worker_processes auto;

events {
    worker_connections 1024;
}

http {
    # Docker internal DNS IP so we always get the newer containers without having to 
    # restart/reload the docker container / nginx configuration
    resolver {{ nginx_internal_resolver }} valid=5s;
    # set the real_ip when from docker internal ranges. Ensuring our internal nginx
    # container can always see the correct ips in the logs
    set_real_ip_from 172.0.0.0/8;
    # We construct a string consistent of the "request method" and "http accept header"
    # and then apply soem ~simply regexp matches to that combination to decide on the
    # HTTP upstream we should proxy the request to.
    #
    # Example strings:
    #
    #   "GET:application/activity+json"
    #   "GET:text/html"
    #   "POST:application/activity+json"
    #
    # You can see some basic match tests in this regex101 matching this configuration
    # https://regex101.com/r/vwMJNc/1
    #
    # Learn more about nginx maps here http://nginx.org/en/docs/http/ngx_http_map_module.html
    map "$request_method:$http_accept" $proxpass {
        # If no explicit matches exists below, send traffic to lemmy-ui
        default "http://lemmy-ui:1234";

        # GET/HEAD requests that accepts ActivityPub or Linked Data JSON should go to lemmy.
        #
        # These requests are used by Mastodon and other fediverse instances to look up profile information,
        # discover site information and so on.
        "~^(?:GET|HEAD):.*?application\/(?:activity|ld)\+json" "http://lemmy:8536";

        # All non-GET/HEAD requests should go to lemmy
        #
        # Rather than calling out POST, PUT, DELETE, PATCH, CONNECT and all the verbs manually
        # we simply negate the GET|HEAD pattern from above and accept all possibly $http_accept values
        "~^(?!(GET|HEAD)).*:" "http://lemmy:8536";
    }

    server {
        set $lemmy_ui "lemmy-ui:1234";
        set $lemmy "lemmy:8536";
        # this is the port inside docker, not the public one yet
        listen 1236;
        listen 8536;

        # change if needed, this is facing the public web
        server_name localhost;
        server_tokens off;

        # Upload limit, relevant for pictrs
        client_max_body_size 20M;

        # Send actual client IP upstream
        include proxy_params;

        # frontend general requests
        location / {
            proxy_pass $proxpass;
            rewrite ^(.+)/+$ $1 permanent;
        }

        # security.txt
        location = /.well-known/security.txt {
            proxy_pass "http://$lemmy_ui";
        }

        # backend
        location ~ ^/(api|pictrs|feeds|nodeinfo|.well-known|version|sitemap.xml) {
            proxy_pass "http://$lemmy";

            # Send actual client IP upstream
            include proxy_params;
        }
    }
}