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apps/frontend/lib/google/io/Google_IO.php

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+<?php
+/**
+ * Copyright 2010 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+require_once 'io/Google_HttpRequest.php';
+require_once 'io/Google_HttpStreamIO.php';
+require_once 'io/Google_CurlIO.php';
+require_once 'io/Google_REST.php';
+
+/**
+ * Abstract IO class
+ *
+ * @author Chris Chabot <chabotc@google.com>
+ */
+abstract class Google_IO {
+  const CONNECTION_ESTABLISHED = "HTTP/1.0 200 Connection established\r\n\r\n";
+  const FORM_URLENCODED = 'application/x-www-form-urlencoded';
+  /**
+   * An utility function that first calls $this->auth->sign($request) and then executes makeRequest()
+   * on that signed request. Used for when a request should be authenticated
+   * @param Google_HttpRequest $request
+   * @return Google_HttpRequest $request
+   */
+  abstract function authenticatedRequest(Google_HttpRequest $request);
+
+  /**
+   * Executes a apIHttpRequest and returns the resulting populated httpRequest
+   * @param Google_HttpRequest $request
+   * @return Google_HttpRequest $request
+   */
+  abstract function makeRequest(Google_HttpRequest $request);
+
+  /**
+   * Set options that update the transport implementation's behavior.
+   * @param $options
+   */
+  abstract function setOptions($options);
+
+  /**
+   * @visible for testing.
+   * Cache the response to an HTTP request if it is cacheable.
+   * @param Google_HttpRequest $request
+   * @return bool Returns true if the insertion was successful.
+   * Otherwise, return false.
+   */
+  protected function setCachedRequest(Google_HttpRequest $request) {
+    // Determine if the request is cacheable.
+    if (Google_CacheParser::isResponseCacheable($request)) {
+      Google_Client::$cache->set($request->getCacheKey(), $request);
+      return true;
+    }
+
+    return false;
+  }
+
+  /**
+   * @visible for testing.
+   * @param Google_HttpRequest $request
+   * @return Google_HttpRequest|bool Returns the cached object or
+   * false if the operation was unsuccessful.
+   */
+  protected function getCachedRequest(Google_HttpRequest $request) {
+    if (false == Google_CacheParser::isRequestCacheable($request)) {
+      false;
+    }
+
+    return Google_Client::$cache->get($request->getCacheKey());
+  }
+
+  /**
+   * @visible for testing
+   * Process an http request that contains an enclosed entity.
+   * @param Google_HttpRequest $request
+   * @return Google_HttpRequest Processed request with the enclosed entity.
+   */
+  protected function processEntityRequest(Google_HttpRequest $request) {
+    $postBody = $request->getPostBody();
+    $contentType = $request->getRequestHeader("content-type");
+
+    // Set the default content-type as application/x-www-form-urlencoded.
+    if (false == $contentType) {
+      $contentType = self::FORM_URLENCODED;
+      $request->setRequestHeaders(array('content-type' => $contentType));
+    }
+
+    // Force the payload to match the content-type asserted in the header.
+    if ($contentType == self::FORM_URLENCODED && is_array($postBody)) {
+      $postBody = http_build_query($postBody, '', '&');
+      $request->setPostBody($postBody);
+    }
+
+    // Make sure the content-length header is set.
+    if (!$postBody || is_string($postBody)) {
+      $postsLength = strlen($postBody);
+      $request->setRequestHeaders(array('content-length' => $postsLength));
+    }
+
+    return $request;
+  }
+
+  /**
+   * Check if an already cached request must be revalidated, and if so update
+   * the request with the correct ETag headers.
+   * @param Google_HttpRequest $cached A previously cached response.
+   * @param Google_HttpRequest $request The outbound request.
+   * return bool If the cached object needs to be revalidated, false if it is
+   * still current and can be re-used.
+   */
+  protected function checkMustRevaliadateCachedRequest($cached, $request) {
+    if (Google_CacheParser::mustRevalidate($cached)) {
+      $addHeaders = array();
+      if ($cached->getResponseHeader('etag')) {
+        // [13.3.4] If an entity tag has been provided by the origin server,
+        // we must use that entity tag in any cache-conditional request.
+        $addHeaders['If-None-Match'] = $cached->getResponseHeader('etag');
+      } elseif ($cached->getResponseHeader('date')) {
+        $addHeaders['If-Modified-Since'] = $cached->getResponseHeader('date');
+      }
+
+      $request->setRequestHeaders($addHeaders);
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  /**
+   * Update a cached request, using the headers from the last response.
+   * @param Google_HttpRequest $cached A previously cached response.
+   * @param mixed Associative array of response headers from the last request.
+   */
+  protected function updateCachedRequest($cached, $responseHeaders) {
+    if (isset($responseHeaders['connection'])) {
+      $hopByHop = array_merge(
+        self::$HOP_BY_HOP,
+        explode(',', $responseHeaders['connection'])
+      );
+
+      $endToEnd = array();
+      foreach($hopByHop as $key) {
+        if (isset($responseHeaders[$key])) {
+          $endToEnd[$key] = $responseHeaders[$key];
+        }
+      }
+      $cached->setResponseHeaders($endToEnd);
+    }
+  }
+}