http/url_map.php

   1 <?php
   2 // Hoplite
   3 // Copyright (c) 2011 Blue Static
   4 //
   5 // This program is free software: you can redistribute it and/or modify it
   6 // under the terms of the GNU General Public License as published by the Free
   7 // Software Foundation, either version 3 of the License, or any later version.
   8 //
   9 // This program is distributed in the hope that it will be useful, but WITHOUT
  10 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 // FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12 // more details.
  13 //
  14 // You should have received a copy of the GNU General Public License along with
  15 // this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 namespace hoplite\http;
  18
  19 /*!
  20   A UrlMap will translate a raw HTTP request into a http\Request object. It does
  21   so by matching the incoming URL to a pattern. For information on the format of
  22   patterns @see ::set_map().
  23 */
  24 class UrlMap
  25 {
  26   /*! @var RootController */
  27   private $controller;
  28
  29   /*! @var array The map of URLs to actions. */
  30   private $map = array();
  31
  32   /*!
  33     Constructs the object with a reference to the RootController.
  34     @param RootController
  35   */
  36   public function __construct(RootController $controller)
  37   {
  38     $this->controller = $controller;
  39   }
  40
  41   /*! Accessor for the RootController */
  42   public function controller() { return $this->controller; }
  43
  44   /*! Gets the URL map */
  45   public function map() { return $this->map; }
  46   /*! @brief Sets the URL map.
  47     The URL map is an associative array of URL prefix patterns to Actions or
  48     file paths containing actions.
  49
  50     The keys can be either a URL prefix or a regular expression.
  51
  52     For URL prefixes, the pattern is matched relative to the root of the entry-
  53     point as specified by the RootController. Patterns should not begin with a
  54     slash. Path fragment parameter extraction can be performed as well. For
  55     example, the pattern 'user/view/{id}' will match a URL like
  56       http://example.com/webapp/user/view/42
  57     And the http\Request's data will have a member called 'id' with value 42.
  58
  59     Typically prefix matching will be done for the above patterns. This may be
  60     unwanted if a more general path needs to execute before a more descendent
  61     one. Using strict matching, invoked by ending a pattern with two slashes,
  62     pattern matching becomes exact in that all path components must match.
  63
  64     Regular expression matching is not limited to prefix patterns and can match
  65     any part of the URL (though prefix matching can be enforced using the
  66     the standard regex '^' character). Regex patterns must begin and end with
  67     '/' characters. During evaluation, if any pattern groups are matched, the
  68     resulting matches will be placed in Request data via the 'url_pattern' key.
  69     The following will match the same URL as above:
  70       '/^user\/view\/([0-9]+)/'
  71
  72     Values can be a class name or a relative path to a file that contains an
  73     Action class by the same name, or just the name of an Action class. The
  74     conventions for each are governed by ::LookupAction().
  75
  76     @see ::Evaluate()
  77     @see ::LookupAction()
  78   */
  79   public function set_map(array $map) { $this->map = $map; }
  80
  81   /*! @brief Evalutes the URL map and finds a match.
  82     This will take the incoming URL from the request and will match it against
  83     the patterns in the internal map.
  84
  85     Matching occurs in a linear scan of the URL map, so precedence can be
  86     enforced by ordering rules appropriately. Regular expressions are matched
  87     and URL parameter extraction occurs each time a different rule is evaluated.
  88
  89     This may mutate the request with extracted data if a match is made and
  90     returned.
  91     @see ::set_map() for more information.
  92
  93     If a match is made, this will return the corresponding value for the matched
  94     key in the map. To get an Action object from this, use ::LookupAction().
  95
  96     @return string|NULL A matched value in the ::map() or NULL if no match.
  97   */
  98   public function Evaluate(Request $request)
  99   {
 100     $fragments = explode('/', $request->url);
 101     $path_length = strlen($request->url);
 102
 103     foreach ($this->map as $rule => $action) {
 104       // Check if this is a regular expression rule and match it.
 105       if ($rule[0] == '/' && substr($rule, -1) == '/') {
 106         $matches = array();
 107         if (preg_match($rule, $request->url, $matches)) {
 108           // This pattern matched, so fill out the request and return.
 109           $request->data['url_pattern'] = $matches;
 110           return $action;
 111         }
 112       }
 113       // Otherwise, this is just a normal string match.
 114       else {
 115         // Patterns that end with two slashes are exact.
 116         $is_strict = substr($rule, -2) == '//';
 117         if ($is_strict)
 118           $rule = substr($rule, 0, -2);
 119
 120         // Set up some variables for the loop.
 121         $is_match = TRUE;
 122         $rule_fragments = explode('/', $rule);
 123         $count_rule_fragments = count($rule_fragments);
 124         $count_fragments = count($fragments);
 125         $extractions = array();
 126
 127         // If this is a strict matcher, then do a quick test based on fragments.
 128         if ($is_strict && $count_rule_fragments != $count_fragments)
 129           continue;
 130
 131         // Loop over the pieces of the rule, matching the fragments to that of
 132         // the request.
 133         foreach ($rule_fragments as $i => $rule_frag) {
 134           // Don't iterate past the length of the request. Prefix matching means
 135           // that this can still be a match.
 136           if ($i >= $count_fragments)
 137             break;
 138
 139           // If this fragment is a key to be extracted, do so into a temporary
 140           // array.
 141           if ($rule_frag[0] == '{' && substr($rule_frag, -1) == '}') {
 142             $key = substr($rule_frag, 1, -1);
 143             $extractions[$key] = $fragments[$i];
 144           }
 145           // Otherwise, the path components mutch match.
 146           else if ($rule_frag != $fragments[$i]) {
 147             $is_match = FALSE;
 148             break;
 149           }
 150         }
 151
 152         // If no match was made, try the next rule.
 153         if (!$is_match)
 154           continue;
 155
 156         // A match was made, so merge the path components that were extracted by
 157         // key and return the match.
 158         $request->data = array_merge($extractions, $request->data);
 159         return $action;
 160       }
 161     }
 162   }
 163
 164   /*! @brief Takes a value from the map and returns an Action object.
 165     The values in the map are either an Action class name or a relative path to
 166     a file containing an Action class.
 167
 168     Mapping to a class requires that the value start with an upper-case letter.
 169
 170     Paths start with a lower-case letter. The last path component will be
 171     transformed into a class name via ::_ClassNameFromFileName(). Note that if
 172     the file extension is not included  in the path, .php will be automatically
 173     appended.
 174
 175     @return Action|NULL The loaded action, or NULL on error.
 176   */
 177   public function LookupAction($map_value)
 178   {}
 179
 180   /*!
 181     Takes a file name and returns the name of an Action class. This uses an
 182     under_score to CamelCase transformation with an 'Action' suffix:
 183       lost_password -> LostPasswordAction
 184
 185     This can be overridden to provide a custom transformation.
 186
 187     @return string Action class name.
 188   */
 189   protected function _ClassNameFromFileName($file_name)
 190   {}
 191 }