Master PHP’s get_headers(): Retrieve HTTP Headers with Code Examples

In PHP development we often need to obtain the response headers of a web page or remote resource. The PHP function get_headers() conveniently retrieves the target URL’s response headers and returns them as an array.

The get_headers() function can fetch the specified URL’s response headers and return them in array form. Its basic syntax is:

array get_headers(string $url, int $format = 0)

$url

is the target URL. $format is optional; when set to 0 (default) it returns an associative array with indexes and values, and when set to 1 it returns an indexed array.

Example code:

$url = "https://www.example.com";
$headers = get_headers($url);

// Print all response headers
print_r($headers);

// Print specific headers
echo $headers[0]; // First header
echo $headers[1]; // Second header

Sample output:

Array (
    [0] => HTTP/1.1 200 OK
    [1] => Date: Thu, 19 Nov 2020 08:00:00 GMT
    [2] => Server: Apache/2.4.41
    [3] => Content-Type: text/html; charset=UTF-8
    [4] => Content-Length: 12345
    ...
)

Common Use Cases

Obtain remote file information such as size and MIME type by reading response headers.

Check whether a remote file exists by examining the HTTP status code.

Use in crawlers and network monitoring to decide further processing based on header data.

Note that get_headers() works only with HTTP protocol responses and is not applicable to other protocols like FTP.

Conclusion

The get_headers() function is a practical PHP tool for retrieving various HTTP header information, such as status codes, dates, server details, and file sizes, which can improve code usability and efficiency when applied appropriately.