Call PHP from virtual/custom “web server”

Invoking a CGI script is pretty simple. PHP has a few peculiarities, but you basically only need to setup a list of environment variables, then call the PHP-CGI binary:

setenv GATEWAY_INTERFACE="CGI/1.1"
setenv SCRIPT_FILENAME=/path/to/script.php
setenv QUERY_STRING="id=123&name=title&parm=333"
setenv REQUEST_METHOD="GET"
...

exec /usr/bin/php-cgi

Most of them are boilerplate. SCRIPT_FILENAME is how you pass the actual php filename to the PHP interpreter, not as exec parameter. Crucial for PHP is also the non-standard variable REDIRECT_STATUS=200.

For a GET request you only need the environment variables. For a POST request, you simply pipe the HTTP request body as stdin to the executed php-cgi binary. The returned stdout is the CGI response consisting of an incomplete HTTP header, \r\n\r\n, and the page body.

(Just from memory. There maybe a few more gotchas.)

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