OAuthForFlickr.java

package oauthflickr;

import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URLEncoder;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.List;

import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.utils.URIUtils;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;

/**
 * a simple program to get flickr token and token secret.
 * 
 * @author Mark Zang
 * 
 */
public class OAuthForFlickr {

	private static String key = "1f24ea7aa557e67fb2dfdc4632242285";
	private static String secret = "0192b6f68c0abe9d";

	private static final String HMAC_SHA1 = "HmacSHA1";

	private static final String ENC = "UTF-8";

	private static Base64 base64 = new Base64();

	/**
	 * 
	 * @param url
	 *            the url for "request_token" URLEncoded.
	 * @param params
	 *            parameters string, URLEncoded.
	 * @return
	 * @throws UnsupportedEncodingException
	 * @throws NoSuchAlgorithmException
	 * @throws InvalidKeyException
	 */
	private static String getSignature(String url, String params)
			throws UnsupportedEncodingException, NoSuchAlgorithmException,
			InvalidKeyException {
		/**
		 * base has three parts, they are connected by "&": 1) protocol 2) URL
		 * (need to be URLEncoded) 3) Parameter List (need to be URLEncoded).
		 */
		StringBuilder base = new StringBuilder();
		base.append("GET&");
		base.append(url);
		base.append("&");
		base.append(params);
		System.out.println("Stirng for oauth_signature generation:" + base);
		// yea, don't ask me why, it is needed to append a "&" to the end of
		// secret key.
		byte[] keyBytes = (secret + "&").getBytes(ENC);

		SecretKey key = new SecretKeySpec(keyBytes, HMAC_SHA1);

		Mac mac = Mac.getInstance(HMAC_SHA1);
		mac.init(key);

		// encode it, base64 it, change it to string and return.
		return new String(base64.encode(mac.doFinal(base.toString().getBytes(
				ENC))), ENC).trim();
	}

	/**
	 * @param args
	 * @throws IOException
	 * @throws ClientProtocolException
	 * @throws URISyntaxException
	 * @throws NoSuchAlgorithmException
	 * @throws InvalidKeyException
	 */
	public static void main(String[] args) throws ClientProtocolException,
			IOException, URISyntaxException, InvalidKeyException,
			NoSuchAlgorithmException {

		HttpClient httpclient = new DefaultHttpClient();
		List<NameValuePair> qparams = new ArrayList<NameValuePair>();
		// These params should ordered in key
		qparams.add(new BasicNameValuePair("oauth_callback", "oob"));
		qparams.add(new BasicNameValuePair("oauth_consumer_key", key));
		qparams.add(new BasicNameValuePair("oauth_nonce", ""
				+ (int) (Math.random() * 100000000)));
		qparams.add(new BasicNameValuePair("oauth_signature_method",
				"HMAC-SHA1"));
		qparams.add(new BasicNameValuePair("oauth_timestamp", ""
				+ (System.currentTimeMillis() / 1000)));
		qparams.add(new BasicNameValuePair("oauth_version", "1.0"));

		// generate the oauth_signature
		String signature = getSignature(URLEncoder.encode(
				"http://www.flickr.com/services/oauth/request_token", ENC),
				URLEncoder.encode(URLEncodedUtils.format(qparams, ENC), ENC));

		// add it to params list
		qparams.add(new BasicNameValuePair("oauth_signature", signature));

		// generate URI which lead to access_token and token_secret.
		URI uri = URIUtils.createURI("http", "www.flickr.com", -1,
				"/services/oauth/request_token",
				URLEncodedUtils.format(qparams, ENC), null);

		System.out.println("Get Token and Token Secrect from:"
				+ uri.toString());

		HttpGet httpget = new HttpGet(uri);
		// output the response content.
		System.out.println("Token and Token Secrect:");

		HttpResponse response = httpclient.execute(httpget);
		HttpEntity entity = response.getEntity();
		if (entity != null) {
			InputStream instream = entity.getContent();
			int len;
			byte[] tmp = new byte[2048];
			while ((len = instream.read(tmp)) != -1) {
				System.out.println(new String(tmp, 0, len, ENC));
			}
		}
	}

}