Mods to support OAuth2 login (#111).

src/main/java/org/gitlab4j/api/GitLabApi.java

 package org.gitlab4j.api;
 
+import java.util.Map;
+
+import javax.ws.rs.core.Response;
+
 import org.gitlab4j.api.Constants.TokenType;
+import org.gitlab4j.api.models.OauthTokenResponse;
 import org.gitlab4j.api.models.Session;
 import org.gitlab4j.api.models.User;
 import org.gitlab4j.api.models.Version;
 
-import javax.ws.rs.core.Response;
-import java.util.Map;
-
 /**
  * This class is provides a simplified interface to a GitLab API server, and divides the API up into
  * a separate API class for each concern.
@@ -19,7 +21,7 @@ public class GitLabApi {
 
     /** Specifies the version of the GitLab API to communicate with. */
     public enum ApiVersion {
-        V3, V4;
+        V3, V4, OAUTH2_CLIENT;
 
         public String getApiNamespace() {
             return ("/api/" + name().toLowerCase());
@@ -51,6 +53,102 @@ public class GitLabApi {
     private Session session;
 
 
+    /**
+     * <p>Logs into GitLab using OAuth2 with the provided {@code username} and {@code password},
+     * and creates a new {@code GitLabApi} instance using returned access token.</p>
+     *
+     * @param url GitLab URL
+     * @param username user name for which private token should be obtained
+     * @param password password for a given {@code username}
+     * @return new {@code GitLabApi} instance configured for a user-specific token
+     * @throws GitLabApiException GitLabApiException if any exception occurs during execution
+     */
+    public static GitLabApi oauth2Login(String url, String username, String password) throws GitLabApiException {
+        return (GitLabApi.oauth2Login(ApiVersion.V4, url, username, password, null, null, false));
+    }
+
+    /**
+     * <p>Logs into GitLab using OAuth2 with the provided {@code username} and {@code password},
+     * and creates a new {@code GitLabApi} instance using returned access token.</p>
+     *
+     * @param url GitLab URL
+     * @param username user name for which private token should be obtained
+     * @param password password for a given {@code username}
+     * @param ignoreCertificateErrors if true will set up the Jersey system ignore SSL certificate errors
+     * @return new {@code GitLabApi} instance configured for a user-specific token
+     * @throws GitLabApiException GitLabApiException if any exception occurs during execution
+     */
+    public static GitLabApi oauth2Login(String url, String username, String password, boolean ignoreCertificateErrors) throws GitLabApiException {
+        return (GitLabApi.oauth2Login(ApiVersion.V4, url, username, password, null, null, ignoreCertificateErrors));
+    }
+
+    /**
+     * <p>Logs into GitLab using OAuth2 with the provided {@code username} and {@code password},
+     * and creates a new {@code GitLabApi} instance using returned access token.</p>
+     *
+     * @param url GitLab URL
+     * @param username user name for which private token should be obtained
+     * @param password password for a given {@code username}
+     * @param secretToken use this token to validate received payloads
+     * @param clientConfigProperties Map instance with additional properties for the Jersey client connection
+     * @param ignoreCertificateErrors if true will set up the Jersey system ignore SSL certificate errors
+     * @return new {@code GitLabApi} instance configured for a user-specific token
+     * @throws GitLabApiException GitLabApiException if any exception occurs during execution
+     */
+    public static GitLabApi oauth2Login(String url, String username, String password,
+            String secretToken, Map<String, Object> clientConfigProperties, boolean ignoreCertificateErrors)
+            throws GitLabApiException {
+        return (GitLabApi.oauth2Login(ApiVersion.V4, url, username, password, secretToken, clientConfigProperties, ignoreCertificateErrors));
+    }
+
+    /**
+     * <p>Logs into GitLab using OAuth2 with the provided {@code username} and {@code password},
+     * and creates a new {@code GitLabApi} instance using returned access token.</p>
+     *
+     * @param url GitLab URL
+     * @param apiVersion the ApiVersion specifying which version of the API to use
+     * @param username user name for which private token should be obtained
+     * @param password password for a given {@code username}
+     * @param secretToken use this token to validate received payloads
+     * @param clientConfigProperties Map instance with additional properties for the Jersey client connection
+     * @param ignoreCertificateErrors if true will set up the Jersey system ignore SSL certificate errors
+     * @return new {@code GitLabApi} instance configured for a user-specific token
+     * @throws GitLabApiException GitLabApiException if any exception occurs during execution
+     */
+    public static GitLabApi oauth2Login(ApiVersion apiVersion, String url, String username, String password, 
+            String secretToken, Map<String, Object> clientConfigProperties, boolean ignoreCertificateErrors)
+            throws GitLabApiException {
+
+        if (username == null || username.trim().length() == 0) {
+            throw new IllegalArgumentException("both username and email cannot be empty or null");
+        }
+
+        GitLabApi gitLabApi = new GitLabApi(ApiVersion.OAUTH2_CLIENT, url, (String)null);
+        if (ignoreCertificateErrors) {
+            gitLabApi.setIgnoreCertificateErrors(true);
+        }
+
+        class Oauth2Api extends AbstractApi {
+            Oauth2Api(GitLabApi gitlabApi) {
+                super(gitlabApi);
+            }
+        }
+
+        GitLabApiForm formData = new GitLabApiForm()
+            .withParam("grant_type", "password", true)
+            .withParam("username", username, true)
+            .withParam("password", password, true);
+
+        Response response = new Oauth2Api(gitLabApi).post(Response.Status.OK, formData, "oauth", "token");
+        OauthTokenResponse oauthToken = response.readEntity(OauthTokenResponse.class);
+        gitLabApi = new GitLabApi(apiVersion, url, TokenType.ACCESS, oauthToken.getAccessToken(), secretToken, clientConfigProperties);
+        if (ignoreCertificateErrors) {
+            gitLabApi.setIgnoreCertificateErrors(true);
+        }
+
+        return (gitLabApi);
+    }
+
     /**
      * <p>Logs into GitLab using provided {@code username} and {@code password}, and creates a new {@code GitLabApi} instance
      * using returned private token and the specified GitLab API version.</p>
@@ -65,7 +163,7 @@ public class GitLabApi {
      * @throws GitLabApiException GitLabApiException if any exception occurs during execution
      */
     public static GitLabApi login(ApiVersion apiVersion, String url, String username, String password) throws GitLabApiException {
-        return (login(apiVersion, url, username, password, false));
+        return (GitLabApi.login(apiVersion, url, username, password, false));
     }
 
     /**
@@ -81,7 +179,7 @@ public class GitLabApi {
      * @throws GitLabApiException GitLabApiException if any exception occurs during execution
      */
     public static GitLabApi login(String url, String username, String password) throws GitLabApiException {
-        return (login(ApiVersion.V4, url, username, password, false));
+        return (GitLabApi.login(ApiVersion.V4, url, username, password, false));
     }
 
     /**
@@ -105,12 +203,22 @@ public class GitLabApi {
             gitLabApi.setIgnoreCertificateErrors(true);
         }
 
-        SessionApi sessionApi = gitLabApi.getSessionApi();
-        Session session = sessionApi.login(username, null, password);
-        gitLabApi = new GitLabApi(apiVersion, url, session);
+        try {
 
-        if (ignoreCertificateErrors) {
-            gitLabApi.setIgnoreCertificateErrors(true);
+            SessionApi sessionApi = gitLabApi.getSessionApi();
+            Session session = sessionApi.login(username, null, password);
+            gitLabApi = new GitLabApi(apiVersion, url, session);
+
+            if (ignoreCertificateErrors) {
+                gitLabApi.setIgnoreCertificateErrors(true);
+            }
+
+        } catch (GitLabApiException gle) {
+            if (gle.getHttpStatus() != Response.Status.NOT_FOUND.getStatusCode()) {
+                throw (gle);
+            } else {
+                gitLabApi = GitLabApi.oauth2Login(apiVersion, url, username, password, null, null, ignoreCertificateErrors);
+            }
         }
 
         return (gitLabApi);
@@ -130,7 +238,7 @@ public class GitLabApi {
      * @throws GitLabApiException GitLabApiException if any exception occurs during execution
      */
     public static GitLabApi login(String url, String username, String password, boolean ignoreCertificateErrors) throws GitLabApiException {
-        return (login(ApiVersion.V4, url, username, password, ignoreCertificateErrors));
+        return (GitLabApi.login(ApiVersion.V4, url, username, password, ignoreCertificateErrors));
     }
 
     /**
@@ -148,7 +256,7 @@ public class GitLabApi {
      */
     @Deprecated
     public static GitLabApi create(String url, String username, String password) throws GitLabApiException {
-        return (login(url, username, password));
+        return (GitLabApi.login(url, username, password));
     }
 
     /**

src/main/java/org/gitlab4j/api/GitLabApiClient.java

@@ -194,7 +194,11 @@ public class GitLabApiClient {
     public GitLabApiClient(ApiVersion apiVersion, String hostUrl, TokenType tokenType, String authToken, String secretToken, Map<String, Object> clientConfigProperties) {
 
         // Remove the trailing "/" from the hostUrl if present
-        this.hostUrl = (hostUrl.endsWith("/") ? hostUrl.replaceAll("/$", "") : hostUrl) + apiVersion.getApiNamespace();
+        this.hostUrl = (hostUrl.endsWith("/") ? hostUrl.replaceAll("/$", "") : hostUrl);
+        if (ApiVersion.OAUTH2_CLIENT != apiVersion) {
+            this.hostUrl += apiVersion.getApiNamespace();
+        }
+
         this.tokenType = tokenType;
         this.authToken = authToken;
 

src/test/java/org/gitlab4j/api/TestGitLabLogin.java

@@ -2,6 +2,7 @@ package org.gitlab4j.api;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assume.assumeFalse;
 import static org.junit.Assume.assumeTrue;
 
 import org.gitlab4j.api.GitLabApi.ApiVersion;
@@ -20,7 +21,7 @@ import org.junit.Test;
  * 
  * If any of the above are NULL, all tests in this class will be skipped.
  */
-public class TestGitLabSession {
+public class TestGitLabLogin {
 
     // The following needs to be set to your test repository
     private static final String TEST_USERNAME;
@@ -35,8 +36,9 @@ public class TestGitLabSession {
     }
 
     private static String problems = "";
+    private static boolean hasSession;
 
-    public TestGitLabSession() {
+    public TestGitLabLogin() {
         super();
     }
 
@@ -62,24 +64,18 @@ public class TestGitLabSession {
         }
 
         if (problems.isEmpty()) {
-            String savedVersion = null;
             try {
                 GitLabApi gitLabApi = new GitLabApi(ApiVersion.V4, TEST_HOST_URL, TEST_PRIVATE_TOKEN);
                 Version version = gitLabApi.getVersion();
-                savedVersion = version.getVersion();
                 String[] parts = version.getVersion().split(".", -1);
                 if (parts.length == 3) {
                     if (Integer.parseInt(parts[0]) < 10 || 
                             (Integer.parseInt(parts[0]) == 10 && Integer.parseInt(parts[1]) < 2)) {
-                        savedVersion = null;
+                        hasSession = true;
                     }
                 }
             } catch (Exception e) {                
             }
-            
-            if (savedVersion != null) {
-                problems += "GitLab version " + savedVersion + " does not support sessions\n";
-            }
         }
 
         if (!problems.isEmpty()) {
@@ -95,6 +91,7 @@ public class TestGitLabSession {
     @Test
     public void testSession() throws GitLabApiException {
 
+        assumeTrue(hasSession);
         GitLabApi gitLabApi = GitLabApi.login(ApiVersion.V4, TEST_HOST_URL, TEST_USERNAME, TEST_PASSWORD);
         assertNotNull(gitLabApi);
         assertNotNull(gitLabApi.getSession());
@@ -104,9 +101,29 @@ public class TestGitLabSession {
     @Test
     public void testSessionV3() throws GitLabApiException {
 
+        assumeTrue(hasSession);
         GitLabApi gitLabApi = GitLabApi.login(ApiVersion.V3, TEST_HOST_URL, TEST_USERNAME, TEST_PASSWORD);
         assertNotNull(gitLabApi);
         assertNotNull(gitLabApi.getSession());
         assertEquals(TEST_PRIVATE_TOKEN, gitLabApi.getSession().getPrivateToken());
     }
+
+    @Test
+    public void testSessionFallover() throws GitLabApiException {
+
+        assumeFalse(hasSession);
+        GitLabApi gitLabApi = GitLabApi.login(ApiVersion.V4, TEST_HOST_URL, TEST_USERNAME, TEST_PASSWORD);
+        assertNotNull(gitLabApi);
+        Version version = gitLabApi.getVersion();
+        assertNotNull(version);
+    }
+
+    @Test
+    public void testOauth2Login() throws GitLabApiException {
+
+        GitLabApi gitLabApi = GitLabApi.oauth2Login(TEST_HOST_URL, TEST_USERNAME, TEST_PASSWORD, null, null, true);
+        assertNotNull(gitLabApi);
+        Version version = gitLabApi.getVersion();
+        assertNotNull(version);
+    }
 }