New class for external resources

src/Core/StorageManager.php

@@ -126,6 +126,9 @@ class StorageManager
 					case Storage\SystemResource::getName():
 						$this->backendInstances[$name] = new Storage\SystemResource();
 						break;
+					case Storage\ExternalResource::getName():
+						$this->backendInstances[$name] = new Storage\ExternalResource();
+						break;
 					default:
 						$data = [
 							'name'    => $name,
@@ -158,7 +161,7 @@ class StorageManager
 	public function isValidBackend(string $name = null, bool $onlyUserBackend = false)
 	{
 		return array_key_exists($name, $this->backends) ||
-		       (!$onlyUserBackend && $name === Storage\SystemResource::getName());
+		       (!$onlyUserBackend && in_array($name, [Storage\SystemResource::getName(), Storage\ExternalResource::getName()]));
 	}
 
 	/**

src/Model/Photo.php

@@ -27,6 +27,7 @@ use Friendica\Core\System;
 use Friendica\Database\DBA;
 use Friendica\Database\DBStructure;
 use Friendica\DI;
+use Friendica\Model\Storage\ExternalResource;
 use Friendica\Model\Storage\SystemResource;
 use Friendica\Object\Image;
 use Friendica\Util\DateTimeFormat;
@@ -263,6 +264,28 @@ class Photo
 		return $photo;
 	}
 
+	/**
+	 * Construct a photo array for an external resource image
+	 *
+	 * @param string $url      Image URL
+	 * @param string $mimetype Image mime type. Defaults to "image/jpeg"
+	 *
+	 * @return array
+	 * @throws \Exception
+	 */
+	public static function createPhotoForExternalResource($url, $mimetype = "image/jpeg")
+	{
+		$fields = self::getFields();
+		$values = array_fill(0, count($fields), "");
+
+		$photo                  = array_combine($fields, $values);
+		$photo['backend-class'] = ExternalResource::NAME;
+		$photo['backend-ref']   = $url;
+		$photo['type']          = $mimetype;
+		$photo['cacheable']     = false;
+
+		return $photo;
+	}
 
 	/**
 	 * store photo metadata in db and binary in default backend

src/Model/Storage/ExternalResource.php

@@ -0,0 +1,99 @@
+<?php
+/**
+ * @copyright Copyright (C) 2010-2021, the Friendica project
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Friendica\Model\Storage;
+
+use \BadMethodCallException;
+use Friendica\DI;
+
+/**
+ * External resource storage class
+ *
+ * This class is used to load external resources, like images.
+ * Is not intended to be selectable by admins as default storage class.
+ */
+class ExternalResource implements IStorage
+{
+	const NAME = 'ExternalResource';
+
+	/**
+	 * @inheritDoc
+	 */
+	public function get(string $filename)
+	{
+		$parts = parse_url($filename);
+		if (empty($parts['scheme']) || empty($parts['host'])) {
+			return "";
+		}
+
+		$curlResult = DI::httpRequest()->get($filename);
+		if ($curlResult->isSuccess()) {
+			return $curlResult->getBody();
+		} else {
+			return "";
+		}
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function put(string $data, string $filename = '')
+	{
+		throw new BadMethodCallException();
+	}
+
+	public function delete(string $filename)
+	{
+		throw new BadMethodCallException();
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function getOptions()
+	{
+		return [];
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function saveOptions(array $data)
+	{
+		return [];
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function __toString()
+	{
+		return self::NAME;
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public static function getName()
+	{
+		return self::NAME;
+	}
+}

src/Model/Storage/SystemResource.php

@@ -22,7 +22,6 @@
 namespace Friendica\Model\Storage;
 
 use \BadMethodCallException;
-use Friendica\DI;
 
 /**
  * System resource storage class
@@ -42,16 +41,6 @@ class SystemResource implements IStorage
 	 */
 	public function get(string $filename)
 	{
-		$parts = parse_url($filename);
-		if (!empty($parts['scheme']) && !empty($parts['host'])) {
-			$curlResult = DI::httpRequest()->get($filename);
-			if ($curlResult->isSuccess()) {
-				return $curlResult->getBody();
-			} else {
-				return "";
-			}
-		}
-
 		$folder = dirname($filename);
 		if (!in_array($folder, self::VALID_FOLDERS)) {
 			return "";

src/Module/Photo.php

@@ -167,7 +167,7 @@ class Photo extends BaseModule
 				} else {
 					$url = DI::baseUrl() . Contact::DEFAULT_AVATAR_PHOTO;
 				}
-				return MPhoto::createPhotoForSystemResource($url);
+				return MPhoto::createPhotoForExternalResource($url);
 			case "header":
 				$contact = Contact::getById($uid, ['uid', 'url', 'header']);
 				if (empty($contact)) {
@@ -181,7 +181,7 @@ class Photo extends BaseModule
 				} else {
 					$url = DI::baseUrl() . '/images/blank.png';
 				}
-				return MPhoto::createPhotoForSystemResource($url);
+				return MPhoto::createPhotoForExternalResource($url);
 			case "profile":
 			case "custom":
 				$scale = 4;
@@ -211,7 +211,12 @@ class Photo extends BaseModule
 					$default = Contact::getDefaultAvatar($contact, Proxy::SIZE_THUMB);
 			}
 	
-			$photo = MPhoto::createPhotoForSystemResource($default);
+			$parts = parse_url($default);
+			if (!empty($parts['scheme']) || !empty($parts['host'])) {
+				$photo = MPhoto::createPhotoForExternalResource($default);
+			} else {
+				$photo = MPhoto::createPhotoForSystemResource($default);
+			}
 		}
 		return $photo;
 	}