[5.6] Add a HTTP cache middleware

src/Illuminate/Http/Middleware/Cache.php

@@ -0,0 +1,47 @@
+<?php
+
+namespace Illuminate\Http\Middleware;
+
+use Closure;
+
+class Cache
+{
+    /**
+     * 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 = [])
+    {
+        /**
+         * @var $response \Symfony\Component\HttpFoundation\Response
+         */
+        $response = $next($request);
+        if (! $request->isMethodCacheable() || ! $response->getContent()) {
+            return $response;
+        }
+
+        if (\is_string($options)) {
+            $parsedOptions = [];
+            foreach (explode(';', $options) as $opt) {
+                $data = explode('=', $opt, 2);
+                $parsedOptions[$data[0]] = $data[1] ?? true;
+            }
+
+            $options = $parsedOptions;
+        }
+
+        if (isset($options['etag']) && true === $options['etag']) {
+            $options['etag'] = md5($response->getContent());
+        }
+
+        $response->setCache($options);
+        $response->isNotModified($request);
+
+        return $response;
+    }
+}

tests/Http/Middleware/CacheTest.php

@@ -0,0 +1,85 @@
+<?php
+
+namespace Illuminate\Tests\Http\Middleware;
+
+use Illuminate\Http\Request;
+use Illuminate\Http\Response;
+use PHPUnit\Framework\TestCase;
+use Illuminate\Http\Middleware\Cache;
+
+class CacheTest extends TestCase
+{
+    public function testDoNotSetHeaderWhenMethodNotCacheable()
+    {
+        $request = new Request();
+        $request->setMethod('PUT');
+
+        $response = (new Cache())->handle($request, function () {
+            return new Response('Hello Laravel');
+        }, 'max_age=120;s_maxage=60');
+
+        $this->assertNull($response->getMaxAge());
+    }
+
+    public function testDoNotSetHeaderWhenNoContent()
+    {
+        $response = (new Cache())->handle(new Request(), function () {
+            return new Response();
+        }, 'max_age=120;s_maxage=60');
+
+        $this->assertNull($response->getMaxAge());
+        $this->assertNull($response->getEtag());
+    }
+
+    public function testAddHeaders()
+    {
+        $response = (new Cache())->handle(new Request(), function () {
+            return new Response('some content');
+        }, 'max_age=100;s_maxage=200;etag=ABC');
+
+        $this->assertSame('"ABC"', $response->getEtag());
+        $this->assertSame('max-age=100, public, s-maxage=200', $response->headers->get('Cache-Control'));
+    }
+
+    public function testAddHeadersUsingArray()
+    {
+        $response = (new Cache())->handle(new Request(), function () {
+            return new Response('some content');
+        }, ['max_age' => 100, 's_maxage' => 200, 'etag' => 'ABC']);
+
+        $this->assertSame('"ABC"', $response->getEtag());
+        $this->assertSame('max-age=100, public, s-maxage=200', $response->headers->get('Cache-Control'));
+    }
+
+    public function testGenerateEtag()
+    {
+        $response = (new Cache())->handle(new Request(), function () {
+            return new Response('some content');
+        }, 'etag;max_age=100;s_maxage=200');
+
+        $this->assertSame('"9893532233caff98cd083a116b013c0b"', $response->getEtag());
+        $this->assertSame('max-age=100, public, s-maxage=200', $response->headers->get('Cache-Control'));
+    }
+
+    public function testIsNotModified()
+    {
+        $request = new Request();
+        $request->headers->set('If-None-Match', '"9893532233caff98cd083a116b013c0b"');
+
+        $response = (new Cache())->handle($request, function () {
+            return new Response('some content');
+        }, 'etag;max_age=100;s_maxage=200');
+
+        $this->assertSame(304, $response->getStatusCode());
+    }
+
+    /**
+     * @expectedException \InvalidArgumentException
+     */
+    public function testInvalidOption()
+    {
+        (new Cache())->handle(new Request(), function () {
+            return new Response('some content');
+        }, 'invalid');
+    }
+}