| 1 |
<?php |
| 2 |
|
| 3 |
namespace WPSP\API; |
| 4 |
|
| 5 |
use WPSP\Helper; |
| 6 |
|
| 7 |
/** |
| 8 |
* AI Caption API Handler |
| 9 |
* |
| 10 |
* Generates social captions for a post via the OpenAI Chat Completions API. |
| 11 |
* Reads the OpenAI API key saved on the SchedulePress Settings → AI panel |
| 12 |
* (`openai_api_key` in the `wpsp_settings_v5` option). |
| 13 |
* |
| 14 |
* Route: POST wp-scheduled-posts/v1/ai-caption/{post_id} |
| 15 |
* Response: { success: true, captions: { facebook: "...", twitter: "..." } } |
| 16 |
* |
| 17 |
* @since 5.3.0 |
| 18 |
*/ |
| 19 |
class AICaption |
| 20 |
{ |
| 21 |
/** |
| 22 |
* Instance of this class. |
| 23 |
* |
| 24 |
* @var object |
| 25 |
*/ |
| 26 |
protected static $instance = null; |
| 27 |
|
| 28 |
/** |
| 29 |
* OpenAI chat completions endpoint. |
| 30 |
*/ |
| 31 |
const OPENAI_ENDPOINT = 'https://api.openai.com/v1/chat/completions'; |
| 32 |
|
| 33 |
/** |
| 34 |
* OpenAI models endpoint — used to cheaply validate an API key. |
| 35 |
*/ |
| 36 |
const OPENAI_MODELS_ENDPOINT = 'https://api.openai.com/v1/models'; |
| 37 |
|
| 38 |
/** |
| 39 |
* Per-platform display name + character budget used to guide the model. |
| 40 |
* |
| 41 |
* @var array |
| 42 |
*/ |
| 43 |
protected $platform_meta = [ |
| 44 |
'facebook' => ['name' => 'Facebook', 'limit' => 63206], |
| 45 |
'twitter' => ['name' => 'X (Twitter)', 'limit' => 280], |
| 46 |
'linkedin' => ['name' => 'LinkedIn', 'limit' => 3000], |
| 47 |
'pinterest' => ['name' => 'Pinterest', 'limit' => 500], |
| 48 |
'instagram' => ['name' => 'Instagram', 'limit' => 2200], |
| 49 |
'medium' => ['name' => 'Medium', 'limit' => 45000], |
| 50 |
'threads' => ['name' => 'Threads', 'limit' => 500], |
| 51 |
'google_business' => ['name' => 'Google Business Profile', 'limit' => 1500], |
| 52 |
'bluesky' => ['name' => 'Bluesky', 'limit' => 300], |
| 53 |
'mastodon' => ['name' => 'Mastodon', 'limit' => 500], |
| 54 |
]; |
| 55 |
|
| 56 |
/** |
| 57 |
* Initialize hooks. |
| 58 |
*/ |
| 59 |
private function __construct() |
| 60 |
{ |
| 61 |
add_action('rest_api_init', array($this, 'register_routes')); |
| 62 |
} |
| 63 |
|
| 64 |
/** |
| 65 |
* Register the AI caption REST route. |
| 66 |
*/ |
| 67 |
public function register_routes() |
| 68 |
{ |
| 69 |
$namespace = WPSP_PLUGIN_SLUG . '/v1'; |
| 70 |
|
| 71 |
register_rest_route($namespace, 'ai-caption/(?P<post_id>\d+)', array( |
| 72 |
'methods' => 'POST', |
| 73 |
'callback' => array($this, 'generate_captions'), |
| 74 |
'permission_callback' => function () { |
| 75 |
return current_user_can('edit_posts'); |
| 76 |
}, |
| 77 |
'args' => array( |
| 78 |
'post_id' => array( |
| 79 |
'required' => true, |
| 80 |
'validate_callback' => function ($param) { |
| 81 |
return is_numeric($param); |
| 82 |
}, |
| 83 |
), |
| 84 |
), |
| 85 |
)); |
| 86 |
|
| 87 |
// Validate an OpenAI API key from the settings panel. |
| 88 |
register_rest_route($namespace, 'ai-test-key', array( |
| 89 |
'methods' => 'POST', |
| 90 |
'callback' => array($this, 'test_connection'), |
| 91 |
'permission_callback' => function () { |
| 92 |
return current_user_can('manage_options'); |
| 93 |
}, |
| 94 |
)); |
| 95 |
} |
| 96 |
|
| 97 |
/** |
| 98 |
* Test an OpenAI API key by hitting the models endpoint. |
| 99 |
* |
| 100 |
* Accepts an `api_key` param (the value currently typed into the settings |
| 101 |
* field) and falls back to the saved key when none is supplied. |
| 102 |
* |
| 103 |
* @param \WP_REST_Request $request |
| 104 |
* @return \WP_REST_Response |
| 105 |
*/ |
| 106 |
public function test_connection($request) |
| 107 |
{ |
| 108 |
$api_key = $request->get_param('api_key'); |
| 109 |
$api_key = is_string($api_key) ? trim($api_key) : ''; |
| 110 |
|
| 111 |
if (empty($api_key)) { |
| 112 |
$saved = Helper::get_settings('openai_api_key'); |
| 113 |
$api_key = is_string($saved) ? trim($saved) : ''; |
| 114 |
} |
| 115 |
|
| 116 |
if (empty($api_key)) { |
| 117 |
return new \WP_REST_Response(array( |
| 118 |
'success' => false, |
| 119 |
'message' => __('Please enter an API key before testing the connection.', 'wp-scheduled-posts'), |
| 120 |
), 400); |
| 121 |
} |
| 122 |
|
| 123 |
$response = wp_remote_get(self::OPENAI_MODELS_ENDPOINT, array( |
| 124 |
'timeout' => 30, |
| 125 |
'headers' => array( |
| 126 |
'Authorization' => 'Bearer ' . $api_key, |
| 127 |
), |
| 128 |
)); |
| 129 |
|
| 130 |
if (is_wp_error($response)) { |
| 131 |
return new \WP_REST_Response(array( |
| 132 |
'success' => false, |
| 133 |
'message' => $response->get_error_message(), |
| 134 |
), 502); |
| 135 |
} |
| 136 |
|
| 137 |
$code = wp_remote_retrieve_response_code($response); |
| 138 |
|
| 139 |
if ($code === 200) { |
| 140 |
return new \WP_REST_Response(array( |
| 141 |
'success' => true, |
| 142 |
'message' => __('Connection successful. Your API key is valid.', 'wp-scheduled-posts'), |
| 143 |
), 200); |
| 144 |
} |
| 145 |
|
| 146 |
$data = json_decode(wp_remote_retrieve_body($response), true); |
| 147 |
$message = isset($data['error']['message']) |
| 148 |
? $data['error']['message'] |
| 149 |
: __('Connection failed. Please verify your API key and try again.', 'wp-scheduled-posts'); |
| 150 |
|
| 151 |
return new \WP_REST_Response(array( |
| 152 |
'success' => false, |
| 153 |
'message' => $message, |
| 154 |
), 200); |
| 155 |
} |
| 156 |
|
| 157 |
/** |
| 158 |
* Generate captions for the selected platforms. |
| 159 |
* |
| 160 |
* @param \WP_REST_Request $request |
| 161 |
* @return \WP_REST_Response |
| 162 |
*/ |
| 163 |
public function generate_captions($request) |
| 164 |
{ |
| 165 |
$post_id = (int) $request->get_param('post_id'); |
| 166 |
|
| 167 |
if (!get_post($post_id) || !current_user_can('edit_post', $post_id)) { |
| 168 |
return new \WP_REST_Response(array( |
| 169 |
'success' => false, |
| 170 |
'message' => __('Post not found or insufficient permissions.', 'wp-scheduled-posts'), |
| 171 |
), 403); |
| 172 |
} |
| 173 |
|
| 174 |
$api_key = Helper::get_settings('openai_api_key'); |
| 175 |
$api_key = is_string($api_key) ? trim($api_key) : ''; |
| 176 |
|
| 177 |
if (empty($api_key)) { |
| 178 |
return new \WP_REST_Response(array( |
| 179 |
'success' => false, |
| 180 |
'message' => __('OpenAI API key is not configured. Add it in SchedulePress → Settings → AI.', 'wp-scheduled-posts'), |
| 181 |
), 400); |
| 182 |
} |
| 183 |
|
| 184 |
// Read and sanitize request payload. |
| 185 |
$platforms = (array) $request->get_param('platforms'); |
| 186 |
$platforms = array_values(array_intersect( |
| 187 |
array_map('sanitize_key', $platforms), |
| 188 |
array_keys($this->platform_meta) |
| 189 |
)); |
| 190 |
|
| 191 |
if (empty($platforms)) { |
| 192 |
return new \WP_REST_Response(array( |
| 193 |
'success' => false, |
| 194 |
'message' => __('Please select at least one social platform.', 'wp-scheduled-posts'), |
| 195 |
), 400); |
| 196 |
} |
| 197 |
|
| 198 |
$prompt = sanitize_textarea_field((string) $request->get_param('prompt')); |
| 199 |
$auto_generate = filter_var($request->get_param('autoGenerate'), FILTER_VALIDATE_BOOLEAN); |
| 200 |
$tone = sanitize_text_field((string) $request->get_param('tone')) ?: 'professional'; |
| 201 |
$length = sanitize_key((string) $request->get_param('length')) ?: 'auto'; |
| 202 |
$generate_hashtags = filter_var($request->get_param('generateHashtags'), FILTER_VALIDATE_BOOLEAN); |
| 203 |
$include_emojis = filter_var($request->get_param('includeEmojis'), FILTER_VALIDATE_BOOLEAN); |
| 204 |
|
| 205 |
// Post context. |
| 206 |
$post = get_post($post_id); |
| 207 |
$post_title = get_the_title($post_id); |
| 208 |
$post_content = wp_strip_all_tags($post->post_content); |
| 209 |
$post_content = trim(preg_replace('/\s+/', ' ', $post_content)); |
| 210 |
$post_excerpt = function_exists('mb_substr') ? mb_substr($post_content, 0, 1500) : substr($post_content, 0, 1500); |
| 211 |
$permalink = get_permalink($post_id); |
| 212 |
|
| 213 |
$messages = $this->build_messages( |
| 214 |
$platforms, |
| 215 |
compact('prompt', 'auto_generate', 'tone', 'length', 'generate_hashtags', 'include_emojis'), |
| 216 |
array( |
| 217 |
'title' => $post_title, |
| 218 |
'excerpt' => $post_excerpt, |
| 219 |
'permalink' => $permalink, |
| 220 |
) |
| 221 |
); |
| 222 |
|
| 223 |
$captions = $this->request_openai($api_key, $messages, $platforms); |
| 224 |
|
| 225 |
if (is_wp_error($captions)) { |
| 226 |
return new \WP_REST_Response(array( |
| 227 |
'success' => false, |
| 228 |
'message' => $captions->get_error_message(), |
| 229 |
), 502); |
| 230 |
} |
| 231 |
|
| 232 |
return new \WP_REST_Response(array( |
| 233 |
'success' => true, |
| 234 |
'captions' => $captions, |
| 235 |
), 200); |
| 236 |
} |
| 237 |
|
| 238 |
/** |
| 239 |
* Build the OpenAI chat messages (system + user). |
| 240 |
* |
| 241 |
* @param array $platforms |
| 242 |
* @param array $opts |
| 243 |
* @param array $post |
| 244 |
* @return array |
| 245 |
*/ |
| 246 |
protected function build_messages($platforms, $opts, $post) |
| 247 |
{ |
| 248 |
// Character ranges the AI generates to. Keep these in sync with |
| 249 |
// LENGTH_OPTIONS in src/components/modals/socialTemplates/AICaptionDrawer.js. |
| 250 |
$length_guide = array( |
| 251 |
'auto' => 'an appropriate length for each platform', |
| 252 |
'short' => 'short and punchy — roughly 50-120 characters (1-2 sentences)', |
| 253 |
'medium' => 'a moderate length — roughly 120-250 characters (2-4 sentences)', |
| 254 |
'long' => 'detailed and engaging — roughly 250-500 characters (multiple sentences)', |
| 255 |
); |
| 256 |
$length_text = isset($length_guide[$opts['length']]) ? $length_guide[$opts['length']] : $length_guide['auto']; |
| 257 |
|
| 258 |
// Per-platform constraints. Use the limits configured in settings (the |
| 259 |
// same ones template validation enforces) so generated captions fit. |
| 260 |
$limits = Helper::get_social_platform_limits(); |
| 261 |
$platform_lines = array(); |
| 262 |
foreach ($platforms as $key) { |
| 263 |
$meta = $this->platform_meta[$key]; |
| 264 |
$limit = isset($limits[$key]) ? $limits[$key] : $meta['limit']; |
| 265 |
$platform_lines[] = sprintf('- "%s" (%s, max %d characters — never exceed this)', $key, $meta['name'], $limit); |
| 266 |
} |
| 267 |
$platform_block = implode("\n", $platform_lines); |
| 268 |
$keys_list = '"' . implode('", "', $platforms) . '"'; |
| 269 |
|
| 270 |
$system = 'You are an expert social media copywriter. You write engaging, platform-native captions that drive engagement. ' |
| 271 |
. 'You always respond with a single valid JSON object and nothing else — no markdown, no code fences, no commentary.'; |
| 272 |
|
| 273 |
$user = "Write a social media caption for each of the following platforms, tailored to each platform's style and character limit:\n"; |
| 274 |
$user .= $platform_block . "\n\n"; |
| 275 |
$user .= "Post title: " . $post['title'] . "\n"; |
| 276 |
if (!empty($post['excerpt'])) { |
| 277 |
$user .= "Post content: " . $post['excerpt'] . "\n"; |
| 278 |
} |
| 279 |
if (!empty($post['permalink'])) { |
| 280 |
$user .= "Post URL: " . $post['permalink'] . "\n"; |
| 281 |
} |
| 282 |
$user .= "\nRequirements:\n"; |
| 283 |
if ($opts['tone'] === 'post_specific') { |
| 284 |
// Match the post's own voice instead of applying a fixed preset. |
| 285 |
$user .= "- Tone/style: analyze the tone, voice, and writing style of the post title and content above, then write each caption to match that same tone and style.\n"; |
| 286 |
} else { |
| 287 |
$user .= "- Tone/style: {$opts['tone']}.\n"; |
| 288 |
} |
| 289 |
$user .= "- Length: {$length_text}.\n"; |
| 290 |
$user .= '- Hashtags: ' . ($opts['generate_hashtags'] ? 'include a few relevant hashtags.' : 'do not include hashtags.') . "\n"; |
| 291 |
$user .= '- Emojis: ' . ($opts['include_emojis'] ? 'use tasteful, relevant emojis.' : 'do not use emojis.') . "\n"; |
| 292 |
|
| 293 |
if (!empty($opts['prompt'])) { |
| 294 |
$user .= "- Extra instructions from the user: {$opts['prompt']}\n"; |
| 295 |
} elseif (!empty($opts['auto_generate'])) { |
| 296 |
$user .= "- Base the captions on the post title and content above.\n"; |
| 297 |
} |
| 298 |
|
| 299 |
$user .= "\nReturn a JSON object whose keys are exactly {$keys_list} and whose values are the caption strings. Respect each platform's character limit."; |
| 300 |
|
| 301 |
return array( |
| 302 |
array('role' => 'system', 'content' => $system), |
| 303 |
array('role' => 'user', 'content' => $user), |
| 304 |
); |
| 305 |
} |
| 306 |
|
| 307 |
/** |
| 308 |
* Call the OpenAI API and parse captions out of the response. |
| 309 |
* |
| 310 |
* @param string $api_key |
| 311 |
* @param array $messages |
| 312 |
* @param array $platforms |
| 313 |
* @return array|\WP_Error Map of platform => caption, or WP_Error on failure. |
| 314 |
*/ |
| 315 |
protected function request_openai($api_key, $messages, $platforms) |
| 316 |
{ |
| 317 |
$model = apply_filters('wpsp_openai_model', 'gpt-4o-mini'); |
| 318 |
|
| 319 |
$body = array( |
| 320 |
'model' => $model, |
| 321 |
'messages' => $messages, |
| 322 |
'temperature' => 0.7, |
| 323 |
'response_format' => array('type' => 'json_object'), |
| 324 |
); |
| 325 |
|
| 326 |
$response = wp_remote_post(self::OPENAI_ENDPOINT, array( |
| 327 |
'timeout' => 60, |
| 328 |
'headers' => array( |
| 329 |
'Content-Type' => 'application/json', |
| 330 |
'Authorization' => 'Bearer ' . $api_key, |
| 331 |
), |
| 332 |
'body' => wp_json_encode($body), |
| 333 |
)); |
| 334 |
|
| 335 |
if (is_wp_error($response)) { |
| 336 |
return new \WP_Error('wpsp_openai_request_failed', $response->get_error_message()); |
| 337 |
} |
| 338 |
|
| 339 |
$code = wp_remote_retrieve_response_code($response); |
| 340 |
$raw = wp_remote_retrieve_body($response); |
| 341 |
$data = json_decode($raw, true); |
| 342 |
|
| 343 |
if ($code !== 200) { |
| 344 |
$message = isset($data['error']['message']) |
| 345 |
? $data['error']['message'] |
| 346 |
: __('OpenAI request failed. Please verify your API key and try again.', 'wp-scheduled-posts'); |
| 347 |
return new \WP_Error('wpsp_openai_error', $message); |
| 348 |
} |
| 349 |
|
| 350 |
$content = isset($data['choices'][0]['message']['content']) |
| 351 |
? $data['choices'][0]['message']['content'] |
| 352 |
: ''; |
| 353 |
|
| 354 |
if (empty($content)) { |
| 355 |
return new \WP_Error('wpsp_openai_empty', __('OpenAI returned an empty response.', 'wp-scheduled-posts')); |
| 356 |
} |
| 357 |
|
| 358 |
$parsed = json_decode($content, true); |
| 359 |
|
| 360 |
// Fallback: if the model didn't return clean JSON, apply the text to every platform. |
| 361 |
if (!is_array($parsed)) { |
| 362 |
$text = trim($content); |
| 363 |
$parsed = array(); |
| 364 |
foreach ($platforms as $key) { |
| 365 |
$parsed[$key] = $text; |
| 366 |
} |
| 367 |
} |
| 368 |
|
| 369 |
// Keep only requested platforms and coerce to trimmed strings. |
| 370 |
// Hard-trim to each platform's character limit so the generated caption |
| 371 |
// always passes template validation when the user saves it. |
| 372 |
$limits = Helper::get_social_platform_limits(); |
| 373 |
$captions = array(); |
| 374 |
foreach ($platforms as $key) { |
| 375 |
if (isset($parsed[$key])) { |
| 376 |
$caption = is_string($parsed[$key]) ? trim($parsed[$key]) : trim(wp_json_encode($parsed[$key])); |
| 377 |
$limit = isset($limits[$key]) ? $limits[$key] : 0; |
| 378 |
$captions[$key] = $this->enforce_limit($caption, $limit); |
| 379 |
} |
| 380 |
} |
| 381 |
|
| 382 |
if (empty($captions)) { |
| 383 |
return new \WP_Error('wpsp_openai_unparsable', __('Could not parse captions from the AI response.', 'wp-scheduled-posts')); |
| 384 |
} |
| 385 |
|
| 386 |
return $captions; |
| 387 |
} |
| 388 |
|
| 389 |
/** |
| 390 |
* Trim a caption to a platform character limit without cutting mid-word. |
| 391 |
* |
| 392 |
* Counts characters (not bytes) so emojis are handled correctly, and backs |
| 393 |
* up to the last whitespace when possible to avoid a chopped word. |
| 394 |
* |
| 395 |
* @param string $text |
| 396 |
* @param int $limit Character limit; 0 or less means "no limit". |
| 397 |
* @return string |
| 398 |
*/ |
| 399 |
protected function enforce_limit($text, $limit) |
| 400 |
{ |
| 401 |
$limit = (int) $limit; |
| 402 |
$length = function_exists('mb_strlen') ? mb_strlen($text) : strlen($text); |
| 403 |
|
| 404 |
if ($limit <= 0 || $length <= $limit) { |
| 405 |
return $text; |
| 406 |
} |
| 407 |
|
| 408 |
$cut = function_exists('mb_substr') ? mb_substr($text, 0, $limit) : substr($text, 0, $limit); |
| 409 |
$space = function_exists('mb_strrpos') ? mb_strrpos($cut, ' ') : strrpos($cut, ' '); |
| 410 |
|
| 411 |
// Only honour the word boundary if it does not discard too much text. |
| 412 |
if ($space !== false && $space > (int) ($limit * 0.6)) { |
| 413 |
$cut = function_exists('mb_substr') ? mb_substr($cut, 0, $space) : substr($cut, 0, $space); |
| 414 |
} |
| 415 |
|
| 416 |
return rtrim($cut); |
| 417 |
} |
| 418 |
|
| 419 |
/** |
| 420 |
* Return an instance of this class. |
| 421 |
* |
| 422 |
* @return object |
| 423 |
*/ |
| 424 |
public static function get_instance() |
| 425 |
{ |
| 426 |
if (null == self::$instance) { |
| 427 |
self::$instance = new self; |
| 428 |
} |
| 429 |
|
| 430 |
return self::$instance; |
| 431 |
} |
| 432 |
} |
| 433 |
|
