A way to modify headers like host as in nginx

[ankit-sapkota]

Is there a way to modify headers like host?

Let's say I have a Web server running at 3000 and I want to use this reverse proxy to pass requests received at localhost:8005. But I need the host header to be localhost:3000 as it is required by the web server. How can I achieve this.

There does not seem to be a function to modify any thing. Am I missing something here? Or is it not yet supported ?

[WSH032]

Hi @ankit-sapkota555 .

Is there a way to modify headers like host?

Have you read https://wsh032.github.io/fastapi-proxy-lib/Usage/Advanced/#modify-request ? Does it meet your needs?

newest link: https://www.python-httpx.org/advanced/authentication/#custom-authentication-schemes

---

I'm not sure if I understand your meaning correctly. Do you mean that there is a server running on port 8005, and you want to forward all requests received on port 8005 to port 3000?

And you want the requests received on port 3000 to have a request header with host: "localhost:3000" ?

Actually, this library will automatically modify the corresponding host for you, which follows common HTTP standards.

fastapi-proxy-lib/src/fastapi_proxy_lib/core/_tool.py

Line 459 in 7e3d4a7

new_headers["host"] = target_url.netloc.decode("ascii")

Have you encountered any specific errors while using it? Let me know, and perhaps I can help resolve it.

[ankit-sapkota]

Yes this follows common HTTP standards, but what I need is to forward all requests in port 8005 to 3000, but the web server expects the host header to be localhost:3000 (For my specific use case), So, to test that the proxy gateway will work as expected upon deployment, I need to modify the host header. Just curious if this is achievable through this package.

I will look into the docs refs and let you konw if they cover my use case. Thanks for the reply.

[WSH032]

Just curious if this is achievable through this package.

Of course. Refer to the following code:

import httpx
from fastapi_proxy_lib.fastapi.app import reverse_http_app

class MyCustomAuth(httpx.Auth):

    def auth_flow(self, request: httpx.Request):
        # whatever you want to do with the headers of the request
        request.headers["host"] = "localhost:3000"
        yield request

app = reverse_http_app(
    client=httpx.AsyncClient(auth=MyCustomAuth()),
    base_url="http://localhost:3000/",
)

Please let me know if it works for you.

[WSH032]

In fact, regardless of the request headers received on port 8005, the requests forwarded to port 3000 will always have "host": "localhost:3000". This functionality is available out of the box, so it's quite likely that you don't need to do anything.