Why are some $_POST values missing in PHP and how can I fix it?

Missing $_POST Values in PHP

When submitting an HTML form via POST request, it's expected that all submitted values will populate the $_POST superglobal. However, in some cases, certain values may be missing.

What Causes the Missing Values?

PHP automatically modifies values containing specific characters (e.g., space, dot, open square bracket) to ensure compatibility with the deprecated register_globals feature. This modification can lead to values being omitted from $_POST.

Solving the Issue

To resolve this issue, various workarounds can be employed. One popular method is to read the raw POST data using file_get_contents('php://input') and manually parse it to extract the missing values.

Below is an example function that can be used to "fix" the $_POST values:

<code class="php">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;
}</code>

By using this function or similar workarounds, you can ensure that all submitted values are correctly parsed and available in the $_POST array.

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