OAuthUtils.java

package com.googlecode.flickrjandroid.oauth;



import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Locale;

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

import com.googlecode.flickrjandroid.FlickrException;
import com.googlecode.flickrjandroid.Parameter;
import com.googlecode.flickrjandroid.RequestContext;
import com.googlecode.flickrjandroid.uploader.ImageParameter;
import com.googlecode.flickrjandroid.util.Base64;
import com.googlecode.flickrjandroid.util.UrlUtilities;

/**
 * a simple program to get flickr token and token secret.
 * 
 * @author Mark Zang, Toby Yu
 * 
 */
public class OAuthUtils {
	private static final String PARAMETER_SEPARATOR = "&";
	private static final String NAME_VALUE_SEPARATOR = "=";
	
	public static final String ENC = "UTF-8";
	/** Default charsets */
	public static final String DEFAULT_CONTENT_CHARSET = "ISO-8859-1";

	private static final String HMAC_SHA1 = "HmacSHA1";
	
	public static final String REQUEST_METHOD_GET = "GET";
	public static final String REQUEST_METHOD_POST = "POST";
	
//	private static final Logger logger = LoggerFactory.getLogger(OAuthUtils.class);
	
	public static void addOAuthParams(String apiSharedSecret, String url, List<Parameter> parameters) 
	throws FlickrException {
		addBasicOAuthParams(parameters);
		signPost(apiSharedSecret, url, parameters);
	}
	
	public static void addOAuthToken(List<Parameter> parameters) throws OAuthException {
		OAuth oauth = RequestContext.getRequestContext().getOAuth();
		if (oauth == null || oauth.getToken() == null)
			throw new OAuthException("OAuth token not set");
		parameters.add(new OAuthTokenParameter(oauth.getToken().getOauthToken()));
	}
	
	public static void signGet(String apiSharedSecret, String url, List<Parameter>  parameters) throws FlickrException {
		sign(OAuthUtils.REQUEST_METHOD_GET, url, apiSharedSecret, parameters);
	}
	
	public static void signPost(String apiSharedSecret, String url, List<Parameter>  parameters) throws FlickrException {
		sign(OAuthUtils.REQUEST_METHOD_POST, url, apiSharedSecret, parameters);
	}
	
	public static void sign(String requestMethod, String url, String apiSharedSecret, List<Parameter>  parameters) throws FlickrException {
		OAuth oauth = RequestContext.getRequestContext().getOAuth();
		
		String tokenSecret = oauth != null && oauth.getToken() != null 
		? oauth.getToken().getOauthTokenSecret() : "";
		// generate the oauth_signature
		String signature = OAuthUtils.getSignature(
				requestMethod, 
				url, 
				parameters,
				apiSharedSecret, tokenSecret);
		// This method call must be signed.
		parameters.add(new Parameter("oauth_signature", signature));
	}
	
	public static boolean hasSigned() {
		OAuth oauth = RequestContext.getRequestContext().getOAuth();
		if (oauth == null)
			return false;
		
		return oauth.getToken() != null;
	}
	
	public static void addBasicOAuthParams(List<Parameter> parameters) {
		OAuthUtils.addOAuthNonce(parameters);
		OAuthUtils.addOAuthTimestamp(parameters);
		OAuthUtils.addOAuthSignatureMethod(parameters);
		OAuthUtils.addOAuthVersion(parameters);
	}
	
	public static String getSignature(String requestMethod, String url, List<Parameter> parameters
			, String apiSecret, String tokenSecret)
	throws FlickrException {
		String baseString;
		try {
			baseString = getRequestBaseString(requestMethod, url.toLowerCase(Locale.US), parameters);
//			logger.debug("Generated OAuth Base String: {}", baseString);
			return hmacsha1(baseString, apiSecret, tokenSecret);
		} catch (UnsupportedEncodingException e) {
			throw new FlickrException(e);
		} catch (InvalidKeyException e) {
			throw new FlickrException(e);
		} catch (IllegalStateException e) {
			throw new FlickrException(e);
		} catch (NoSuchAlgorithmException e) {
			throw new FlickrException(e);
		}
	}
	
	public static String getSignature(String url, List<Parameter> parameters
			, String apiSecret, String tokenSecret)
	throws FlickrException {
		return getSignature(REQUEST_METHOD_GET, url, parameters, apiSecret, tokenSecret);
	}
	
	public static String getRequestBaseString(String oauth_request_method, String url, List<Parameter> parameters) throws UnsupportedEncodingException {
		StringBuffer result = new StringBuffer();
		result.append(oauth_request_method);
		result.append(PARAMETER_SEPARATOR);
		result.append(UrlUtilities.encode(url));
		result.append(PARAMETER_SEPARATOR);
		
		Collections.sort(parameters, new Comparator<Parameter>() {

			@Override
			public int compare(Parameter o1, Parameter o2) {
				if (o1 instanceof ImageParameter && (o2 instanceof ImageParameter) == false) {
					return 1;
				}
				if (o2 instanceof ImageParameter && (o1 instanceof ImageParameter) == false) {
					return -1;
				}
				
				int result = o1.getName().compareTo(o2.getName());
				if (result == 0) {
					result = o1.getValue().toString().compareTo(o2.getValue().toString());
				}
				return result;
			}
			
		});
		
		return result.append(UrlUtilities.encode(format(parameters, ENC))).toString();
	}
	
	public static String hmacsha1(String data, String key, String tokenSecret) throws IllegalStateException, UnsupportedEncodingException, NoSuchAlgorithmException, InvalidKeyException {
		byte[] byteHMAC = null;
		Mac mac = Mac.getInstance(HMAC_SHA1);
		if (tokenSecret == null) {
			tokenSecret = "";
		}
		SecretKeySpec spec = new SecretKeySpec((key + PARAMETER_SEPARATOR + tokenSecret).getBytes(), HMAC_SHA1);
		mac.init(spec);
		byteHMAC = mac.doFinal(data.getBytes(ENC));

		return new String(Base64.encode(byteHMAC));
	}

	/**
	 * Returns a String that is suitable for use as an <code>application/x-www-form-urlencoded</code>
	 * list of parameters in an HTTP PUT or HTTP POST.
	 *
	 * @param parameters  The parameters to include.
	 * @param encoding The encoding to use.
	 */
	public static String format (
			final List<Parameter> parameters,
			final String encoding) {
		final StringBuilder result = new StringBuilder();
		for (final Parameter parameter : parameters) {
			Object valueObj = parameter.getValue();
			if ((parameter instanceof ImageParameter) == false) {
				final String encodedName = UrlUtilities.encode(parameter.getName());
				final String value = String.valueOf(valueObj);
				final String encodedValue = value != null ? UrlUtilities.encode(value) : "";
				if (result.length() > 0)
					result.append(PARAMETER_SEPARATOR);
				result.append(encodedName);
				result.append(NAME_VALUE_SEPARATOR);
				result.append(encodedValue);
			}
		}
		return result.toString();
	}

	public static String decode (final String content, final String encoding) {
		try {
			return URLDecoder.decode(content,
					encoding != null ? encoding : DEFAULT_CONTENT_CHARSET);
		} catch (UnsupportedEncodingException problem) {
			throw new IllegalArgumentException(problem);
		}
	}
	
	private static void addOAuthNonce(final List<Parameter> parameters) {
		parameters.add(new Parameter("oauth_nonce", Long.toString(System.nanoTime())));
	}
	
	private static void addOAuthSignatureMethod(final List<Parameter> parameters) {
		parameters.add(new Parameter("oauth_signature_method", "HMAC-SHA1"));
	}
	
	private static void addOAuthTimestamp(final List<Parameter> parameters) {
		parameters.add(new Parameter("oauth_timestamp", String.valueOf((System.currentTimeMillis() / 1000))));
	}
	
	private static void addOAuthVersion(final List<Parameter> parameters) {
		parameters.add(new Parameter("oauth_version", "1.0"));
	}

}