Network Programming Wikiclass | Tutorial / Access Web Services with PHP

Overview: In this tutorial, you will study how to use PHP to access Site Explorer APIs from Yahoo! Search.

Activity One

Study the following PHP script. Answer the questions that follow. You can discuss the questions with your classmates.

    <?php

    $api_service_url = "http://search.yahooapis.com/SiteExplorerService/V1/inlinkData";
    $apiid = "pQzlchXV34GhgyFFcNhE8ijvqemS0pw4G3VIf1fLyspIx.9Cg5cRIU1ESXNHD9c6BXXZ";
    $query  = "http://www.stepwise.hk";
    $entire_site  = "";   // "1" to provide results for the entire site
    $omit_inlinks = "domain";
    $linksperrequest = 10;   // 100 is max value
    $startposition = 1;

    $request_url = sprintf("%s?appid=%s&query=%s&entire_site=%s&omit_inlinks=%s&output=php", $api_service_url, $apiid, urlencode($query), $entire_site, $omit_inlinks);

    $currentpos = 0;
    while ($currentpos++ >= 0) {

       // Formating API request url
       $requrl = sprintf("%s&start=%s&results=%s", $request_url, ($currentpos-1)*$linksperrequest+$startposition, $linksperrequest);

       // Handle errors
       if (($content = file_get_contents($requrl)) === FALSE ) {
       echo "HTTP error: $requrl";
       exit;
       }

       // Unserialize data from response
       $data = unserialize($content);

       if (!array_key_exists("ResultSet", $data)) {
       echo "Error: Bad response from server";
       exit;
       }

       // Extracting each link from array
       for ($i=0; $i<sizeof($data["ResultSet"]["Result"]); $i++) {
          $url = $data["ResultSet"]["Result"][$i]["Url"];
          $title = $data["ResultSet"]["Result"][$i]["Title"];

          echo '<p><a href="'.$url.'">'.$title.'</a></p>';


       }

       // End loop if no more results
       if (sizeof($data["ResultSet"]["Result"]) < $linksperrequest) break;
    }

    ?>

(The API key shown in the PHP script is not a real one. Please obtain and use your own API key if you want to test the program in your server.)

Questions for Activity One

(Q1) Find the webpage that has the details about the API used in the script.

(Q2) State the request URL.

(Q3) State all the possible request parameters.

(Q4) State only the required request parameters.

(Q5) What types of Web Services (SOAP, REST, or XML-RPC) the script accesss?

(Q6) Can you test the Web Service API without the script? If yes, explain how. If not, explain.

Activity Two

Run the PHP script with a Web server that supports PHP.
Test the Web Service API with different queries.

Activity Three

Test the Web Service API only with your browser.

(Q7) Write down the general format of the XML in the response.

Submission

Please submit your work to Steven by email: sochoy@ouhk.edu.hk.
Please use SXXXXXXX - NP Tutorial 15 Submission as the email subject.