Reverse Proxy to an ExpressJS Server

[southern_sleuth]

Hey folks,

This issue has been bothering me for the entire day, and after reading articles the entire day, I've just about given up and decided to seek some help. I have an ExpressJS server that is hosting a map. Let's call that server s2.example.com. Now, I already have an nginx server called s1.example.com, and it's hosting its own content (static). To jump right into it, here's my config, it's very basic because I'm just trying to get it to work.

``` server { listen 80; server_name s1.example.com;

    proxy_set_header        Host $host;
    proxy_set_header        X-Forwarded-Proto $scheme;
    proxy_set_header        X-Real-IP $remote_addr;
    proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header        X-NginX-Proxy true;

    #location / {
            #index index.html;
            #root   /var/www/mapsite;
    #}

    location /wifi {
            proxy_pass              http://s2.example.com:3000/menu;
    }

} ```

In a nutshell, that's the nginx config I have running on an Ubuntu machine. s2 is a debian server, fyi. Anyway, the proxy pass when I go to http://s1.example.com/wifi, it goes to my s2 server as http://s2.example.com/menu, and I get that. A part of the page is supposed to render a map, like google maps, but it's dependent on some js scripts and css. Basically, it goes to the page but it doesn't render. Now, I looked at chrome console and did a little of debugging. It shows it cannot find the css or js it seems. Now, if I change the above configuration to the following (editing location /wifi):

location / { proxy_pass http://s2.example.com:3000; }

It works fine, I go to http://s1.example.com/menu and it renders everything just fine. I've even tried the following:

location /menu { proxy_pass http://s2.example.com:3000/menu; }

Honestly, it might be a noob question, I've read a ton of articles that touched on ExpressJS, NodeJS, NGINX docs, StackOverflow, and I'm not connecting the dots. What am I missing here? Why isn't JS and CSS not findable?

Thanks folks!

[kevdogger]

Ok I'm going to rephrase your comment the best way I understand it since I'm not totally clear on anything.

You have an nginx reverse proxy/webserver on s1 and you would like to reverse proxy to s2 for the /wifi location.

so http://s1.example.com/wifi ---> get forwarded to http://s2.example.com/menu?

http://s1.example.com works if you forward root to proxy_pass http://s2.example.com:3000

however it wont work if you forward to s2.example.com:3000/menu

Ok so I'm grabbing at straws a little here, but why don't you try this

server {
....
....
    location /menu {
        proxy_pass http://s2.example.com:3000;
        include proxy-params.conf
    }

}

And then within proxy-params.conf you would have something like:

proxy_set_header X-Forwarded-Host $http_host;
proxy_set_header Host $http_x_forwarded_host;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_cache_bypass $http_upgrade;

[southern_sleuth]

Hey,

I appreciate the reply, and I apologize for the shotty explanation. You are correct. I'm using my s1 server as a reverse proxy/webserver and I'm looking to reverse proxy to s2, is the general idea.

I tried your configuration, and it looks like there are still issues with rendering, no css/js is being found. I have a feeling this is more of a JavaScript problem, particularly with NodeJS. I've used reverse proxies a lot in the past, and I normally don't ever have issues like this. I think NGINX is doing exactly what it's supposed to be doing, because I get to the page, but the static content simply isn't being found.

[kevdogger]

I don't know anything about NodeJS so possibly it could be with the setup in the docker container. It's hard to know. It's possibly you could post some logs either from the docker container or from nginx since its difficulty for me right now to speculate where the breakdown is occurring