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 require_once HOPLITE_ROOT . '/base/functions.php';
  20
  21 /*!
  22   A UrlMap will translate a raw HTTP request into a http\Request object. It does
  23   so by matching the incoming URL to a pattern. For information on the format of
  24   patterns @see ::set_map().
  25 */
  26 class UrlMap
  27 {
  28   /*! @var FrontController */
  29   private $controller;
  30
  31   /*! @var array The map of URLs to actions. */
  32   private $map = array();
  33
  34   /*! @var Closure(string) Loads the file for the appropriate action class name. */
  35   private $file_loader = NULL;
  36
  37   /*!
  38     Constructs the object with a reference to the FrontController.
  39     @param FrontController
  40   */
  41   public function __construct(FrontController $controller)
  42   {
  43     $this->controller = $controller;
  44   }
  45
  46   /*! Accessor for the FrontController */
  47   public function controller() { return $this->controller; }
  48
  49   /*! Gets the URL map */
  50   public function map() { return $this->map; }
  51   /*! @brief Sets the URL map.
  52     The URL map is an associative array of URL prefix patterns to Actions or
  53     file paths containing actions.
  54
  55     The keys can be either a URL prefix or a regular expression.
  56
  57     For URL prefixes, the pattern is matched relative to the root of the entry-
  58     point as specified by the FrontController. Patterns should not begin with a
  59     slash. Path fragment parameter extraction can be performed as well. For
  60     example, the pattern 'user/view/{id}' will match a URL like
  61       http://example.com/webapp/user/view/42
  62     And the http\Request's data will have a member called 'id' with value 42.
  63
  64     Typically prefix matching will be done for the above patterns. This may be
  65     unwanted if a more general path needs to execute before a more descendent
  66     one. Using strict matching, invoked by ending a pattern with two slashes,
  67     pattern matching becomes exact in that all path components must match.
  68
  69     Regular expression matching is not limited to prefix patterns and can match
  70     any part of the URL (though prefix matching can be enforced using the
  71     the standard regex '^' character). Regex patterns must begin and end with
  72     '/' characters. During evaluation, if any pattern groups are matched, the
  73     resulting matches will be placed in Request data via the 'url_pattern' key.
  74     The following will match the same URL as above:
  75       '/^user\/view\/([0-9]+)/'
  76
  77     Values can be a class name or a relative path to a file that contains an
  78     Action class by the same name, or just the name of an Action class. The
  79     conventions for each are governed by ::LookupAction().
  80
  81     @see ::Evaluate()
  82     @see ::LookupAction()
  83   */
  84   public function set_map(array $map) { $this->map = $map; }
  85
  86   /*! @brief The file loading helper function.
  87     This function is called in ::LookupAction() and will load the necessary file
  88     for this class so that it can be instantiated. Should return the class name
  89     to instantiate. This can either be the first argument passed to it
  90     unaltered, or modified for example with a namespace.
  91     Closure(string $class_name, string $map_value) -> string $new_class_name
  92   */
  93   public function set_file_loader(\Closure $fn) { $this->file_loader = $fn; }
  94
  95   /*! @brief Evalutes the URL map and finds a match.
  96     This will take the incoming URL from the request and will match it against
  97     the patterns in the internal map.
  98
  99     Matching occurs in a linear scan of the URL map, so precedence can be
 100     enforced by ordering rules appropriately. Regular expressions are matched
 101     and URL parameter extraction occurs each time a different rule is evaluated.
 102
 103     This may mutate the request with extracted data if a match is made and
 104     returned.
 105     @see ::set_map() for more information.
 106
 107     If a match is made, this will return the corresponding value for the matched
 108     key in the map. To get an Action object from this, use ::LookupAction().
 109
 110     @return string|NULL A matched value in the ::map() or NULL if no match.
 111   */
 112   public function Evaluate(Request $request)
 113   {
 114     $fragments = explode('/', $request->url);
 115     $path_length = strlen($request->url);
 116
 117     foreach ($this->map as $rule => $action) {
 118       // First check if this is the empty rule.
 119       if (empty($rule)) {
 120         if (empty($request->url))
 121           return $action;
 122         else
 123           continue;
 124       }
 125
 126       // Check if this is a regular expression rule and match it.
 127       if ($rule[0] == '/' && substr($rule, -1) == '/') {
 128         $matches = array();
 129         if (preg_match($rule, $request->url, $matches)) {
 130           // This pattern matched, so fill out the request and return.
 131           $request->data['url_pattern'] = $matches;
 132           return $action;
 133         }
 134       }
 135       // Otherwise, this is just a normal string match.
 136       else {
 137         // Patterns that end with two slashes are exact.
 138         $is_strict = substr($rule, -2) == '//';
 139         if ($is_strict)
 140           $rule = substr($rule, 0, -2);
 141
 142         // Set up some variables for the loop.
 143         $is_match = TRUE;
 144         $rule_fragments = explode('/', $rule);
 145         $count_rule_fragments = count($rule_fragments);
 146         $count_fragments = count($fragments);
 147         $extractions = array();
 148
 149         // If this is a strict matcher, then do a quick test based on fragments.
 150         if ($is_strict && $count_rule_fragments != $count_fragments)
 151           continue;
 152
 153         // Loop over the pieces of the rule, matching the fragments to that of
 154         // the request.
 155         foreach ($rule_fragments as $i => $rule_frag) {
 156           // Don't iterate past the length of the request. Prefix matching means
 157           // that this can still be a match.
 158           if ($i >= $count_fragments)
 159             break;
 160
 161           // If this fragment is a key to be extracted, do so into a temporary
 162           // array.
 163           if (strlen($rule_frag) && $rule_frag[0] == '{' && substr($rule_frag, -1) == '}') {
 164             $key = substr($rule_frag, 1, -1);
 165             $extractions[$key] = $fragments[$i];
 166           }
 167           // Otherwise, the path components mutch match.
 168           else if ($rule_frag != $fragments[$i]) {
 169             $is_match = FALSE;
 170             break;
 171           }
 172         }
 173
 174         // If no match was made, try the next rule.
 175         if (!$is_match)
 176           continue;
 177
 178         // A match was made, so merge the path components that were extracted by
 179         // key and return the match.
 180         $request->data = array_merge($extractions, $request->data);
 181         return $action;
 182       }
 183     }
 184   }
 185
 186   /*! @brief Takes a value from the map and returns an Action object.
 187     The values in the map are either an Action class name or a relative path to
 188     a file containing an Action class.
 189
 190     Mapping to a class requires that the value start with an upper-case letter.
 191
 192     Paths start with a lower-case letter. The last path component will be
 193     transformed into a class name via ::_ClassNameFromFileName(). Note that if
 194     the file extension is not included  in the path, .php will be automatically
 195     appended.
 196
 197     @return Action|NULL The loaded action, or NULL on error.
 198   */
 199   public function LookupAction($map_value)
 200   {
 201     // If the first character is uppercase or a namespaced class, simply return
 202     // the value.
 203     $first_char = $map_value[0];
 204     if ($first_char == '\\' || ctype_upper($first_char)) {
 205       $class = $map_value;
 206     } else {
 207       // Otherwise this is a path. Check if an extension is present, and if not,
 208       // add one.
 209       $pathinfo = pathinfo($map_value);
 210       if (!isset($pathinfo['extension'])) {
 211         $map_value .= '.php';
 212         $pathinfo['extension'] = 'php';
 213       }
 214
 215       $class = $this->_ClassNameFromFileName($pathinfo);
 216     }
 217
 218     if ($this->file_loader) {
 219       $loader = $this->file_loader;
 220       $class = $loader($class, $map_value);
 221     }
 222
 223     return new $class($this->controller());
 224   }
 225
 226   /*!
 227     Takes a file name and returns the name of an Action class. This uses an
 228     under_score to CamelCase transformation with an 'Action' suffix:
 229       lost_password -> LostPasswordAction
 230
 231     This can be overridden to provide a custom transformation.
 232
 233     @param array Result of a pathinfo() call
 234
 235     @return string Action class name.
 236   */
 237   protected function _ClassNameFromFileName($pathinfo)
 238   {
 239     $filename = $pathinfo['filename'];
 240     return \hoplite\base\UnderscoreToCamelCase($filename);
 241   }
 242 }