includes/PathRouter.php

   1 <?php
   2 /**
   3  * Parser to extract query parameters out of REQUEST_URI paths.
   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 /**
  24  * PathRouter class.
  25  * This class can take patterns such as /wiki/$1 and use them to
  26  * parse query parameters out of REQUEST_URI paths.
  27  *
  28  * $router->add( "/wiki/$1" );
  29  *   - Matches /wiki/Foo style urls and extracts the title
  30  * $router->add( [ 'edit' => "/edit/$key" ], [ 'action' => '$key' ] );
  31  *   - Matches /edit/Foo style urls and sets action=edit
  32  * $router->add( '/$2/$1',
  33  *   [ 'variant' => '$2' ],
  34  *   [ '$2' => [ 'zh-hant', 'zh-hans' ] ]
  35  * );
  36  *   - Matches /zh-hant/Foo or /zh-hans/Foo
  37  * $router->addStrict( "/foo/Bar", [ 'title' => 'Baz' ] );
  38  *   - Matches /foo/Bar explicitly and uses "Baz" as the title
  39  * $router->add( '/help/$1', [ 'title' => 'Help:$1' ] );
  40  *   - Matches /help/Foo with "Help:Foo" as the title
  41  * $router->add( '/$1', [ 'foo' => [ 'value' => 'bar$2' ] ] );
  42  *   - Matches /Foo and sets 'foo' to 'bar$2' without $2 being replaced
  43  * $router->add( '/$1', [ 'data:foo' => 'bar' ], [ 'callback' => 'functionname' ] );
  44  *   - Matches /Foo, adds the key 'foo' with the value 'bar' to the data array
  45  *     and calls functionname( &$matches, $data );
  46  *
  47  * Path patterns:
  48  *   - Paths may contain $# patterns such as $1, $2, etc...
  49  *   - $1 will match 0 or more while the rest will match 1 or more
  50  *   - Unless you use addStrict "/wiki" and "/wiki/" will be expanded to "/wiki/$1"
  51  *
  52  * Params:
  53  *   - In a pattern $1, $2, etc... will be replaced with the relevant contents
  54  *   - If you used a keyed array as a path pattern, $key will be replaced with
  55  *     the relevant contents
  56  *   - The default behavior is equivalent to `array( 'title' => '$1' )`,
  57  *     if you don't want the title parameter you can explicitly use `array( 'title' => false )`
  58  *   - You can specify a value that won't have replacements in it
  59  *     using `'foo' => [ 'value' => 'bar' ];`
  60  *
  61  * Options:
  62  *   - The option keys $1, $2, etc... can be specified to restrict the possible values
  63  *     of that variable. A string can be used for a single value, or an array for multiple.
  64  *   - When the option key 'strict' is set (Using addStrict is simpler than doing this directly)
  65  *     the path won't have $1 implicitly added to it.
  66  *   - The option key 'callback' can specify a callback that will be run when a path is matched.
  67  *     The callback will have the arguments ( &$matches, $data ) and the matches array can
  68  *     be modified.
  69  *
  70  * @since 1.19
  71  * @author Daniel Friesen
  72  */
  73 class PathRouter {
  74
  75         /**
  76          * @var array
  77          */
  78         private $patterns = [];
  79
  80         /**
  81          * Protected helper to do the actual bulk work of adding a single pattern.
  82          * This is in a separate method so that add() can handle the difference between
  83          * a single string $path and an array() $path that contains multiple path
  84          * patterns each with an associated $key to pass on.
  85          * @param string $path
  86          * @param array $params
  87          * @param array $options
  88          * @param null|string $key
  89          */
  90         protected function doAdd( $path, $params, $options, $key = null ) {
  91                 // Make sure all paths start with a /
  92                 if ( $path[0] !== '/' ) {
  93                         $path = '/' . $path;
  94                 }
  95
  96                 if ( !isset( $options['strict'] ) || !$options['strict'] ) {
  97                         // Unless this is a strict path make sure that the path has a $1
  98                         if ( strpos( $path, '$1' ) === false ) {
  99                                 if ( substr( $path, -1 ) !== '/' ) {
 100                                         $path .= '/';
 101                                 }
 102                                 $path .= '$1';
 103                         }
 104                 }
 105
 106                 // If 'title' is not specified and our path pattern contains a $1
 107                 // Add a default 'title' => '$1' rule to the parameters.
 108                 if ( !isset( $params['title'] ) && strpos( $path, '$1' ) !== false ) {
 109                         $params['title'] = '$1';
 110                 }
 111                 // If the user explicitly marked 'title' as false then omit it from the matches
 112                 if ( isset( $params['title'] ) && $params['title'] === false ) {
 113                         unset( $params['title'] );
 114                 }
 115
 116                 // Loop over our parameters and convert basic key => string
 117                 // patterns into fully descriptive array form
 118                 foreach ( $params as $paramName => $paramData ) {
 119                         if ( is_string( $paramData ) ) {
 120                                 if ( preg_match( '/\$(\d+|key)/u', $paramData ) ) {
 121                                         $paramArrKey = 'pattern';
 122                                 } else {
 123                                         // If there's no replacement use a value instead
 124                                         // of a pattern for a little more efficiency
 125                                         $paramArrKey = 'value';
 126                                 }
 127                                 $params[$paramName] = [
 128                                         $paramArrKey => $paramData
 129                                 ];
 130                         }
 131                 }
 132
 133                 // Loop over our options and convert any single value $# restrictions
 134                 // into an array so we only have to do in_array tests.
 135                 foreach ( $options as $optionName => $optionData ) {
 136                         if ( preg_match( '/^\$\d+$/u', $optionName ) ) {
 137                                 if ( !is_array( $optionData ) ) {
 138                                         $options[$optionName] = [ $optionData ];
 139                                 }
 140                         }
 141                 }
 142
 143                 $pattern = (object)[
 144                         'path' => $path,
 145                         'params' => $params,
 146                         'options' => $options,
 147                         'key' => $key,
 148                 ];
 149                 $pattern->weight = self::makeWeight( $pattern );
 150                 $this->patterns[] = $pattern;
 151         }
 152
 153         /**
 154          * Add a new path pattern to the path router
 155          *
 156          * @param string|array $path The path pattern to add
 157          * @param array $params The params for this path pattern
 158          * @param array $options The options for this path pattern
 159          */
 160         public function add( $path, $params = [], $options = [] ) {
 161                 if ( is_array( $path ) ) {
 162                         foreach ( $path as $key => $onePath ) {
 163                                 $this->doAdd( $onePath, $params, $options, $key );
 164                         }
 165                 } else {
 166                         $this->doAdd( $path, $params, $options );
 167                 }
 168         }
 169
 170         /**
 171          * Add a new path pattern to the path router with the strict option on
 172          * @see self::add
 173          * @param string|array $path
 174          * @param array $params
 175          * @param array $options
 176          */
 177         public function addStrict( $path, $params = [], $options = [] ) {
 178                 $options['strict'] = true;
 179                 $this->add( $path, $params, $options );
 180         }
 181
 182         /**
 183          * Protected helper to re-sort our patterns so that the most specific
 184          * (most heavily weighted) patterns are at the start of the array.
 185          */
 186         protected function sortByWeight() {
 187                 $weights = [];
 188                 foreach ( $this->patterns as $key => $pattern ) {
 189                         $weights[$key] = $pattern->weight;
 190                 }
 191                 array_multisort( $weights, SORT_DESC, SORT_NUMERIC, $this->patterns );
 192         }
 193
 194         /**
 195          * @param object $pattern
 196          * @return float|int
 197          */
 198         protected static function makeWeight( $pattern ) {
 199                 # Start with a weight of 0
 200                 $weight = 0;
 201
 202                 // Explode the path to work with
 203                 $path = explode( '/', $pattern->path );
 204
 205                 # For each level of the path
 206                 foreach ( $path as $piece ) {
 207                         if ( preg_match( '/^\$(\d+|key)$/u', $piece ) ) {
 208                                 # For a piece that is only a $1 variable add 1 points of weight
 209                                 $weight += 1;
 210                         } elseif ( preg_match( '/\$(\d+|key)/u', $piece ) ) {
 211                                 # For a piece that simply contains a $1 variable add 2 points of weight
 212                                 $weight += 2;
 213                         } else {
 214                                 # For a solid piece add a full 3 points of weight
 215                                 $weight += 3;
 216                         }
 217                 }
 218
 219                 foreach ( $pattern->options as $key => $option ) {
 220                         if ( preg_match( '/^\$\d+$/u', $key ) ) {
 221                                 # Add 0.5 for restrictions to values
 222                                 # This way given two separate "/$2/$1" patterns the
 223                                 # one with a limited set of $2 values will dominate
 224                                 # the one that'll match more loosely
 225                                 $weight += 0.5;
 226                         }
 227                 }
 228
 229                 return $weight;
 230         }
 231
 232         /**
 233          * Parse a path and return the query matches for the path
 234          *
 235          * @param string $path The path to parse
 236          * @return array The array of matches for the path
 237          */
 238         public function parse( $path ) {
 239                 // Make sure our patterns are sorted by weight so the most specific
 240                 // matches are tested first
 241                 $this->sortByWeight();
 242
 243                 $matches = null;
 244
 245                 foreach ( $this->patterns as $pattern ) {
 246                         $matches = self::extractTitle( $path, $pattern );
 247                         if ( !is_null( $matches ) ) {
 248                                 break;
 249                         }
 250                 }
 251
 252                 // We know the difference between null (no matches) and
 253                 // array() (a match with no data) but our WebRequest caller
 254                 // expects array() even when we have no matches so return
 255                 // a array() when we have null
 256                 return is_null( $matches ) ? [] : $matches;
 257         }
 258
 259         /**
 260          * @param string $path
 261          * @param string $pattern
 262          * @return array|null
 263          */
 264         protected static function extractTitle( $path, $pattern ) {
 265                 // Convert the path pattern into a regexp we can match with
 266                 $regexp = preg_quote( $pattern->path, '#' );
 267                 // .* for the $1
 268                 $regexp = preg_replace( '#\\\\\$1#u', '(?P<par1>.*)', $regexp );
 269                 // .+ for the rest of the parameter numbers
 270                 $regexp = preg_replace( '#\\\\\$(\d+)#u', '(?P<par$1>.+?)', $regexp );
 271                 $regexp = "#^{$regexp}$#";
 272
 273                 $matches = [];
 274                 $data = [];
 275
 276                 // Try to match the path we were asked to parse with our regexp
 277                 if ( preg_match( $regexp, $path, $m ) ) {
 278                         // Ensure that any $# restriction we have set in our {$option}s
 279                         // matches properly here.
 280                         foreach ( $pattern->options as $key => $option ) {
 281                                 if ( preg_match( '/^\$\d+$/u', $key ) ) {
 282                                         $n = intval( substr( $key, 1 ) );
 283                                         $value = rawurldecode( $m["par{$n}"] );
 284                                         if ( !in_array( $value, $option ) ) {
 285                                                 // If any restriction does not match return null
 286                                                 // to signify that this rule did not match.
 287                                                 return null;
 288                                         }
 289                                 }
 290                         }
 291
 292                         // Give our $data array a copy of every $# that was matched
 293                         foreach ( $m as $matchKey => $matchValue ) {
 294                                 if ( preg_match( '/^par\d+$/u', $matchKey ) ) {
 295                                         $n = intval( substr( $matchKey, 3 ) );
 296                                         $data['$' . $n] = rawurldecode( $matchValue );
 297                                 }
 298                         }
 299                         // If present give our $data array a $key as well
 300                         if ( isset( $pattern->key ) ) {
 301                                 $data['$key'] = $pattern->key;
 302                         }
 303
 304                         // Go through our parameters for this match and add data to our matches and data arrays
 305                         foreach ( $pattern->params as $paramName => $paramData ) {
 306                                 $value = null;
 307                                 // Differentiate data: from normal parameters and keep the correct
 308                                 // array key around (ie: foo for data:foo)
 309                                 if ( preg_match( '/^data:/u', $paramName ) ) {
 310                                         $isData = true;
 311                                         $key = substr( $paramName, 5 );
 312                                 } else {
 313                                         $isData = false;
 314                                         $key = $paramName;
 315                                 }
 316
 317                                 if ( isset( $paramData['value'] ) ) {
 318                                         // For basic values just set the raw data as the value
 319                                         $value = $paramData['value'];
 320                                 } elseif ( isset( $paramData['pattern'] ) ) {
 321                                         // For patterns we have to make value replacements on the string
 322                                         $value = $paramData['pattern'];
 323                                         $replacer = new PathRouterPatternReplacer;
 324                                         $replacer->params = $m;
 325                                         if ( isset( $pattern->key ) ) {
 326                                                 $replacer->key = $pattern->key;
 327                                         }
 328                                         $value = $replacer->replace( $value );
 329                                         if ( $value === false ) {
 330                                                 // Pattern required data that wasn't available, abort
 331                                                 return null;
 332                                         }
 333                                 }
 334
 335                                 // Send things that start with data: to $data, the rest to $matches
 336                                 if ( $isData ) {
 337                                         $data[$key] = $value;
 338                                 } else {
 339                                         $matches[$key] = $value;
 340                                 }
 341                         }
 342
 343                         // If this match includes a callback, execute it
 344                         if ( isset( $pattern->options['callback'] ) ) {
 345                                 call_user_func_array( $pattern->options['callback'], [ &$matches, $data ] );
 346                         }
 347                 } else {
 348                         // Our regexp didn't match, return null to signify no match.
 349                         return null;
 350                 }
 351                 // Fall through, everything went ok, return our matches array
 352                 return $matches;
 353         }
 354
 355 }
 356
 357 class PathRouterPatternReplacer {
 358
 359         public $key, $params, $error;
 360
 361         /**
 362          * Replace keys inside path router patterns with text.
 363          * We do this inside of a replacement callback because after replacement we can't tell the
 364          * difference between a $1 that was not replaced and a $1 that was part of
 365          * the content a $1 was replaced with.
 366          * @param string $value
 367          * @return string|false
 368          */
 369         public function replace( $value ) {
 370                 $this->error = false;
 371                 $value = preg_replace_callback( '/\$(\d+|key)/u', [ $this, 'callback' ], $value );
 372                 if ( $this->error ) {
 373                         return false;
 374                 }
 375                 return $value;
 376         }
 377
 378         /**
 379          * @param array $m
 380          * @return string
 381          */
 382         protected function callback( $m ) {
 383                 if ( $m[1] == "key" ) {
 384                         if ( is_null( $this->key ) ) {
 385                                 $this->error = true;
 386                                 return '';
 387                         }
 388                         return $this->key;
 389                 } else {
 390                         $d = $m[1];
 391                         if ( !isset( $this->params["par$d"] ) ) {
 392                                 $this->error = true;
 393                                 return '';
 394                         }
 395                         return rawurldecode( $this->params["par$d"] );
 396                 }
 397         }
 398
 399 }