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| 1 | <?php |
| 2 | declare( strict_types=1 ); |
| 3 | |
| 4 | /** |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License as published by |
| 7 | * the Free Software Foundation; either version 2 of the License, or |
| 8 | * (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License along |
| 16 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 17 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
| 18 | * http://www.gnu.org/copyleft/gpl.html |
| 19 | * |
| 20 | * @file |
| 21 | */ |
| 22 | |
| 23 | namespace Wikimedia\JsonCodec; |
| 24 | |
| 25 | use Exception; |
| 26 | use InvalidArgumentException; |
| 27 | use Psr\Container\ContainerInterface; |
| 28 | use Psr\Container\NotFoundExceptionInterface; |
| 29 | use stdClass; |
| 30 | |
| 31 | /** |
| 32 | * Helper class to serialize/unserialize things to/from JSON. |
| 33 | */ |
| 34 | class JsonCodec implements JsonCodecInterface { |
| 35 | /** @var ContainerInterface Service container */ |
| 36 | protected ContainerInterface $serviceContainer; |
| 37 | |
| 38 | /** @var array<class-string,JsonClassCodec> Class codecs */ |
| 39 | protected array $codecs; |
| 40 | |
| 41 | /** |
| 42 | * Name of the property where class information is stored; it also |
| 43 | * is used to mark "complex" arrays, and as a place to store the contents |
| 44 | * of any pre-existing array property that happened to have the same name. |
| 45 | */ |
| 46 | protected const TYPE_ANNOTATION = '_type_'; |
| 47 | |
| 48 | /** |
| 49 | * @param ?ContainerInterface $serviceContainer |
| 50 | */ |
| 51 | public function __construct( ?ContainerInterface $serviceContainer = null ) { |
| 52 | $this->serviceContainer = $serviceContainer ?? |
| 53 | // Use an empty container if none is provided. |
| 54 | new class implements ContainerInterface { |
| 55 | /** |
| 56 | * @param string $id |
| 57 | * @return never |
| 58 | */ |
| 59 | public function get( $id ) { |
| 60 | throw new class( "not found" ) extends Exception implements NotFoundExceptionInterface { |
| 61 | }; |
| 62 | } |
| 63 | |
| 64 | /** @inheritDoc */ |
| 65 | public function has( string $id ): bool { |
| 66 | return false; |
| 67 | } |
| 68 | }; |
| 69 | $this->addCodecFor( |
| 70 | stdClass::class, JsonStdClassCodec::getInstance() |
| 71 | ); |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * Recursively converts a given object to a JSON-encoded string. |
| 76 | * While serializing the $value JsonCodec delegates to the appropriate |
| 77 | * JsonClassCodecs of any classes which implement JsonCodecable. |
| 78 | * |
| 79 | * If a $classHint is provided and matches the type of the value, |
| 80 | * then type information will not be included in the generated JSON; |
| 81 | * otherwise an appropriate class name will be added to the JSON to |
| 82 | * guide deserialization. |
| 83 | * |
| 84 | * @param mixed|null $value |
| 85 | * @param ?class-string $classHint An optional hint to |
| 86 | * the type of the encoded object. If this is provided and matches |
| 87 | * the type of $value, then explicit type information will be omitted |
| 88 | * from the generated JSON, which saves some space. |
| 89 | * @return string |
| 90 | */ |
| 91 | public function toJsonString( $value, ?string $classHint = null ): string { |
| 92 | return json_encode( |
| 93 | $this->toJsonArray( $value, $classHint ), |
| 94 | JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | |
| 95 | JSON_HEX_TAG | JSON_HEX_AMP |
| 96 | ); |
| 97 | } |
| 98 | |
| 99 | /** |
| 100 | * Recursively converts a JSON-encoded string to an object value or scalar. |
| 101 | * While deserializing the $json JsonCodec delegates to the appropriate |
| 102 | * JsonClassCodecs of any classes which implement JsonCodecable. |
| 103 | * |
| 104 | * For objects encoded using implicit class information, a "class hint" |
| 105 | * can be provided to guide deserialization; this is unnecessary for |
| 106 | * objects serialized with explicit classes. |
| 107 | * |
| 108 | * @param string $json A JSON-encoded string |
| 109 | * @param ?class-string $classHint An optional hint to |
| 110 | * the type of the encoded object. In the absence of explicit |
| 111 | * type information in the JSON, this will be used as the type of |
| 112 | * the created object. |
| 113 | * @return mixed|null |
| 114 | */ |
| 115 | public function newFromJsonString( $json, ?string $classHint = null ) { |
| 116 | return $this->newFromJsonArray( |
| 117 | json_decode( $json, true ), $classHint |
| 118 | ); |
| 119 | } |
| 120 | |
| 121 | /** |
| 122 | * Maintain a cache giving the codec for a given class name. |
| 123 | * |
| 124 | * Reusing this JsonCodec object will also reuse this cache, which |
| 125 | * could improve performance somewhat. |
| 126 | * |
| 127 | * @param class-string $className |
| 128 | * @return ?JsonClassCodec a codec for the class, or null if the class is |
| 129 | * not serializable. |
| 130 | */ |
| 131 | protected function codecFor( string $className ): ?JsonClassCodec { |
| 132 | $codec = $this->codecs[$className] ?? null; |
| 133 | if ( !$codec ) { |
| 134 | if ( !is_a( $className, JsonCodecable::class, true ) ) { |
| 135 | return null; |
| 136 | } |
| 137 | $codec = $this->codecs[$className] = |
| 138 | $className::jsonClassCodec( $this, $this->serviceContainer ); |
| 139 | } |
| 140 | return $codec; |
| 141 | } |
| 142 | |
| 143 | /** |
| 144 | * Allow the use of a customized encoding for the given class; the given |
| 145 | * className need not be a JsonCodecable and if it *does* correspond to |
| 146 | * a JsonCodecable it will override the class codec specified by the |
| 147 | * JsonCodecable. |
| 148 | * @param class-string $className |
| 149 | * @param JsonClassCodec $codec A codec to use for $className |
| 150 | */ |
| 151 | public function addCodecFor( string $className, JsonClassCodec $codec ): void { |
| 152 | if ( $this->codecs[$className] ?? false ) { |
| 153 | throw new InvalidArgumentException( |
| 154 | "Codec already present for $className" |
| 155 | ); |
| 156 | } |
| 157 | $this->codecs[$className] = $codec; |
| 158 | } |
| 159 | |
| 160 | /** |
| 161 | * Recursively converts a given object to an associative array |
| 162 | * which can be json-encoded. (When embedding an object into |
| 163 | * another context it is sometimes useful to have the array |
| 164 | * representation rather than the string JSON form of the array; |
| 165 | * this can also be useful if you want to pretty-print the result, |
| 166 | * etc.) While converting $value the JsonCodec delegates to the |
| 167 | * appropriate JsonClassCodecs of any classes which implement |
| 168 | * JsonCodecable. |
| 169 | * |
| 170 | * If a $classHint is provided and matches the type of the value, |
| 171 | * then type information will not be included in the generated JSON; |
| 172 | * otherwise an appropriate class name will be added to the JSON to |
| 173 | * guide deserialization. |
| 174 | * |
| 175 | * @param mixed|null $value |
| 176 | * @param ?class-string $classHint An optional hint to |
| 177 | * the type of the encoded object. If this is provided and matches |
| 178 | * the type of $value, then explicit type information will be omitted |
| 179 | * from the generated JSON, which saves some space. |
| 180 | * @return mixed|null |
| 181 | */ |
| 182 | public function toJsonArray( $value, ?string $classHint = null ) { |
| 183 | $is_complex = false; |
| 184 | $className = 'array'; |
| 185 | $codec = null; |
| 186 | // Adjust class hint for arrays. |
| 187 | $arrayClassHint = null; |
| 188 | if ( $classHint !== null && str_ends_with( $classHint, '[]' ) ) { |
| 189 | $arrayClassHint = substr( $classHint, 0, -2 ); |
| 190 | $classHint = 'array'; |
| 191 | } |
| 192 | if ( is_object( $value ) ) { |
| 193 | $className = get_class( $value ); |
| 194 | $codec = $this->codecFor( $className ); |
| 195 | if ( $codec !== null ) { |
| 196 | $value = $codec->toJsonArray( $value ); |
| 197 | $is_complex = true; |
| 198 | } |
| 199 | } elseif ( |
| 200 | is_array( $value ) && $this->isArrayMarked( $value ) |
| 201 | ) { |
| 202 | $is_complex = true; |
| 203 | } |
| 204 | if ( is_array( $value ) ) { |
| 205 | // Recursively convert array values to serializable form |
| 206 | foreach ( $value as $key => &$v ) { |
| 207 | if ( is_object( $v ) || is_array( $v ) ) { |
| 208 | $propClassHint = $codec === null ? $arrayClassHint : |
| 209 | // phan can't tell that $codec is null when $className is 'array' |
| 210 | // @phan-suppress-next-line PhanUndeclaredClassReference |
| 211 | $codec->jsonClassHintFor( $className, (string)$key ); |
| 212 | $v = $this->toJsonArray( $v, $propClassHint ); |
| 213 | if ( |
| 214 | $this->isArrayMarked( $v ) || |
| 215 | $propClassHint !== null |
| 216 | ) { |
| 217 | // an array which contains complex components is |
| 218 | // itself complex. |
| 219 | $is_complex = true; |
| 220 | } |
| 221 | } |
| 222 | } |
| 223 | // Ok, now mark the array, being careful to transfer away |
| 224 | // any fields with the same names as our markers. |
| 225 | if ( $is_complex || $classHint !== null ) { |
| 226 | // Even if $className === $classHint we need to record this |
| 227 | // array as "complex" (ie, requires recursion to process |
| 228 | // individual values during deserialization) |
| 229 | // @phan-suppress-next-line PhanUndeclaredClassReference 'array' |
| 230 | $this->markArray( |
| 231 | $value, $className, $classHint |
| 232 | ); |
| 233 | } |
| 234 | } elseif ( !is_scalar( $value ) && $value !== null ) { |
| 235 | throw new InvalidArgumentException( |
| 236 | 'Unable to serialize JSON.' |
| 237 | ); |
| 238 | } |
| 239 | return $value; |
| 240 | } |
| 241 | |
| 242 | /** |
| 243 | * Recursively converts an associative array (or scalar) to an |
| 244 | * object value (or scalar). While converting this value JsonCodec |
| 245 | * delegates to the appropriate JsonClassCodecs of any classes which |
| 246 | * implement JsonCodecable. |
| 247 | * |
| 248 | * For objects encoded using implicit class information, a "class hint" |
| 249 | * can be provided to guide deserialization; this is unnecessary for |
| 250 | * objects serialized with explicit classes. |
| 251 | * |
| 252 | * @param mixed|null $json |
| 253 | * @param ?class-string $classHint An optional hint to |
| 254 | * the type of the encoded object. In the absence of explicit |
| 255 | * type information in the JSON, this will be used as the type of |
| 256 | * the created object. |
| 257 | * @return mixed|null |
| 258 | */ |
| 259 | public function newFromJsonArray( $json, ?string $classHint = null ) { |
| 260 | if ( $json instanceof stdClass ) { |
| 261 | // We *shouldn't* be given an object... but we might. |
| 262 | $json = (array)$json; |
| 263 | } |
| 264 | // Adjust class hint for arrays. |
| 265 | $arrayClassHint = null; |
| 266 | if ( $classHint !== null && str_ends_with( $classHint, '[]' ) ) { |
| 267 | $arrayClassHint = substr( $classHint, 0, -2 ); |
| 268 | $classHint = 'array'; |
| 269 | } |
| 270 | // Is this an array containing a complex value? |
| 271 | if ( |
| 272 | is_array( $json ) && ( |
| 273 | $this->isArrayMarked( $json ) || $classHint !== null |
| 274 | ) |
| 275 | ) { |
| 276 | // Read out our metadata |
| 277 | // @phan-suppress-next-line PhanUndeclaredClassReference 'array' |
| 278 | $className = $this->unmarkArray( $json, $classHint ); |
| 279 | // Create appropriate codec |
| 280 | $codec = null; |
| 281 | if ( $className !== 'array' ) { |
| 282 | $codec = $this->codecFor( $className ); |
| 283 | if ( $codec === null ) { |
| 284 | throw new InvalidArgumentException( |
| 285 | "Unable to deserialize JSON for $className" |
| 286 | ); |
| 287 | } |
| 288 | } |
| 289 | // Recursively unserialize the array contents. |
| 290 | $unserialized = []; |
| 291 | foreach ( $json as $key => $value ) { |
| 292 | $propClassHint = $codec === null ? $arrayClassHint : |
| 293 | // phan can't tell that $codec is null when $className is 'array' |
| 294 | // @phan-suppress-next-line PhanUndeclaredClassReference |
| 295 | $codec->jsonClassHintFor( $className, (string)$key ); |
| 296 | if ( |
| 297 | is_array( $value ) && ( |
| 298 | $this->isArrayMarked( $value ) || $propClassHint !== null |
| 299 | ) |
| 300 | ) { |
| 301 | $unserialized[$key] = $this->newFromJsonArray( $value, $propClassHint ); |
| 302 | } else { |
| 303 | $unserialized[$key] = $value; |
| 304 | } |
| 305 | } |
| 306 | // Use a JsonCodec to create the object instance if appropriate. |
| 307 | if ( $className === 'array' ) { |
| 308 | $json = $unserialized; |
| 309 | } else { |
| 310 | $json = $codec->newFromJsonArray( $className, $unserialized ); |
| 311 | } |
| 312 | } |
| 313 | return $json; |
| 314 | } |
| 315 | |
| 316 | // Functions to mark/unmark arrays and record a class name using a |
| 317 | // single reserved field, named by self::TYPE_ANNOTATION. A |
| 318 | // subclass can provide alternate implementations of these methods |
| 319 | // if it wants to use a different reserved field or else wishes to |
| 320 | // reserve more fields/encode certain types more compactly/flag |
| 321 | // certain types of values. For example: a subclass could choose |
| 322 | // to discard all hints in `markArray` in order to explicitly mark |
| 323 | // all types in preparation for a format change; or all values of |
| 324 | // type DocumentFragment might get a marker flag added so they can |
| 325 | // be identified without knowledge of the class hint; or perhaps a |
| 326 | // separate schema can be used to record class names more |
| 327 | // compactly. |
| 328 | |
| 329 | /** |
| 330 | * Determine if the given value is "marked"; that is, either |
| 331 | * represents a object type encoded using a JsonClassCodec or else |
| 332 | * is an array which contains values (or contains arrays |
| 333 | * containing values, etc) which are object types. The values of |
| 334 | * unmarked arrays are not decoded, in order to speed up the |
| 335 | * decoding process. Arrays may also be marked even if they do |
| 336 | * not represent object types (or an array recursively containing |
| 337 | * them) if they contain keys that need to be escaped ("false |
| 338 | * marks"); as such this method is called both on the raw results |
| 339 | * of JsonClassCodec (to check for "false marks") as well as on |
| 340 | * encoded arrays (to find "true marks"). |
| 341 | * |
| 342 | * Arrays do not have to be marked if the decoder has a class hint. |
| 343 | * |
| 344 | * @param array $value An array result from `JsonClassCodec::toJsonArray()`, |
| 345 | * or an array result from `::markArray()` |
| 346 | * @return bool Whether the $value is marked |
| 347 | */ |
| 348 | protected function isArrayMarked( array $value ): bool { |
| 349 | return array_key_exists( self::TYPE_ANNOTATION, $value ); |
| 350 | } |
| 351 | |
| 352 | /** |
| 353 | * Record a mark in the array, reversibly. |
| 354 | * |
| 355 | * The mark should record the class name, if it is different from |
| 356 | * the class hint. The result does not need to trigger |
| 357 | * `::isArrayMarked` if there is an accurate class hint present, |
| 358 | * but otherwise the result should register as marked. The |
| 359 | * provided value may be a "complex" array (one that recursively |
| 360 | * contains encoded object) or an array with a "false mark"; in |
| 361 | * both cases the provided $className will be `array`. |
| 362 | * |
| 363 | * @param array &$value An array result from `JsonClassCodec::toJsonArray()` |
| 364 | * or a "complex" array |
| 365 | * @param 'array'|class-string $className The name of the class encoded |
| 366 | * by the codec, or else `array` if $value is a "complex" array or a |
| 367 | * "false mark" |
| 368 | * @param class-string|'array'|null $classHint The class name provided as |
| 369 | * a hint to the encoder, and which will be in turn provided as a hint |
| 370 | * to the decoder, or `null` if no hint was provided. The class hint |
| 371 | * will be `array` when the array is a homogeneous list of objects. |
| 372 | */ |
| 373 | protected function markArray( array &$value, string $className, ?string $classHint ): void { |
| 374 | // We're going to use an array key, but first we have to see whether it |
| 375 | // was already present in the array we've been given, in which case |
| 376 | // we need to escape it (by hoisting into a child array). |
| 377 | if ( array_key_exists( self::TYPE_ANNOTATION, $value ) ) { |
| 378 | if ( $className !== $classHint ) { |
| 379 | $value[self::TYPE_ANNOTATION] = [ $value[self::TYPE_ANNOTATION], $className ]; |
| 380 | } else { |
| 381 | // Omit $className since it matches the $classHint, but we still |
| 382 | // need to escape the field to make it clear it was marked. |
| 383 | // (If the class hint hadn't matched, the proper class name |
| 384 | // would be here in an array, and we need to distinguish that |
| 385 | // case from the case where the "actual value" is an array.) |
| 386 | $value[self::TYPE_ANNOTATION] = [ $value[self::TYPE_ANNOTATION] ]; |
| 387 | } |
| 388 | } elseif ( |
| 389 | $className !== $classHint || |
| 390 | ( array_is_list( $value ) && $className !== 'array' ) |
| 391 | ) { |
| 392 | // Include the type annotation if it doesn't match the hint; |
| 393 | // but also include it if necessary to break up a list. This |
| 394 | // ensures that all objects have an encoding in the '{...}' style, |
| 395 | // even if they happen to have all-numeric keys. |
| 396 | $value[self::TYPE_ANNOTATION] = $className; |
| 397 | } |
| 398 | } |
| 399 | |
| 400 | /** |
| 401 | * Remove a mark from an encoded array, and return an |
| 402 | * encoded class name if present. |
| 403 | * |
| 404 | * The provided array may not trigger `::isArrayMarked` is there |
| 405 | * was a class hint provided. |
| 406 | * |
| 407 | * If the provided array had a "false mark" or recursively |
| 408 | * contained objects, the returned class name should be 'array'. |
| 409 | * |
| 410 | * @param array &$value An encoded array |
| 411 | * @param 'array'|class-string|null $classHint The class name provided as a hint to |
| 412 | * the decoder, which was previously provided as a hint to the encoder, |
| 413 | * or `null` if no hint was provided. |
| 414 | * @return 'array'|class-string The class name to be used for decoding, or |
| 415 | * 'array' if the value was a "complex" or "false mark" array. |
| 416 | */ |
| 417 | protected function unmarkArray( array &$value, ?string $classHint ): string { |
| 418 | $className = $value[self::TYPE_ANNOTATION] ?? $classHint; |
| 419 | // Remove our marker and restore the previous state of the |
| 420 | // json array (restoring a pre-existing field if needed) |
| 421 | if ( is_array( $className ) ) { |
| 422 | $value[self::TYPE_ANNOTATION] = $className[0]; |
| 423 | $className = $className[1] ?? $classHint; |
| 424 | } else { |
| 425 | unset( $value[self::TYPE_ANNOTATION] ); |
| 426 | } |
| 427 | return $className; |
| 428 | } |
| 429 | |
| 430 | } |