Consuming Restful Webservice in AEM

In this article , I am going to write about how to consume data from a third-party Restful Webservice in Adobe Experience Manager. I am fetching live cricket score from  Cricinfo using their XML data with the help of org.apache.http package.

Steps to consume Restful web service - 

1.Create and Setup Maven project 

2.Create and compile Java classes that performs the Restful request. 

3.Build and deploy OSGi bundle to Adobe CQ

4.Create template and component to display web service response in webpage.

Create and Setup Maven Project

By performing below steps we can create an Adobe CQ archetype project

   i.Open cmd prompt and go to working project folder

  ii.Execute Maven script to create project folders

mvn archetype:generate -DarchetypeRepository=http://repo.adobe.com/nexus/content/groups/public/ -DarchetypeGroupId=com.day.jcr.vault -DarchetypeArtifactId=multimodule-content-package-archetype -DarchetypeVersion=1.0.2 -DgroupId=my-group-id -DartifactId=myproject -Dversion=1.0-SNAPSHOT -Dpackage=com.mycompany.myproject -DappsFolderName=myproject -DartifactName="My Project" -DcqVersion="5.6.1" -DpackageGroup="My Company"

mvn eclipse:eclipse

iii.After executing this script , we can import this project into Eclipse.

Create and Compile required Java files

Add the following Java files to the com.mycompany.myproject package:

• A Java interface named Cricketscore.
• A Java class named CricketscoreImpl that extends the Cricketscore interface under impl folder.

Cricketscore.java

package com.mycompany.myproject;
 
public interface Cricketscore {
     
    //Returns array data that represents the live score updates
 public String[] getLivescore();
   
}

CricketscoreImpl.java

In this development article , we used the Apache HttpClient library which simplifies handling HTTP request.

We can retrieve and send data via the HttpClient class.An instance of this class can be created with new DefaultHttpClient().The HttpClient uses a HttpUriRequest to send and receive data.Important subclass of HttpUriRequest are HttpGet and HttpPost. By using HttpGet, we are getting response from http://static.cricinfo.com/rss/livescores.xml

We can get the response of the HttpClient as an InputStream. So below lines of code used to get response from service and by using BufferedReader & InputStreamReader we are processing that response to get XML data as String.

            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpGet getRequest = new HttpGet("http://static.cricinfo.com/rss/livescores.xml");
            getRequest.addHeader("accept", "application/xml");
            HttpResponse response = httpClient.execute(getRequest);
            if (response.getStatusLine().getStatusCode() != 200) {
                            throw new RuntimeException("Failed : HTTP error code : "
                                    + response.getStatusLine().getStatusCode());
            }
            BufferedReader br = new BufferedReader(new InputStreamReader((response.getEntity().getContent())));
            String score;
            String xmldata="" ;
            while ((score= br.readLine()) != null) {
                    xmldata= myJSON + score;
                }
            httpClient.getConnectionManager().shutdown();

Then by using XML parser (javax.xml.parsers & org.xml.sax.InputSource) , we are going to parse response data and extract required node items . Store these data in String array then return it to Client viewer.

             DocumentBuilderFactory dbf =DocumentBuilderFactory.newInstance();
             DocumentBuilder db = dbf.newDocumentBuilder();
             InputSource is = new InputSource();
             is.setCharacterStream(new StringReader(xmldata));
             Document doc = db.parse(is);
             NodeList nodes = doc.getElementsByTagName("item");
             String[] titles = new String[nodes.getLength()];
                // iterate the nodes
             for (int i = 0; i < nodes.getLength(); i++) {
                   Element element = (Element) nodes.item(i);
                   NodeList name = element.getElementsByTagName("title");
                   Element titlexml = (Element) name.item(0);
                   title =getCharacterDataFromElement(titlexml);
                   titles[i]=title;
             }
             return titles;

Here is the all lines of code for CricketscoreImpl.java

package com.mycompany.myproject;
 
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Service;
import javax.xml.parsers.*;
import org.xml.sax.InputSource;
import org.w3c.dom.*;
import java.io.*;
import java.util.*;
 
//This is a component so it can provide or consume services
@Component  
    
@Service
 
public class CricketscoreImpl implements Cricketscore {
 protected final Logger log = LoggerFactory.getLogger(this.getClass());
    @Override
    public String[] getLivescore() {
        // TODO Auto-generated method stub
         
        try
        {
        
         String title = "";
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpGet getRequest = new HttpGet("http://static.cricinfo.com/rss/livescores.xml");
            getRequest.addHeader("accept", "application/xml");
            HttpResponse response = httpClient.execute(getRequest);
            if (response.getStatusLine().getStatusCode() != 200) {
              throw new RuntimeException("Failed : HTTP error code : " + response.getStatusLine().getStatusCode());
            }
            BufferedReader br = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
            String myXMLdata = "";
            String output;
            while ((output = br.readLine()) != null) {
             myXMLdata = myXMLdata + output;
            }
            httpClient.getConnectionManager().shutdown();
                        
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db = dbf.newDocumentBuilder();
            InputSource is = new InputSource();
            is.setCharacterStream(new StringReader(myXMLdata));
            Document doc = db.parse(is);
            NodeList nodes = doc.getElementsByTagName("item");
            String[] titles = new String[nodes.getLength()];
            for (int i = 0; i < nodes.getLength(); i++)
            {
              Element element = (Element)nodes.item(i);
              NodeList name = element.getElementsByTagName("title");
              Element line = (Element)name.item(0);
              title = getCharacterDataFromElement(line);
              titles[i] = title;
            }
            return titles;
        }
        catch (Exception e)
        {
            e.printStackTrace() ; 
        }
        return null;
    }
    public static String getCharacterDataFromElement(Element e) {
        Node child = e.getFirstChild();
        if (child instanceof CharacterData) {
           CharacterData cd = (CharacterData) child;
           return cd.getData();
        }
        return "";
      }
  }

Next we need to add the Apache HttpComponents dependency in Maven POM file located at bundle folder in created project. So add below lines in POM.xml before end of  </dependencies>.

<dependency>

        <groupId>org.apache.httpcomponents</groupId>

        <artifactId>httpclient</artifactId>

        <version>4.1.1</version>

    </dependency>




Build and deploy the OSGi bundle using Maven 

Follow below steps to build the OSGi component,

i.Navigate to pom.xml located folder , then hold ctrl + shift then right-click to open cmd prompt from that folder

ii. Execute the maven command : mvn clean install

iii.After successful build, we can find OSGi bundle at (project folder)\bundle\target

iv.To deploy this bundle, open Apache Felix Console (http://server:port/system/console/bundles  )

v. In bundles tab, browse and install the created bundle under (project folder)\bundle\target

vi.After installing, reload and check bundle status must be Active. 

To display the webservice response , we need to follow below steps 

Open  (http://server:port/system/console/bundles  ) and create project as per below structure 

Create a template and Component

To display the component in page we need template, so first we will create a template  ,

1. Right-click the template folder within your application and select  Create -> Create Template and sling:resourceType to below created component path

2. Enter required information to create basic component and name the component as livescore 

3. Open livescore.jsp and paste below code to display Live Create Score

<@include file="/libs/foundation/global.jsp">
<cq:includeclientlib categories="jquerysamples"></cq:includeclientlib>
<html>
   <head>
         <!-- Below script used to reload page
            <script>
            $(document).ready(function(){
               setInterval(function(){cache_clear()},60000);
            });
            function cache_clear()
            {
              window.location.reload(true);
            }
         </script> -->

         <style>
            #page-wrap {
               width: 800px;
               margin: 0 auto;
               border: 3px solid #73AD21;
               padding: 10px;
               background-image:
                  linear-gradient(
                     to right, 
                     #0896A8,
                     #0896A8 15%,
                     #0896A8 15%,
                     #82C8D1 50%,
                     #82C8D1 50%
                  );
             }
         </style>
         <%
            com.mycompany.myproject.Cricketscore cs = sling.getService(com.mycompany.myproject.Cricketscore.class);
            String[] xmldata= cs.getLivescore() ; 
            request.setAttribute("xmldata", xmldata);
         %>
         <body>
           <div id="page-wrap">
              <h3>
Live Cricket Score Feed from CRICINFO</h3>
<hr />
              <c:foreach items="${xmldata}" var="xmldatascore">
                     <c:if test="${not empty xmldatascore}">
                        <strong><c:out value="${xmldatascore}"></c:out></strong><hr />
                     </c:if>
              </c:foreach>
           </div>
</body>
    </head>
</html>

In above code, i have added jquery to refresh the page for every 60 secs so include jquerysample Client libraries 

Create the web page to display Live Cricket Score from Cricinfo that based on the above created template.