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http – How to pass POST data to the PHP-CGI?

Posted by: admin July 12, 2020 Leave a comment

Questions:

Update:

In a fit of desperation, I did the following in a shell:

REDIRECT_STATUS=true
SCRIPT_FILENAME=/var/www/...
REQUEST_METHOD=POST
GATEWAY_INTERFACE=CGI/1.1
export REDIRECT_STATUS
export SCRIPT_FILENAME
export REQUEST_METHOD
export GATEWAY_INTERFACE
echo "test=1" | php-cgi

…and STILL no $_POST variables are showing up in the output of this:

<?php var_dump($_POST); ?>

I am trying to create a small webserver that interfaces with the php-cgi binary. However, things aren’t going so well. The php-cgi binary correctly handles GET requests. When it comes to POST requests, the $_POST array is empty, even when things are getting POSTed.

I’ve checked the HTTP headers being fed into the php-cgi binary and they do indeed include the POST data and the Content-type: application/x-www-form-urlencoded header.

What could be keeping the php-cgi binary from seeing that there’s POST data included in the request?


I’m making progress, I’ve dug up some stuff from the PHP source code:

  • /sapi/cgi/cgi_main.c:

    468: static int sapi_cgi_read_post(char *buffer, uint count_bytes TSRMLS_DC)

(I have no idea where this function is invoked from.)


After reading the answer below, I tried:

<?php

var_dump($HTTP_RAW_POST_DATA);

?>

…which yielded the output:

NULL

…indicating that something even stranger is at work here.


I’m getting closer… I found this function in /main/php_content_types.c:

SAPI_API SAPI_POST_READER_FUNC(php_default_post_reader)

…and it seems to be the code that processes POST requests.

How to&Answers:

I finally figured it out:

Apparently the CONTENT_LENGTH environment variable needs to be set.

Adding:

CONTENT_LENGTH=6
export CONTENT_LENGTH

to my example above causes it to work properly!

Answer:

You mentioned that your system did GETs just fine. content length only needs to be set for POSTs

Also this might help, it’s the CGI/1.1 specification. It shows what environment variables need to be set:

http://graphcomp.com/info/specs/cgi11.html and this lib.ru/WEBMASTER/cgi1_1spec/interface.html

What were the minimum environment variables you needed to get GET requests working?

Answer:

Try checking the $HTTP_RAW_POST_DATA variable.

http://php.net/manual/en/reserved.variables.httprawpostdata.php