Viewing file:  absolute-to-relative-urls.php (11.64 KB) -rw-rw-rw-
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<?php
/*
Absolute-to-Relative URLs 0.3.4 <http://www.svachon.com/blog/absolute-to-relative-urls/>
A class for use in shortening URL links.
*/
class Absolute_to_Relative_URLs
{
//protected static $_instance;
protected $custom_ports;
protected $site_port_is_default;
protected $site_url;
/*
$custom_site_url :: should be a valid URL, with scheme and host
$custom_ports :: e.g., array('ssh'=>22)
*/
public function __construct($custom_site_url='', $custom_ports=array())
{
$this->custom_ports = $custom_ports;
$this->get_site_url($custom_site_url);
if ($this->site_url === false)
{
trigger_error('Invalid site URL');
}
}
/*
Initialize class for absolute_to_relative_url()
Nice idea, BUT slower than using a global variable
*/
/*public static function instance()
{
if (self::$_instance === null)
{
self::$_instance = new Absolute_to_Relative_URLs();
}
return self::$_instance;
}*/
protected function build_url($url, $output_type)
{
$has_fragment = isset($url['fragment']);
$has_resource = isset($url['resource']);
$has_query = isset($url['query']);
if ( isset($url['scheme']) )
{
$first_half = $url['scheme'] . ':';
}
else
{
$first_half = '';
}
if ( isset($url['host']) )
{
$first_half .= '//';
$user_or_pass = false;
if ( isset($url['user']) )
{
$first_half .= $url['user'];
$user_or_pass = true;
}
if ( isset($url['pass']) )
{
$first_half .= ':' . $url['pass'];
$user_or_pass = true;
}
if ($user_or_pass)
{
$first_half .= '@';
}
$first_half .= $url['host'];
if ( isset($url['port']) )
{
$first_half .= ':' . $url['port'];
}
$second_half = $url['path'];
}
else
{
if ($output_type===1 || $output_type===2)
{
$absolute_path = $url['path'];
$relative_path = (isset($url['path_relative'])) ? $url['path_relative'] : false;
if ($relative_path !== false)
{
if ($output_type === 2)
{
$second_half = (strlen($relative_path) <= strlen($absolute_path)) ? $relative_path : $absolute_path;
}
else
{
$second_half = $relative_path;
}
}
else
{
$second_half = $absolute_path;
}
}
else if ($output_type === 0)
{
$second_half = $url['path'];
}
if ($has_resource || $has_query || $has_fragment)
{
if ($second_half==='./' || ($second_half==='/' && $this->site_url['path']==='/'))
{
$second_half = '';
}
}
}
if ($has_resource)
{
$second_half .= $url['resource'];
}
if ($has_query)
{
$second_half .= '?'. $url['query'];
}
if ($has_fragment)
{
$second_half .= '#'. $url['fragment'];
}
return $first_half . $second_half;
}
protected function get_default_port($scheme)
{
switch ($scheme)
{
case 'http' : return 80;
case 'https' : return 443;
case 'ftp' : return 21;
}
foreach ($this->custom_ports as $port_name => $port)
{
$port_name = strtolower($port_name);
if ($port_name === $scheme)
{
return $port;
}
}
// No listed match found
return -1;
}
protected function get_site_url($custom_site_url)
{
if ($custom_site_url === '')
{
$this->custom_site_url = true;
$url = ( !isset($_SERVER['HTTPS']) ) ? 'http://' : 'https://';
if ( isset($_SERVER['PHP_AUTH_USER']) )
{
$url .= $_SERVER['PHP_AUTH_USER'] .':'. $_SERVER['PHP_AUTH_PW'] .'@';
}
$url .= $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
}
else
{
$url = $custom_site_url;
}
$url = $this->parse_url($url, true);
if ($url !== false)
{
if ( isset($url['port']) )
{
$this->site_port_is_default = ($url['port'] === $this->get_default_port($url['scheme']));
}
else
{
$url['port'] = $this->get_default_port($url['scheme']);
$this->site_port_is_default = true;
}
$url['host_stripped'] = $this->remove_www($url['host']);
}
$this->site_url = $url;
}
/*
Return an path string.
*/
protected function implode_path($path, $absolute_output)
{
if (!empty($path))
{
$path = implode('/', $path) .'/';
if ($absolute_output)
{
$path = '/'.$path;
}
}
else
{
$path = (!$absolute_output) ? './' : '/';
}
return $path;
}
/*
Return an absolute path.
*/
protected function parse_path($path)
{
if ($path !== '/')
{
$path = explode('/', $path);
$absolute_path = array();
$first_dir = $path[0];
// Check if not absolute: '/dir/' becomes array('','dir','')
if ($first_dir !== '')
{
if ($first_dir==='.' || $first_dir==='..')
{
$path = array_merge($this->site_url['path_array'], $path);
}
}
foreach ($path as $dir)
{
if ($dir !== '')
{
if ($dir !== '..')
{
if ($dir !== '.')
{
array_push($absolute_path, $dir);
}
}
else
{
$parent_index = count($absolute_path) - 1;
if ($parent_index >= 0)
{
unset( $absolute_path[$parent_index] );
$absolute_path = array_values($absolute_path);
}
}
}
}
return $absolute_path;
}
else
{
// Faster to skip the above block and just create an array
return array();
}
}
/*
Return the components of a URL.
*/
protected function parse_url($url, $init=false)
{
if ( stripos($url,'data:')===0 || stripos($url,'javascript:')===0 )
{
// Nothing can be done with data/javascript URIs
return false;
}
else if (strpos($url, '//') === 0)
{
// Cannot parse scheme-relative URLs with parse_url
$url = $this->site_url['scheme'] . ':' . $url;
}
// With PHP versions earlier than 5.3.3, an E_WARNING is emitted when URL parsing fails
// REMOVE when WordPress enforces a higher version as it will increase performance
$url = @parse_url($url);
if ($url !== false)
{
if ($init)
{
// Checks for host to catch "host:80"
if ( !isset($url['scheme']) || !isset($url['host']) )
{
// Invalid site url
return false;
}
}
if ( isset($url['path']) )
{
$path = str_replace(' ', '%20', $url['path']);
$last_slash = strrpos($path, '/');
if ($last_slash !== false)
{
$last_slash++;
if ($last_slash < strlen($path))
{
// Isolate resource from path
$url['resource'] = substr($path, $last_slash);
$path = substr($path, 0, $last_slash);
}
$url['path_array'] = $this->parse_path($path);
$url['path'] = $this->implode_path($url['path_array'], true);
}
else
{
// No slashes found
$url['resource'] = $path;
$url['path'] = $this->site_url['path'];
$url['path_array'] = $this->site_url['path_array'];
}
}
else if ( isset($url['host']) )
{
$url['path'] = '/';
$url['path_array'] = array();
}
else
{
$url['path'] = $this->site_url['path'];
$url['path_array'] = $this->site_url['path_array'];
}
}
return $url;
}
/*
Return a path relative to the site path.
*/
protected function relate_path($absolute_path)
{
$relative_path = array();
$site_path = $this->site_url['path_array'];
// At this point, it's related to the host
$related = true;
$parent_index = -1;
// Find parents
foreach ($site_path as $i => $dir)
{
if ($related)
{
$absolute_dir = (isset($absolute_path[$i])) ? $absolute_path[$i] : null;
if ($dir !== $absolute_dir)
{
$related = false;
}
else
{
$parent_index = $i;
}
}
if (!$related)
{
// Up one level
array_push($relative_path, '..');
}
}
// Form path
foreach ($absolute_path as $i => $dir)
{
if ($i > $parent_index)
{
array_push($relative_path, $dir);
}
}
return $relative_path;
}
/*
Return a URL relative to the site URL.
$ignore_www :: optionally, ignore "www" subdomain
$output_type :: optionally, return either a:
0: root-relative URL (/child-of-root/etc/)
1: path-relative URL (../child-of-parent/etc/)
2: shortest possible URL (root- or path-relative)
*/
public function relate_url($url, $ignore_www=false, $output_type=2)
{
if ($this->site_url !== false)
{
if ($url==='' || $url==='.' || $url==='./')
{
if ($this->site_url['path'] !== '/')
{
if ($output_type===1 || $output_type===2)
{
return './';
}
else if ($output_type === 0)
{
return $this->site_url['path'];
}
}
else
{
return '/';
}
}
else if ($url === '/')
{
return '/';
}
else if ($url === '#')
{
return '#';
}
$original_url = $url;
$url = $this->parse_url($url);
if ($url === false)
{
// Unusable format
return $original_url;
}
}
else
{
// Invalid site url
return $url;
}
$related = false;
if ( isset($url['scheme']) )
{
$scheme = $url['scheme'];
if ($scheme === $this->site_url['scheme'])
{
unset($url['scheme']);
if ($ignore_www)
{
$url['host'] = $this->remove_www($url['host']);
$site_host = $this->site_url['host_stripped'];
}
else
{
$site_host = $this->site_url['host'];
}
if ($url['host'] === $site_host)
{
$related = true;
if ( isset($url['port']) )
{
if ($url['port'] === $this->site_url['port'])
{
unset($url['port']);
}
else
{
$related = false;
}
}
else if (!$this->site_port_is_default)
{
$related = false;
}
if ( isset($url['user']) )
{
if (!isset($this->site_url['user']) || $url['user'] !== $this->site_url['user'])
{
$related = false;
}
}
/*else if ( isset($this->site_url['user']) )
{
$related = false;
}*/
if ( isset($url['pass']) )
{
if (!isset($this->site_url['pass']) || $url['pass'] !== $this->site_url['pass'])
{
$related = false;
}
}
/*else if ( isset($this->site_url['pass']) )
{
$related = false;
}*/
if ($related)
{
unset($url['host'], $url['user'], $url['pass']);
}
}
else if ( isset($url['port']) )
{
if ($url['port'] === $this->get_default_port($scheme))
{
unset($url['port']);
}
}
}
else if ( isset($url['port']) )
{
if ($url['port'] === $this->get_default_port($scheme))
{
unset($url['port']);
}
}
}
if ( !isset($url['host']) )
{
$url['path_relative_array'] = $this->relate_path($url['path_array']);
$url['path_relative'] = $this->implode_path($url['path_relative_array'], false);
}
return $this->build_url($url, $output_type);
}
protected function remove_www($host)
{
if (strpos($host, 'www.') === 0)
{
$host = substr($host, 4);
}
return $host;
}
}
/*function absolute_to_relative_url($url, $ignore_www=true, $choose_shortest=true)
{
return Absolute_to_Relative_URLs::instance()->relate_url($url, $ignore_www, $choose_shortest);
}*/
/*
Return a URL relative to the current site URL.
$ignore_www :: optionally, ignore "www" subdomain
$output_type :: optionally, return either a:
0: root-relative URL (/child-of-root/etc/)
1: path-relative URL (../child-of-parent/etc/)
2: shortest possible URL (root- or path-relative)
*/
function absolute_to_relative_url($url, $ignore_www=false, $output_type=2)
{
global $absolute_to_relative_url_instance;
if (!isset($absolute_to_relative_url_instance))
{
$absolute_to_relative_url_instance = new Absolute_to_Relative_URLs();
}
return $absolute_to_relative_url_instance->relate_url($url, $ignore_www, $output_type);
}
?>
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