利用Yahoo! Search API开发自已的搜索引擎-php版

美国东部时间3月1日，雅虎公司联合创始人之一的杨致远将宣布公司的搜索网络将进入Web服务。雅虎公司在 www.developer.yahoo.com 网站建立了Yahoo Search Developer Network，公司计划在此纽约举行的搜索引擎战略大会(Search Engine Strategies Conference)上推出这一计划。该网络将允许开发者在雅虎搜索之上建立新的应用程序，其中包括图像、视频、新闻以及地区搜索等内容。想要使用这项服务的会员必须先去 http://api.search.yahoo.com/webservices/register_application 申请一个自已的ID号，注：每个ID号每天只能搜索5000次。

下面我们看一下，如何用PHP脚本调用Yahoo! Search API实现搜索的效果，全部脚本如下：

 1   
 2// Yahoo Web Services PHP Example Code   
 3// Rasmus Lerdorf 
 4
 5$appid = 'YahooDemo';   
 6// 在这输入你申请的ID号 
 7
 8$service = array('image'=>'http://api.search.yahoo.com/ImageSearchService/V1/imageSearch',   
 9'local'=>'http://api.local.yahoo.com/LocalSearchService/V1/localSearch',   
10'news'=>'http://api.search.yahoo.com/NewsSearchService/V1/newsSearch',   
11'video'=>'http://api.search.yahoo.com/VideoSearchService/V1/videoSearch',   
12'web'=>'http://api.search.yahoo.com/WebSearchService/V1/webSearch');

1<html>
2<head><title>PHP Yahoo Web Service Example Code</title></head>
3<body>
4<form action="YahooSearchExample.php" method="GET">   
5Search Term: <input name="query" type="text"/><br/>   
6Zip Code: <input name="zip" type="text"/> (for local search)<br/>
7<input type="submit" value=" Go! "/>
8<select name="type">

foreach($service as $name => $val) {
if(!empty($_REQUEST['type']) && $name == $_REQUEST['type'])
echo "<option selected="">$name</option>\n";
else echo "<option>$name</option>\n";
}

1</select>
2</form>

function done() {

1</body></html>

 1   
 2exit;   
 3} 
 4
 5if(empty($_REQUEST['query']) || !in_array($_REQUEST['type'],array_keys($service))) done(); 
 6
 7// Ok, here we go, we have the query and the type of search is valid   
 8// First build the query   
 9$q = '?query='.rawurlencode($_REQUEST['query']);   
10if(!empty($_REQUEST['zip'])) $q.="&zip=".$_REQUEST['zip'];   
11if(!empty($_REQUEST['start'])) $q.="&start=".$_REQUEST['start'];   
12$q .= "&appid=$appid"; 
13
14// Then send it to the appropriate service   
15$xml = file_get_contents($service[$_REQUEST['type']].$q); 
16
17// Parse the XML and check it for errors   
18if (!$dom = domxml_open_mem($xml,DOMXML_LOAD_PARSING,$error)) {   
19echo "XML parse error\n";   
20foreach ($error as $errorline) {   
21/* For production use this should obviously be logged to a file instead */   
22echo $errorline['errormessage']."

1\n";   
2echo " Node : " . $errorline['nodename'] . "

1\n";   
2echo " Line : " . $errorline['line'] . "

1\n";   
2echo " Column : " . $errorline['col'] . "

 1\n";   
 2}   
 3done();   
 4} 
 5
 6// Now traverse the DOM with this function   
 7// It is basically a generic parser that turns limited XML into a PHP array   
 8// with only a couple of hardcoded tags which are common across all the   
 9// result xml from the web services   
10function xml_to_result($dom) {   
11$root = $dom->document_element();   
12$res['totalResultsAvailable'] = $root->get_attribute('totalResultsAvailable');   
13$res['totalResultsReturned'] = $root->get_attribute('totalResultsReturned');   
14$res['firstResultPosition'] = $root->get_attribute('firstResultPosition'); 
15
16$node = $root->first_child();   
17$i = 0;   
18while($node) {   
19switch($node->tagname) {   
20case 'Result':   
21$subnode = $node->first_child();   
22while($subnode) {   
23$subnodes = $subnode->child_nodes();   
24if(!empty($subnodes)) foreach($subnodes as $k=>$n) {   
25if(empty($n->tagname)) $res[$i][$subnode->tagname] = trim($n->get_content());   
26else $res[$i][$subnode->tagname][$n->tagname]=trim($n->get_content());   
27}   
28$subnode = $subnode->next_sibling();   
29}   
30break;   
31default:   
32$res[$node->tagname] = trim($node->get_content());   
33$i--;   
34break;   
35}   
36$i++;   
37$node = $node->next_sibling();   
38}   
39return $res;   
40} 
41
42$res = xml_to_result($dom); 
43
44// Ok, now that we have the results in an easy to use format,   
45// display them. It's quite ugly because I am using a single   
46// display loop to display every type and I don't really understand HTML   
47$first = $res['firstResultPosition'];   
48$last = $first + $res['totalResultsReturned']-1;   
49echo "

Matched ${res[totalResultsAvailable]}, showing $first to $last

1\n";   
2if(!empty($res['ResultSetMapUrl'])) {   
3echo "

Result Set Map: <a href='"${res[ResultSetMapUrl]}"'>${res[ResultSetMapUrl]}</a>

1\n";   
2}   
3for($i=0; $i<$res['totalResultsReturned']; $i++) {   
4foreach($res[$i] as $key=>$value) {   
5switch($key) {   
6case 'Thumbnail':   
7echo "

1\n";   
2break;   
3case 'Cache':   
4echo "Cache:

<a href='"${value[Url]}"'>${value[Url]}</a>

1[${value[Size]}]

1\n";   
2break;   
3case 'PublishDate':   
4echo "

$key:

1".strftime('%X %x',$value);   
2break;   
3default:   
4if(stristr($key,'url')) echo "

<a href='"$value"'>$value</a>

1\n";   
2else echo "

$key:

1$value

1";   
2break;   
3}   
4}   
5echo "

<hr/>

1\n";   
2} 
3
4// Create Previous/Next Page links   
5if($start > 1)   
6echo '

1';   
2if($last < $res['totalResultsAvailable'])   
3echo '

1';   
2done();