Fiddler showing browser WebSockets, but not showing windows win32 app WebSocket connections?

[Navjot]

Hi,

 

I am trying to capture WebSocket connection of an app in windows (Win32).

I also created a test app with websocketsharp and connected to ws://echo.websocket.org and unfortunately this was not captured in fiddler.

Any help?

 

Fiddler version: v5.0.20194.41348 for .NET 4.6.1
Built: Thursday, October 3, 2019

[Navjot]

Fiddler showing browser WebSockets, but NOT* showing windows win32 app WebSocket connections?

[Eric R | Senior Technical Support Engineer]

Hi Navjot,

Generally, Fiddler is a HTTP(S)/WebSocket proxy and doesn't visualize socket traffic that doesn't use those protocols. Typically, the traffic that can be captured is using the WinINET networking stack. See the Proxy documentation for more details.

However, if the win32 app doesn't rely on WinINET and uses WinHTTP instead, it may be possible to capture traffic as shown in the Using Fiddler with WinHTTP blog post.

I hope this helps. Please let me know if you need any additional information. Thank you for using the Fiddler Forums.

Regards,

Eric R | Senior Technical Support Engineer
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[Navjot]

Unfortunately, it didn't worked.

 

You can also test out by making a simple websocketsharp c# application.

[Eric R | Senior Technical Support Engineer]

Hi Navjot,

In order to capture traffic, the client should pass through the Fiddler Proxy endpoint, e.g., WinINET/WinHTTP or localhost:8888. Once the proxy information is set, the WebSocketSharp Example will capture. See the below code snippet and line number for reference.

Additionally, Fiddler can also capture the same traffic using http://websocket.org/echo.html in the browser. For reference, I have attached a short video displaying the results from the browser. 

Please let me know if you need any additional information. Thank you for using Fiddler. 

Regards,

Eric R | Senior Technical Support Engineer
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