From 7c0a25be7f7f26c6d16324ea4d5d26f15846ee6b Mon Sep 17 00:00:00 2001
From: drigato <denise.rigato@sourcefabric.org>
Date: Mon, 1 Dec 2014 21:05:46 -0500
Subject: [PATCH] SAAS-505: Extract Amazon_S3 class and have it inherit from a
 general 'cloud backend' class

---
 airtime_mvc/application/amazon/Amazon_S3.php  | 72 -----------------
 .../application/cloud_storage/Amazon_S3.php   | 74 ++++++++++++++++++
 .../cloud_storage/ProxyStorageBackend.php     | 44 +++++++++++
 .../cloud_storage/StorageBackend.php          | 55 +++++++++++++
 airtime_mvc/application/configs/conf.php      |  1 +
 .../application/models/airtime/CloudFile.php  | 77 +++++--------------
 airtime_mvc/public/index.php                  |  4 +-
 7 files changed, 194 insertions(+), 133 deletions(-)
 delete mode 100644 airtime_mvc/application/amazon/Amazon_S3.php
 create mode 100644 airtime_mvc/application/cloud_storage/Amazon_S3.php
 create mode 100644 airtime_mvc/application/cloud_storage/ProxyStorageBackend.php
 create mode 100644 airtime_mvc/application/cloud_storage/StorageBackend.php

diff --git a/airtime_mvc/application/amazon/Amazon_S3.php b/airtime_mvc/application/amazon/Amazon_S3.php
deleted file mode 100644
index ce1615b1e..000000000
--- a/airtime_mvc/application/amazon/Amazon_S3.php
+++ /dev/null
@@ -1,72 +0,0 @@
-<?php
-
-require_once 'Zend/Service/Amazon/S3.php';
-
-/**
- * 
- * This is a wrapper class for Zend_Service_Amazon_S3.
- * Zend_Service_Amazon_S3 doesn't have getters and setters for the bucket,
- * access key, or secret key. This functionality would greatly refine our
- * use of the service so we decided to write our own here.
- *
- */
-class Amazon_S3
-{
-    private $bucket;
-    private $accessKey;
-    private $secretKey;
-    private $zendServiceAmazonS3;
-    
-    function Amazon_S3()
-    {
-        $this->initZendServiceAmazonS3();
-    }
-    
-    private function initZendServiceAmazonS3()
-    {
-        $CC_CONFIG = Config::getConfig();
-        
-        $this->setBucket($CC_CONFIG['storage_backend']['bucket']);
-        $this->setAccessKey($CC_CONFIG['storage_backend']['api_key']);
-        $this->setSecretKey($CC_CONFIG['storage_backend']['api_key_secret']);
-        
-        $this->zendServiceAmazonS3 = new Zend_Service_Amazon_S3(
-            $this->getAccessKey(),
-            $this->getSecretKey());
-    }
-    
-    public function getZendServiceAmazonS3()
-    {
-    	return $this->zendServiceAmazonS3;
-    }
-    
-    public function getBucket()
-    {
-        return $this->bucket;
-    }
-    
-    private function setBucket($bucket)
-    {
-        $this->bucket = $bucket;
-    }
-    
-    public function getAccessKey()
-    {
-        return $this->accessKey;
-    }
-    
-    private function setAccessKey($accessKey)
-    {
-        $this->accessKey = $accessKey;
-    }
-    
-    public function getSecretKey()
-    {
-        return $this->secretKey;
-    }
-    
-    private function setSecretKey($secretKey)
-    {
-        $this->secretKey = $secretKey;
-    }
-}
\ No newline at end of file
diff --git a/airtime_mvc/application/cloud_storage/Amazon_S3.php b/airtime_mvc/application/cloud_storage/Amazon_S3.php
new file mode 100644
index 000000000..b9e405032
--- /dev/null
+++ b/airtime_mvc/application/cloud_storage/Amazon_S3.php
@@ -0,0 +1,74 @@
+<?php
+
+require_once 'StorageBackend.php';
+
+class Amazon_S3 extends StorageBackend
+{
+    private $zendServiceAmazonS3;
+    
+    public function Amazon_S3()
+    {
+        $CC_CONFIG = Config::getConfig();
+        
+        $this->setBucket($CC_CONFIG['storage_backend']['bucket']);
+        $this->setAccessKey($CC_CONFIG['storage_backend']['api_key']);
+        $this->setSecretKey($CC_CONFIG['storage_backend']['api_key_secret']);
+        
+        $this->zendServiceAmazonS3 = new Zend_Service_Amazon_S3(
+            $this->getAccessKey(),
+            $this->getSecretKey());
+    }
+    
+    public function getAbsoluteFilePath($resourceId)
+    {
+        $endpoint = $this->zendServiceAmazonS3->getEndpoint();
+        $scheme = $endpoint->getScheme();
+        $host = $endpoint->getHost();
+        $bucket = $this->getBucket();
+        return "$scheme://$bucket.$host/".utf8_encode($resourceId);
+    }
+
+    public function getSignedURL($resourceId)
+    {
+        //URL will be active for 30 minutes
+        $expires = time()+1800;
+        
+        $bucket = $this->getBucket();
+        $secretKey = $this->getSecretKey();
+        $accessKey = $this->getAccessKey();
+        
+        $string_to_sign = utf8_encode("GET\n\n\n$expires\n/$bucket/$resourceId");
+        // We need to urlencode the entire signature in case the hashed signature
+        // has spaces. (NOTE: utf8_encode() does not work here because it turns
+        // spaces into non-breaking spaces)
+        $signature = urlencode(base64_encode((hash_hmac("sha1", $string_to_sign, $secretKey, true))));
+        
+        $resourceURL = $this->getAbsoluteFilePath($resourceId);
+        return $resourceURL."?AWSAccessKeyId=$accessKey&Expires=$expires&Signature=$signature";
+    }
+    
+    public function getFileSize($resourceId)
+    {
+        $bucket = $this->getBucket();
+        
+        $amz_resource = utf8_encode("$bucket/$resourceId");
+        $amz_resource_info = $this->zendServiceAmazonS3->getInfo($amz_resource);
+        return $amz_resource_info["size"];
+    }
+    
+    public function deletePhysicalFile($resourceId)
+    {
+        $bucket = $this->getBucket();
+        $amz_resource = utf8_encode("$bucket/$resourceId");
+        
+        if ($this->zendServiceAmazonS3->isObjectAvailable($amz_resource)) {
+           // removeObject() returns true even if the object was not deleted (bug?)
+           // so that is not a good way to do error handling. isObjectAvailable()
+           // does however return the correct value; We have to assume that if the
+           // object is available the removeObject() function will work.
+           $this->zendServiceAmazonS3->removeObject($amz_resource);
+           } else {
+               throw new Exception("ERROR: Could not locate object on Amazon S3");
+           }
+    }
+}
diff --git a/airtime_mvc/application/cloud_storage/ProxyStorageBackend.php b/airtime_mvc/application/cloud_storage/ProxyStorageBackend.php
new file mode 100644
index 000000000..db475c04a
--- /dev/null
+++ b/airtime_mvc/application/cloud_storage/ProxyStorageBackend.php
@@ -0,0 +1,44 @@
+<?php
+
+require_once 'StorageBackend.php';
+require_once 'Amazon_S3.php';
+
+/**
+ * 
+ * Controls access to the storage backend class where a file is stored.
+ *
+ */
+class ProxyStorageBackend extends StorageBackend
+{
+    private $storageBackend;
+    
+    /**
+     * Receives the file's storage backend and instantiates the approriate
+     * object.
+     */
+    public function ProxyStorageBackend($storageBackend)
+    {
+        $this->storageBackend = new $storageBackend();
+    }
+    
+    public function getAbsoluteFilePath($resourceId)
+    {
+        return $this->storageBackend->getAbsoluteFilePath($resourceId);
+    }
+    
+    public function getSignedURL($resourceId)
+    {
+        return $this->storageBackend->getSignedURL($resourceId);
+    }
+    
+    public function getFileSize($resourceId)
+    {
+        return $this->storageBackend->getFileSize($resourceId);
+    }
+    
+    public function deletePhysicalFile($resourceId)
+    {
+        $this->storageBackend->deletePhysicalFile($resourceId);
+    }
+
+}
diff --git a/airtime_mvc/application/cloud_storage/StorageBackend.php b/airtime_mvc/application/cloud_storage/StorageBackend.php
new file mode 100644
index 000000000..84a9a8d72
--- /dev/null
+++ b/airtime_mvc/application/cloud_storage/StorageBackend.php
@@ -0,0 +1,55 @@
+<?php
+
+/**
+ * 
+ * Provides access to file objects stored on a specific storage backend.
+ */
+abstract class StorageBackend
+{
+    private $bucket;
+    private $accessKey;
+    private $secretKey;
+    
+    /** Returns the file object's URL to the storage backend it is located on. */
+    abstract public function getAbsoluteFilePath($resourceId);
+    
+    /** Returns the file object's signed URL. The URL must be signed since they
+     *  privately stored on the storage backend. */
+    abstract public function getSignedURL($resourceId);
+    
+    /** Returns the file's size in bytes. */
+    abstract public function getFileSize($resourceId);
+    
+    /** Deletes the file from the storage backend. */
+    abstract public function deletePhysicalFile($resourceId);
+    
+    protected function getBucket()
+    {
+        return $this->bucket;
+    }
+    
+    protected function setBucket($bucket)
+    {
+        $this->bucket = $bucket;
+    }
+    
+    protected function getAccessKey()
+    {
+        return $this->accessKey;
+    }
+    
+    protected function setAccessKey($accessKey)
+    {
+        $this->accessKey = $accessKey;
+    }
+    
+    protected function getSecretKey()
+    {
+        return $this->secretKey;
+    }
+    
+    protected function setSecretKey($secretKey)
+    {
+        $this->secretKey = $secretKey;
+    }
+}
diff --git a/airtime_mvc/application/configs/conf.php b/airtime_mvc/application/configs/conf.php
index 00eaecdbe..fda19171a 100644
--- a/airtime_mvc/application/configs/conf.php
+++ b/airtime_mvc/application/configs/conf.php
@@ -29,6 +29,7 @@ class Config {
         $cloudStorageConfig = isset($_SERVER['CLOUD_STORAGE_CONF']) ? $_SERVER['CLOUD_STORAGE_CONF'] : "/etc/airtime-saas/cloud_storage.conf";
         $cloudStorageValues = parse_ini_file($cloudStorageConfig, true);
         $currentStorageBackend = $cloudStorageValues['current_backend']['storage_backend'];
+        $CC_CONFIG['current_backend'] = $cloudStorageValues['current_backend']['storage_backend'];
         $CC_CONFIG['storage_backend'] = $cloudStorageValues[$currentStorageBackend];
         
         $values = parse_ini_file($filename, true);
diff --git a/airtime_mvc/application/models/airtime/CloudFile.php b/airtime_mvc/application/models/airtime/CloudFile.php
index c1d5b3b7a..099f7c4fa 100644
--- a/airtime_mvc/application/models/airtime/CloudFile.php
+++ b/airtime_mvc/application/models/airtime/CloudFile.php
@@ -1,13 +1,13 @@
 <?php
 
-require_once 'Amazon_S3.php';
+require_once 'ProxyStorageBackend.php';
 
 /**
  * Skeleton subclass for representing a row from the 'cloud_file' table.
  *
  * Each cloud_file has a corresponding cc_file referenced as a foreign key.
  * The file's metadata is stored in the cc_file table. This, cloud_file,
- * table represents files that are stored on Amazon S3.
+ * table represents files that are stored in the cloud.
  *
  * You should add additional methods to this class to meet the
  * application requirements.  This class will only be generated as
@@ -17,6 +17,7 @@ require_once 'Amazon_S3.php';
  */
 class CloudFile extends BaseCloudFile
 {
+    private $proxyStorageBackend;
 
     /**
      * Returns a signed URL to the file's object on Amazon S3. Since we are
@@ -25,7 +26,10 @@ class CloudFile extends BaseCloudFile
      */
     public function getURLForTrackPreviewOrDownload()
     {
-        return $this->getAbsoluteFilePath()."?".$this->getAuthenticationParams();
+        if ($this->proxyStorageBackend == null) {
+            $this->proxyStorageBackend = new ProxyStorageBackend($this->getStorageBackend());
+        }
+        return $this->proxyStorageBackend->getSignedURL($this->getResourceId());
     }
     
     /**
@@ -34,39 +38,10 @@ class CloudFile extends BaseCloudFile
      */
     public function getAbsoluteFilePath()
     {
-        $amazon_s3 = new Amazon_S3();
-        $zend_s3 = $amazon_s3->getZendServiceAmazonS3();
-        $resource_id = $this->getResourceId();
-        $endpoint = $zend_s3->getEndpoint();
-        $scheme = $endpoint->getScheme();
-        $host = $endpoint->getHost();
-        $s3_bucket = $amazon_s3->getBucket();
-        return "$scheme://$s3_bucket.$host/".utf8_encode($resource_id);
-    }
-    
-    /**
-     * 
-     * Returns a string of authentication paramaters to append to the cloud
-     * object's URL. We need this for track preview and download because the
-     * objects are privately stored on Amazon S3.
-     */
-    public function getAuthenticationParams()
-    {
-        $expires = time()+120;
-        $resource_id = $this->getResourceId();
-
-        $amazon_s3 = new Amazon_S3();
-        $s3_bucket = $amazon_s3->getBucket();
-        $s3_secret_key = $amazon_s3->getSecretKey();
-        $s3_access_key = $amazon_s3->getAccessKey();
-        
-        $string_to_sign = utf8_encode("GET\n\n\n$expires\n/$s3_bucket/$resource_id");
-        // We need to urlencode the entire signature in case the hashed signature
-        // has spaces. (NOTE: utf8_encode() does not work here because it turns
-        // spaces into non-breaking spaces)
-        $signature = urlencode(base64_encode((hash_hmac("sha1", $string_to_sign, $s3_secret_key, true))));
-        
-        return "AWSAccessKeyId=$s3_access_key&Expires=$expires&Signature=$signature";
+        if ($this->proxyStorageBackend == null) {
+            $this->proxyStorageBackend = new ProxyStorageBackend($this->getStorageBackend());
+        }
+        return $this->proxyStorageBackend->getAbsoluteFilePath($this->getResourceId());
     }
     
     /**
@@ -74,15 +49,10 @@ class CloudFile extends BaseCloudFile
      */
     public function getFileSize()
     {
-        $amazon_s3 = new Amazon_S3();
-        
-        $zend_s3 = $amazon_s3->getZendServiceAmazonS3();
-        $bucket = $amazon_s3->getBucket();
-        $resource_id = $this->getResourceId();
-        
-        $amz_resource = utf8_encode("$bucket/$resource_id");
-        $amz_resource_info = $zend_s3->getInfo($amz_resource);
-        return $amz_resource_info["size"];
+        if ($this->proxyStorageBackend == null) {
+            $this->proxyStorageBackend = new ProxyStorageBackend($this->getStorageBackend());
+        }
+        return $this->proxyStorageBackend->getFileSize($this->getResourceId());
     }
     
     public function getFilename()
@@ -119,21 +89,10 @@ class CloudFile extends BaseCloudFile
      */
     public function deletePhysicalFile()
     {
-        $amazon_s3 = new Amazon_S3();
-        $zend_s3 = $amazon_s3->getZendServiceAmazonS3();
-        $bucket = $amazon_s3->getBucket();
-        $resource_id = $this->getResourceId();
-        $amz_resource = utf8_encode("$bucket/$resource_id");
-        
-        if ($zend_s3->isObjectAvailable($amz_resource)) {
-            // removeObject() returns true even if the object was not deleted (bug?)
-            // so that is not a good way to do error handling. isObjectAvailable()
-            // does however return the correct value; We have to assume that if the
-            // object is available the removeObject() function will work.
-            $zend_s3->removeObject($amz_resource);
-        } else {
-            throw new Exception("ERROR: Could not locate object on Amazon S3");
+        if ($this->proxyStorageBackend == null) {
+            $this->proxyStorageBackend = new ProxyStorageBackend($this->getStorageBackend());
         }
+        $this->proxyStorageBackend->deletePhysicalFile($this->getResourceId());
     }
     
     /**
diff --git a/airtime_mvc/public/index.php b/airtime_mvc/public/index.php
index a20586e82..fd1335ee3 100644
--- a/airtime_mvc/public/index.php
+++ b/airtime_mvc/public/index.php
@@ -57,8 +57,8 @@ if (file_exists('/usr/share/php/libzend-framework-php')) {
     set_include_path('/usr/share/php/libzend-framework-php' . PATH_SEPARATOR . get_include_path());
 }
 
-//amazon directory
-set_include_path(APPLICATION_PATH . '/amazon' . PATH_SEPARATOR . get_include_path());
+//cloud storage directory
+set_include_path(APPLICATION_PATH . '/cloud_storage' . PATH_SEPARATOR . get_include_path());
 
 /** Zend_Application */
 require_once 'Zend/Application.php';