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   1  <?php
   2  
   3  /*
   4   * This file is part of the Symfony package.
   5   *
   6   * (c) Fabien Potencier <fabien@symfony.com>
   7   *
   8   * For the full copyright and license information, please view the LICENSE
   9   * file that was distributed with this source code.
  10   */
  11  
  12  namespace Symfony\Component\Routing;
  13  
  14  /**
  15   * RouteCompiler compiles Route instances to CompiledRoute instances.
  16   *
  17   * @author Fabien Potencier <fabien@symfony.com>
  18   * @author Tobias Schultze <http://tobion.de>
  19   */
  20  class RouteCompiler implements RouteCompilerInterface
  21  {
  22      const REGEX_DELIMITER = '#';
  23  
  24      /**
  25       * This string defines the characters that are automatically considered separators in front of
  26       * optional placeholders (with default and no static text following). Such a single separator
  27       * can be left out together with the optional placeholder from matching and generating URLs.
  28       */
  29      const SEPARATORS = '/,;.:-_~+*=@|';
  30  
  31      /**
  32       * {@inheritdoc}
  33       *
  34       * @throws \LogicException  If a variable is referenced more than once
  35       * @throws \DomainException If a variable name is numeric because PHP raises an error for such
  36       *                          subpatterns in PCRE and thus would break matching, e.g. "(?P<123>.+)".
  37       */
  38      public static function compile(Route $route)
  39      {
  40          $hostVariables = array();
  41          $variables = array();
  42          $hostRegex = null;
  43          $hostTokens = array();
  44  
  45          if ('' !== $host = $route->getHost()) {
  46              $result = self::compilePattern($route, $host, true);
  47  
  48              $hostVariables = $result['variables'];
  49              $variables = $hostVariables;
  50  
  51              $hostTokens = $result['tokens'];
  52              $hostRegex = $result['regex'];
  53          }
  54  
  55          $path = $route->getPath();
  56  
  57          $result = self::compilePattern($route, $path, false);
  58  
  59          $staticPrefix = $result['staticPrefix'];
  60  
  61          $pathVariables = $result['variables'];
  62          $variables = array_merge($variables, $pathVariables);
  63  
  64          $tokens = $result['tokens'];
  65          $regex = $result['regex'];
  66  
  67          return new CompiledRoute(
  68              $staticPrefix,
  69              $regex,
  70              $tokens,
  71              $pathVariables,
  72              $hostRegex,
  73              $hostTokens,
  74              $hostVariables,
  75              array_unique($variables)
  76          );
  77      }
  78  
  79      private static function compilePattern(Route $route, $pattern, $isHost)
  80      {
  81          $tokens = array();
  82          $variables = array();
  83          $matches = array();
  84          $pos = 0;
  85          $defaultSeparator = $isHost ? '.' : '/';
  86  
  87          // Match all variables enclosed in "{}" and iterate over them. But we only want to match the innermost variable
  88          // in case of nested "{}", e.g. {foo{bar}}. This in ensured because \w does not match "{" or "}" itself.
  89          preg_match_all('#\{\w+\}#', $pattern, $matches, PREG_OFFSET_CAPTURE | PREG_SET_ORDER);
  90          foreach ($matches as $match) {
  91              $varName = substr($match[0][0], 1, -1);
  92              // get all static text preceding the current variable
  93              $precedingText = substr($pattern, $pos, $match[0][1] - $pos);
  94              $pos = $match[0][1] + strlen($match[0][0]);
  95              $precedingChar = strlen($precedingText) > 0 ? substr($precedingText, -1) : '';
  96              $isSeparator = '' !== $precedingChar && false !== strpos(static::SEPARATORS, $precedingChar);
  97  
  98              if (is_numeric($varName)) {
  99                  throw new \DomainException(sprintf('Variable name "%s" cannot be numeric in route pattern "%s". Please use a different name.', $varName, $pattern));
 100              }
 101              if (in_array($varName, $variables)) {
 102                  throw new \LogicException(sprintf('Route pattern "%s" cannot reference variable name "%s" more than once.', $pattern, $varName));
 103              }
 104  
 105              if ($isSeparator && strlen($precedingText) > 1) {
 106                  $tokens[] = array('text', substr($precedingText, 0, -1));
 107              } elseif (!$isSeparator && strlen($precedingText) > 0) {
 108                  $tokens[] = array('text', $precedingText);
 109              }
 110  
 111              $regexp = $route->getRequirement($varName);
 112              if (null === $regexp) {
 113                  $followingPattern = (string) substr($pattern, $pos);
 114                  // Find the next static character after the variable that functions as a separator. By default, this separator and '/'
 115                  // are disallowed for the variable. This default requirement makes sure that optional variables can be matched at all
 116                  // and that the generating-matching-combination of URLs unambiguous, i.e. the params used for generating the URL are
 117                  // the same that will be matched. Example: new Route('/{page}.{_format}', array('_format' => 'html'))
 118                  // If {page} would also match the separating dot, {_format} would never match as {page} will eagerly consume everything.
 119                  // Also even if {_format} was not optional the requirement prevents that {page} matches something that was originally
 120                  // part of {_format} when generating the URL, e.g. _format = 'mobile.html'.
 121                  $nextSeparator = self::findNextSeparator($followingPattern);
 122                  $regexp = sprintf(
 123                      '[^%s%s]+',
 124                      preg_quote($defaultSeparator, self::REGEX_DELIMITER),
 125                      $defaultSeparator !== $nextSeparator && '' !== $nextSeparator ? preg_quote($nextSeparator, self::REGEX_DELIMITER) : ''
 126                  );
 127                  if (('' !== $nextSeparator && !preg_match('#^\{\w+\}#', $followingPattern)) || '' === $followingPattern) {
 128                      // When we have a separator, which is disallowed for the variable, we can optimize the regex with a possessive
 129                      // quantifier. This prevents useless backtracking of PCRE and improves performance by 20% for matching those patterns.
 130                      // Given the above example, there is no point in backtracking into {page} (that forbids the dot) when a dot must follow
 131                      // after it. This optimization cannot be applied when the next char is no real separator or when the next variable is
 132                      // directly adjacent, e.g. '/{x}{y}'.
 133                      $regexp .= '+';
 134                  }
 135              }
 136  
 137              $tokens[] = array('variable', $isSeparator ? $precedingChar : '', $regexp, $varName);
 138              $variables[] = $varName;
 139          }
 140  
 141          if ($pos < strlen($pattern)) {
 142              $tokens[] = array('text', substr($pattern, $pos));
 143          }
 144  
 145          // find the first optional token
 146          $firstOptional = PHP_INT_MAX;
 147          if (!$isHost) {
 148              for ($i = count($tokens) - 1; $i >= 0; --$i) {
 149                  $token = $tokens[$i];
 150                  if ('variable' === $token[0] && $route->hasDefault($token[3])) {
 151                      $firstOptional = $i;
 152                  } else {
 153                      break;
 154                  }
 155              }
 156          }
 157  
 158          // compute the matching regexp
 159          $regexp = '';
 160          for ($i = 0, $nbToken = count($tokens); $i < $nbToken; ++$i) {
 161              $regexp .= self::computeRegexp($tokens, $i, $firstOptional);
 162          }
 163  
 164          return array(
 165              'staticPrefix' => 'text' === $tokens[0][0] ? $tokens[0][1] : '',
 166              'regex' => self::REGEX_DELIMITER.'^'.$regexp.'$'.self::REGEX_DELIMITER.'s'.($isHost ? 'i' : ''),
 167              'tokens' => array_reverse($tokens),
 168              'variables' => $variables,
 169          );
 170      }
 171  
 172      /**
 173       * Returns the next static character in the Route pattern that will serve as a separator.
 174       *
 175       * @param string $pattern The route pattern
 176       *
 177       * @return string The next static character that functions as separator (or empty string when none available)
 178       */
 179      private static function findNextSeparator($pattern)
 180      {
 181          if ('' == $pattern) {
 182              // return empty string if pattern is empty or false (false which can be returned by substr)
 183              return '';
 184          }
 185          // first remove all placeholders from the pattern so we can find the next real static character
 186          $pattern = preg_replace('#\{\w+\}#', '', $pattern);
 187  
 188          return isset($pattern[0]) && false !== strpos(static::SEPARATORS, $pattern[0]) ? $pattern[0] : '';
 189      }
 190  
 191      /**
 192       * Computes the regexp used to match a specific token. It can be static text or a subpattern.
 193       *
 194       * @param array $tokens        The route tokens
 195       * @param int   $index         The index of the current token
 196       * @param int   $firstOptional The index of the first optional token
 197       *
 198       * @return string The regexp pattern for a single token
 199       */
 200      private static function computeRegexp(array $tokens, $index, $firstOptional)
 201      {
 202          $token = $tokens[$index];
 203          if ('text' === $token[0]) {
 204              // Text tokens
 205              return preg_quote($token[1], self::REGEX_DELIMITER);
 206          } else {
 207              // Variable tokens
 208              if (0 === $index && 0 === $firstOptional) {
 209                  // When the only token is an optional variable token, the separator is required
 210                  return sprintf('%s(?P<%s>%s)?', preg_quote($token[1], self::REGEX_DELIMITER), $token[3], $token[2]);
 211              } else {
 212                  $regexp = sprintf('%s(?P<%s>%s)', preg_quote($token[1], self::REGEX_DELIMITER), $token[3], $token[2]);
 213                  if ($index >= $firstOptional) {
 214                      // Enclose each optional token in a subpattern to make it optional.
 215                      // "?:" means it is non-capturing, i.e. the portion of the subject string that
 216                      // matched the optional subpattern is not passed back.
 217                      $regexp = "(?:$regexp";
 218                      $nbTokens = count($tokens);
 219                      if ($nbTokens - 1 == $index) {
 220                          // Close the optional subpatterns
 221                          $regexp .= str_repeat(')?', $nbTokens - $firstOptional - (0 === $firstOptional ? 1 : 0));
 222                      }
 223                  }
 224  
 225                  return $regexp;
 226              }
 227          }
 228      }
 229  }