeme

[Eric Lawrence]

Hello, Graeme--

Interesting, thanks for reporting this; sadly, the logging here is bad. Did you see the error message instantly, or did it take a while (as if the failure happened midway through the save?)

You can filter down what is saved by clicking the "Details" button, selecting unwanted entries in the list, and hitting Delete.

Regards,
Eric Lawrence
Telerik

 

 

[Graeme]

It wasn't instant, but only took about 5 seconds (maybe less) to happen. I didn't know the delete button would remove sessions. I'll try to whittle it down and see if I can save it then.

Thanks!

[Graeme]

Just did it again so I can give you a more accurate time: 1.5 to 2 seconds when trying to save to the desktop with 63GB free (only little xmls in the request/responses so not likely due to a lack of disk space)

[Eric Lawrence]

Hello,

Thanks so much for the very cool bug report! This is an issue with the Zip library that FiddlerCap now uses; Fiddler doesn't have the problem.

By default, the FiddlerCap application uses DotNetZip, which has a 65535 file limit; SAZ stores 3 files per session, so the max archive you can store with FiddlerCap is 21844 sessions.

Also, another note: I never built the "bulk delete optimization" into FiddlerCap, which means that bulk deleting from the end of a huge session list is *extremely* slow (due to a bug in .NET/Windows). If you delete as many sessions from the top of the list as possible first, the process will go MUCH faster.

I will fix these issues for the next release. Thanks so much for bringing this to my attention!

Eric Lawrence
Telerik

 

 

[Graeme]

I deleted approx. half the sessions and it had the same issue, then I halved it again to leave me with 16,769 sessions and this time I could save it (took about 7 seconds).

Hopefully the sessions I managed to save will include the 1 that I'm looking for. Fingers crossed...

Thanks for that workaround.

[Eric Lawrence]

Hello, Graeme-- Thanks again for the bugs; they should be fixed in version 2.4.9.0 of FiddlerCap, now available from here: http://www.telerik.com/fiddler/fiddlercap

Regards,
Eric Lawrence
Telerik