In what scenarios is it recommended to include the Content-Length header in PHP responses and when can it be omitted for better performance?

Including the Content-Length header in PHP responses is recommended when you need to specify the exact length of the response body. This is important for certain protocols or when the client needs to know the total size of the response before processing it. However, in scenarios where the response is dynamically generated and the exact length is unknown or can vary, omitting the Content-Length header can improve performance by allowing the response to be sent in smaller chunks or using chunked encoding. 

<?php
// Include Content-Length header
header('Content-Length: ' . strlen($responseBody));

// Omit Content-Length header for better performance
// header('Transfer-Encoding: chunked');

// Send response body
echo $responseBody;
?>

Keywords

Content-Length header PHP responses performance scenarios omitting

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