PHP some $_POST values missing but are present in php://input

Solution 1:

PHP modifies fields containing the characters space, dot, open square bracket and others to be compatible with with the deprecated register_globals

you can find a lot of workarounds in the comments here: PHP: Variables From External Sources

For Exampe (comment by POSTer):

<?php
//Function to fix up PHP's messing up POST input containing dots, etc.
function getRealPOST() {
    $pairs = explode("&", file_get_contents("php://input"));
    $vars = array();
    foreach ($pairs as $pair) {
        $nv = explode("=", $pair);
        $name = urldecode($nv[0]);
        $value = urldecode($nv[1]);
        $vars[$name] = $value;
    }
    return $vars;
}
?>

Solution 2:

I just fixed this issue by adding a value to max_input_vars in my PHP configuration file. According to this. it was introduced in 5.3.9, yet after some package upgrades I experienced the issue in 5.3.2.

The default for max_input_vars is 1000, which was too small for my form.