怎样配置干净的 PHP 接口链接？ How to configure Nginx to have clean PHP API URL?

不好意思，因为在公司写英文，所以以下问题是用英文写的。

Configuration 1:

server {
  index index.html index.php

  location / {
    try_files $uri $uri/;
  }

  location ~ [^/]\.php(/|$) {
    fastcgi_pass unix:/dev/shm/php-cgi.sock;
    fastcgi_index index.php;
    include fastcgi.conf;
  }
}

Configuration like the above (Configuration 1) will return 500 Internal Server Error when visiting ...domain.../20170223, ...domain.../20170223/ but not ...domain.../20170223/index.php.

So I am think try_files is executed before index and then cause a internal redirect loop thus 500 Server Internal Error because if index runs first then .../20170223/ should works just fine while in fact is not.

But

Configuration 2:

server {
  index index.html index.php

  location / {
    try_files $uri $uri/ =404;
  }

  location ~ [^/]\.php(/|$) {
    fastcgi_pass unix:/dev/shm/php-cgi.sock;
    fastcgi_index index.php;
    include fastcgi.conf;
  }
}

works for all ...domain.../20170223, ...domain.../20170223/ and ...domain.../20170223/index.php.

Which leads me to think when try_files is encountered with folder URI like .../20170223/ it makes an internal redirect. But contradiction is if try_files runs before index, it will be a redirect loop which is not true in this practice.

Then there is again not clue which one (try_files or index) runs first.

To exclude the position of index directive problem, the following configuration 3 & 4 are tested with same result as Configuration 1.

Configuration 3:

server {

  location / {
    index index.html index.php
    try_files $uri $uri/;
  }

  location ~ [^/]\.php(/|$) {
    fastcgi_pass unix:/dev/shm/php-cgi.sock;
    fastcgi_index index.php;
    include fastcgi.conf;
  }
}

Configuration 4:

server {

  location / {
    try_files $uri $uri/;
    index index.html index.php
  }

  location ~ [^/]\.php(/|$) {
    fastcgi_pass unix:/dev/shm/php-cgi.sock;
    fastcgi_index index.php;
    include fastcgi.conf;
  }
}

And there comes my problem.

The Configuration 2 doesn't receive POST data from a <form> submit when action is assigned with ...domain.../20170223 but works for ...domain.../20170223/ and ...domain.../20170223/index.php.

So why??? Does internal redirect lost POST data? Does try_files append index.php to folder uri according to index first and then make a redirect? In the different words for same meaning, does try_files make redirect but index never make redirect? Is index a dictionary for try_files whose default value is just try_files $uri =404; (this assumption still didn't explain for Configuration 1 practice)?

No idea according to the following official documents:

[Official] index, https://nginx.org/en/docs/http/ngx_http_index_module.html
[Official] try_files, http://nginx.org/en/docs/http/ngx_http_core_module.html#try_files

with the summary:

index processes requests ending with the slash character (‘/’), and note that using an index file causes an internal redirect, and the request can be processed in a different location (for instance, a “/” request may actually be processed in a second location as “/index.html ”.).
try_files has specified ordered file lists and uri or =code at last, if none of the files were found, then an internal redirect to the uri specified in the last parameter is made. (Notice: only the last part is internal redirect, the ones ahead are all served directly by Nginx as static files.)

And is there any solve to have a clean post action url without tailing slash /?