<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\Routing;
/**
* RouteCompiler compiles Route instances to CompiledRoute instances.
*
* @author Fabien Potencier <fabien@symfony.com>
* @author Tobias Schultze <http://tobion.de>
*/
class RouteCompiler implements RouteCompilerInterface
{
const REGEX_DELIMITER = '#';
/**
* This string defines the characters that are automatically considered separators in front of
* optional placeholders (with default and no static text following). Such a single separator
* can be left out together with the optional placeholder from matching and generating URLs.
*/
const SEPARATORS = '/,;.:-_~+*=@|';
/**
* {@inheritDoc}
*
* @throws \LogicException If a variable is referenced more than once
* @throws \DomainException If a variable name is numeric because PHP raises an error for such
* subpatterns in PCRE and thus would break matching, e.g. "(?P<123>.+)".
*/
public static function compile(Route $route)
{
$staticPrefix = null;
$hostVariables = array();
$pathVariables = array();
$variables = array();
$tokens = array();
$regex = null;
$hostRegex = null;
$hostTokens = array();
if ('' !== $host = $route->getHost()) {
$result = self::compilePattern($route, $host, true);
$hostVariables = $result['variables'];
$variables = array_merge($variables, $hostVariables);
$hostTokens = $result['tokens'];
$hostRegex = $result['regex'];
}
$path = $route->getPath();
$result = self::compilePattern($route, $path, false);
$staticPrefix = $result['staticPrefix'];
$pathVariables = $result['variables'];
$variables = array_merge($variables, $pathVariables);
$tokens = $result['tokens'];
$regex = $result['regex'];
return new CompiledRoute(
$staticPrefix,
$regex,
$tokens,
$pathVariables,
$hostRegex,
$hostTokens,
$hostVariables,
array_unique($variables)
);
}
private static function compilePattern(Route $route, $pattern, $isHost)
{
$tokens = array();
$variables = array();
$matches = array();
$pos = 0;
$defaultSeparator = $isHost ? '.' : '/';
// Match all variables enclosed in "{}" and iterate over them. But we only want to match the innermost variable
// in case of nested "{}", e.g. {foo{bar}}. This in ensured because \w does not match "{" or "}" itself.
preg_match_all('#\{\w+\}#', $pattern, $matches, PREG_OFFSET_CAPTURE | PREG_SET_ORDER);
foreach ($matches as $match) {
$varName = substr($match[0][0], 1, -1);
// get all static text preceding the current variable
$precedingText = substr($pattern, $pos, $match[0][1] - $pos);
$pos = $match[0][1] + strlen($match[0][0]);
$precedingChar = strlen($precedingText) > 0 ? substr($precedingText, -1) : '';
$isSeparator = '' !== $precedingChar && false !== strpos(static::SEPARATORS, $precedingChar);
if (is_numeric($varName)) {
throw new \DomainException(sprintf('Variable name "%s" cannot be numeric in route pattern "%s". Please use a different name.', $varName, $pattern));
}
if (in_array($varName, $variables)) {
throw new \LogicException(sprintf('Route pattern "%s" cannot reference variable name "%s" more than once.', $pattern, $varName));
}
if ($isSeparator && strlen($precedingText) > 1) {
$tokens[] = array('text', substr($precedingText, 0, -1));
} elseif (!$isSeparator && strlen($precedingText) > 0) {
$tokens[] = array('text', $precedingText);
}
$regexp = $route->getRequirement($varName);
if (null === $regexp) {
$followingPattern = (string) substr($pattern, $pos);
// Find the next static character after the variable that functions as a separator. By default, this separator and '/'
// are disallowed for the variable. This default requirement makes sure that optional variables can be matched at all
// and that the generating-matching-combination of URLs unambiguous, i.e. the params used for generating the URL are
// the same that will be matched. Example: new Route('/{page}.{_format}', array('_format' => 'html'))
// If {page} would also match the separating dot, {_format} would never match as {page} will eagerly consume everything.
// Also even if {_format} was not optional the requirement prevents that {page} matches something that was originally
// part of {_format} when generating the URL, e.g. _format = 'mobile.html'.
$nextSeparator = self::findNextSeparator($followingPattern);
$regexp = sprintf(
'[^%s%s]+',
preg_quote($defaultSeparator, self::REGEX_DELIMITER),
$defaultSeparator !== $nextSeparator && '' !== $nextSeparator ? preg_quote($nextSeparator, self::REGEX_DELIMITER) : ''
);
if (('' !== $nextSeparator && !preg_match('#^\{\w+\}#', $followingPattern)) || '' === $followingPattern) {
// When we have a separator, which is disallowed for the variable, we can optimize the regex with a possessive
// quantifier. This prevents useless backtracking of PCRE and improves performance by 20% for matching those patterns.
// Given the above example, there is no point in backtracking into {page} (that forbids the dot) when a dot must follow
// after it. This optimization cannot be applied when the next char is no real separator or when the next variable is
// directly adjacent, e.g. '/{x}{y}'.
$regexp .= '+';
}
}
$tokens[] = array('variable', $isSeparator ? $precedingChar : '', $regexp, $varName);
$variables[] = $varName;
}
if ($pos < strlen($pattern)) {
$tokens[] = array('text', substr($pattern, $pos));
}
// find the first optional token
$firstOptional = PHP_INT_MAX;
if (!$isHost) {
for ($i = count($tokens) - 1; $i >= 0; $i--) {
$token = $tokens[$i];
if ('variable' === $token[0] && $route->hasDefault($token[3])) {
$firstOptional = $i;
} else {
break;
}
}
}
// compute the matching regexp
$regexp = '';
for ($i = 0, $nbToken = count($tokens); $i < $nbToken; $i++) {
$regexp .= self::computeRegexp($tokens, $i, $firstOptional);
}
return array(
'staticPrefix' => 'text' === $tokens[0][0] ? $tokens[0][1] : '',
'regex' => self::REGEX_DELIMITER.'^'.$regexp.'$'.self::REGEX_DELIMITER.'s',
'tokens' => array_reverse($tokens),
'variables' => $variables,
);
}
/**
* Returns the next static character in the Route pattern that will serve as a separator.
*
* @param string $pattern The route pattern
*
* @return string The next static character that functions as separator (or empty string when none available)
*/
private static function findNextSeparator($pattern)
{
if ('' == $pattern) {
// return empty string if pattern is empty or false (false which can be returned by substr)
return '';
}
// first remove all placeholders from the pattern so we can find the next real static character
$pattern = preg_replace('#\{\w+\}#', '', $pattern);
return isset($pattern[0]) && false !== strpos(static::SEPARATORS, $pattern[0]) ? $pattern[0] : '';
}
/**
* Computes the regexp used to match a specific token. It can be static text or a subpattern.
*
* @param array $tokens The route tokens
* @param integer $index The index of the current token
* @param integer $firstOptional The index of the first optional token
*
* @return string The regexp pattern for a single token
*/
private static function computeRegexp(array $tokens, $index, $firstOptional)
{
$token = $tokens[$index];
if ('text' === $token[0]) {
// Text tokens
return preg_quote($token[1], self::REGEX_DELIMITER);
} else {
// Variable tokens
if (0 === $index && 0 === $firstOptional) {
// When the only token is an optional variable token, the separator is required
return sprintf('%s(?P<%s>%s)?', preg_quote($token[1], self::REGEX_DELIMITER), $token[3], $token[2]);
} else {
$regexp = sprintf('%s(?P<%s>%s)', preg_quote($token[1], self::REGEX_DELIMITER), $token[3], $token[2]);
if ($index >= $firstOptional) {
// Enclose each optional token in a subpattern to make it optional.
// "?:" means it is non-capturing, i.e. the portion of the subject string that
// matched the optional subpattern is not passed back.
$regexp = "(?:$regexp";
$nbTokens = count($tokens);
if ($nbTokens - 1 == $index) {
// Close the optional subpatterns
$regexp .= str_repeat(")?", $nbTokens - $firstOptional - (0 === $firstOptional ? 1 : 0));
}
}
return $regexp;
}
}
}
}
