Using Web Service APIs (Amazon and Yahoo!) with PEAR - Services_Yahoo

The Yahoo! API allows you to provide Yahoo! search results directly on your site. The API is fairly new, and thus the PEAR Package is in an "alpha" state. As an alternative to specifying the exact version, as we did with Amazon, we can tell PEAR that we're looking for an alpha version:

> sudo pear -d preferred_state=alpha install Services_Yahoo

downloading Services_Yahoo-0.2.0.tgz ...

Starting to download Services_Yahoo-0.2.0.tgz (13,381 bytes)

.....done: 13,381 bytes

install ok: channel://pear.php.net/Services_Yahoo-0.2.0

You have the package installed and no access key is required, so you are ready to make a search page. In this example, we'll create a simple box for our home page, that lists the top results for "mallard ducks."

Instead of using the PEAR::isError() the Services_Yahoo calls throw exceptions whenever there is an error, so you will need to wrap all calls in a try/catch block. This also means that you don't need to include the PEAR.php file.

<?php

// This brings in the API

require_once "Services/Yahoo/Search.php";

print '<div id="duckbox">';

try {

// Create a web services object for web results

$client = Services_Yahoo_Search::factory("web");

// Perform the search

$results = $client->searchFor("mallard ducks");

printf('<h1>lShowing %d Mallard Duck Results</h1>',

$results->getTotalResultsReturned());

print '<ul>';

foreach ($results as $result) {

// Results is an array of associative arrays

printf('<li><a href="%s">%s</a> - %s<p>%s</p></li>',

$result['Url'], $result['Title'],

$result['DisplayUrl'], $result['Summary']);

}

print '</ul>';

} catch (Services_Yahoo_Exception $e) {

// Something went wrong, here, we'll display the technical

// error details to the user. (Normally you wouldn't do this.)

print 'Sorry, couldn't get your duck results: ';

print $e->getMessage() . '<br/ >';

print join(', ', $e->getErrors());

}

print '</div>';

?>

The entire process is very simple, with the API returning an array of results. Each result is an associative array with various keys, including URL, Title and Summary.

When you instantiate the search client, you specify what type of search you want to run. Above, we searched the web - other options are "news," "images," "video" and "local." You simply pass one of these options to the factory() method.

The Services_Yahoo package also provides an interface to Yahoo's content analysis services. Two of these services are term extraction and spelling suggestions.

Term extraction takes a chunk of text, and returns significant words or phrases found within the text. You might use this to index forum posts, without indexing every word. You would pass the body of the post to the term extraction API, and then catalog the returned terms in a table mapping the terms to the ID of that forum post.

require_once "Services/Yahoo/ContentAnalysis.php";

function indexPost($post_id, $body_text) {

try {

// Create the client

$yahoo = Services_Yahoo_ContentAnalysis::factory("termExtraction");

// Tell it what we're indexing

$yahoo->setContext($body_text);

$results = $yahoo->submit();

// Store each of the key terms

foreach ($results as $term) {

mysql_query( sprintf('INSERT INTO post_terms (post_id, term) VALUES("%d",
"%S")',

$post_id,

mysql_escape_string($term)));

}

} catch (Services_Yahoo_Exception $e) {

return FALSE;

}

return TRUE;

}

Spelling suggestions are equally simple. One result is always returned. The general use for this would be the "Did you mean ____" helpers you'll see on many web pages.

<?php

require_once "Services/Yahoo/ContentAnalysis.php";

$suggestion = FALSE;

try {

// Create the client

$yahoo = Services_Yahoo_ContentAnalysis::factory("spellingSuggestion");

// Tell it what word we want

$yahoo->setQuery('alphabet');

$results = $yahoo->submit();

// We still loop over the results, even though there is only

// one, as the result is an iterator

foreach ($results as $term) {

$suggestion = $term;

}

} catch (Services_Yahoo_Exception $e) {

// print $e->getMessage();

$suggestion = FALSE;

}

if ($suggestion !== FALSE) {

printf('Did you mean %s?', $suggestion);

} ?>

Next: Further Steps >>
 

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