Dave Jarvis' Repositories

<?php
namespace com\whitemagicsoftware;

/**
 * Syntax based normalization of URI's
 *
 * This normalises URI's based on the specification RFC 3986
 * http://www.apps.ietf.org/rfc/rfc3986.html
 *
 * Example usage:
 * <pre>
 * require_once 'Normalizer.php';
 *
 * $url = 'eXAMPLE://a/./b/../b/%63/%7bfoo%7d';
 * $un = new Normalizer();
 * $un->setUrl( $url );
 * echo $un->normalize();
 *
 * // result: "example://a/b/c/%7Bfoo%7D"
 * </pre>
 *
 * @author Glen Scott <glen@glenscott.co.uk>
 */
class Normalizer {
  private $url;
  private $scheme;
  private $host;
  private $port;
  private $user;
  private $pass;
  private $path;
  private $query;
  private $fragment;
  private $default_scheme_ports = array( 'http:' => 80, 'https:' => 443, );
  private $components = array( 'scheme', 'host', 'port', 'user', 'pass', 'path', 'query', 'fragment', );

  public function __construct( $url=null ) {
    if ( $url ) {
      $this->setUrl( $url );
    }
  }

  private function getQuery($query) {
    $qs = array();
    foreach($query as $qk => $qv) {
      if(is_array($qv)) {
        $qs[rawurldecode($qk)] = $this->getQuery($qv);
      }
      else {
        $qs[rawurldecode($qk)] = rawurldecode($qv);
      }
    }
    return $qs;
  }

  public function getUrl() {
    return $this->url;
  }

  /**
   * Added to ensure the URL always has a scheme.
   *
   * @param The URL to prepend http:// to.
   * @return The URL with a valid scheme (default http://).
   */
  private function addScheme( $url, $scheme = "http://" ) {
    return parse_url($url, PHP_URL_SCHEME) === null ?
      $scheme . $url : $url;
  }

  public function setUrl( $url ) {
      $this->url = $this->addScheme( $url );

      // parse URL into respective parts
      $url_components = parse_url( $this->url );

      if ( ! $url_components ) {
          // Reset URL
          $this->url = '';

          // Flush properties
          foreach ( $this->components as $key ) {
              if ( property_exists( $this, $key ) ) {
                  $this->$key = '';
              }
          }

          return false;
      }
      else {
          // Update properties
          foreach ( $url_components as $key => $value ) {
              if ( property_exists( $this, $key ) ) {
                  $this->$key = $value;
              }
          }

          // Flush missing components
          $missing_components = array_diff (
              array_values( $this->components ),
              array_keys( $url_components )
          );

          foreach ( $missing_components as $key ) {
              if ( property_exists( $this, $key ) ) {
                  $this->$key = '';
              }
          }

          return true;
      }
  }

  public function normalize() {
      // URI Syntax Components
      // scheme authority path query fragment
      // @see http://www.apps.ietf.org/rfc/rfc3986.html#sec-3

      // Scheme
      // @see http://www.apps.ietf.org/rfc/rfc3986.html#sec-3.1

      if ( $this->scheme ) {
          // Converting the scheme to lower case
          $this->scheme = strtolower( $this->scheme ) . ':';
      }

      // Authority
      // @see http://www.apps.ietf.org/rfc/rfc3986.html#sec-3.2

      $authority = '';
      if ( $this->host ) {
          $authority .= '//';

          // User Information
          // @see http://www.apps.ietf.org/rfc/rfc3986.html#sec-3.2.1

          if ( $this->user ) {
              if ( $this->pass ) {
                  $authority .= $this->user . ':' . $this->pass . '@';
              }
              else {
                  $authority .= $this->user . '@';
              }
          }

          // Host
          // @see http://www.apps.ietf.org/rfc/rfc3986.html#sec-3.2.2

          // Converting the host to lower case
          $authority .= strtolower( $this->host );

          // Port
          // @see http://www.apps.ietf.org/rfc/rfc3986.html#sec-3.2.3

          // Removing the default port
          if ( isset( $this->default_scheme_ports[$this->scheme] )
                  && $this->port == $this->default_scheme_ports[$this->scheme]) {
              $this->port = '';
          }

          if ( $this->port ) {
              $authority .= ':' . $this->port;
          }
      }

      // Path
      // @see http://www.apps.ietf.org/rfc/rfc3986.html#sec-3.3

      if ( $this->path ) {
          // Removing dot-segments
          $this->path = $this->removeDotSegments( $this->path );
          $this->path = $this->urlDecodeUnreservedChars( $this->path );
          $this->path = $this->urlDecodeReservedSubDelimChars( $this->path );
      }
      // Add default path only when valid URL is present
      elseif ( $this->url ) {
          // Adding trailing /
          $this->path = '/';
      }

      // Query
      // @see http://www.apps.ietf.org/rfc/rfc3986.html#sec-3.4

      if ( $this->query ) {
          parse_str( $this->query, $query );

          //encodes every parameter correctly
          $qs = $this->getQuery($query);
          $this->query = '?' . str_replace( '+', '%20', http_build_query( $qs, null, '&' ) );
          
          // Fix http_build_query adding equals sign to empty keys
          $this->query = str_replace( '=&', '&', rtrim( $this->query, '=' ));
      }

      // Fragment
      // @see http://www.apps.ietf.org/rfc/rfc3986.html#sec-3.5

      if ( $this->fragment ) {
          $this->fragment = rawurldecode( $this->fragment );
          $this->fragment = rawurlencode( $this->fragment );
          $this->fragment = '#' . $this->fragment;
      }

      $this->setUrl( $this->scheme . $authority . $this->path . $this->query . $this->fragment );

      return $this->getUrl();
  }

  /**
   * Path segment normalization
   * http://www.apps.ietf.org/rfc/rfc3986.html#sec-5.2.4
   */
  public function removeDotSegments( $path ) {
      $new_path = '';

      while ( ! empty( $path ) ) {
           // A
          $pattern_a   = '!^(\.\./|\./)!x';
          $pattern_b_1 = '!^(/\./)!x';
          $pattern_b_2 = '!^(/\.)$!x';
          $pattern_c   = '!^(/\.\./|/\.\.)!x';
          $pattern_d   = '!^(\.|\.\.)$!x';
          $pattern_e   = '!(/*[^/]*)!x';

          if ( preg_match( $pattern_a, $path ) ) {
              // remove prefix from $path
              $path = preg_replace( $pattern_a, '', $path );
          }
          elseif ( preg_match( $pattern_b_1, $path, $matches ) || preg_match( $pattern_b_2, $path, $matches ) ) {
              $path = preg_replace( "!^" . $matches[1] . "!", '/', $path );
          }
          elseif ( preg_match( $pattern_c, $path, $matches ) ) {
              $path = preg_replace( '!^' . preg_quote( $matches[1], '!' ) . '!x', '/', $path );

              // remove the last segment and its preceding "/" (if any) from output buffer
              $new_path = preg_replace( '!/([^/]+)$!x', '', $new_path );
          }
          elseif ( preg_match( $pattern_d, $path ) ) {
              $path = preg_replace( $pattern_d, '', $path );
          }
          else {
              if ( preg_match( $pattern_e, $path, $matches ) ) {
                  $first_path_segment = $matches[1];

                  $path = preg_replace( '/^' . preg_quote( $first_path_segment, '/' ) . '/', '', $path, 1 );

                  $new_path .= $first_path_segment;
              }
          }
      }

      return $new_path;
  }

  public function getScheme() {
      return $this->scheme;
  }

  /**
   * Decode unreserved characters
   * 
   * @see http://www.apps.ietf.org/rfc/rfc3986.html#sec-2.3
   */
  public function urlDecodeUnreservedChars( $string ) {
      $string = rawurldecode( $string );
      $string = rawurlencode( $string );
      $string = str_replace( array( '%2F', '%3A', '%40' ), array( '/', ':', '@' ), $string );

      return $string;
  }

  /**
   * Decode reserved sub-delims
   *
   * @see http://www.apps.ietf.org/rfc/rfc3986.html#sec-2.2
   */
  public function urlDecodeReservedSubDelimChars( $string ) {
      return str_replace( array( '%21', '%24', '%26', '%27', '%28', '%29', '%2A', '%2B', '%2C', '%3B', '%3D' ), 
                          array( '!', '$', '&', "'", '(', ')', '*', '+', ',', ';', '=' ), $string );
  }
}