/helpers/library/HTMLPurifier/URI.php

<?php



/**

 * HTML Purifier's internal representation of a URI.

 * @note

 *      Internal data-structures are completely escaped. If the data needs

 *      to be used in a non-URI context (which is very unlikely), be sure

 *      to decode it first. The URI may not necessarily be well-formed until

 *      validate() is called.

 */

class HTMLPurifier_URI

{



    public $scheme, $userinfo, $host, $port, $path, $query, $fragment;



    /**

     * @note Automatically normalizes scheme and port

     */

    public function __construct($scheme, $userinfo, $host, $port, $path, $query, $fragment) {

        $this->scheme = is_null($scheme) || ctype_lower($scheme) ? $scheme : strtolower($scheme);

        $this->userinfo = $userinfo;

        $this->host = $host;

        $this->port = is_null($port) ? $port : (int) $port;

        $this->path = $path;

        $this->query = $query;

        $this->fragment = $fragment;

    }



    /**

     * Retrieves a scheme object corresponding to the URI's scheme/default

     * @param $config Instance of HTMLPurifier_Config

     * @param $context Instance of HTMLPurifier_Context

     * @return Scheme object appropriate for validating this URI

     */

    public function getSchemeObj($config, $context) {

        $registry = HTMLPurifier_URISchemeRegistry::instance();

        if ($this->scheme !== null) {

            $scheme_obj = $registry->getScheme($this->scheme, $config, $context);

            if (!$scheme_obj) return false; // invalid scheme, clean it out

        } else {

            // no scheme: retrieve the default one

            $def = $config->getDefinition('URI');

            $scheme_obj = $registry->getScheme($def->defaultScheme, $config, $context);

            if (!$scheme_obj) {

                // something funky happened to the default scheme object

                trigger_error(

                    'Default scheme object "' . $def->defaultScheme . '" was not readable',

                    E_USER_WARNING

                );

                return false;

            }

        }

        return $scheme_obj;

    }



    /**

     * Generic validation method applicable for all schemes. May modify

     * this URI in order to get it into a compliant form.

     * @param $config Instance of HTMLPurifier_Config

     * @param $context Instance of HTMLPurifier_Context

     * @return True if validation/filtering succeeds, false if failure

     */

    public function validate($config, $context) {



        // ABNF definitions from RFC 3986

        $chars_sub_delims = '!$&\'()*+,;=';

        $chars_gen_delims = ':/?#[]@';

        $chars_pchar = $chars_sub_delims . ':@';



        // validate host

        if (!is_null($this->host)) {

            $host_def = new HTMLPurifier_AttrDef_URI_Host();

            $this->host = $host_def->validate($this->host, $config, $context);

            if ($this->host === false) $this->host = null;

        }



        // validate scheme

        // NOTE: It's not appropriate to check whether or not this

        // scheme is in our registry, since a URIFilter may convert a

        // URI that we don't allow into one we do.  So instead, we just

        // check if the scheme can be dropped because there is no host

        // and it is our default scheme.

        if (!is_null($this->scheme) && is_null($this->host) || $this->host === '') {

            // support for relative paths is pretty abysmal when the

            // scheme is present, so axe it when possible

            $def = $config->getDefinition('URI');

            if ($def->defaultScheme === $this->scheme) {

                $this->scheme = null;

            }

        }



        // validate username

        if (!is_null($this->userinfo)) {

            $encoder = new HTMLPurifier_PercentEncoder($chars_sub_delims . ':');

            $this->userinfo = $encoder->encode($this->userinfo);

        }



        // validate port

        if (!is_null($this->port)) {

            if ($this->port < 1 || $this->port > 65535) $this->port = null;

        }



        // validate path

        $path_parts = array();

        $segments_encoder = new HTMLPurifier_PercentEncoder($chars_pchar . '/');

        if (!is_null($this->host)) { // this catches $this->host === ''

            // path-abempty (hier and relative)

            // http://www.example.com/my/path

            // //www.example.com/my/path (looks odd, but works, and

            //                            recognized by most browsers)

            // (this set is valid or invalid on a scheme by scheme

            // basis, so we'll deal with it later)

            // file:///my/path

            // ///my/path

            $this->path = $segments_encoder->encode($this->path);

        } elseif ($this->path !== '') {

            if ($this->path[0] === '/') {

                // path-absolute (hier and relative)

                // http:/my/path

                // /my/path

                if (strlen($this->path) >= 2 && $this->path[1] === '/') {

                    // This could happen if both the host gets stripped

                    // out

                    // http://my/path

                    // //my/path

                    $this->path = '';

                } else {

                    $this->path = $segments_encoder->encode($this->path);

                }

            } elseif (!is_null($this->scheme)) {

                // path-rootless (hier)

                // http:my/path

                // Short circuit evaluation means we don't need to check nz

                $this->path = $segments_encoder->encode($this->path);

            } else {

                // path-noscheme (relative)

                // my/path

                // (once again, not checking nz)

                $segment_nc_encoder = new HTMLPurifier_PercentEncoder($chars_sub_delims . '@');

                $c = strpos($this->path, '/');

                if ($c !== false) {

                    $this->path =

                        $segment_nc_encoder->encode(substr($this->path, 0, $c)) .

                        $segments_encoder->encode(substr($this->path, $c));

                } else {

                    $this->path = $segment_nc_encoder->encode($this->path);

                }

            }

        } else {

            // path-empty (hier and relative)

            $this->path = ''; // just to be safe

        }



        // qf = query and fragment

        $qf_encoder = new HTMLPurifier_PercentEncoder($chars_pchar . '/?');



        if (!is_null($this->query)) {

            $this->query = $qf_encoder->encode($this->query);

        }



        if (!is_null($this->fragment)) {

            $this->fragment = $qf_encoder->encode($this->fragment);

        }



        return true;



    }



    /**

     * Convert URI back to string

     * @return String URI appropriate for output

     */

    public function toString() {

        // reconstruct authority

        $authority = null;

        // there is a rendering difference between a null authority

        // (http:foo-bar) and an empty string authority

        // (http:///foo-bar).

        if (!is_null($this->host)) {

            $authority = '';

            if(!is_null($this->userinfo)) $authority .= $this->userinfo . '@';

            $authority .= $this->host;

            if(!is_null($this->port))     $authority .= ':' . $this->port;

        }



        // Reconstruct the result

        // One might wonder about parsing quirks from browsers after

        // this reconstruction.  Unfortunately, parsing behavior depends

        // on what *scheme* was employed (file:///foo is handled *very*

        // differently than http:///foo), so unfortunately we have to

        // defer to the schemes to do the right thing.

        $result = '';

        if (!is_null($this->scheme))    $result .= $this->scheme . ':';

        if (!is_null($authority))       $result .=  '//' . $authority;

        $result .= $this->path;

        if (!is_null($this->query))     $result .= '?' . $this->query;

        if (!is_null($this->fragment))  $result .= '#' . $this->fragment;



        return $result;

    }



}



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