Hi, Here is a brief guide to setup PyCharm to send its traffic generated by requests through Fiddler.
Usage: If you get errors while implementing an extracted protocol from a Fiddler traces, you can forward the traffic to Fiddler, so that you can check the captured traces against the traffic generated from PyCharm to debug your code. For example, you can solve issues when receiving Code 422 in response.
Running PyCharm Traffic through Fiddler
First, you need to update proxy settings at PyCharm with Fiddler proxy details. This will ask to install Fiddler generated certificates at PyCharm. However, this step only allows PyCharm to direct it’s traffic to Fiddler, but your python code fails since this setting does not apply to urllib3 used by requests. Hence, we have to bypass certificate verification in the code.
Step 1: Add Fiddler Generated Certificates to PyCharm
- At PyCharm IDE Goto -> File -> Settings ->Appearance & Behaviour -> System Settings -> HTTP Proxy -> Provide Fiddler proxy settings as follows (Host: 127.0.0.1, Port: 8888)
- Restart PyCharm -> It will prompt to Accept the Fiddler generated certificates for JetBrains.
- You can check the saved certificates at File -> Settings ->Tools-> Server Certificates
Step2: Update Python Code
In the python code, I’m using requests package to send HTTPS requests. Update the request with an additional argument as verify=False. Otherwise, it will throw an verification failed exception (ssl.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:646))
initResponse = requests.get(initURL, params=initParams, headers=headerInit,verify=False)
Now, it will only give a warning (InsecureRequestWarning: Unverified HTTPS request is being made to host ‘127.0.0.1’. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.io/en/latest/advanced-usage.html#ssl-warnings
InsecureRequestWarning,) and pass the code. Assuming you are aware of the security of the URL you are visiting, this can help you forward PyCharm traffic through Fiddler without much hassle.
Cheers ! 🙂
Hi, When setting up an Android device with Fiddler on the host machine, you need to set up proxy settings on Android Wi-Fi giving the IP address shown on Fiddler (Online) as host and port as 8888. After that, you need to visit http://ipv4.fiddler:8888 on your browser to download the Fiddler Root Certificate. However, when visiting the http://ipv4.fiddler:8888 on the Android browser, you might get ERR_CONNECTION_ TIMED_OUT. This could be due to many reasons.
Reasons and Solutions:
- If you are connecting your Android with Fiddler for the first time recheck the settings on Fiddler. Goto -> Tools -> Options -> Connection -> Tick “Allow remote computers to connect”. To allow HTTPS decryption, ensure you have ticked “Decrypt HTTPS traffic” under Options-> HTTPS, and then install the root certificate.
- If you are trying to reconnect you Android with Fiddler which was working with a different host, and now getting ERR_CONNECTION_ TIMED_OUT on the Android browser,
- You can first try removing current certificates on the Fiddler host machine and try reinstalling the certificates..
- First, Goto -> Tools -> Options -> HTTPS-> Untick “Decrypt HTTPS traffic”.
- Then, select ‘Actions’ on the same dialog -> select “Remove interception certificates”
- Then follow the normal procedure to enable HTTPS traffic decryption
- The ultimate try is to uninstall and reinstall the Fiddler from the beginning on your host machine. After that, your Android browser can visit http://ipv4.fiddler:8888 and download a new Fiddler Root Certificate.
Even after successfully installing the Fiddler root certificate on your Android device, if you are not able to capture the HTTTPS traffic. It might be that you are using an older fiddler root certificate or a certificate you installed when working with a different Fiddle r host machine. Hence, remove the current installed certificate from your android device. After that, try reconnecting with the Fiddler host to reinstall the new root certificate.
rm < current root certificate e.g. e5c3944b.0>
In the worst case It may be due to certificate pinning used in the application you are trying to test. In that case, you may have to use an instrumentation tool like Xposed to bypass such conditions.
Cheers ! 🙂