Correct proxy configuration for nginx server to access rest api - nginx

Question

I have a nginx-server configured as follows:
server {
listen 3000;
listen [::]:3000;
server_name .+;
add_header Strict-Transport-Security "max-age=15552000; includeSubDomains" always;
...
index index.html;
root /usr/share/nginx/html;
location /cam/ {
proxy_pass http://cam:8000/;
}
location /api {
proxy_pass https://some_ip:some_port;
proxy_pass_request_headers on;
proxy_set_header X-API-KEY xxxxx;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "Upgrade";
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Forwarded-Host $server_name;
proxy_ssl_server_name on;
}
location /share/ {
alias /usr/src/share;
}
location / {
try_files $uri $uri/ /index.html;
}
add_header 'Access-Control-Allow-Origin' '*' always;
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS' always;
add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range' always;
client_max_body_size 1M;
keepalive_timeout 10;
}
For displaying my frontend, this configuration works fine. The proxy for the cam is also working correctly.
I am getting problems in the configuration of the proxy for the api. The api has a sanity-check under "https://some_ip:some_port", which just returns "200: ok". Otherwise I should be able to make request using a fetch request such as
const res = await fetch(`api/subaddress/${system_id.toString()}/base`, {
method: 'POST',
headers: {
'Content-type': 'application/json',
'X-API-KEY': xxxxx,
'Access-Control-Allow-Origin': '*',
'Access-Control-Allow-Methods': 'HEAD, GET, POST, PUT, PATCH, DELETE',
'Access-Control-Allow-Headers': 'Origin, Content-Type, X-Auth-Token'
},
body: JSON.stringify(data_body),
});
Which, if successfull, returns "202: ok".
If I make such a request using curl, it works just fine (both of the requests), so the api should not be the problem.
At the current configuration, I get a "200: ok", which tells me that I have connected to the api, but the proxy does not take in account my subaddresses.
Besides the given configuration, I tried the following:
location /api {
proxy_pass https://some_ip:some_port$request_uri;
...
}
which always gives me "502: bad gateway"
location /api/ {
proxy_pass https://some_ip:some_port/;
...
}
which always gives me "403: forbidden"
location /api {
rewrite ^/api/(.*) /$1 break;
proxy_pass https://some_ip:some_port/$1;
...
}
which causes nginx to crash, as it tells me that it cannot resolve it. I would like to avoid using a resolver, unless definitly necessary (I have tried it using a resolver before too and it did not work either).
What is the correct way to accomplish this?

Answer 1

I solved this. Apparently the 403: forbidden was caused my some of the configurations of the proxy. After removing those, I did not get that error anymore.
In the end I used
location /api {
rewrite ^/api/(.*) /$1 break;
proxy_pass https://some_ip:some_port/$1;
...
}
which I made work by putting
resolver 1.1.1.1 valid=30s;
at the top of the configuration file.