WIP azure rest API blob store wrapper

classes/azure_blob_file_system.php

@@ -0,0 +1,35 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle 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 General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * File system for Azure Blob Storage.
+ *
+ * @package    tool_objectfs
+ * @author     Matthew Hilton <[email protected]>
+ * @copyright  Catalyst IT
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace tool_objectfs;
+
+use tool_objectfs\local\store\azure\file_system;
+
+/**
+ * Azure blob file system header.
+ */
+class azure_blob_file_system extends file_system {
+
+}

classes/local/store/azure_blob/client.php

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+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle 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 General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace tool_objectfs\local\store\azure_blob;
+
+use core\lang_string;
+use GuzzleHttp\Psr7\Utils;
+use local_azureblobstorage\api;
+use stdClass;
+use tool_objectfs\local\store\object_client_base;
+
+/**
+ * Azure Blob Storage client.
+ *
+ * @package    tool_objectfs
+ * @author     Matthew Hilton <[email protected]>
+ * @copyright  Catalyst IT
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class client extends object_client_base {
+
+    /** @var Api $client Azure rest API interface. */
+    protected $client;
+
+    /** @var string Container name, used for constructing paths */
+    protected $container;
+
+    /**
+     * The azure client constructor.
+     *
+     * @param \stdclass $config
+     */
+    public function __construct($config) {
+        global $CFG;
+        $this->autoloader = $CFG->dirroot . '/local/azure_storage/vendor/autoload.php';
+
+        if ($this->get_availability() && !empty($config)) {
+            $this->client = new api($config->azure_accountname, $config->azure_container, $this->clean_sastoken($config->azure_sastoken));
+            $this->container = $config->azure_container;
+        } else {
+            parent::__construct($config);
+        }
+    }
+
+    /**
+     * Sets the StreamWrapper to allow accessing the remote content via a blob:// path.
+     */
+    public function register_stream_wrapper() {
+        if ($this->get_availability()) {
+            stream_wrapper::register($this->client);
+        } else {
+            parent::register_stream_wrapper();
+        }
+    }
+
+    /**
+     * Returns azure fullpath to use with php file functions.
+     *
+     * @param  string $contenthash contenthash used as key in azure.
+     * @return string fullpath to azure object.
+     */
+    public function get_fullpath_from_hash($contenthash) {
+        $filepath = $this->get_filepath_from_hash($contenthash);
+        return "blob://$this->container/$filepath";
+    }
+
+    /**
+     * Deletes file (blob) in azure blob storage.
+     *
+     * @param string $fullpath path to azure blob.
+     */
+    public function delete_file($fullpath) {
+        // TODO get hash from fullpath
+        // TODo call $client->delete_blob($hash)
+    }
+
+    /**
+     * Moves file (blob) within azure blob storage.
+     *
+     * @param string $currentpath     current path to file to be moved.
+     * @param string $destinationpath destination path to file.
+     */
+    public function rename_file($currentpath, $destinationpath) {
+        copy($currentpath, $destinationpath);
+
+        $this->delete_file($currentpath);
+    }
+
+    /**
+     * Returns relative path to blob from fullpath to use with php file functions.
+     *
+     * @param    string    $fullpath full path to azure blob.
+     * @return   string    relative path to azure blob.
+     */
+    public function get_relative_path_from_fullpath($fullpath) {
+        $relativepath = str_replace("blob://$this->container/", '', $fullpath);
+
+        return $relativepath;
+    }
+
+    /**
+     * Returns a context for the stream that is seekable.
+     *
+     * @return resource
+     */
+    public function get_seekable_stream_context() {
+        $context = stream_context_create([
+            'blob' => [
+                'seekable' => true,
+            ],
+        ]);
+        return $context;
+    }
+
+    /**
+     * TODO this might not be necessary anymore ?
+     *
+     * Trim a leading '?' character from the sas token.
+     *
+     * @param string $sastoken
+     * @return bool|string
+     */
+    private function clean_sastoken($sastoken) {
+        if (substr($sastoken, 0, 1) === '?') {
+            $sastoken = substr($sastoken, 1);
+        }
+
+        return $sastoken;
+    }
+
+    /**
+     * Gets the md5 for a file that is currently stored in Azure.
+     * Generally this is used for upload verification.
+     *
+     * @param string $contenthash
+     * @return string MD5 hash
+     */
+    private function get_md5_from_hash($contenthash) {
+        try {
+            $key = $this->get_filepath_from_hash($contenthash);
+
+            $result = $this->client->get_blob_properties($this->container, $key)->wait();
+
+        // TODO catch different exception ?
+        } catch (\MicrosoftAzure\Storage\Common\Exceptions\ServiceException $e) {
+            return false;
+        }
+
+        // TODO get the proper header name.
+        $contentmd5 = $result['x-ms-contentmd5'];
+
+        // TODO should we leave as base64 or decode it ??
+        if ($contentmd5) {
+            $md5 = bin2hex(base64_decode($contentmd5));
+        } else {
+            $md5 = trim($result->getETag(), '"'); // Strip quotation marks.
+        }
+
+        return $md5;
+    }
+
+    /**
+     * Verifies the object using the md5 stored in moodle vs blob storage.
+     *
+     * @param string $contenthash
+     * @param string $localpath
+     *
+     * @return bool
+     */
+    public function verify_object($contenthash, $localpath) {
+        $localmd5 = ''; // TODO.
+        $remotemd5 = $this->get_md5_from_hash($contenthash);
+        return $localmd5 == $remotemd5;
+    }
+
+    /**
+     * Return filepath from the content hash.
+     *
+     * @param string $contenthash
+     *
+     * @return string
+     */
+    protected function get_filepath_from_hash($contenthash) {
+        $l1 = $contenthash[0] . $contenthash[1];
+        $l2 = $contenthash[2] . $contenthash[3];
+        return "$l1/$l2/$contenthash";
+    }
+
+    /**
+     * Tests connection by trying to create a test blob.
+     *
+     * @return stdClass
+     */
+    public function test_connection() {
+        $connection = new \stdClass();
+        $connection->success = true;
+        $connection->details = '';
+
+        try {
+            $md5 = hex2bin(md5('connection_check_file'));
+            $this->client->put_blob('connection_check_file', Utils::streamFor('connection_check_file'), $md5);
+
+        // TODO catch different exceptions
+        } catch (\MicrosoftAzure\Storage\Common\Exceptions\ServiceException $e) {
+            $connection->success = false;
+            $connection->details = $this->get_exception_details($e);
+        } catch (\GuzzleHttp\Exception\ConnectException $e) {
+            $connection->success = false;
+            $connection->details = $e->getMessage();
+        }
+
+        return $connection;
+    }
+
+    /**
+     * TEsts permissions by trying to create, get and delete a blob.
+     * @param mixed $testdelete
+     *
+     * @return stdClass
+     */
+    public function test_permissions($testdelete) {
+        // TODO redo this and make it neat and tidy.
+        // TODO also support when objectfs deletion is disabled, don't check deletion.
+
+        $permissions = new \stdClass();
+        $permissions->success = true;
+        $permissions->messages = [];
+
+        // try {
+        //     $result = $this->client->createBlockBlob($this->container, 'permissions_check_file', 'permissions_check_file');
+        // } catch (\MicrosoftAzure\Storage\Common\Exceptions\ServiceException $e) {
+        //     $details = $this->get_exception_details($e);
+        //     $permissions->messages[get_string('settings:writefailure', 'tool_objectfs') . $details] = 'notifyproblem';
+        //     $permissions->success = false;
+        // }
+
+        // try {
+        //     $result = $this->client->getBlob($this->container, 'permissions_check_file');
+        // } catch (\MicrosoftAzure\Storage\Common\Exceptions\ServiceException $e) {
+        //     $errorcode = $this->get_body_error_code($e);
+
+        //     // Write could have failed.
+        //     if ($errorcode !== 'BlobNotFound') {
+        //         $details = $this->get_exception_details($e);
+        //         $permissions->messages[get_string('settings:permissionreadfailure', 'tool_objectfs') . $details] = 'notifyproblem';
+        //         $permissions->success = false;
+        //     }
+        // }
+
+        // try {
+        //     $result = $this->client->deleteBlob($this->container, 'permissions_check_file');
+        //     $permissions->messages[get_string('settings:deletesuccess', 'tool_objectfs')] = 'warning';
+        //     $permissions->success = false;
+        // } catch (\MicrosoftAzure\Storage\Common\Exceptions\ServiceException $e) {
+        //     $errorcode = $this->get_body_error_code($e);
+
+        //     // Something else went wrong.
+        //     if ($errorcode !== 'AuthorizationPermissionMismatch') {
+        //         $details = $this->get_exception_details($e);
+        //         $permissions->messages[get_string('settings:deleteerror', 'tool_objectfs') . $details] = 'notifyproblem';
+        //         $permissions->success = false;
+        //     }
+        // }
+
+        // if ($permissions->success) {
+        //     $permissions->messages[get_string('settings:permissioncheckpassed', 'tool_objectfs')] = 'notifysuccess';
+        // }
+
+        return $permissions;
+    }
+
+    /**
+     * Azure settings form with the following elements:
+     *
+     * Storage account name.
+     * Container name.
+     * Shared Access Signature.
+     *
+     * @param admin_settingpage $settings
+     * @param  \stdClass $config
+     * @return admin_settingpage
+     */
+    public function define_client_section($settings, $config) {
+
+        $settings->add(new \admin_setting_heading('tool_objectfs/azure',
+            new lang_string('settings:azure:header', 'tool_objectfs'), $this->define_client_check()));
+
+        $settings->add(new \admin_setting_configtext('tool_objectfs/azure_accountname',
+            new lang_string('settings:azure:accountname', 'tool_objectfs'),
+            new lang_string('settings:azure:accountname_help', 'tool_objectfs'), ''));
+
+        $settings->add(new \admin_setting_configtext('tool_objectfs/azure_container',
+            new lang_string('settings:azure:container', 'tool_objectfs'),
+            new lang_string('settings:azure:container_help', 'tool_objectfs'), ''));
+
+        $settings->add(new \admin_setting_configpasswordunmask('tool_objectfs/azure_sastoken',
+            new lang_string('settings:azure:sastoken', 'tool_objectfs'),
+            new lang_string('settings:azure:sastoken_help', 'tool_objectfs'), ''));
+
+        return $settings;
+    }
+}