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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       * The maximum supported length of a PCRE subpattern name
  33       * http://pcre.org/current/doc/html/pcre2pattern.html#SEC16.
  34       *
  35       * @internal
  36       */
  37      const VARIABLE_MAXIMUM_LENGTH = 32;
  38  
  39      /**
  40       * {@inheritdoc}
  41       *
  42       * @throws \LogicException  If a variable is referenced more than once
  43       * @throws \DomainException if a variable name starts with a digit or if it is too long to be successfully used as
  44       *                          a PCRE subpattern
  45       */
  46      public static function compile(Route $route)
  47      {
  48          $hostVariables = array();
  49          $variables = array();
  50          $hostRegex = null;
  51          $hostTokens = array();
  52  
  53          if ('' !== $host = $route->getHost()) {
  54              $result = self::compilePattern($route, $host, true);
  55  
  56              $hostVariables = $result['variables'];
  57              $variables = $hostVariables;
  58  
  59              $hostTokens = $result['tokens'];
  60              $hostRegex = $result['regex'];
  61          }
  62  
  63          $path = $route->getPath();
  64  
  65          $result = self::compilePattern($route, $path, false);
  66  
  67          $staticPrefix = $result['staticPrefix'];
  68  
  69          $pathVariables = $result['variables'];
  70          $variables = array_merge($variables, $pathVariables);
  71  
  72          $tokens = $result['tokens'];
  73          $regex = $result['regex'];
  74  
  75          return new CompiledRoute(
  76              $staticPrefix,
  77              $regex,
  78              $tokens,
  79              $pathVariables,
  80              $hostRegex,
  81              $hostTokens,
  82              $hostVariables,
  83              array_unique($variables)
  84          );
  85      }
  86  
  87      private static function compilePattern(Route $route, $pattern, $isHost)
  88      {
  89          $tokens = array();
  90          $variables = array();
  91          $matches = array();
  92          $pos = 0;
  93          $defaultSeparator = $isHost ? '.' : '/';
  94  
  95          // Match all variables enclosed in "{}" and iterate over them. But we only want to match the innermost variable
  96          // in case of nested "{}", e.g. {foo{bar}}. This in ensured because \w does not match "{" or "}" itself.
  97          preg_match_all('#\{\w+\}#', $pattern, $matches, PREG_OFFSET_CAPTURE | PREG_SET_ORDER);
  98          foreach ($matches as $match) {
  99              $varName = substr($match[0][0], 1, -1);
 100              // get all static text preceding the current variable
 101              $precedingText = substr($pattern, $pos, $match[0][1] - $pos);
 102              $pos = $match[0][1] + \strlen($match[0][0]);
 103              $precedingChar = \strlen($precedingText) > 0 ? substr($precedingText, -1) : '';
 104              $isSeparator = '' !== $precedingChar && false !== strpos(static::SEPARATORS, $precedingChar);
 105  
 106              // A PCRE subpattern name must start with a non-digit. Also a PHP variable cannot start with a digit so the
 107              // variable would not be usable as a Controller action argument.
 108              if (preg_match('/^\d/', $varName)) {
 109                  throw new \DomainException(sprintf('Variable name "%s" cannot start with a digit in route pattern "%s". Please use a different name.', $varName, $pattern));
 110              }
 111              if (\in_array($varName, $variables)) {
 112                  throw new \LogicException(sprintf('Route pattern "%s" cannot reference variable name "%s" more than once.', $pattern, $varName));
 113              }
 114  
 115              if (\strlen($varName) > self::VARIABLE_MAXIMUM_LENGTH) {
 116                  throw new \DomainException(sprintf('Variable name "%s" cannot be longer than %s characters in route pattern "%s". Please use a shorter name.', $varName, self::VARIABLE_MAXIMUM_LENGTH, $pattern));
 117              }
 118  
 119              if ($isSeparator && \strlen($precedingText) > 1) {
 120                  $tokens[] = array('text', substr($precedingText, 0, -1));
 121              } elseif (!$isSeparator && \strlen($precedingText) > 0) {
 122                  $tokens[] = array('text', $precedingText);
 123              }
 124  
 125              $regexp = $route->getRequirement($varName);
 126              if (null === $regexp) {
 127                  $followingPattern = (string) substr($pattern, $pos);
 128                  // Find the next static character after the variable that functions as a separator. By default, this separator and '/'
 129                  // are disallowed for the variable. This default requirement makes sure that optional variables can be matched at all
 130                  // and that the generating-matching-combination of URLs unambiguous, i.e. the params used for generating the URL are
 131                  // the same that will be matched. Example: new Route('/{page}.{_format}', array('_format' => 'html'))
 132                  // If {page} would also match the separating dot, {_format} would never match as {page} will eagerly consume everything.
 133                  // Also even if {_format} was not optional the requirement prevents that {page} matches something that was originally
 134                  // part of {_format} when generating the URL, e.g. _format = 'mobile.html'.
 135                  $nextSeparator = self::findNextSeparator($followingPattern);
 136                  $regexp = sprintf(
 137                      '[^%s%s]+',
 138                      preg_quote($defaultSeparator, self::REGEX_DELIMITER),
 139                      $defaultSeparator !== $nextSeparator && '' !== $nextSeparator ? preg_quote($nextSeparator, self::REGEX_DELIMITER) : ''
 140                  );
 141                  if (('' !== $nextSeparator && !preg_match('#^\{\w+\}#', $followingPattern)) || '' === $followingPattern) {
 142                      // When we have a separator, which is disallowed for the variable, we can optimize the regex with a possessive
 143                      // quantifier. This prevents useless backtracking of PCRE and improves performance by 20% for matching those patterns.
 144                      // Given the above example, there is no point in backtracking into {page} (that forbids the dot) when a dot must follow
 145                      // after it. This optimization cannot be applied when the next char is no real separator or when the next variable is
 146                      // directly adjacent, e.g. '/{x}{y}'.
 147                      $regexp .= '+';
 148                  }
 149              }
 150  
 151              $tokens[] = array('variable', $isSeparator ? $precedingChar : '', $regexp, $varName);
 152              $variables[] = $varName;
 153          }
 154  
 155          if ($pos < \strlen($pattern)) {
 156              $tokens[] = array('text', substr($pattern, $pos));
 157          }
 158  
 159          // find the first optional token
 160          $firstOptional = PHP_INT_MAX;
 161          if (!$isHost) {
 162              for ($i = \count($tokens) - 1; $i >= 0; --$i) {
 163                  $token = $tokens[$i];
 164                  if ('variable' === $token[0] && $route->hasDefault($token[3])) {
 165                      $firstOptional = $i;
 166                  } else {
 167                      break;
 168                  }
 169              }
 170          }
 171  
 172          // compute the matching regexp
 173          $regexp = '';
 174          for ($i = 0, $nbToken = \count($tokens); $i < $nbToken; ++$i) {
 175              $regexp .= self::computeRegexp($tokens, $i, $firstOptional);
 176          }
 177  
 178          return array(
 179              'staticPrefix' => 'text' === $tokens[0][0] ? $tokens[0][1] : '',
 180              'regex' => self::REGEX_DELIMITER.'^'.$regexp.'$'.self::REGEX_DELIMITER.'sD'.($isHost ? 'i' : ''),
 181              'tokens' => array_reverse($tokens),
 182              'variables' => $variables,
 183          );
 184      }
 185  
 186      /**
 187       * Returns the next static character in the Route pattern that will serve as a separator.
 188       *
 189       * @param string $pattern The route pattern
 190       *
 191       * @return string The next static character that functions as separator (or empty string when none available)
 192       */
 193      private static function findNextSeparator($pattern)
 194      {
 195          if ('' == $pattern) {
 196              // return empty string if pattern is empty or false (false which can be returned by substr)
 197              return '';
 198          }
 199          // first remove all placeholders from the pattern so we can find the next real static character
 200          $pattern = preg_replace('#\{\w+\}#', '', $pattern);
 201  
 202          return isset($pattern[0]) && false !== strpos(static::SEPARATORS, $pattern[0]) ? $pattern[0] : '';
 203      }
 204  
 205      /**
 206       * Computes the regexp used to match a specific token. It can be static text or a subpattern.
 207       *
 208       * @param array $tokens        The route tokens
 209       * @param int   $index         The index of the current token
 210       * @param int   $firstOptional The index of the first optional token
 211       *
 212       * @return string The regexp pattern for a single token
 213       */
 214      private static function computeRegexp(array $tokens, $index, $firstOptional)
 215      {
 216          $token = $tokens[$index];
 217          if ('text' === $token[0]) {
 218              // Text tokens
 219              return preg_quote($token[1], self::REGEX_DELIMITER);
 220          } else {
 221              // Variable tokens
 222              if (0 === $index && 0 === $firstOptional) {
 223                  // When the only token is an optional variable token, the separator is required
 224                  return sprintf('%s(?P<%s>%s)?', preg_quote($token[1], self::REGEX_DELIMITER), $token[3], $token[2]);
 225              } else {
 226                  $regexp = sprintf('%s(?P<%s>%s)', preg_quote($token[1], self::REGEX_DELIMITER), $token[3], $token[2]);
 227                  if ($index >= $firstOptional) {
 228                      // Enclose each optional token in a subpattern to make it optional.
 229                      // "?:" means it is non-capturing, i.e. the portion of the subject string that
 230                      // matched the optional subpattern is not passed back.
 231                      $regexp = "(?:$regexp";
 232                      $nbTokens = \count($tokens);
 233                      if ($nbTokens - 1 == $index) {
 234                          // Close the optional subpatterns
 235                          $regexp .= str_repeat(')?', $nbTokens - $firstOptional - (0 === $firstOptional ? 1 : 0));
 236                      }
 237                  }
 238  
 239                  return $regexp;
 240              }
 241          }
 242      }
 243  }