Nginx - location with root in other directory and PHP

Question

I tried to set a location similar as "Apache Alias" with Nginx but I don't able to process PHP script in this folder.

Here is my folder structure (for Dev environment):

/var/www
+-  dev/public/ <-- This is my normal Web root : "/"
|   +- assets/
|   |  +- app.css
|   |  +- app.js
|   |
|   +-  index.php
|   +-  favicon.png
|    
+-  cut/public/ <-- This must like an "Apache Alias" : "/cut"
    +- assets/
    |  +- app.css
    |  +- app.js
    |
    +-  index.php
    +-  other_other_file.php (why not)

I've tried different solutions but none of them are working.

Here is my best Nginx configuration :

server {
    listen   80;

    server_name _;
    root  /var/www/dev/public/;
    index index.php index.html;
    autoindex on;

    # Logs
    rewrite_log on;
    error_log /var/log/nginx/error.log;
    access_log /var/log/nginx/access.log;

    # Serving files
    location / {
        try_files $uri $uri/ @php;
    }

    location /cut {
        root /var/www/cut/public;
        try_files $uri $uri/ @php;
    }

    # PHP
    location @php {
        rewrite ^(.*)/?$ /index.php$is_args$args last;
    }

    location ~* \.php(/|$) {
        fastcgi_pass  php:9000;
        fastcgi_split_path_info ^(.+\.php)(/.*)$;
        fastcgi_param DOCUMENT_ROOT $document_root;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        include fastcgi_params;
    }
}

With this one, all the content of my cut/public/ folder is redirected to the dev/public/index.php and interpreted (cause of try_file, I presume).

That is why your help would be welcome.

Final Solution

After the answer of @richard-smith, here's the implemented solution :

server {
    listen   80;

    server_name _;
    root  /var/www/dev/public/;
    index index.php index.html;

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

    location ^~ /cut {
        rewrite ^/cut/?(.*)$ /cut/public/$1 last;
    }

    location ^~ /cut/public {
        root /var/www/;
        try_files $uri $uri/ /cut/index.php$is_args$args;

        location ~* \.php(/|$) {
            fastcgi_pass  php:9000;
            fastcgi_split_path_info ^(.+\.php)(/.*)$;
            fastcgi_param DOCUMENT_ROOT $document_root;
            fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
            include fastcgi_params;
        }
    }

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

    location ~* \.php(/|$) {
        fastcgi_pass  php:9000;
        fastcgi_split_path_info ^(.+\.php)(/.*)$;
        fastcgi_param DOCUMENT_ROOT $document_root;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        include fastcgi_params;
    }
}

Answer 1

Running two PHP applications side-by-side, you either need a common document root, or you need two location ~* \.php (or similar) blocks to ensure the correct SCRIPT_FILENAME is sent to the fastcgi backend.

Use nested location blocks to isolate the /cut subdirectory, and use the ^~ modifier at the top level to avoid other top level regular expression location blocks from interfering (see this documentation).

The alias directive (see this documentation) is used to map /cut to /var/www/cut/public. The root directive can only concatenate, which would make /var/www/cut/public/cut (which you do not want).

However, I would not recommend using the alias directive with the try_files directive because of this long term issue.

So, a solution would be to silently rewrite /cut to /cut/public and use a value of root /var/www.

For example:

location ^~ /cut {
    rewrite ^/cut(.*)$ /cut/public$1 last;
}
location ^~ /cut/public {
    root /var/www;
    try_files $uri $uri/ /cut/index.php$is_args$args;

    location ~* \.php(/|$) {
        fastcgi_pass  php:9000;
        fastcgi_split_path_info ^(.+\.php)(/.*)$;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    }
}