How to remove http header information in php? Brief analysis of methods

PHP is a very popular server-side language with many practical functions. One of the common requirements is to remove HTTP header information. HTTP headers are information included at the beginning of an HTTP request or response. It contains a lot of useful data, such as: response status, server type, date, cookies, etc.

However, sometimes we need to remove the HTTP header information in the PHP program. This may be because we need to download a large file quickly, or handle some complex requests in the program. Whatever the reason, here are some ways to remove HTTP header information:

Method 1: Use PHP built-in function header()

PHP provides a popular built-in function header() HTTP headers can be sent. We can use the header() function to send a blank HTTP header to remove all HTTP header information. The code is as follows:

header('Content-Type: ');
header('Content-Disposition: attachment; filename=file.zip');
header('Content-Length: ' . filesize($file));
readfile($file);

This code will output a blank Content-Type header, Content-Length header and Content-Disposition header. Next, use the readfile() function to read the content from the file and output it.

Method 2: Use cURL library

cURL is a popular client library in PHP, which can be used to send HTTP requests and get responses. By using the cURL library, we can send an HTTP HEAD request to get only the metadata of the file and not the actual content.

$ch = curl_init('http://example.com');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HEADER, true);
curl_setopt($ch, CURLOPT_NOBODY, true);
$response = curl_exec($ch);
$header_size = curl_getinfo($ch, CURLINFO_HEADER_SIZE);
$header = substr($response, 0, $header_size);
curl_close($ch);
echo $header;

In this code, we first create a cURL handle using the curl_init() function and pass in the URL. Then we set a few options to tell cURL that we only want to get HTTP header information. When executing the curl_exec() function, cURL will send an HTTP HEAD request and return a response. We get the HTTP header information from the response and output it.

Method 3: Use Apache’s mod_headers module

If you are using Apache as a web server, you can use its mod_headers module to directly modify HTTP headers. This requires that you have permission to edit Apache's configuration files. Add the following code to the httpd.conf file:

   Header unset Server
   Header unset X-Powered-By
   Header unset Transfer-Encoding
   Header unset Content-Length

This code will match all index.php files and remove four HTTP headers: Server, X-Powered-By, Transfer-Encoding and Content -Length.

Summary

Whether using PHP’s header() function, cURL library or Apache’s mod_headers module, we can easily remove HTTP header information. This little trick will be useful when writing web applications or processing data.

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