Add Foursquare2 API and example

changelog.txt

@@ -41,3 +41,4 @@
   * FEATURE: Added rawResponse to Token, for extracting additional parameters (thanks Dirk McCormick)
   * FEATURE: Added Dropbox Api
   * FIX: Token responses now work despite of the token/secret order
+  * FEATURE: Added Foursquare OAuth 2.0 Api (thanks Tom Tasche)

src/main/java/org/scribe/builder/api/Foursquare2Api.java

@@ -0,0 +1,29 @@
+package org.scribe.builder.api;
+
+import org.scribe.extractors.*;
+import org.scribe.model.*;
+import org.scribe.utils.*;
+
+public class Foursquare2Api extends DefaultApi20
+{
+  private static final String AUTHORIZATION_URL = "https://foursquare.com/oauth2/authenticate?client_id=%s&response_type=code&redirect_uri=%s";
+
+  @Override
+  public String getAccessTokenEndpoint()
+  {
+    return "https://foursquare.com/oauth2/access_token?grant_type=authorization_code";
+  }
+
+  @Override
+  public String getAuthorizationUrl(OAuthConfig config)
+  {
+    Preconditions.checkValidUrl(config.getCallback(), "Must provide a valid url as callback. Foursquare2 does not support OOB");
+    return String.format(AUTHORIZATION_URL, config.getApiKey(), URLUtils.formURLEncode(config.getCallback()));
+  }
+
+  @Override
+  public AccessTokenExtractor getAccessTokenExtractor()
+  {
+    return new JsonTokenExtractor();
+  }
+}

src/main/java/org/scribe/extractors/FoursquareAccessTokenExtractor.java

@@ -0,0 +1,28 @@
+package org.scribe.extractors;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.scribe.exceptions.OAuthException;
+import org.scribe.extractors.TokenExtractor20Impl;
+import org.scribe.model.Token;
+import org.scribe.utils.Preconditions;
+import org.scribe.utils.URLUtils;
+
+public class FoursquareAccessTokenExtractor extends TokenExtractor20Impl {
+
+    private static final String TOKEN_REGEX = ".[\\s]+\"access_token\":\"(\\S*?)(&(\\S*))?\"[\\s]+.";
+    private static final String EMPTY_SECRET = "";
+
+    public Token extract(String response) {
+        Preconditions.checkEmptyString(response, "Response body is incorrect. Can't extract a token from an empty string");
+
+        Matcher matcher = Pattern.compile(TOKEN_REGEX).matcher(response);
+        if (matcher.matches()) {
+            String token = URLUtils.formURLDecode(matcher.group(1));
+            return new Token(token, EMPTY_SECRET);
+        } else {
+            throw new OAuthException("Response body is incorrect. Can't extract a token from this: '" + response + "'", null);
+        }
+    }
+}

src/main/java/org/scribe/extractors/JsonTokenExtractor.java

@@ -0,0 +1,28 @@
+package org.scribe.extractors;
+
+import java.util.regex.*;
+
+import org.scribe.exceptions.*;
+import org.scribe.model.*;
+import org.scribe.utils.*;
+
+public class JsonTokenExtractor implements AccessTokenExtractor
+{
+  private Pattern accessTokenPattern = Pattern.compile("\"access_token\":\"(\\S*)\"");
+
+  @Override
+  public Token extract(String response)
+  {
+    Preconditions.checkEmptyString(response, "Cannot extract a token from a null or empty String");
+    Matcher matcher = accessTokenPattern.matcher(response);
+    if(matcher.find())
+    {
+      return new Token(matcher.group(1), "");
+    }
+    else
+    {
+      throw new OAuthException("Cannot extract an acces token. Response was: "+response);
+    }
+  }
+
+}

src/test/java/org/scribe/examples/Foursquare2Example.java

@@ -0,0 +1,63 @@
+package org.scribe.examples;
+
+import java.util.*;
+
+import org.scribe.builder.*;
+import org.scribe.builder.api.*;
+import org.scribe.model.*;
+import org.scribe.oauth.*;
+
+public class Foursquare2Example
+{
+  private static final String PROTECTED_RESOURCE_URL = "https://api.foursquare.com/v2/users/self/friends?oauth_token=";
+  private static final Token EMPTY_TOKEN = null;
+
+  public static void main(String[] args)
+  {
+    // Replace these with your own api key and secret
+    String apiKey = "FEGFXJUFANVVDHVSNUAMUKTTXCP1AJQD53E33XKJ44YP1S4I";
+    String apiSecret = "AYWKUL5SWPNC0CTQ202QXRUG2NLZYXMRA34ZSDW4AUYBG2RC";
+    OAuthService service = new ServiceBuilder()
+                                  .provider(Foursquare2Api.class)
+                                  .apiKey(apiKey)
+                                  .apiSecret(apiSecret)
+                                  .callback("http://localhost:9000/")
+                                  .build();
+    Scanner in = new Scanner(System.in);
+
+    System.out.println("=== Foursquare2's OAuth Workflow ===");
+    System.out.println();
+
+    // Obtain the Authorization URL
+    System.out.println("Fetching the Authorization URL...");
+    String authorizationUrl = service.getAuthorizationUrl(EMPTY_TOKEN);
+    System.out.println("Got the Authorization URL!");
+    System.out.println("Now go and authorize Scribe here:");
+    System.out.println(authorizationUrl);
+    System.out.println("And paste the authorization code here");
+    System.out.print(">>");
+    Verifier verifier = new Verifier(in.nextLine());
+    System.out.println();
+    
+    // Trade the Request Token and Verfier for the Access Token
+    System.out.println("Trading the Request Token for an Access Token...");
+    Token accessToken = service.getAccessToken(EMPTY_TOKEN, verifier);
+    System.out.println("Got the Access Token!");
+    System.out.println("(if your curious it looks like this: " + accessToken + " )");
+    System.out.println();
+
+    // Now let's go and ask for a protected resource!
+    System.out.println("Now we're going to access a protected resource...");
+    OAuthRequest request = new OAuthRequest(Verb.GET, PROTECTED_RESOURCE_URL + accessToken.getToken());
+    service.signRequest(accessToken, request);
+    Response response = request.send();
+    System.out.println("Got it! Lets see what we found...");
+    System.out.println();
+    System.out.println(response.getCode());
+    System.out.println(response.getBody());
+
+    System.out.println();
+    System.out.println("Thats it man! Go and build something awesome with Scribe! :)");
+
+  }
+}

src/test/java/org/scribe/extractors/JsonTokenExtractorTest.java

@@ -0,0 +1,31 @@
+package org.scribe.extractors;
+
+import static org.junit.Assert.*;
+
+import org.junit.*;
+import org.scribe.model.*;
+
+public class JsonTokenExtractorTest
+{
+  private String response = "'{ \"access_token\":\"I0122HHJKLEM21F3WLPYHDKGKZULAUO4SGMV3ABKFTDT3T3X\"}'";
+  private JsonTokenExtractor extractor = new JsonTokenExtractor();
+
+  @Test
+  public void shouldParseResponse()
+  {
+    Token token = extractor.extract(response);
+    assertEquals(token.getToken(), "I0122HHJKLEM21F3WLPYHDKGKZULAUO4SGMV3ABKFTDT3T3X");
+  }
+
+  @Test(expected=IllegalArgumentException.class)
+  public void shouldThrowExceptionIfForNullParameters()
+  {
+    extractor.extract(null);
+  }
+
+  @Test(expected=IllegalArgumentException.class)
+  public void shouldThrowExceptionIfForEmptyStrings()
+  {
+    extractor.extract("");
+  }
+}