CODEWITHSUNDEEP
nginxfastapinginx-reverse-proxy
Robert McKay
Robert McKay

Reputation: 89

Nginx proxy redirect with FastAPI routers

I am attempting to develop a web app with nginx and fastapi and react. These are all new to me.

Regarding the fastapi, I have a main FastAPI that has a login route. I have added additional routes with APIRouter class and FastAPI.include_router method. I refered to this documentation

Development setup

Everything works as expected and the axios calls return correct response.

Production setup

I based the following nginx conf file on this documentation

# conf file for server

# proxy pass for api requests
upstream api {
    server backend;
}

# main server for app
server {
    listen       80;
    server_name  localhost;

    access_log /var/log/nginx/frontend;
    error_log /var/log/nginx/frontend;

    location / {
        root   /usr/share/nginx/html;
        index  index.html index.htm;
        try_files $uri $uri/ /index.html;
    }

    location /api {
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-Host $server_name;
        proxy_redirect off;
        proxy_pass http://api;
    }

    #error_page  404              /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }
}

Note that I am using docker compose and have a backend service and a frontend service. With this configuration the login route works correctly, but the routes added via FastAPI.include_router return HTTP 307 redirect and the response header shows requested url as http://api/api/path/to/route instead of http://localhost/api/path/to/route. So it appears that nginx successfully proxy passes requests for a route directly in the main fastapi app module but redirects to the wrong url for requests to routes added with app.include_router. According to this reference, I should have proxy_redirect off; in the /api location block, but if I remove this line, then nginx redirects the request and returns the correct response.

question

Upvotes: 5

Views: 2474

Answers (1)

JBM
JBM

Reputation: 5

I think the issue might not be with Nginx, but with how FastAPI handles trailing slashes

If you define the routes as "api/route/" and try to reach "api/route", FastAPI will attempt to redirect to "api/route/" (and vice-versa for "api/route" and "api/route/")

You can disable this behaviour with a flag in FastAPI

app = FastAPI(redirect_slashes=False)

Nginx proxy redirect with FastAPI routers

https://fastapi.tiangolo.com/reference/fastapi/#fastapi.FastAPI--example

Upvotes: 0

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