Nginx Use As Application Remapper

This text provides detailed instructions on configuring Nginx for tasks like authentication, debug logging, port remapping, and CORS error handling. It explains geo-based access rules and basic HTTP authentication with code examples.

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for more accurate results, use nginx-geoip2

to disable access by ip origin while exclude certain ranges, you can do this:

apt install -y libnginx-mod-http-geoip libgeoip

http {
geoip_country /usr/share/GeoIP/GeoIP.dat;
geoip_proxy <internal_ip_ranges>;
geo $external_ip {
default 1;
<custom_exclusion_range> 0;
}
log_format geologfmt '$remote_addr - $remote_user <$geoip_country_code> [$time_local] '
'"$request" $status $body_bytes_sent '
'"$http_referer" "$http_user_agent"';
access_log /var/log/nginx/access.log geologfmt;
}
server {
# boolean operator in nginx
# better do this with njs instead
set $a 0;
set $b 0;
if ($geoip_country_code != "<YOUR_COUNTRY_CODE>"){
set $a 1;
}
if ($external_ip){
set $a 1$a;
}
if ($a = 11){
set $b 1;
}
if ($b){return 444;}
}

remember to restart nginx service afterwards

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enable http basic auth

sudo htpasswd -c /etc/nginx/passwd <username>

server {
auth_basic "<auth_window_title>";
auth_basic_user_file passwd;
}

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Run nginx with debug info:

# within /etc/nginx/nginx.conf
http {
access_log /var/log/nginx/access.log debug;
error_log /var/log/nginx/error.log debug;
}

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Remap a range of ports to suburl:

location ~ /server/(1[0-9][0-9][0-9][0-9]) {
proxy_pass http://localhost:$1/;
}

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To handle CORS errors, one can write:

location /api/ {
# add_header Access-Control-Allow-Origin *;
add_header Access-Control-Allow-Origin $http_origin;
add_header 'Access-Control-Allow-Headers' 'Content-Type';
if ($request_method = OPTIONS) {
add_header Access-Control-Allow-Origin *;
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
add_header 'Access-Control-Allow-Headers' 'Content-Type, x-requested-with';
add_header 'Access-Control-Max-Age' 1728000;
add_header 'Content-Type' 'text/plain; charset=utf-8';
return 204;
}
proxy_pass http://localhost:7861/;
# proxy_set_header X-Forwarded-Prefix /api;
sub_filter "openapi.json" "api/openapi.json";
# sub_filter "SwaggerUIBundle({" "SwaggerUIBundle({ basePath: '/api', 'servers': [{url:'/api'}],";
sub_filter "static-offline-docs" "api/static-offline-docs";
sub_filter_once off;
}

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After installing nginx, a default page is created under /var/www/html and config files are at /etc/nginx.

Run sudo systemctl restart nginx after config modification.

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Edit the file at /etc/nginx/sites-available/default:

server {
listen 80;
server_name localhost;
location /app1 {
proxy_pass http://localhost:8000;
}
location /app2 { # websocket support
proxy_pass http://localhost:8001;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_set_header Origin ""; // to prevent unwanted 403
}
}

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If you want to route FastAPI docs to nginx, you have to rewrite contents.

server {
location /vllm/openapi.json {
proxy_pass http://localhost:8000/openapi.json;
sub_filter "\"paths\"" "\"servers\": [{\"url\": \"/vllm\"}], \"paths\"";
sub_filter_types application/json;
}
location /vllm/ {
proxy_pass http://localhost:8000/;
sub_filter "openapi.json" "vllm/openapi.json";
sub_filter_once off;
}
}