How to Properly Access JSON POST Data in PHP?

Accessing POST Data in PHP: Decoding JSON Body

In PHP, handling POST requests requires accessing the request body to extract submitted data. When receiving a JSON-encoded body, it's important to use the appropriate approach to retrieve the desired information.

JSON Extraction

To access the JSON data in the POST body, do not rely on $_POST. Instead, use file_get_contents('php://input'):

$json_input = file_get_contents('php://input');
$data = json_decode($json_input, true);

This reads the raw POST body as a string, which is then decoded into a PHP array using json_decode().

Handling multipart/form-data

If your POST request has multipart/form-data encoding, the data will be parsed automatically into the $_POST superglobal. However, note that you cannot access the raw JSON body using php://input in this case.

Example

For example, if you submit a POST request with the following JSON body:

{"a": 1}

Your PHP code can decode it as follows:

$json_input = file_get_contents('php://input');
$data = json_decode($json_input, true);

var_dump($data['a']); // Outputs: 1

Note on Seekability

php://input is not seekable, meaning it can only be read once. If you need to preserve the stream for multiple read operations, consider constructing a temporary stream using stream_copy_to_stream() or using php://temp for better memory management.

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