issue: rerank api does not follow openai API convention and requires full url to be put in the config

[Busboy3129]

Check Existing Issues

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• [x] I am using the latest version of Open WebUI.

Installation Method

Docker

Open WebUI Version

v0.6.36

Ollama Version (if applicable)

No response

Operating System

Linux

Browser (if applicable)

No response

Confirmation

• [x] I have read and followed all instructions in README.md.
• [x] I am using the latest version of both Open WebUI and Ollama.
• [x] I have included the browser console logs.
• [x] I have included the Docker container logs.
• [x] I have provided every relevant configuration, setting, and environment variable used in my setup.
• [x] I have clearly listed every relevant configuration, custom setting, environment variable, and command-line option that influences my setup (such as Docker Compose overrides, .env values, browser settings, authentication configurations, etc).
• [x] I have documented step-by-step reproduction instructions that are precise, sequential, and leave nothing to interpretation. My steps:
• Start with the initial platform/version/OS and dependencies used,
• Specify exact install/launch/configure commands,
• List URLs visited, user input (incl. example values/emails/passwords if needed),
• Describe all options and toggles enabled or changed,
• Include any files or environmental changes,
• Identify the expected and actual result at each stage,
• Ensure any reasonably skilled user can follow and hit the same issue.

Expected Behavior

https://github.com/open-webui/open-webui/blob/main/backend/open_webui/routers/openai.py

Actual Behavior

https://github.com/open-webui/open-webui/blob/e0d5de16978786b8a7538adf1efcde5258f38faf/backend/open_webui/retrieval/models/external.py#L19

Steps to Reproduce

put api.openai.com/v1 doesn't work put api.openai.com/v1/rerank and it works

Logs & Screenshots

> File "/app/backend/open_webui/retrieval/models/external.py", line 62, in predict
     r.raise_for_status()
     │ └ <function Response.raise_for_status at 0x7de068594180>
    └ <Response [404]>

   File "/usr/local/lib/python3.11/site-packages/requests/models.py", line 1026, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
       │         │                        └ <Response [404]>
       │         └ '404 Client Error: Not Found for url: https://api.openai.com/v1'
      └ <class 'requests.exceptions.HTTPError'>
requests.exceptions.HTTPError: 404 Client Error: Not Found for url: https://api.openai.com/v1

Additional Information

No response

[tjbck]

Should be addressed from the docs, "rerank" is not a legitimate OpenAI compatible endpoint.