TwitterButton.java

package org.vaadin.oauth;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.scribe.builder.api.Api;
import org.scribe.builder.api.TwitterApi;
import org.scribe.exceptions.OAuthException;
import org.scribe.model.Token;
import org.scribe.utils.OAuthEncoder;

import com.google.gson.annotations.SerializedName;

public class TwitterButton extends OAuthButton {

    /**
     * Creates a "Log in with Twitter" button that will use the given API
     * key/secret to authenticate the user with Twitter, and then call the given
     * callback with {@link User} details.
     * 
     * @param caption
     *            button caption
     * @param apiKey
     *            API key from the service providing OAuth
     * @param apiSecret
     *            API secret from the service providing OAuth
     * @param authListener
     *            called once the user has been authenticated
     */
    public TwitterButton(String apiKey, String apiSecret,
            OAuthListener authListener) {
        super("Log in with Twitter", apiKey, apiSecret, authListener);
    }

    /**
     * Creates a button with the given caption that will use the given API
     * key/secret to authenticate the user with Twitter, and then call the given
     * callback with {@link User} details.
     * 
     * @param caption
     *            button caption
     * @param apiKey
     *            API key from the service providing OAuth
     * @param apiSecret
     *            API secret from the service providing OAuth
     * @param authListener
     *            called once the user has been authenticated
     */
    public TwitterButton(String caption, String apiKey, String apiSecret,
            OAuthListener authListener) {
        super(caption, apiKey, apiSecret, authListener);
    }

    @Override
    protected String getAuthUrl() {
        requestToken = getService().getRequestToken();
        return getService().getAuthorizationUrl(requestToken);
    }

    @Override
    protected Class<? extends Api> getApi() {
        return MyTwitterApi.class;
    }

    @Override
    protected String getVerifierName() {
        return "oauth_verifier";
    }

    @Override
    protected String getJsonDataUrl() {
        String response = accessToken.getRawResponse();
        String id = extract(response, USER_REGEX);
        return "https://api.twitter.com/1/users/show.json?user_id=" + id;
    }

    @Override
    protected Class<? extends User> getUserClass() {
        return TwitterUser.class;
    }

    private static final Pattern USER_REGEX = Pattern
            .compile("user_id=([^&]+)");

    private String extract(String response, Pattern p) {
        Matcher matcher = p.matcher(response);
        if (matcher.find() && matcher.groupCount() >= 1) {
            return OAuthEncoder.decode(matcher.group(1));
        } else {
            throw new OAuthException(
                    "Response body is incorrect. Can't extract token and secret from this: '"
                            + response + "'", null);
        }
    }

    public static class MyTwitterApi extends TwitterApi {

        private static final String AUTHENTICATE_URL = "https://api.twitter.com/oauth/authenticate?oauth_token=%s";

        @Override
        public String getAuthorizationUrl(Token requestToken) {
            return String.format(AUTHENTICATE_URL, requestToken.getToken());
        }

    }

    public static class TwitterUser implements User {

        @SerializedName("screen_name")
        private String screenName;
        private String id;
        private String name;
        private String token;
        private String tokenSecret;

        public String getToken() {
            return token;
        }

        public String getTokenSecret() {
            return tokenSecret;
        }

        public String getName() {
            return name;
        }

        public String getScreenName() {
            return screenName;
        }

        public String getPictureUrl() {
            return "https://api.twitter.com/1/users/profile_image?screen_name="
                    + screenName;
        }

        public String getId() {
            return id;
        }

        public String getPublicProfileUrl() {
            return "https://twitter.com/" + screenName;
        }

        public String getService() {
            return "twitter";
        }

        public String getEmail() {
            return null;
        }

    }
}