Extend TwitterApi with a method for OAuth-signed requests

2 files changed, 71 insertions, 2 deletions

diff --git a/src/mining/OAuthRequester.java b/src/mining/OAuthRequester.java
index 76d21c4..f740916 100644
--- a/src/mining/OAuthRequester.java
+++ b/src/mining/OAuthRequester.java
@@ -99,6 +99,15 @@ public class OAuthRequester extends AbstractRequester {
         }
     }
 
+    public OAuthAccessTokenSecret getSecrets() {
+        String token = consumer.getToken();
+        String secret = consumer.getTokenSecret();
+        if (token == null || secret == null) {
+            return null;
+        }
+        return new OAuthAccessTokenSecret(token, secret);
+    }
+
     @Override
     public boolean isValid() throws IOException {
         if (consumer.getToken() == null) {
diff --git a/src/mining/TwitterApi.java b/src/mining/TwitterApi.java
index e45f7b7..7ea4e57 100644
--- a/src/mining/TwitterApi.java
+++ b/src/mining/TwitterApi.java
@@ -10,6 +10,7 @@ import org.apache.http.client.utils.URLEncodedUtils;
 import org.apache.http.message.BasicNameValuePair;
 import org.json.JSONObject;
 import support.ConsumerKeySecret;
+import support.OAuthAccessTokenSecret;
 import utils.Configuration;
 
 /**
@@ -18,6 +19,8 @@ import utils.Configuration;
 public class TwitterApi {
 
     private static final String CFG_BEARER_TOKEN = "bearer-token";
+    private static final String CFG_OAUTH_TOKEN = "oauth-token";
+    private static final String CFG_OAUTH_SECRET = "oauth-secret";
     private final Requester requester;
 
     public TwitterApi(Requester requester) {
@@ -25,8 +28,7 @@ public class TwitterApi {
     }
 
     /**
-     * Establishes an instance using application-only authentication using a
-     * file as cache.
+     * Establishes an instance using application-only authentication.
      *
      * @return An API context usable for requests using app-only auth.
      * @throws IOException
@@ -53,6 +55,64 @@ public class TwitterApi {
         return new TwitterApi(breq);
     }
 
+    /**
+     * Establishes an instance using a user context (OAuth signing).
+     *
+     * @param ps A supplier of the PIN for a given URL. May be null if not
+     * supported.
+     * @return An API context usable for requests using OAuth.
+     * @throws IOException if no usable context can be instantiated.
+     */
+    public static TwitterApi getOAuth(PinSupplier ps) throws IOException {
+        Configuration cfg = Configuration.getConfig();
+        OAuthAccessTokenSecret secrets = null;
+        ConsumerKeySecret cks = getConsumerKeySecret();
+        OAuthRequester oreq = new OAuthRequester(cks);
+
+        /* check if the stored access tokens are still valid */
+        {
+            String token, secret;
+            token = cfg.getProperty(CFG_OAUTH_TOKEN);
+            secret = cfg.getProperty(CFG_OAUTH_SECRET);
+            if (token != null && secret != null) {
+                secrets = new OAuthAccessTokenSecret(token, secret);
+                oreq.setAccessToken(secrets);
+                if (!oreq.isValid()) {
+                    Logger.getLogger(TwitterApi.class.getName())
+                            .info("OAuth access tokens invalid");
+                    secrets = null;
+                }
+            }
+        }
+        /* if no valid secrets are available, request a new access token */
+        if (secrets == null) {
+            if (ps == null) {
+                throw new IOException("Unable to retrieve an access token");
+            }
+            String authUrl = oreq.getAuthURL();
+            oreq.supplyPINForTokens(ps.requestPin(authUrl));
+            secrets = oreq.getSecrets();
+            assert secrets != null : "PIN accepted, but no access tokens?";
+            cfg.setProperty(CFG_OAUTH_TOKEN, secrets.getToken());
+            cfg.setProperty(CFG_OAUTH_SECRET, secrets.getSecret());
+            cfg.save();
+        }
+        return new TwitterApi(oreq);
+    }
+
+    public interface PinSupplier {
+
+        /**
+         * Given a URL, the pin supplier must synchronously request a PIN.
+         *
+         * @param url The URL to be presented to the user.
+         * @return A non-null string that can be exchanged for access tokens.
+         * @throws IOException if the PIN could not be retrieved.
+         */
+        public String requestPin(String url) throws IOException;
+
+    }
+
     private static ConsumerKeySecret getConsumerKeySecret() {
         // static consumer keys retrieved from dev.twitter.com
         return new ConsumerKeySecret(Configuration.CONSUMER_KEY,