MDL-82627 AI: Provider Plugin - Open AI

Initial Open AI API Provider plugin.
Originally implemented in MDL-80894

Co-authored-by: Huong Nguyen <huongnv13@gmail.com>

ai/provider/openai/classes/process_generate_image.php

@@ -0,0 +1,201 @@
+<?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 aiprovider_openai;
+
+use core_ai\aiactions\responses\response_base;
+use core_ai\aiactions\responses\response_generate_image;
+use Psr\Http\Message\ResponseInterface;
+
+defined('MOODLE_INTERNAL') || die();
+
+require_once($CFG->libdir . '/filelib.php');
+
+/**
+ * Class process image generation.
+ *
+ * @package    aiprovider_openai
+ * @copyright  2024 Matt Porritt <matt.porritt@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class process_generate_image extends process_generate_text {
+    /** @var string The API endpoint to make requests against. */
+    private string $aiendpoint = 'https://api.openai.com/v1/images/generations';
+
+    /** @var string The API model to use. */
+    private string $model = 'dall-e-3';
+
+    /** @var int The number of images to generate dall-e-3 only supports 1. */
+    private int $numberimages = 1;
+
+    /** @var string Response format: url or b64_json. */
+    private string $responseformat = 'url';
+
+    /**
+     * Process the AI request.
+     *
+     * @return response_base The result of the action.
+     */
+    public function process(): response_base {
+        // Check the rate limiter.
+        $ratelimitcheck = $this->provider->is_request_allowed($this->action);
+        if ($ratelimitcheck !== true) {
+            return new response_generate_image(
+                success: false,
+                actionname: 'generate_image',
+                errorcode: $ratelimitcheck['errorcode'],
+                errormessage: $ratelimitcheck['errormessage'],
+            );
+        }
+
+        $userid = $this->provider->generate_userid($this->action->get_configuration('userid'));
+        $client = $this->provider->create_http_client($this->aiendpoint);
+
+        // Create the request object.
+        $requestobj = $this->create_request_object($this->action, $userid);
+
+        // Make the request to the OpenAI API.
+        $response = $this->query_ai_api($client, $requestobj);
+
+        // If the request was successful, save the URL to a file.
+        if ($response['success']) {
+            $fileobj = $this->url_to_file(
+                $this->action->get_configuration('userid'),
+                $response['sourceurl']
+            );
+            // Add the file to the response, so the calling placement can do whatever they want with it.
+            $response['draftfile'] = $fileobj;
+        }
+
+        // Format the action response object.
+        return $this->prepare_response($response);
+    }
+
+    /**
+     * Convert the given aspect ratio to an image size
+     * that is compatible with the OpenAI API.
+     *
+     * @param string $ratio The aspect ratio of the image.
+     * @return string The size of the image.
+     * @throws \coding_exception
+     */
+    private function calculate_size(string $ratio): string {
+        if ($ratio === 'square') {
+            $size = '1024x1024';
+        } else if ($ratio === 'landscape') {
+            $size = '1792x1024';
+        } else if ($ratio === 'portrait') {
+            $size = '1024x1792';
+        } else {
+            throw new \coding_exception('Invalid aspect ratio: ' . $ratio);
+        }
+        return $size;
+    }
+
+    /**
+     * Create the request object to send to the OpenAI API.
+     * This object contains all the required parameters for the request.
+     *
+     * @param \core_ai\aiactions\base $action The action to process.
+     * @param string $userid The user id.
+     * @return \stdClass The request object to send to the OpenAI API.
+     * @throws \coding_exception
+     */
+    private function create_request_object(\core_ai\aiactions\base $action, string $userid): \stdClass {
+        $requestobj = new \stdClass();
+        $requestobj->prompt = $action->get_configuration('prompttext');
+        $requestobj->model = $this->model;
+        $requestobj->n = $this->numberimages;
+        $requestobj->quality = $action->get_configuration('quality');
+        $requestobj->response_format = $this->responseformat;
+        $requestobj->size = $this->calculate_size($action->get_configuration('aspectratio'));
+        $requestobj->style = $action->get_configuration('style');
+        $requestobj->user = $userid;
+
+        return $requestobj;
+    }
+
+    /**
+     * Handle a successful response from the external AI api.
+     *
+     * @param ResponseInterface $response The response object.
+     * @return array The response.
+     */
+    protected function handle_api_success(ResponseInterface $response): array {
+        $responsebody = $response->getBody();
+        $bodyobj = json_decode($responsebody->getContents());
+
+        return [
+            'success' => true,
+            'sourceurl' => $bodyobj->data[0]->url,
+            'revisedprompt' => $bodyobj->data[0]->revised_prompt,
+        ];
+    }
+
+    /**
+     * Prepare the response object.
+     *
+     * @param array $response The response object.
+     * @return response_generate_image The action response object.
+     * @throws \coding_exception
+     */
+    private function prepare_response(array $response): response_generate_image {
+        if ($response['success']) {
+            $generatedimage = new response_generate_image(
+                success: true,
+                actionname: 'generate_image',
+            );
+            $generatedimage->set_response($response);
+            return $generatedimage;
+        } else {
+            return new response_generate_image(
+                success: false,
+                actionname: 'generate_image',
+                errorcode: $response['errorcode'],
+                errormessage: $response['errormessage'],
+            );
+        }
+    }
+
+    /**
+     * Convert the url for the image  to a file.
+     *
+     * Placements can't interact with the provider AI directly,
+     * therefore we need to provide the image file in a format that can
+     * be used by placements. So we use the file API.
+     *
+     * @param int $userid The user id.
+     * @param string $url The URL to the image.
+     * @return \stored_file The file object.
+     */
+    private function url_to_file(int $userid, string $url): \stored_file {
+        $parsedurl = parse_url($url, PHP_URL_PATH); // Parse the URL to get the path.
+        $filename = basename($parsedurl); // Get the basename of the path.
+
+        // We put the file in the user draft area initially.
+        // Placements (on behalf of the user) can then move it to the correct location.
+        $fileinfo = new \stdClass();
+        $fileinfo->contextid = \context_user::instance($userid)->id;
+        $fileinfo->filearea = 'draft';
+        $fileinfo->component = 'user';
+        $fileinfo->itemid = file_get_unused_draft_itemid();
+        $fileinfo->filepath = '/';
+        $fileinfo->filename = $filename;
+
+        $fs = get_file_storage();
+        return $fs->create_file_from_url($fileinfo, $url);
+    }
+}