nginx HTTP configuration for SPA, with reverse proxy for API

default.conf

# Typically I use this file as a boilerplate to configure an nginx docker container
#
# This goes in /etc/nginx/conf.d/default.conf

# If you are reverse proxying an API
upstream api {
    server API_SERVER_GOES_HERE:port;
}

server {
    listen 80; // SSL is not configured, but would be configured here

    # If you are proxied, and the proxy doesn't support URL re-writing, A rewrite rule can be added here
    # rewrite ^REWRITE_URL_GOES_HERE(.*)$ /$1;
    
    location / {
        root /usr/share/nginx/html;

        # This is due to nginx and the try_files behavior below, it will always
        # try to hit the index as part of try_files.  If I set index as something
        # that doesn't resolve, we don't have to worry about index.html being cached.
        #
        # If frequent updates occur, it's important that index.html not be cached 
        # in the browser.  Otherwise the software update will only occur when the
        # cached page expires.  The If-Modified-Since is a better way to handle this
        # for SPAs with frequent updates.
        index unresolvable-file-html.html;

        try_files $uri @index;
    }

    # This seperate location is so the no cache policy only applies to the index and nothing else.
    location @index {
        root /usr/share/nginx/html;
        add_header Cache-Control no-cache;
        expires 0;
        try_files /index.html =404;
    }
    
    location /api/ {
        proxy_set_header X-Forwarded-For $remote_addr;
        proxy_set_header Host $http_host;
        # If you have any long running API calls, the read timeout needs to be increased here
        # proxy_read_timeout 120s;
        proxy_pass http://api/;
    }
}