includes/PathRouter.php

   1 <?php
   2 /**
   3  * PathRouter class.
   4  * This class can take patterns such as /wiki/$1 and use them to
   5  * parse query parameters out of REQUEST_URI paths.
   6  *
   7  * $router->add( "/wiki/$1" );
   8  *   - Matches /wiki/Foo style urls and extracts the title
   9  * $router->add( array( 'edit' => "/edit/$1" ), array( 'action' => '$key' ) );
  10  *   - Matches /edit/Foo style urls and sets action=edit
  11  * $router->add( '/$2/$1',
  12  *   array( 'variant' => '$2' ),
  13  *   array( '$2' => array( 'zh-hant', 'zh-hans' )
  14  * );
  15  *   - Matches /zh-hant/Foo or /zh-hans/Foo
  16  * $router->addStrict( "/foo/Bar", array( 'title' => 'Baz' ) );
  17  *   - Matches /foo/Bar explicitly and uses "Baz" as the title
  18  * $router->add( '/help/$1', array( 'title' => 'Help:$1' ) );
  19  *   - Matches /help/Foo with "Help:Foo" as the title
  20  * $router->add( '/$1', array( 'foo' => array( 'value' => 'bar$2' ) );
  21  *   - Matches /Foo and sets 'foo' to 'bar$2' without $2 being replaced
  22  * $router->add( '/$1', array( 'data:foo' => 'bar' ), array( 'callback' => 'functionname' ) );
  23  *   - Matches /Foo, adds the key 'foo' with the value 'bar' to the data array
  24  *     and calls functionname( &$matches, $data );
  25  *
  26  * Path patterns:
  27  *   - Paths may contain $# patterns such as $1, $2, etc...
  28  *   - $1 will match 0 or more while the rest will match 1 or more
  29  *   - Unless you use addStrict "/wiki" and "/wiki/" will be expanded to "/wiki/$1"
  30  *
  31  * Params:
  32  *   - In a pattern $1, $2, etc... will be replaced with the relevant contents
  33  *   - If you used a keyed array as a path pattern, $key will be replaced with
  34  *     the relevant contents
  35  *   - The default behavior is equivalent to `array( 'title' => '$1' )`,
  36  *     if you don't want the title parameter you can explicitly use `array( 'title' => false )`
  37  *   - You can specify a value that won't have replacements in it
  38  *     using `'foo' => array( 'value' => 'bar' );`
  39  *
  40  * Options:
  41  *   - The option keys $1, $2, etc... can be specified to restrict the possible values
  42  *     of that variable. A string can be used for a single value, or an array for multiple.
  43  *   - When the option key 'strict' is set (Using addStrict is simpler than doing this directly)
  44  *     the path won't have $1 implicitly added to it.
  45  *   - The option key 'callback' can specify a callback that will be run when a path is matched.
  46  *     The callback will have the arguments ( &$matches, $data ) and the matches array can
  47  *     be modified.
  48  *
  49  * @since 1.19
  50  * @author Daniel Friesen
  51  */
  52 class PathRouter {
  53
  54         /**
  55          * Protected helper to do the actual bulk work of adding a single pattern.
  56          * This is in a separate method so that add() can handle the difference between
  57          * a single string $path and an array() $path that contains multiple path
  58          * patterns each with an associated $key to pass on.
  59          */
  60         protected function doAdd( $path, $params, $options, $key = null ) {
  61                 // Make sure all paths start with a /
  62                 if ( $path[0] !== '/' ) {
  63                         $path = '/' . $path;
  64                 }
  65
  66                 if ( !isset( $options['strict'] ) || !$options['strict'] ) {
  67                         // Unless this is a strict path make sure that the path has a $1
  68                         if ( strpos( $path, '$1' ) === false ) {
  69                                 if ( substr( $path, -1 ) !== '/' ) {
  70                                         $path .= '/';
  71                                 }
  72                                 $path .= '$1';
  73                         }
  74                 }
  75
  76                 // If 'title' is not specified and our path pattern contains a $1
  77                 // Add a default 'title' => '$1' rule to the parameters.
  78                 if ( !isset( $params['title'] ) && strpos( $path, '$1' ) !== false ) {
  79                         $params['title'] = '$1';
  80                 }
  81                 // If the user explicitly marked 'title' as false then omit it from the matches
  82                 if ( isset( $params['title'] ) && $params['title'] === false ) {
  83                         unset( $params['title'] );
  84                 }
  85
  86                 // Loop over our parameters and convert basic key => string
  87                 // patterns into fully descriptive array form
  88                 foreach ( $params as $paramName => $paramData ) {
  89                         if ( is_string( $paramData ) ) {
  90                                 if ( preg_match( '/\$(\d+|key)/u', $paramData ) ) {
  91                                         $paramArrKey = 'pattern';
  92                                 } else {
  93                                         // If there's no replacement use a value instead
  94                                         // of a pattern for a little more efficiency
  95                                         $paramArrKey = 'value';
  96                                 }
  97                                 $params[$paramName] = array(
  98                                         $paramArrKey => $paramData
  99                                 );
 100                         }
 101                 }
 102
 103                 // Loop over our options and convert any single value $# restrictions
 104                 // into an array so we only have to do in_array tests.
 105                 foreach ( $options as $optionName => $optionData ) {
 106                         if ( preg_match( '/^\$\d+$/u', $optionName ) ) {
 107                                 if ( !is_array( $optionData ) ) {
 108                                         $options[$optionName] = array( $optionData );
 109                                 }
 110                         }
 111                 }
 112
 113                 $pattern = (object)array(
 114                         'path'    => $path,
 115                         'params'  => $params,
 116                         'options' => $options,
 117                         'key'     => $key,
 118                 );
 119                 $pattern->weight = self::makeWeight( $pattern );
 120                 $this->patterns[] = $pattern;
 121         }
 122
 123         /**
 124          * Add a new path pattern to the path router
 125          *
 126          * @param $path The path pattern to add
 127          * @param $params The params for this path pattern
 128          * @param $options The options for this path pattern
 129          */
 130         public function add( $path, $params = array(), $options = array() ) {
 131                 if ( is_array( $path ) ) {
 132                         foreach ( $path as $key => $onePath ) {
 133                                 $this->doAdd( $onePath, $params, $options, $key );
 134                         }
 135                 } else {
 136                         $this->doAdd( $path, $params, $options );
 137                 }
 138         }
 139
 140         /**
 141          * Add a new path pattern to the path router with the strict option on
 142          * @see self::add
 143          */
 144         public function addStrict( $path, $params = array(), $options = array() ) {
 145                 $options['strict'] = true;
 146                 $this->add( $path, $params, $options );
 147         }
 148
 149         /**
 150          * Protected helper to re-sort our patterns so that the most specific
 151          * (most heavily weighted) patterns are at the start of the array.
 152          */
 153         protected function sortByWeight() {
 154                 $weights = array();
 155                 foreach( $this->patterns as $key => $pattern ) {
 156                         $weights[$key] = $pattern->weight;
 157                 }
 158                 array_multisort( $weights, SORT_DESC, SORT_NUMERIC, $this->patterns );
 159         }
 160
 161         protected static function makeWeight( $pattern ) {
 162                 # Start with a weight of 0
 163                 $weight = 0;
 164
 165                 // Explode the path to work with
 166                 $path = explode( '/', $pattern->path );
 167
 168                 # For each level of the path
 169                 foreach( $path as $piece ) {
 170                         if ( preg_match( '/^\$(\d+|key)$/u', $piece ) ) {
 171                                 # For a piece that is only a $1 variable add 1 points of weight
 172                                 $weight += 1;
 173                         } elseif ( preg_match( '/\$(\d+|key)/u', $piece ) ) {
 174                                 # For a piece that simply contains a $1 variable add 2 points of weight
 175                                 $weight += 2;
 176                         } else {
 177                                 # For a solid piece add a full 3 points of weight
 178                                 $weight += 3;
 179                         }
 180                 }
 181
 182                 foreach ( $pattern->options as $key => $option ) {
 183                         if ( preg_match( '/^\$\d+$/u', $key ) ) {
 184                                 # Add 0.5 for restrictions to values
 185                                 # This way given two separate "/$2/$1" patterns the
 186                                 # one with a limited set of $2 values will dominate
 187                                 # the one that'll match more loosely
 188                                 $weight += 0.5;
 189                         }
 190                 }
 191
 192                 return $weight;
 193         }
 194
 195         /**
 196          * Parse a path and return the query matches for the path
 197          *
 198          * @param $path The path to parse
 199          * @return Array The array of matches for the path
 200          */
 201         public function parse( $path ) {
 202                 // Make sure our patterns are sorted by weight so the most specific
 203                 // matches are tested first
 204                 $this->sortByWeight();
 205
 206                 $matches = null;
 207
 208                 foreach ( $this->patterns as $pattern ) {
 209                         $matches = self::extractTitle( $path, $pattern );
 210                         if ( !is_null( $matches ) ) {
 211                                 break;
 212                         }
 213                 }
 214
 215                 // We know the difference between null (no matches) and
 216                 // array() (a match with no data) but our WebRequest caller
 217                 // expects array() even when we have no matches so return
 218                 // a array() when we have null
 219                 return is_null( $matches ) ? array() : $matches;
 220         }
 221
 222         protected static function extractTitle( $path, $pattern ) {
 223                 // Convert the path pattern into a regexp we can match with
 224                 $regexp = preg_quote( $pattern->path, '#' );
 225                 // .* for the $1
 226                 $regexp = preg_replace( '#\\\\\$1#u', '(?P<par1>.*)', $regexp );
 227                 // .+ for the rest of the parameter numbers
 228                 $regexp = preg_replace( '#\\\\\$(\d+)#u', '(?P<par$1>.+?)', $regexp );
 229                 $regexp = "#^{$regexp}$#";
 230
 231                 $matches = array();
 232                 $data = array();
 233
 234                 // Try to match the path we were asked to parse with our regexp
 235                 if ( preg_match( $regexp, $path, $m ) ) {
 236                         // Ensure that any $# restriction we have set in our {$option}s
 237                         // matches properly here.
 238                         foreach ( $pattern->options as $key => $option ) {
 239                                 if ( preg_match( '/^\$\d+$/u', $key ) ) {
 240                                         $n = intval( substr( $key, 1 ) );
 241                                         $value = rawurldecode( $m["par{$n}"] );
 242                                         if ( !in_array( $value, $option ) ) {
 243                                                 // If any restriction does not match return null
 244                                                 // to signify that this rule did not match.
 245                                                 return null;
 246                                         }
 247                                 }
 248                         }
 249
 250                         // Give our $data array a copy of every $# that was matched
 251                         foreach ( $m as $matchKey => $matchValue ) {
 252                                 if ( preg_match( '/^par\d+$/u', $matchKey ) ) {
 253                                         $n = intval( substr( $matchKey, 3 ) );
 254                                         $data['$'.$n] = rawurldecode( $matchValue );
 255                                 }
 256                         }
 257                         // If present give our $data array a $key as well
 258                         if ( isset( $pattern->key ) ) {
 259                                 $data['$key'] = $pattern->key;
 260                         }
 261
 262                         // Go through our parameters for this match and add data to our matches and data arrays
 263                         foreach ( $pattern->params as $paramName => $paramData ) {
 264                                 $value = null;
 265                                 // Differentiate data: from normal parameters and keep the correct
 266                                 // array key around (ie: foo for data:foo)
 267                                 if ( preg_match( '/^data:/u', $paramName ) ) {
 268                                         $isData = true;
 269                                         $key = substr( $paramName, 5 );
 270                                 } else {
 271                                         $isData = false;
 272                                         $key = $paramName;
 273                                 }
 274
 275                                 if ( isset( $paramData['value'] ) ) {
 276                                         // For basic values just set the raw data as the value
 277                                         $value = $paramData['value'];
 278                                 } elseif ( isset( $paramData['pattern'] ) ) {
 279                                         // For patterns we have to make value replacements on the string
 280                                         $value = $paramData['pattern'];
 281                                         // For each $# match replace any $# within the value
 282                                         foreach ( $m as $matchKey => $matchValue ) {
 283                                                 if ( preg_match( '/^par\d+$/u', $matchKey ) ) {
 284                                                         $n = intval( substr( $matchKey, 3 ) );
 285                                                         $value = str_replace( '$' . $n, rawurldecode( $matchValue ), $value );
 286                                                 }
 287                                         }
 288                                         // If a key was set replace any $key within the value
 289                                         if ( isset( $pattern->key ) ) {
 290                                                 $value = str_replace( '$key', $pattern->key, $value );
 291                                         }
 292                                         if ( preg_match( '/\$(\d+|key)/u', $value ) ) {
 293                                                 // Still contains $# or $key patterns after replacement
 294                                                 // Seams like we don't have all the data, abort
 295                                                 return null;
 296                                         }
 297                                 }
 298
 299                                 // Send things that start with data: to $data, the rest to $matches
 300                                 if ( $isData ) {
 301                                         $data[$key] = $value;
 302                                 } else {
 303                                         $matches[$key] = $value;
 304                                 }
 305                         }
 306
 307                         // If this match includes a callback, execute it
 308                         if ( isset( $pattern->options['callback'] ) ) {
 309                                 call_user_func_array( $pattern->options['callback'], array( &$matches, $data ) );
 310                         }
 311                 } else {
 312                         // Our regexp didn't match, return null to signify no match.
 313                         return null;
 314                 }
 315                 // Fall through, everything went ok, return our matches array
 316                 return $matches;
 317         }
 318
 319 }