Add http client pool

Author: joelwurtz

spec/HttpClientPool/LeastUsedClientPoolSpec.php

@@ -0,0 +1,71 @@
+<?php
+
+namespace spec\Http\Client\Common\HttpClientPool;
+
+use Http\Client\Common\HttpClientPoolItem;
+use Http\Client\HttpAsyncClient;
+use Http\Client\HttpClient;
+use Http\Promise\Promise;
+use PhpSpec\ObjectBehavior;
+use Prophecy\Argument;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+
+class LeastUsedClientPoolSpec extends ObjectBehavior
+{
+    public function it_is_initializable()
+    {
+        $this->shouldHaveType('Http\Client\Common\HttpClientPool\LeastUsedClientPool');
+    }
+
+    public function it_is_an_http_client()
+    {
+        $this->shouldImplement('Http\Client\HttpClient');
+    }
+
+    public function it_is_an_async_http_client()
+    {
+        $this->shouldImplement('Http\Client\HttpAsyncClient');
+    }
+
+    public function it_throw_exception_with_no_client(RequestInterface $request)
+    {
+        $this->shouldThrow('Http\Client\Common\Exception\NotFoundHttpClientException')->duringSendRequest($request);
+        $this->shouldThrow('Http\Client\Common\Exception\NotFoundHttpClientException')->duringSendAsyncRequest($request);
+    }
+
+    public function it_sends_request(HttpClient $httpClient, RequestInterface $request, ResponseInterface $response)
+    {
+        $this->addHttpClient($httpClient);
+        $httpClient->sendRequest($request)->willReturn($response);
+
+        $this->sendRequest($request)->shouldReturn($response);
+    }
+
+    public function it_sends_async_request(HttpAsyncClient $httpAsyncClient, RequestInterface $request, Promise $promise)
+    {
+        $this->addHttpClient($httpAsyncClient);
+        $httpAsyncClient->sendAsyncRequest($request)->willReturn($promise);
+        $promise->then(Argument::type('callable'), Argument::type('callable'))->willReturn($promise);
+
+        $this->sendAsyncRequest($request)->shouldReturn($promise);
+    }
+
+    public function it_throw_exception_if_no_more_enable_client(HttpClient $client, RequestInterface $request)
+    {
+        $this->addHttpClient($client);
+        $client->sendRequest($request)->willThrow('Http\Client\Exception\HttpException');
+
+        $this->shouldThrow('Http\Client\Exception\HttpException')->duringSendRequest($request);
+        $this->shouldThrow('Http\Client\Common\Exception\NotFoundHttpClientException')->duringSendRequest($request);
+    }
+
+    public function it_reenable_client(HttpClient $client, RequestInterface $request)
+    {
+        $this->addHttpClient(new HttpClientPoolItem($client->getWrappedObject(), 0));
+        $client->sendRequest($request)->willThrow('Http\Client\Exception\HttpException');
+
+        $this->shouldThrow('Http\Client\Exception\HttpException')->duringSendRequest($request);
+        $this->shouldThrow('Http\Client\Exception\HttpException')->duringSendRequest($request);
+    }
+}

spec/HttpClientPool/RoundRobinClientPoolSpec.php

@@ -0,0 +1,71 @@
+<?php
+
+namespace spec\Http\Client\Common\HttpClientPool;
+
+use Http\Client\Common\HttpClientPoolItem;
+use Http\Client\HttpAsyncClient;
+use Http\Client\HttpClient;
+use Http\Promise\Promise;
+use PhpSpec\ObjectBehavior;
+use Prophecy\Argument;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+
+class RoundRobinClientPoolSpec extends ObjectBehavior
+{
+    public function it_is_initializable()
+    {
+        $this->shouldHaveType('Http\Client\Common\HttpClientPool\RoundRobinClientPool');
+    }
+
+    public function it_is_an_http_client()
+    {
+        $this->shouldImplement('Http\Client\HttpClient');
+    }
+
+    public function it_is_an_async_http_client()
+    {
+        $this->shouldImplement('Http\Client\HttpAsyncClient');
+    }
+
+    public function it_throw_exception_with_no_client(RequestInterface $request)
+    {
+        $this->shouldThrow('Http\Client\Common\Exception\NotFoundHttpClientException')->duringSendRequest($request);
+        $this->shouldThrow('Http\Client\Common\Exception\NotFoundHttpClientException')->duringSendAsyncRequest($request);
+    }
+
+    public function it_sends_request(HttpClient $httpClient, RequestInterface $request, ResponseInterface $response)
+    {
+        $this->addHttpClient($httpClient);
+        $httpClient->sendRequest($request)->willReturn($response);
+
+        $this->sendRequest($request)->shouldReturn($response);
+    }
+
+    public function it_sends_async_request(HttpAsyncClient $httpAsyncClient, RequestInterface $request, Promise $promise)
+    {
+        $this->addHttpClient($httpAsyncClient);
+        $httpAsyncClient->sendAsyncRequest($request)->willReturn($promise);
+        $promise->then(Argument::type('callable'), Argument::type('callable'))->willReturn($promise);
+
+        $this->sendAsyncRequest($request)->shouldReturn($promise);
+    }
+
+    public function it_throw_exception_if_no_more_enable_client(HttpClient $client, RequestInterface $request)
+    {
+        $this->addHttpClient($client);
+        $client->sendRequest($request)->willThrow('Http\Client\Exception\HttpException');
+
+        $this->shouldThrow('Http\Client\Exception\HttpException')->duringSendRequest($request);
+        $this->shouldThrow('Http\Client\Common\Exception\NotFoundHttpClientException')->duringSendRequest($request);
+    }
+
+    public function it_reenable_client(HttpClient $client, RequestInterface $request)
+    {
+        $this->addHttpClient(new HttpClientPoolItem($client->getWrappedObject(), 0));
+        $client->sendRequest($request)->willThrow('Http\Client\Exception\HttpException');
+
+        $this->shouldThrow('Http\Client\Exception\HttpException')->duringSendRequest($request);
+        $this->shouldThrow('Http\Client\Exception\HttpException')->duringSendRequest($request);
+    }
+}

src/Exception/HttpClientNotFoundException.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace Http\Client\Common\Exception;
+
+use Http\Client\Exception\TransferException;
+
+/**
+ * Thrown when a http client cannot be chosen in a pool.
+ *
+ * @author Joel Wurtz <[email protected]>
+ */
+class HttpClientNotFoundException extends TransferException
+{
+}

src/FlexibleHttpClient.php

@@ -11,7 +11,7 @@
  *
  * @author Joel Wurtz <[email protected]>
  */
-final class FlexibleHttpClient implements HttpClient, HttpAsyncClient
+class FlexibleHttpClient implements HttpClient, HttpAsyncClient
 {
     use HttpClientDecorator;
     use HttpAsyncClientDecorator;

src/HttpClientPool.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace Http\Client\Common;
+
+use Http\Client\Common\Exception\HttpClientNotFoundException;
+use Http\Client\HttpAsyncClient;
+use Http\Client\HttpClient;
+use Psr\Http\Message\RequestInterface;
+
+/**
+ * A http client pool allows to send requests on a pool of different http client using a specific strategy (least used,
+ * round robin, ...).
+ */
+abstract class HttpClientPool implements HttpAsyncClient, HttpClient
+{
+    /** @var HttpClientPoolItem[] */
+    protected $clientPool = [];
+
+    /**
+     * Add a client to the pool.
+     *
+     * @param HttpClient|HttpAsyncClient $client
+     */
+    public function addHttpClient($client)
+    {
+        if (!$client instanceof HttpClientPoolItem) {
+            $client = new HttpClientPoolItem($client);
+        }
+
+        $this->clientPool[] = $client;
+    }
+
+    /**
+     * Return an http client given a specific strategy.
+     *
+     * @throws HttpClientNotFoundException When no http client has been found into the pool
+     *
+     * @return HttpClientPoolItem Return a http client that can do both sync or async
+     */
+    abstract protected function chooseHttpClient();
+
+    /**
+     * {@inheritdoc}
+     */
+    public function sendAsyncRequest(RequestInterface $request)
+    {
+        return $this->chooseHttpClient()->sendAsyncRequest($request);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function sendRequest(RequestInterface $request)
+    {
+        return $this->chooseHttpClient()->sendRequest($request);
+    }
+}

src/HttpClientPool/LeastUsedClientPool.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace Http\Client\Common\HttpClientPool;
+
+use Http\Client\Common\Exception\HttpClientNotFoundException;
+use Http\Client\Common\HttpClientPool;
+use Http\Client\Common\HttpClientPoolItem;
+
+/**
+ * LeastUsedClientPool will choose the client with the less current request in the pool.
+ *
+ * This strategy is only useful when doing async request
+ *
+ * @author Joel Wurtz <[email protected]>
+ */
+class LeastUsedClientPool extends HttpClientPool
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function chooseHttpClient()
+    {
+        $clientPool = array_filter($this->clientPool, function (HttpClientPoolItem $clientPoolItem) {
+            return !$clientPoolItem->isDisabled();
+        });
+
+        if (0 === count($clientPool)) {
+            throw new HttpClientNotFoundException('Cannot choose a http client as there is no one present in the pool');
+        }
+
+        usort($clientPool, function (HttpClientPoolItem $clientA, HttpClientPoolItem $clientB) {
+            if ($clientA->getSendingRequestCount() === $clientB->getSendingRequestCount()) {
+                return 0;
+            }
+
+            if ($clientA->getSendingRequestCount() < $clientB->getSendingRequestCount()) {
+                return -1;
+            }
+
+            return 1;
+        });
+
+        return reset($clientPool);
+    }
+}

src/HttpClientPool/RoundRobinClientPool.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace Http\Client\Common\HttpClientPool;
+
+use Http\Client\Common\Exception\HttpClientNotFoundException;
+use Http\Client\Common\HttpClientPool;
+
+/**
+ * RoundRobinClientPool will choose the next client in the pool.
+ *
+ * @author Joel Wurtz <[email protected]>
+ */
+class RoundRobinClientPool extends HttpClientPool
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function chooseHttpClient()
+    {
+        $last = current($this->clientPool);
+
+        do {
+            $client = next($this->clientPool);
+
+            if (false === $client) {
+                $client = reset($this->clientPool);
+
+                if (false === $client) {
+                    throw new HttpClientNotFoundException('Cannot choose a http client as there is no one present in the pool');
+                }
+            }
+
+            // Case when there is only one and the last one has been disabled
+            if ($last === $client && $client->isDisabled()) {
+                throw new HttpClientNotFoundException('Cannot choose a http client as there is no one enabled in the pool');
+            }
+        } while ($client->isDisabled());
+
+        return $client;
+    }
+}