Nginx Virtual Host Example with Directory Alias

default.conf

server {
    listen  80;

    root /var/www/html;
    index index.nginx-debian.html index.html index.htm index.php;

    access_log off;
    error_log  /var/log/nginx/error.log error;

    charset utf-8;

    location / {
        try_files $uri $uri/ /index.php$is_args$args;
    }

    location /auth {
        alias /var/www/html/application/auth/public;
        try_files $uri $uri/ @auth;

        location ~ \.php$ {
            include fastcgi_params;
            fastcgi_param SCRIPT_FILENAME $request_filename;
            fastcgi_pass unix:/var/run/php/php7.2-fpm.sock;
        }
    }

    location @auth {
        rewrite /auth/(.*)$ /auth/index.php?/$1 last;
    }

    location /backend {
        alias /var/www/html/application/backend/public;
        try_files $uri $uri/ @backend;

        location ~ \.php$ {
            include fastcgi_params;
            fastcgi_param SCRIPT_FILENAME $request_filename;
            fastcgi_pass unix:/var/run/php/php7.2-fpm.sock;
        }
    }

    location @backend {
        rewrite /backend/(.*)$ /backend/index.php?/$1 last;
    }    

    location = /favicon.ico { access_log off; log_not_found off; }
    location = /robots.txt  { access_log off; log_not_found off; }

    sendfile off;

    add_header 'Access-Control-Allow-Origin' '*';
    add_header 'Access-Control-Allow-Headers' '*';
    add_header 'Access-Control-Allow-Methods' 'GET, POST, PUT, DELETE, OPTIONS';

    client_max_body_size 100m;

    location ~ \.php$ {
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_pass unix:/var/run/php/php7.2-fpm.sock;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_intercept_errors off;
        fastcgi_buffer_size 16k;
        fastcgi_buffers 4 16k;
    }

    location ~ /\.ht {
        deny all;
    }
}