Streamlit does not work correctly behind a reverse proxy if a trailing slash is omitted

Summary

When Streamlit is behind a reverse proxy, it won’t work if a trailing slash is not included.

Steps to reproduce

Setup nginx with the following nginx.conf:

worker_processes  1;

events {
    worker_connections 1024;
}

http {
    map $http_upgrade $connection_upgrade {
        default upgrade;
        '' close;
    }

    server {
        listen 5000;
        server_name localhost;

        location /my_prefix/another {
            rewrite /my_prefix/another/(.*) /$1  break;
            rewrite /my_prefix/another /  break;
            proxy_pass http://localhost:8501;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection $connection_upgrade;
        }
    }
}

Run streamlit on localhost.

Access streamlit at http://localhost:5000/my_prefix/another

Expected behavior:

You can access Streamlit

Actual behavior:

Not able to access Streamlit. Path to static resources are broken. They miss a part of the rewrite rule:

Additional information

• Addign a trailing slash as http://localhost:5000/my_prefix/another/ fixes this problem.
• This may show up with other reverse proxy than nginx.
• A quick fix is to add a redirect rule to the address with the trailing slash.

[sorenwacker]

Same problem. Even when serving at / I just get a blank page.

[admo1]

I also have this issue when using K8s ingress.