Could a custom url be used to call Gemini api?

[RythmOfLight]

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1. Is this request related to a challenge you're experiencing? Tell me about your story.

Gemini does not support my area of residence, and I am relaying my requests with Netlify to get around it, which means I usually substitute the usual google api call url with another url determined by Netlify.

However, filling in my Netlify url to Gemini’s “base url” input box in Dify results in the error message "Error -3 while decompressing data: incorrect header check". I am unsure whether this is due to a problem in my input, or if this input box is for some different purpose that I do not realize.

2. Additional context or comments

• I lack the common knowledge related to AI services and the related tools, so this could potentially be due to stupid reasons.
• My Netlify is deployed with Docker.
• This Netlify url works for some other tools and for direct calls using Gemini's Python library.
• My Gemini plugin is version 0.7.4.
• Using a VPN to access Gemini's own default API url (leaving the base url empty) works as intended.

I spent a few days trying to read the source code and figure out what the api call structure would be, but was proved to be incapable of that. I was also unable to find related discussion online, so it appears that I am currently in desperate need of assistance. Thanks in advance to any responders.

[dosubot[bot]]

Hi @RythmOfLight! I'm Dosu and I’m helping the dify team.

Yes, Dify's Gemini plugin does support using a custom base URL (like a Netlify relay) starting from version 0.5.4. However, the error "Error -3 while decompressing data: incorrect header check" usually means the proxy/relay isn't returning responses in the exact format or encoding (such as gzip, deflate, or br) that Dify expects from the native Gemini API. Dify's plugin sets the Accept-Encoding header and expects the endpoint to honor it—if your relay returns plain text or a different encoding, you'll get decompression errors like this¹².

To troubleshoot: use a tool like curl or Postman to call your Netlify URL and inspect the response headers and body. Make sure the Content-Encoding and Content-Type headers match what Gemini's API would return, and that the body is encoded as expected. If your relay can't fully mimic the native Gemini API (including compression and response structure), Dify may not work with it.

As an alternative, you can set HTTP proxy environment variables (like http_proxy and https_proxy) in your dify-api service to route requests through a proxy, which is often more reliable for regional workarounds³.

To reply, just mention @dosu.

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Footnotes

1. Dify Gemini plugin PR for custom base URL ↩

2. Dify plugin request encoding and decompression handling ↩

3. Proxy workaround discussion ↩

[RythmOfLight]

It appears that the proxy returns a "content-encoding" header that indicates a zip file while the content is plain text. One unconfirmed possibility is that netlify automatically unpacked whatever was fetched from google, and the script I was using did not account for that. Either way, this was resolved by deleting that header.