Linked Data &Semantic WebTechnology

Development ofTwitter Applications

Part 3. OAuth

Dr. Myungjin Lee

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Twitter4J

• What is Twitter4J?– an unofficial Java library for the Twitter API– easily to integrate your Java application with the Twit-

ter service– http://twitter4j.org/en/index.html

• Features– 100% Pure Java - works on any Java Platform version

5 or later– Android platform and Google App Engine ready– Zero dependency : No additional jars required– Built-in OAuth support– Out-of-the-box gzip support– 100% Twitter API 1.1 compatible

• API Support matrix– http://twitter4j.org/en/api-support.html

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OAuth

• What is OAuth?– an open standard for authorization– a method for clients to access server resources on be-

half of a resource owner– a process for end-users to authorize third-party access

to their server resources without sharing their creden-tials

• Twitter’s OAuth– OAuth v1.0a to provide authorized access to Twitter

API– using HMAC-SHA1 signature

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OAuth Process for Desktop Application

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Registering Your Application

• https://dev.twitter.com/apps/new

your application nameyour application description

your application’s publicly accessible home page

webpage URL where twitter returns after successfully authenticating

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Registering Your Application

Consumer Key and Secret to get user’s Access Token

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Application type

• Read only– Read Tweets from your timeline.– See who you follow.

• Read and Write– Read Tweets from your timeline.– See who you follow, and follow new people.– Update your profile.– Post Tweets for you.

• Read, Write and Access direct messages– Read Tweets from your timeline.– See who you follow, and follow new people.– Update your profile.– Post Tweets for you.– Access your direct messages.

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Primary Classes and Interfaces of Twit-ter4J

• TwitterFactory Class– A factory class for Twitter

• Twitter Interface– basic interface to use all of APIs

• AccessToken Class– Representing authorized Access Token which is

passed to the service provider in order to access pro-tected resources

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Getting Access Token1. // The factory instance is re-useable and thread safe.2. Twitter twitter = TwitterFactory.getSingleton();3. twitter.setOAuthConsumer("[consumer key]", "[consumer secret]");4. RequestToken requestToken = null;5. try {6. requestToken = twitter.getOAuthRequestToken();7. } catch (TwitterException e) {8. // TODO Auto-generated catch block9. e.printStackTrace();10. }11. AccessToken accessToken = null;12. BufferedReader br = new BufferedReader(new InputStreamReader(System.in));13. while (null == accessToken) {14. System.out.println("Open the following URL and grant access to your ac-

count:");15. System.out.println(requestToken.getAuthorizationURL());16. System.out.print("Enter the PIN(if aviailable) or just hit enter.

[PIN]:");17. String pin = new String();18. try {19. pin = br.readLine();20. } catch (IOException e) {21. // TODO Auto-generated catch block22. e.printStackTrace();23. }24. try {25. if (pin.length() > 0) {26. accessToken =

twitter.getOAuthAccessToken(requestToken, pin);27. } else {28. accessToken = twitter.getOAuthAccessToken();29. }30. } catch (TwitterException te) {31. if (401 == te.getStatusCode()) {32. System.out.println("Unable to get the access

token.");33. } else {34. te.printStackTrace();35. }36. }37. }38. // persist to the accessToken for future reference.39. try {40. storeAccessToken(twitter.verifyCredentials().getId(), accessToken);41. } catch (TwitterException e) {42. // TODO Auto-generated catch block43. e.printStackTrace();44. }

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Getting Access Token1. private static void storeAccessToken(long useId, AccessToken accessToken) {2. // store accessToken.getToken() and accessToken.getTokenSecret()3. System.out.println("User ID: " + useId);4. System.out.println("Access Token: " + accessToken.getToken());5. System.out.println("Access Token Secret: "6. + accessToken.getTokenSe-

cret());7. }

8. public static AccessToken loadAccessToken() {9. String token = "[access token]";10. String tokenSecret = "[access token secret]";11. return new AccessToken(token, tokenSecret);12. }

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Test Code for Authentication1. import twitter4j.IDs;2. import twitter4j.Paging;3. import twitter4j.Twitter;4. import twitter4j.TwitterException;5. import twitter4j.TwitterFactory;6. import twitter4j.User;7. import twitter4j.auth.AccessToken;

8. public class TwitterFriends {9. public static void main(String args[]) {10. Twitter twitter = TwitterFactory.getSingleton();11. AccessToken accessToken = TwitterAccessToken.loadAc-

cessToken();12.

twitter.setOAuthConsumer(TwitterAccessToken.consumerKey,13. TwitterAccessToken.consumer-

Secret);14. twitter.setOAuthAccessToken(accessToken);15. IDs ids = null;16. try {17. ids = twitter.getFollowersIDs(-1);18. } catch (TwitterException e) {19. // TODO Auto-generated catch block20. e.printStackTrace();21. }22. long[] idArray = ids.getIDs();23. for (int i = 0; i < idArray.length; i++) {24. User u = null;25. try {26. u =

twitter.showUser(idArray[i]);27. } catch (TwitterException e) {28. // TODO Auto-generated catch

block29. e.printStackTrace();30. }31. System.out.println("Name: " +

u.getName());32. }33. }34. }

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References• http://en.wikipedia.org/wiki/Oauth• http://twitter4j.org/en/index.html• http://www.semantics.kr/?p=185