SetCacheHeaders.php

TLDR

The file SetCacheHeaders.php is a middleware class in the Illuminate\Http\Middleware namespace. It provides functionality for setting cache-related HTTP headers for responses.

Methods

using

This is a static method that specifies the options for the middleware. It accepts an array or string of options and returns a string representation of the options.

handle

This method is responsible for adding cache-related HTTP headers to the response. It takes in a request object, a closure for the next middleware, and the options for cache headers. It returns a Symfony\Component\HttpFoundation\Response object.

parseOptions

This protected method is used for parsing the header options provided as a string. It takes in a string of options and returns an array.

END

<?php

namespace Illuminate\Http\Middleware;

use Closure;
use Illuminate\Support\Carbon;
use Illuminate\Support\Str;
use Symfony\Component\HttpFoundation\BinaryFileResponse;
use Symfony\Component\HttpFoundation\StreamedResponse;

class SetCacheHeaders
{
    /**
     * Specify the options for the middleware.
     *
     * @param  array|string  $options
     * @return string
     */
    public static function using($options)
    {
        if (is_string($options)) {
            return static::class.':'.$options;
        }

        return collect($options)
            ->map(fn ($value, $key) => is_int($key) ? $value : "{$key}={$value}")
            ->map(fn ($value) => Str::finish($value, ';'))
            ->pipe(fn ($options) => rtrim(static::class.':'.$options->implode(''), ';'));
    }

    /**
     * Add cache related HTTP headers.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @param  string|array  $options
     * @return \Symfony\Component\HttpFoundation\Response
     *
     * @throws \InvalidArgumentException
     */
    public function handle($request, Closure $next, $options = [])
    {
        $response = $next($request);

        if (! $request->isMethodCacheable() || (! $response->getContent() && ! $response instanceof BinaryFileResponse && ! $response instanceof StreamedResponse)) {
            return $response;
        }

        if (is_string($options)) {
            $options = $this->parseOptions($options);
        }

        if (isset($options['etag']) && $options['etag'] === true) {
            $options['etag'] = $response->getEtag() ?? md5($response->getContent());
        }

        if (isset($options['last_modified'])) {
            if (is_numeric($options['last_modified'])) {
                $options['last_modified'] = Carbon::createFromTimestamp($options['last_modified']);
            } else {
                $options['last_modified'] = Carbon::parse($options['last_modified']);
            }
        }

        $response->setCache($options);
        $response->isNotModified($request);

        return $response;
    }

    /**
     * Parse the given header options.
     *
     * @param  string  $options
     * @return array
     */
    protected function parseOptions($options)
    {
        return collect(explode(';', rtrim($options, ';')))->mapWithKeys(function ($option) {
            $data = explode('=', $option, 2);

            return [$data[0] => $data[1] ?? true];
        })->all();
    }
}