Add ability to make asynchronous HTTP requests and return Guzzle prom…

…ises (#15) * Add the ability to return a promise instead of doing the request immediately
bbc · Jan 18, 2018 · 2d8e16f · 2d8e16f
1 parent c621ad7
commit 2d8e16f
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Showing 3 changed files with 145 additions and 44 deletions.
diff --git a/src/BrandingClient.php b/src/BrandingClient.php
@@ -5,8 +5,11 @@
 use DateTime;
 use GuzzleHttp\Client;
 use GuzzleHttp\Exception\RequestException;
+use GuzzleHttp\Promise\FulfilledPromise;
+use Psr\Http\Message\ResponseInterface;
 use Psr\Cache\CacheItemInterface;
 use Psr\Cache\CacheItemPoolInterface;
+use Exception;
 use function GuzzleHttp\Psr7\parse_header;
 
 class BrandingClient
@@ -79,55 +82,56 @@ public function __construct(
     public function getContent($projectId, $themeVersionId = null)
     {
         $url = $this->getUrl($projectId, $themeVersionId);
-        $cacheKey = $this->options['cacheKeyPrefix'] . '.' . md5($url);
+        $cacheItem = $this->fetchCacheItem($url);
+        if ($cacheItem->isHit()) {
+            return $this->mapResultToBrandingObject($cacheItem->get());
+        }
 
-        if ($this->flushCacheItems) {
-            $this->cache->deleteItem($cacheKey);
+        try {
+            $response = $this->client->get($url, [
+                'headers' => ['Accept-Encoding' => 'gzip']
+            ]);
+            $result = $this->parseAndCacheResponse($response, $cacheItem);
+        } catch (RequestException $e) {
+            throw $this->makeInvalidResponseException($e);
         }
-        /** @var CacheItemInterface $cacheItem */
-        $cacheItem = $this->cache->getItem($cacheKey);
-        if (!$cacheItem->isHit()) {
-            try {
-                $response = $this->client->get($url, [
-                    'headers' => ['Accept-Encoding' => 'gzip']
-                ]);
-                $result = json_decode($response->getBody()->getContents(), true);
-            } catch (RequestException $e) {
-                throw new BrandingException('Invalid Branding Response. Could not get data from webservice', 0, $e);
-            }
+        return $this->mapResultToBrandingObject($result);
+    }
 
-            if (!$result || !isset($result['head'])) {
-                throw new BrandingException('Invalid Branding Response. Response JSON object was invalid or malformed');
-            }
+    public function getContentAsync($projectId, $themeVersionId = null)
+    {
+        $url = $this->getUrl($projectId, $themeVersionId);
+        $cacheItem = $this->fetchCacheItem($url);
+        if ($cacheItem->isHit()) {
+            $brandingObject = $this->mapResultToBrandingObject($cacheItem->get());
+            return new FulfilledPromise($brandingObject);
+        }
 
-            // Determine how long to cache for
-            $cacheTime = self::FALLBACK_CACHE_DURATION;
-            if ($this->options['cacheTime']) {
-                $cacheTime = $this->options['cacheTime'];
-            } else {
-                $cacheControl = $response->getHeaderLine('cache-control');
-                if (isset(parse_header($cacheControl)[0]['max-age'])) {
-                    $cacheTime = (int)parse_header($cacheControl)[0]['max-age'];
-                } else {
-                    $expiryDate = $this->getDateFromHeader($response, 'Expires');
-                    $currentDate = $this->getDateFromHeader($response, 'Date');
-                    if ($currentDate && $expiryDate) {
-                        // Beware of a cache time of 0 as 0 is treated by Doctrine
-                        // Cache as "Cache for an infinite time" which is very much
-                        // not what we want. -1 will be treated as already expired
-                        $cacheTime = $expiryDate->getTimestamp() - $currentDate->getTimestamp();
-                        $cacheTime = ($cacheTime > 0 ? $cacheTime : -1);
+        try {
+            $requestPromise = $this->client->requestAsync('GET', $url, [
+                'headers' => ['Accept-Encoding' => 'gzip']
+            ]);
+            $promise = $requestPromise->then(
+                // Success callback
+                function ($response) use ($cacheItem) {
+                    $result = $this->parseAndCacheResponse($response, $cacheItem);
+                    return $this->mapResultToBrandingObject($result);
+                },
+                // Error callback
+                function ($reason) {
+                    if ($reason instanceof RequestException) {
+                        throw $this->makeInvalidResponseException($reason);
+                    }
+                    if ($reason instanceof Exception) {
+                        throw $reason;
                     }
+                    throw new BrandingException("Invalid Branding Response. Unknown error reason in callback");
                 }
-            }
-
-            // cache the result
-            $cacheItem->set($result);
-            $cacheItem->expiresAfter($cacheTime);
-            $this->cache->save($cacheItem);
+            );
+        } catch (RequestException $e) {
+            throw $this->makeInvalidResponseException($e);
         }
-
-        return $this->mapResultToBrandingObject($cacheItem->get());
+        return $promise;
     }
 
     /**
@@ -140,9 +144,9 @@ public function getOptions()
         return $this->options;
     }
 
-    public function setFlushCacheItems(bool $flushCacheItems): void
+    public function setFlushCacheItems($flushCacheItems)
     {
-        $this->flushCacheItems = $flushCacheItems;
+        $this->flushCacheItems = (bool) $flushCacheItems;
     }
 
     private function mapResultToBrandingObject(array $branding)
@@ -198,4 +202,60 @@ private function getDateFromHeader($response, $headerName)
 
         return null;
     }
+
+    private function fetchCacheItem($url)
+    {
+        $cacheKey = $this->options['cacheKeyPrefix'] . '.' . md5($url);
+
+        if ($this->flushCacheItems) {
+            $this->cache->deleteItem($cacheKey);
+        }
+        /** @var CacheItemInterface $cacheItem */
+        $cacheItem = $this->cache->getItem($cacheKey);
+        return $cacheItem;
+    }
+
+    private function parseAndCacheResponse(ResponseInterface $response, CacheItemInterface $cacheItem)
+    {
+        $result = json_decode($response->getBody()->getContents(), true);
+        if (!$result || !isset($result['head'])) {
+            throw new BrandingException('Invalid Branding Response. Response JSON object was invalid or malformed');
+        }
+
+        // Determine how long to cache for
+        $cacheTime = self::FALLBACK_CACHE_DURATION;
+        if ($this->options['cacheTime']) {
+            $cacheTime = $this->options['cacheTime'];
+        } else {
+            $cacheControl = $response->getHeaderLine('cache-control');
+            if (isset(parse_header($cacheControl)[0]['max-age'])) {
+                $cacheTime = (int)parse_header($cacheControl)[0]['max-age'];
+            } else {
+                $expiryDate = $this->getDateFromHeader($response, 'Expires');
+                $currentDate = $this->getDateFromHeader($response, 'Date');
+                if ($currentDate && $expiryDate) {
+                    // Beware of a cache time of 0 as 0 is treated by Doctrine
+                    // Cache as "Cache for an infinite time" which is very much
+                    // not what we want. -1 will be treated as already expired
+                    $cacheTime = $expiryDate->getTimestamp() - $currentDate->getTimestamp();
+                    $cacheTime = ($cacheTime > 0 ? $cacheTime : -1);
+                }
+            }
+        }
+
+        // cache the result
+        $cacheItem->set($result);
+        $cacheItem->expiresAfter($cacheTime);
+        $this->cache->save($cacheItem);
+        return $result;
+    }
+
+    private function makeInvalidResponseException(Exception $innerException)
+    {
+        return new BrandingException(
+            'Invalid Branding Response. Could not get data from webservice',
+            0,
+            $innerException
+        );
+    }
 }
diff --git a/src/BrandingStubClient.php b/src/BrandingStubClient.php
@@ -3,6 +3,7 @@
 namespace BBC\BrandingClient;
 
 use GuzzleHttp\Client;
+use GuzzleHttp\Promise\FulfilledPromise;
 use Psr\Cache\CacheItemPoolInterface;
 
 class BrandingStubClient extends BrandingClient
@@ -15,6 +16,16 @@ public function __construct(
     }
 
     public function getContent($projectId, $themeVersionId = null)
+    {
+        return $this->getMockBranding();
+    }
+
+    public function getContentAsync($projectId, $themeVersionId = null)
+    {
+        return new FulfilledPromise($this->getMockBranding());
+    }
+
+    private function getMockBranding()
     {
         return new Branding(
             '<branding-head/>',

diff --git a/tests/BrandingClientTest.php b/tests/BrandingClientTest.php
@@ -131,6 +131,23 @@ public function testGetContentReturnsBrandingObject()
         $this->assertEquals($expectedContent, $brandingClient->getContent('br-123'));
     }
 
+    public function testGetContentPromiseReturnsBrandingObject()
+    {
+        $expectedContent = new Branding(
+            'headContent',
+            'bodyFirstContent',
+            'bodyLastContent',
+            ['body' => ['bg' => '#eeeeee']],
+            ['language' => 'en']
+        );
+
+        $client = $this->getClient([$this->mockSuccessfulJsonResponse()]);
+
+        $brandingClient = new BrandingClient($client, $this->cache);
+        $promise = $brandingClient->getContentAsync('br-123');
+        $this->assertEquals($expectedContent, $promise->wait(true));
+    }
+
     /**
      * @expectedException BBC\BrandingClient\BrandingException
      * @expectedExceptionMessage Invalid Branding Response. Could not get data from webservice
@@ -143,6 +160,19 @@ public function testInvalidContentThrowsException()
         $brandingClient->getContent('br-123');
     }
 
+    /**
+     * @expectedException BBC\BrandingClient\BrandingException
+     * @expectedExceptionMessage Invalid Branding Response. Could not get data from webservice
+     */
+    public function testInvalidContentThrowsExceptionWhenPromiseResolved()
+    {
+        $client = $this->getClient([$this->mockInvalidJsonResponse()]);
+
+        $brandingClient = new BrandingClient($client, $this->cache);
+        $promise = $brandingClient->getContentAsync('br-123');
+        $promise->wait(true);
+    }
+
     /**
      * @expectedException BBC\BrandingClient\BrandingException
      * @expectedExceptionMessage Invalid Branding Response. Response JSON object was invalid or malformed