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).
function get_thumbnail_link($access_key_id, $secret_access_key, $size, $default_image, $url) {
$timestamp = generate_timestamp();
$url_enc = urlencode($url);
$timestamp_enc = urlencode($timestamp);
$signature_enc = urlencode (
calculate_RFC2104HMAC
("AlexaSiteThumbnail" . "Thumbnail" . $timestamp, $secret_access_key)
);
$request_url = "http://ast.amazonaws.com/xino/?"
. "Service=". "AlexaSiteThumbnail"
. "&Action=". "Thumbnail"
. "&AWSAccessKeyId=". $access_key_id
. "&Timestamp=" . $timestamp_enc
. "&Signature=" . $signature_enc
. "&Size=" . $size
. "&Url=" . $url;
$result = make_http_request($request_url);
$response_doc = new DOMDocument();
$response_doc->loadXML($result);
$thumbnail = $response_doc->getElementsByTagName("Thumbnail")->item(0);
$image_url = $default_image;
$has_default_image = ($default_image != NULL) && (strlen($default_image) > 0);
if ($thumbnail != NULL) {
if (($thumbnail->getAttribute("Exists") == "true") || !$has_default_image) {
$image_url = $thumbnail->firstChild->nodeValue;
}
}
return get_html_snippet($url, $image_url);
}
// Get an array of thumbnail URLs. The order of thumbnail URLs in the returned object is the same as that of $url_array.
// For thumbnail URLs that are missing from the service-response object, the value returned by the method is NULL.
function get_thumbnail_links($access_key_id, $secret_access_key, $size, $default_image, $url_array) {
if (!is_array($url_array)) {
throw new Exception("url_array parameter is not an array.");
}
$urls_param = "";
for ($i = 0; $i < count($url_array); $i++){
$urls_param = $urls_param . "&Thumbnail." . ($i+1) . ".Url=" . urlencode($url_array[$i]);
}
$timestamp = generate_timestamp();
$timestamp_enc = urlencode($timestamp);
$signature_enc = urlencode (
calculate_RFC2104HMAC
("AlexaSiteThumbnail" . "Thumbnail" . $timestamp, $secret_access_key)
);
$request_url = "http://ast.amazonaws.com/xino/?"
. "Service=". "AlexaSiteThumbnail"
. "&Action=". "Thumbnail"
. "&AWSAccessKeyId=". $access_key_id
. "&Timestamp=" . $timestamp_enc
. "&Signature=" . $signature_enc
. "&Shared.Size=" . $size
. $urls_param;
$result = make_http_request($request_url);
$response_doc = new DOMDocument();
$response_doc->loadXML($result);
$has_default_image = ($default_image != NULL) && (strlen($default_image)> 0);
$responses = $response_doc->getElementsByTagName("Response");
$return_array = array();
for ($i = 0; $i < count($url_array); $i++) {
$image_url = $default_image;
$response = $responses->item($i);
$thumbnail = $response->getElementsByTagName("Thumbnail")->item(0);
if ($thumbnail != NULL) {
if (($thumbnail->getAttribute("Exists") == "true") || !$has_default_image) {
$image_url = $thumbnail->firstChild->nodeValue;
}
}
$return_array[$i] = get_html_snippet($url_array[$i], $image_url);
}
return $return_array;
}
// Returns an HTML snippet which will display the thumbnail image url and link to the website. Returns an empty string if the image is null or empty.
function get_html_snippet($url, $image) {
$link = "";
$navigable_url = (stristr($url,"http://") == $url ) ? $url : "http://".$url;
if ($image) {
$link = "
";
}
return $link;
}
// Calculate signature using HMAC: http://www.faqs.org/rfcs/rfc2104.html
function calculate_RFC2104HMAC ($data, $key) {
return base64_encode (
pack("H*", sha1((str_pad($key, 64, chr(0x00))
^(str_repeat(chr(0x5c), 64))) .
pack("H*", sha1((str_pad($key, 64, chr(0x00))
^(str_repeat(chr(0x36), 64))) . $data))))
);
}
// Timestamp format: yyyy-MM-dd'T'HH:mm:ss.SSS'Z'
function generate_timestamp () {
return gmdate("Y-m-d\TH:i:s.\\0\\0\\0\\Z", time());
}
// Make an http request to the specified URL and return the result
function make_http_request($url){
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_TIMEOUT, 2);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$result = curl_exec($ch);
if (curl_errno($ch)) {
}
curl_close($ch);
return $result;
}
?>