ApiExample.java

/*
    This is an example of using the Ohloh API from Java.
    Detailed information can be found at the Ohloh website:

     http://meta.ohloh.net/getting_started

    This examples retrieves a account and simply shows the name associated.

    Pass your Ohloh API key as the first parameter to this example.
    Ohloh API keys are free. If you do not have one, you can obtain one
    at the Ohloh website:

     http://www.ohloh.net/accounts/<your_login>/api_keys/new

    Pass the email address of the account as the second parameter to this script.
*/

import java.net.*;
import java.security.*;
import java.io.*;
import java.util.*;
import org.w3c.dom.*;
import javax.xml.parsers.*;

public class ApiExample
{
    private static final char[] hexChars ={'0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f'};

    public static void usage()
    {
        System.out.println("Usage:");
        System.out.println("java ApiExample [api_key] [user_email]");
    }

    public ApiExample(String apiKey, String userEmail)
    {
        initiate(apiKey, userEmail);
    }

    public void initiate(String apiKey, String userEmail)
    {
        System.out.println("Initialising request.");

        // Calculate MD5 digest from the email address.
        String emailDigest = calculateDigest(userEmail);

        try
        {
            // Request XML file.
            URL url = new URL("http://www.ohloh.net/accounts/" + emailDigest + ".xml?api_key=" + apiKey + "&v=1");
            URLConnection con = url.openConnection();

            // Check for status OK.
            if (con.getHeaderField("Status").startsWith("200"))
            {
                System.out.println("Request succeeded.");
            }
            else
            {
                System.out.println("Request failed. Possibly wrong API key?");
                return;
            }
            System.out.println("Looking up name..");

            // Create a document from the URL's input stream, and parse.
            DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
            Document doc = builder.parse(con.getInputStream());

            NodeList responseNodes = doc.getElementsByTagName("response");
            for (int i = 0; i < responseNodes.getLength(); i++)
            {
                Element element = (Element)responseNodes.item(i);

                // First check for the status code inside the XML file. It is
                //  most likely, though, that if the request would have failed,
                //  it is already returned earlier.
                NodeList statusList = element.getElementsByTagName("status");
                if (statusList.getLength() == 1)
                {
                    Node statusNode = statusList.item(0);

                    // Check if the text inidicates that the request was
                    //  successful.
                    if (!statusNode.getTextContent().equals("success"))
                    {
                        System.out.println("Failed. " + statusNode.getTextContent());
                        return;
                    }
                }

                Element resultElement = (Element)element.getElementsByTagName("result").item(0);
                // We assume we only have one account result here.
                Element accountElement = (Element)resultElement.getElementsByTagName("account").item(0);

                if (accountElement != null)
                {
                    // Lookup name.
                    String realName = accountElement.getElementsByTagName("name").item(0).getTextContent();
                    System.out.println("Located the real name: " + realName);
                }
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    public String calculateDigest(String email)
    {
        return hexStringFromBytes(calculateHash(email.getBytes()));
    }

    private byte[] calculateHash(byte[] dataToHash)
    {
        try
        {
            // Calculate MD5 digest.
            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(dataToHash, 0, dataToHash.length);
            return md.digest();
        }
        catch (NoSuchAlgorithmException e)
        {
            e.printStackTrace();
        }
        return null;
    }

    public String hexStringFromBytes(byte[] b)
    {
        // Conversion from bytes to String.
        String hex = "";

        int msb;

        int lsb = 0;
        int i;

        for (i = 0; i < b.length; i++)
        {
            msb = ((int)b[i] & 0x000000FF) / 16;

            lsb = ((int)b[i] & 0x000000FF) % 16;
            hex = hex + hexChars[msb] + hexChars[lsb];
        }
        return hex;
    }

    public static void main(String[] args)
    {
        if (args.length == 2)
        {
            // Simply pass arguments.
            new ApiExample(args[0], args[1]);
        }
        else
        {
            // Show usage information.
            usage();
        }
    }
}