ETags

Available since v6.6.x

Provides a "profile" based approach to generate ETags of content, in your Laravel application. The default provided implementation is able to generate ETags for weak and strong comparisons.

use Aedart\ETags\Facades\Generator;

// Generate an ETag for strong comparison, of content
$etag = Generator::makeStrong($content);

echo (string) $etag; // "4720b076892bb2fb65e75af902273c73a2967e4a"

Or to generate ETags that are flagged as "weak" (for weak comparison)

$etag = Generator::makeWeak($content);

echo (string) $etag; // W/"0815"

Parsing

To parse ETags from Http headers, you can use the parse() method. It returns a collection of ETag instances.

// E.g. If-None-Match: W/"0815", W/"0816", W/"0817"
$collection = Generator::parse($request->header('If-None-Match'));  

foreach ($collection as $etag) {
    echo (string) $etag;
}

Compare

Lastly, ETags can also be matched against each other, in accordance with RFC9110.

Using Collection

// Etags from Http Header
$collection = Generator::parse($request->header('If-Match')); // E.g. 'W/"0815"' 

// Other Etag for your resource
$etag = Generator::makeWeak($content); // E.g. W/"0815"

// Compare etags against resource's etag
echo $collection->contains($etag, true); // false - strong comparison
echo $collection->contains($etag);       // true - weak comparison

Using Etag instance

You can also compare individual ETag instances, using the matches() method.

$etagA = Generator::parseSingle('W/"0815"');
$etagB = Generator::parseSingle('W/"0815"');

echo $etagA->matches($etagB, true); // false - strong comparison
echo $etagA->matches($etagB);       // true - weak comparison

Onward

For additional examples, installation guide and more, please continue reading the documentation.