feature #30629 [HttpClient] added CachingHttpClient (fabpot)

This PR was merged into the 4.3-dev branch.

Discussion
----------

[HttpClient] added CachingHttpClient

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

The proposed `CachingHttpClient` uses `HttpCache` from the HttpKernel component to provide an HTTP-compliant cache.

If this is accepted, it could replace the corresponding part in #30602

Commits
-------

dae5686 [HttpClient] added CachingHttpClient

src/Symfony/Component/HttpClient/CachingHttpClient.php

@@ -0,0 +1,142 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient;
+
+use Psr\Log\LoggerInterface;
+use Symfony\Component\HttpClient\Response\MockResponse;
+use Symfony\Component\HttpClient\Response\ResponseStream;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\HttpCache\HttpCache;
+use Symfony\Component\HttpKernel\HttpCache\StoreInterface;
+use Symfony\Component\HttpKernel\HttpClientKernel;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+use Symfony\Contracts\HttpClient\ResponseInterface;
+use Symfony\Contracts\HttpClient\ResponseStreamInterface;
+
+/**
+ * Adds caching on top of an HTTP client.
+ *
+ * The implementation buffers responses in memory and doesn't stream directly from the network.
+ * You can disable/enable this layer by setting option "no_cache" under "extra" to true/false.
+ * By default, caching is enabled unless the "buffer" option is set to false.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class CachingHttpClient implements HttpClientInterface
+{
+    use HttpClientTrait;
+
+    private $client;
+    private $cache;
+    private $defaultOptions = self::OPTIONS_DEFAULTS;
+
+    public function __construct(HttpClientInterface $client, StoreInterface $store, array $defaultOptions = [], LoggerInterface $logger = null)
+    {
+        if (!class_exists(HttpClientKernel::class)) {
+             throw new \LogicException(sprintf('Using "%s" requires that the HttpKernel component version 4.3 or higher is installed, try running "composer require symfony/http-kernel:^4.3".', __CLASS__));
+        }
+
+        $this->client = $client;
+        $kernel = new HttpClientKernel($client, $logger);
+        $this->cache = new HttpCache($kernel, $store, null, $defaultOptions);
+
+        unset($defaultOptions['debug']);
+        unset($defaultOptions['default_ttl']);
+        unset($defaultOptions['private_headers']);
+        unset($defaultOptions['allow_reload']);
+        unset($defaultOptions['allow_revalidate']);
+        unset($defaultOptions['stale_while_revalidate']);
+        unset($defaultOptions['stale_if_error']);
+
+        if ($defaultOptions) {
+            [, $this->defaultOptions] = self::prepareRequest(null, null, $defaultOptions, $this->defaultOptions);
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function request(string $method, string $url, array $options = []): ResponseInterface
+    {
+        [$url, $options] = $this->prepareRequest($method, $url, $options, $this->defaultOptions, true);
+        $url = implode('', $url);
+        $options['extra']['no_cache'] = $options['extra']['no_cache'] ?? !$options['buffer'];
+
+        if ($options['extra']['no_cache'] || !empty($options['body']) || !\in_array($method, ['GET', 'HEAD', 'OPTIONS'])) {
+            return $this->client->request($method, $url, $options);
+        }
+
+        $request = Request::create($url, $method);
+        $request->attributes->set('http_client_options', $options);
+
+        foreach ($options['headers'] as $name => $values) {
+            if ('cookie' !== $name) {
+                $request->headers->set($name, $values);
+                continue;
+            }
+
+            foreach ($values as $cookies) {
+                foreach (explode('; ', $cookies) as $cookie) {
+                    if ('' !== $cookie) {
+                        $cookie = explode('=', $cookie, 2);
+                        $request->cookies->set($cookie[0], $cookie[1] ?? null);
+                    }
+                }
+            }
+        }
+
+        $response = $this->cache->handle($request);
+        $response = new MockResponse($response->getContent(), [
+            'http_code' => $response->getStatusCode(),
+            'raw_headers' => $response->headers->allPreserveCase(),
+        ]);
+
+        return MockResponse::fromRequest($method, $url, $options, $response);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function stream($responses, float $timeout = null): ResponseStreamInterface
+    {
+        if ($responses instanceof ResponseInterface) {
+            $responses = [$responses];
+        } elseif (!\is_iterable($responses)) {
+            throw new \TypeError(sprintf('%s() expects parameter 1 to be an iterable of ResponseInterface objects, %s given.', __METHOD__, \is_object($responses) ? \get_class($responses) : \gettype($responses)));
+        }
+
+        $mockResponses = [];
+        $clientResponses = [];
+
+        foreach ($responses as $response) {
+            if ($response instanceof MockResponse) {
+                $mockResponses[] = $response;
+            } else {
+                $clientResponses[] = $response;
+            }
+        }
+
+        if (!$mockResponses) {
+            return $this->client->stream($clientResponses, $timeout);
+        }
+
+        if (!$clientResponses) {
+            return new ResponseStream(MockResponse::stream($mockResponses, $timeout));
+        }
+
+        return new ResponseStream((function () use ($mockResponses, $clientResponses, $timeout) {
+            yield from MockResponse::stream($mockResponses, $timeout);
+            yield $this->client->stream($clientResponses, $timeout);
+        })());
+    }
+}

src/Symfony/Component/HttpClient/HttpClientTrait.php

@@ -147,6 +147,10 @@ private static function mergeDefaultOptions(array $options, array $defaultOption
             $options[$k] = $options[$k] ?? $v;
         }
 
+        if (isset($defaultOptions['extra'])) {
+            $options['extra'] += $defaultOptions['extra'];
+        }
+
         if ($defaultOptions['resolve'] ?? false) {
             $options['resolve'] += array_change_key_case($defaultOptions['resolve']);
         }

src/Symfony/Component/HttpClient/HttpOptions.php

@@ -309,4 +309,14 @@ public function capturePeerCertChain(bool $capture)
 
         return $this;
     }
+
+    /**
+     * @return $this
+     */
+    public function setExtra(string $name, $value)
+    {
+        $this->options['extra'][$name] = $value;
+
+        return $this;
+    }
 }

src/Symfony/Component/HttpClient/composer.json

@@ -26,7 +26,8 @@
     "require-dev": {
         "nyholm/psr7": "^1.0",
         "psr/http-client": "^1.0",
-        "symfony/process": "~4.2"
+        "symfony/http-kernel": "^4.3",
+        "symfony/process": "^4.2"
     },
     "autoload": {
         "psr-4": { "Symfony\\Component\\HttpClient\\": "" },

src/Symfony/Component/HttpKernel/RealHttpKernel.php → src/Symfony/Component/HttpKernel/HttpClientKernel.php

@@ -27,7 +27,7 @@
  *
  * @author Fabien Potencier <fabien@symfony.com>
  */
-final class RealHttpKernel implements HttpKernelInterface
+final class HttpClientKernel implements HttpKernelInterface
 {
     private $client;
     private $logger;

src/Symfony/Contracts/HttpClient/HttpClientInterface.php

@@ -64,6 +64,7 @@ interface HttpClientInterface
         'ciphers' => null,
         'peer_fingerprint' => null,
         'capture_peer_cert_chain' => false,
+        'extra' => [],          // array - additional options that can be ignored if unsupported, unlike regular options
     ];
 
     /**