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49cb2a4a7c
# Invalid images are now removed, rather than replaced with a dud <img src="" alt="Invalid image" />. Previous behavior can be restored with new directive %Core.RemoveInvalidImg set to false. ! New directives %URI.DisableExternalResources and %URI.DisableResources ! New directive %Attr.DisableURI, which eliminates all hyperlinking - Missing "Available since" documentation added git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@575 48356398-32a2-884e-a903-53898d9a118a
235 lines
9.2 KiB
PHP
235 lines
9.2 KiB
PHP
<?php
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require_once 'HTMLPurifier/AttrDef.php';
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require_once 'HTMLPurifier/URIScheme.php';
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require_once 'HTMLPurifier/URISchemeRegistry.php';
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require_once 'HTMLPurifier/AttrDef/Host.php';
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require_once 'HTMLPurifier/PercentEncoder.php';
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HTMLPurifier_ConfigSchema::define(
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'URI', 'DefaultScheme', 'http', 'string',
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'Defines through what scheme the output will be served, in order to '.
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'select the proper object validator when no scheme information is present.'
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);
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HTMLPurifier_ConfigSchema::define(
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'URI', 'Host', null, 'string/null',
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'Defines the domain name of the server, so we can determine whether or '.
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'an absolute URI is from your website or not. Not strictly necessary, '.
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'as users should be using relative URIs to reference resources on your '.
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'website. It will, however, let you use absolute URIs to link to '.
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'subdomains of the domain you post here: i.e. example.com will allow '.
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'sub.example.com. However, higher up domains will still be excluded: '.
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'if you set %URI.Host to sub.example.com, example.com will be blocked. '.
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'This directive has been available since 1.2.0.'
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);
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HTMLPurifier_ConfigSchema::define(
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'URI', 'DisableExternal', false, 'bool',
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'Disables links to external websites. This is a highly effective '.
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'anti-spam and anti-pagerank-leech measure, but comes at a hefty price: no'.
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'links or images outside of your domain will be allowed. Non-linkified '.
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'URIs will still be preserved. If you want to be able to link to '.
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'subdomains or use absolute URIs, specify %URI.Host for your website. '.
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'This directive has been available since 1.2.0.'
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);
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HTMLPurifier_ConfigSchema::define(
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'URI', 'DisableExternalResources', false, 'bool',
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'Disables the embedding of external resources, preventing users from '.
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'embedding things like images from other hosts. This prevents '.
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'access tracking (good for email viewers), bandwidth leeching, '.
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'cross-site request forging, goatse.cx posting, and '.
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'other nasties, but also results in '.
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'a loss of end-user functionality (they can\'t directly post a pic '.
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'they posted from Flickr anymore). Use it if you don\'t have a '.
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'robust user-content moderation team. This directive has been '.
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'available since 1.3.0.'
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);
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HTMLPurifier_ConfigSchema::define(
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'URI', 'DisableResources', false, 'bool',
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'Disables embedding resources, essentially meaning no pictures. You can '.
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'still link to them though. See %URI.DisableExternalResources for why '.
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'this might be a good idea. This directive has been available since 1.3.0.'
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);
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/**
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* Validates a URI as defined by RFC 3986.
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* @note Scheme-specific mechanics deferred to HTMLPurifier_URIScheme
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*/
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class HTMLPurifier_AttrDef_URI extends HTMLPurifier_AttrDef
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{
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var $host;
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var $PercentEncoder;
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var $embeds_resource;
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/**
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* @param $embeds_resource_resource Does the URI here result in an extra HTTP request?
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*/
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function HTMLPurifier_AttrDef_URI($embeds_resource = false) {
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$this->host = new HTMLPurifier_AttrDef_Host();
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$this->PercentEncoder = new HTMLPurifier_PercentEncoder();
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$this->embeds_resource = (bool) $embeds_resource;
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}
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function validate($uri, $config, &$context) {
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// We'll write stack-based parsers later, for now, use regexps to
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// get things working as fast as possible (irony)
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// parse as CDATA
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$uri = $this->parseCDATA($uri);
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// fix up percent-encoding
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$uri = $this->PercentEncoder->normalize($uri);
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// while it would be nice to use parse_url(), that's specifically
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// for HTTP and thus won't work for our generic URI parsing
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// according to the RFC... (but this cuts corners, i.e. non-validating)
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$r_URI = '!'.
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'(([^:/?#<>\'"]+):)?'. // 2. Scheme
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'(//([^/?#<>\'"]*))?'. // 4. Authority
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'([^?#<>\'"]*)'. // 5. Path
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'(\?([^#<>\'"]*))?'. // 7. Query
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'(#([^<>\'"]*))?'. // 8. Fragment
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'!';
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$matches = array();
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$result = preg_match($r_URI, $uri, $matches);
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if (!$result) return false; // invalid URI
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// seperate out parts
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$scheme = !empty($matches[1]) ? $matches[2] : null;
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$authority = !empty($matches[3]) ? $matches[4] : null;
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$path = $matches[5]; // always present, can be empty
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$query = !empty($matches[6]) ? $matches[7] : null;
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$fragment = !empty($matches[8]) ? $matches[9] : null;
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$registry =& HTMLPurifier_URISchemeRegistry::instance();
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if ($scheme !== null) {
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// no need to validate the scheme's fmt since we do that when we
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// retrieve the specific scheme object from the registry
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$scheme = ctype_lower($scheme) ? $scheme : strtolower($scheme);
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$scheme_obj =& $registry->getScheme($scheme, $config, $context);
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if (!$scheme_obj) return false; // invalid scheme, clean it out
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} else {
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$scheme_obj =& $registry->getScheme(
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$config->get('URI', 'DefaultScheme'), $config, $context
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);
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}
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// the URI we're processing embeds_resource a resource in the page, but the URI
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// it references cannot be located
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if ($this->embeds_resource && !$scheme_obj->browsable) {
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return false;
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}
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if ($authority !== null) {
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// remove URI if it's absolute and we disabled externals or
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// if it's absolute and embedded and we disabled external resources
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unset($our_host);
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if (
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$config->get('URI', 'DisableExternal') ||
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(
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$config->get('URI', 'DisableExternalResources') &&
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$this->embeds_resource
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)
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) {
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$our_host = $config->get('URI', 'Host');
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if ($our_host === null) return false;
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}
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$HEXDIG = '[A-Fa-f0-9]';
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$unreserved = 'A-Za-z0-9-._~'; // make sure you wrap with []
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$sub_delims = '!$&\'()'; // needs []
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$pct_encoded = "%$HEXDIG$HEXDIG";
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$r_userinfo = "(?:[$unreserved$sub_delims:]|$pct_encoded)*";
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$r_authority = "/^(($r_userinfo)@)?(\[[^\]]+\]|[^:]*)(:(\d*))?/";
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$matches = array();
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preg_match($r_authority, $authority, $matches);
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// overloads regexp!
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$userinfo = !empty($matches[1]) ? $matches[2] : null;
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$host = !empty($matches[3]) ? $matches[3] : null;
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$port = !empty($matches[4]) ? $matches[5] : null;
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// validate port
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if ($port !== null) {
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$port = (int) $port;
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if ($port < 1 || $port > 65535) $port = null;
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}
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$host = $this->host->validate($host, $config, $context);
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if ($host === false) $host = null;
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// more lenient absolute checking
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if (isset($our_host)) {
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$host_parts = array_reverse(explode('.', $host));
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// could be cached
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$our_host_parts = array_reverse(explode('.', $our_host));
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foreach ($our_host_parts as $i => $discard) {
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if (!isset($host_parts[$i])) return false;
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if ($host_parts[$i] != $our_host_parts[$i]) return false;
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}
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}
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// userinfo and host are validated within the regexp
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} else {
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$port = $host = $userinfo = null;
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}
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// query and fragment are quite simple in terms of definition:
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// *( pchar / "/" / "?" ), so define their validation routines
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// when we start fixing percent encoding
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// path gets to be validated against a hodge-podge of rules depending
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// on the status of authority and scheme, but it's not that important,
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// esp. since it won't be applicable to everyone
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// okay, now we defer execution to the subobject for more processing
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// note that $fragment is omitted
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list($userinfo, $host, $port, $path, $query) =
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$scheme_obj->validateComponents(
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$userinfo, $host, $port, $path, $query, $config, $context
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);
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// reconstruct authority
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$authority = null;
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if (!is_null($userinfo) || !is_null($host) || !is_null($port)) {
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$authority = '';
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if($userinfo !== null) $authority .= $userinfo . '@';
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$authority .= $host;
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if($port !== null) $authority .= ':' . $port;
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}
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// reconstruct the result
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$result = '';
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if ($scheme !== null) $result .= "$scheme:";
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if ($authority !== null) $result .= "//$authority";
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$result .= $path;
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if ($query !== null) $result .= "?$query";
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if ($fragment !== null) $result .= "#$fragment";
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return $result;
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}
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}
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?>
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