<?php
/**
* Implements sourcing thumbnails from http://www.shrinktheweb.com
*
* Dependent on PHP5, but could be easily back-ported. All config
* information is defined in constants. No reason to ever create
* an instance of this class, hence abstract.
*
* @author Entraspan, Based in part on STW sample code
* @copyright Open Source/Creative Commons
*/
abstract class AppSTW {
const ACCESS_KEY = "your key";
const SECRET_KEY = "your user";
const THUMBNAIL_URI = "/images/thumbnails";
const THUMBNAIL_DIR = "/static";
const CACHE_DAYS = 3; // used 7 for Alexa!
private static function make_http_request($url){
$lines = file($url);
return implode("", $lines);
}
/**
* Calls through the API and processes the results based on the
* original sample code from STW. This function is public for
* example only. It really should not be used since thumbnails
* should be cached locally using getThumbnail.
*
* It is common for this routine to return a null value when the
* thumbnail does not yet exist and is queued up for processing.
*
* @param string $url URL to get thumbnail for
* @param array $args Array of parameters to use
* @return string full remote URL to the thumbnail
*/
public static function queryRemoteThumbnail($url, $args = null, $debug = false) {
$args = is_array($args) ? $args : array();
$defaults["Service"] = "ShrinkWebUrlThumbnail";
$defaults["Action"] = "Thumbnail";
$defaults["STWAccessKeyId"] = self::ACCESS_KEY;
$defaults["u"] = self::SECRET_KEY;
foreach ($defaults as $k=>$v)
if (!isset($args[$k]))
$args[$k] = $v;
// read where someone had to put this last to get it to work for a url.
// the arguments should be property encoded so the separators would work
// correctly, so could be a problem with the build query, unrecognized
// chars in the original url, or the argument parsing, by making it last
// then stw should at least get their required args first. I never ran
// into this, but typically only grabbed domain url's, and primarily use
// the soap interface.
$args["Url"] = $url;
$request_url = "http://www.shrinktheweb.com/xino.php?".http_build_query($args);
$line = self::make_http_request($request_url);
if ($debug) {
echo '<pre style=font-size:10px>';
unset($args["STWAccessKeyId"]);
unset($args["u"]);
print_r($args);
echo '</pre>';
echo '<div style=font-size:10px>';
highlight_string($line);
echo '</div>';
}
$regex = '/<[^:]*:Thumbnail\\s*(?:Exists=\"((?:true)|(?:false))\")?[^>]*>([^<]*)<\//';
if (preg_match($regex, $line, $matches) == 1 && $matches[1] == "true")
return $matches[2];
return null;
}
/**
* Refreshes the thumbnail if it is expired or creates it if it does
* not exist. There is no cleanup of the thumbnails for ones that don't
* get used again, e.g. find /static/images/thumbnails -type f -mtime +7 -delete
*
* Every combination of url and call arguments results in a unique filename
* through a MD5 hash. The size argument can also be an array where you can
* add any parameter you wish to the request, or override any default.
*
* It is up to the calling function to decide what to do with the results when
* a null is returned. I often store the src in a database with a timestamp so
* that I do not bombard the server with repeated requests for a thumbnail that
* doesn't yet exist, although STW is very fast at processing.
*
* @param string $url URL to get thumbnail for
* @param array $args Array of parameters to use
* @param boolean $force Force call to bypass cache, was used for debugging
* @return string Local SRC URI for the thumbnail.
*/
public static function getThumbnail($url, $args = null, $force = false) {
$args = $args ? $args : array("Size"=>"lg");
$name = md5($url.serialize($args)).".jpg";
$src = self::THUMBNAIL_URI."/$name";
$path = self::THUMBNAIL_DIR.$src;
$cutoff = time() - 3600 * 24 * self::CACHE_DAYS;
if ($force || !file_exists($path) || filemtime($path) <= $cutoff)
if (($jpgurl = self::queryRemoteThumbnail($url, $args)))
if (($im = imagecreatefromjpeg($jpgurl)))
imagejpeg($im, $path, 100);
if (file_exists($path))
return $src;
return null;
}
/**
* Always retrieves the X-Large thumbnail from STW, then uses
* local gd library to create arbitrary sized thumbnails.
*
* By passing the same arguments used for small/large should
* generate cache hits so the only size every retrieved would
* be xlg.
*
* @param string $url URL to get thumbnail for
* @param string $width The desired image width
* @param string $height The desired image height
* @param string $args Used to make name same as sm/lg fetches.
*/
public static function getScaledThumbnail($url, $width, $height, $args = null, $force = false) {
$args = $args ? $args : array("width"=>$width, "height"=>$height);
$name = md5($url.serialize($args)).".jpg";
$src = self::THUMBNAIL_URI."/$name";
$path = self::THUMBNAIL_DIR.$src;
$cutoff = time() - 3600 * 24 * self::CACHE_DAYS;
if ($force || !file_exists($path) || filemtime($path) <= $cutoff)
if (($xlg = self::getXLargeThumbnail($url)))
if (($im = imagecreatefromjpeg(self::THUMBNAIL_DIR.$xlg))) {
list($xw, $xh) = getimagesize(self::THUMBNAIL_DIR.$xlg);
$scaled = imagecreatetruecolor($width, $height);
if (imagecopyresampled($scaled, $im, 0, 0, 0, 0, $width, $height, $xw, $xh))
imagejpeg($scaled, $path, 100);
}
if (file_exists($path))
return $src;
return null;
}
/**
* Convenience Function for 320x240
*
* @param string $url URL to get thumbnail for
*/
public static function getXLargeThumbnail($url) {
return self::getThumbnail($url, array("Size"=>"xlg"));
}
/**
* Convenience Function for 200x150
*
* @param string $url URL to get thumbnail for
* @param boolean $scaler Scale image from xlg
*/
public static function getLargeThumbnail($url, $scaler = true, $force = false) {
if ($scaler)
return self::getScaledThumbnail($url, 200, 150, array("Size"=>"lg"), $force);
return self::getThumbnail($url);
}
/**
* Convenience Function for 120x90
*
* @param string $url URL to get thumbnail for
* @param boolean $scaler Scale image from xlg
*/
public static function getSmallThumbnail($url, $scaler = true, $force = false) {
if ($scaler)
return self::getScaledThumbnail($url, 120, 90, array("Size"=>"sm"), $force);
return self::getThumbnail($url, array("Size"=>"sm"));
}
}
?>
|
