Nginx redirect to Node.js backend - node.js

Question

I want to redirect a URL e.g domain.com/api/ to a specific Node.js server, the root URL shows my website. At the moment I use this config:
server {
listen 80 default_server;
listen [::]:80 default_server;
root /var/www/html;
server_name _;
location / {
try_files $uri $uri/ =404;
}
location /api {
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;
proxy_pass http://localhost:3031/;
proxy_ssl_session_reuse off;
proxy_set_header Host $http_host;
proxy_cache_bypass $http_upgrade;
proxy_redirect off;
}
but it does not work.
What has gone wrong?
Thanks for help and best regards :)

Answer 1

You fogot closing bracket after location /api section.
Your config working at my machine.
server {
listen 80 default_server;
listen [::]:80 default_server;
root /var/www/html;
server_name _;
location / {
try_files $uri $uri/ =404;
}
location /api {
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;
proxy_pass http://localhost:3031/;
proxy_ssl_session_reuse off;
proxy_set_header Host $http_host;
proxy_cache_bypass $http_upgrade;
proxy_redirect off;
}
}
Also your nodejs backend must handle '/api' requests.

Answer 2

Please note that proxy_pass directive gets argument for backend and optional URI.
That means proxy_pass http://localhost:3031; will get the URI from the user, e.g /api/res.json so final URL for the NODE JS is: http://localhost:3031/api/res.json
But when you provide the URI to the directive itself, it overrides the requested URI in the matching location. e.g location /api and proxy_pass http://localhost:3031/; (note the suffixed slash). so the part /api is replaced by / and final URL is: http://localhost:3031/res.json.
from the NGINX docs:
If the proxy_pass directive is specified with a URI, then when a request is passed to the server, the part of a normalized request URI matching the location is replaced by a URI specified in the directive:
location /name/ {
proxy_pass http://127.0.0.1/remote/;
}
So it's important to understand that the part of the requested URI /name/ is replaced by /remote/ and then the rest of the requested URI is added to the final sent URI.