Nginx Configuration with multiple port apps on same domain, with SSL.

nginx-ssl-config

# the IP(s) on which your node server is running. I chose port 3000.
upstream app_geoforce {
    server 127.0.0.1:3000;
}

upstream app_pcodes{
    server 127.0.0.1:3001;
}

#Point http requests to https
server {
    listen 0.0.0.0:80;
    server_name sub.domain.org;
    server_tokens off;
    return 301 https://$host$request_uri;
}

# the secure nginx server instance
server {
    listen 443 ssl;
    ssl_certificate /etc/nginx/ssl/public.crt;
    ssl_certificate_key /etc/nginx/ssl/private.rsa;

    server_name sub.domain.org;
    access_log /var/log/nginx/myapp.log;
    error_log /var/log/nginx/myapp_error.log;
    # pass the request to the node.js server with the correct headers and much more can be added, see nginx config options

    location /favicon.ico { alias /home/ubuntu/img/favicon_rc.ico; }

    location / {
      # auth_basic "Restricted";
      # auth_basic_user_file /home/ubuntu/app/.htpasswd;
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header Host $http_host;
      proxy_set_header X-NginX-Proxy true;
      proxy_set_header X-Ssl on;

      proxy_pass https://app_geoforce;
      proxy_redirect off;
    }

    location /pcodes/ {
      rewrite /pcodes/(.*)$ /$1 break;

      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header Host $http_host;
      proxy_set_header X-NginX-Proxy true;
      proxy_set_header X-Ssl on;

      proxy_pass https://app_pcodes;
      proxy_redirect off;
    }
 }

I created a config file that looks like this:

# For more information on configuration, see:
#   * Official English Documentation: http://nginx.org/en/docs/
#   * Official Russian Documentation: http://nginx.org/ru/docs/

user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;

# Load dynamic modules. See /usr/share/nginx/README.dynamic.
include /usr/share/nginx/modules/*.conf;

events {
    worker_connections 1024;
}

http {
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 2048;

    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;

    # Load modular configuration files from the /etc/nginx/conf.d directory.
    # See http://nginx.org/en/docs/ngx_core_module.html#include
    # for more information.
    include /etc/nginx/conf.d/*.conf;

    # the IP(s) on which your node server is running. I chose port 3000.
    upstream app_edafos {
        server 127.0.0.1:3000;
    }

    #Point http requests to https
    server {
        listen 0.0.0.0:80;
        server_name edafos.eng.yorku.ca;
        server_tokens off;
        return 301 https://$host$request_uri;
    }

    server {
        listen 443 ssl;
        server_name edafos.eng.yorku.ca;
        ssl_certificate /etc/letsencrypt/live/edafos.eng.yorku.ca/fullchain.pem; # managed by Certbot
        ssl_certificate_key /etc/letsencrypt/live/edafos.eng.yorku.ca/privkey.pem; # managed by Certbot
        include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
        ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
        ssl_session_cache shared:SSL:1m;

        root /var/www/Interface-2.0/Client/dist;     
        index index.html;
        server_name edafos.eng.yorku.ca;
        
        location / {
            try_files $uri /index.html;
            error_page 405 = $uri;
        }

        location /api/ {
            rewrite /api/(.*)$ /$1 break;

            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Host $http_host;
            proxy_set_header X-NginX-Proxy true;
            proxy_set_header X-Ssl on;

            proxy_pass https://app_edafos;
            proxy_redirect off;
        }

        error_page 404 /404.html;
            location = /40x.html {
        }

        error_page 500 502 503 504 /50x.html;
            location = /50x.html {
        }
    }
}

Everything seems to be working fine except for when I try to access the back-end api in the location /api/ block to redirect the traffic to port 3000 in the localhost. In that case, I get a 404 error and I can see in Firefox's debugging tools that NGINX returns its 404 page.
When I try to access that back-end API the URL looks like this: https://edafos.eng.yorku.ca/api/example
Does anyone here know what I could do to fix the problem?

UPDATE: my project is a MERN application where the front-end is served on port 80 and the back-end is redirected to localhost:3000. If my theory is correct, the problem in my config file is the root. Therefore, when I type in https://edafos.eng.yorku.ca/api/example it will try to redirect me to /var/www/Interface-2.0/Client/dist/api/example which obviously does not exist and returns me error 404. Can anyone confirm my thinking is right and, if it is, propose a fix?

this case ? how
mysite.com:3300
Help me guys

Had trouble getting location /first_game/ to work until i wrote the reqwrite part thanks!

rewrite /intra/(.*)$ /$1 break;

This is the line i was missing. ty you sage.

thanks! the rewrite line saved my day!

The rewrite line is the key!

This has helped me solving a BIG issue i was facing for CORS issue for Odoo backend server. Thanks a lot! 👍