How should a FastAPI service handle forwarded headers and a stripped proxy path?

Trusts proxy-derived scheme, host, and client data only from known hops and configures externally visible paths correctly.

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A reverse proxy may terminate TLS and forward the request to Uvicorn over HTTP, so the application needs trusted forwarded headers to reconstruct the external scheme, host, and client address. I configure which proxy addresses are trusted rather than accepting those headers from every caller. If the proxy removes a path prefix, FastAPI's root_path tells routing and OpenAPI generation about the externally visible base path.

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Trusts proxy-derived scheme, host, and client data only from known hops and configures externally visible paths correctly.

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Trusts proxy-derived scheme, host, and client data only from known hops and configures externally visible paths correctly.
A reverse proxy may terminate TLS and forward the request to Uvicorn over HTTP, so the application needs trusted forwarded headers to reconstruct the external scheme, host, and client address. I configure which proxy addresses are trusted rather than accepting those headers from every caller. If the proxy removes a path prefix, FastAPI's root_path tells routing and OpenAPI generation about the externally visible base path.
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These settings affect redirects, absolute URLs, secure-origin logic, logs, and the OpenAPI server URL. A wrong trust boundary lets a direct client spoof its IP or host, while a missing root path makes docs and generated links point to routes that do not exist externally. Host validation remains separate from proxy trust. I test both the public proxy route and any internal route that can reach the application.

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Trusting forwarded headers from any source
Using root_path as URL rewriting middleware
Assuming host validation and proxy trust are the same

How should a FastAPI service handle forwarded headers and a stripped proxy path?

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