Added Client Credential Provider

Author: Nakul Sabharwal

src/main/java/com/microsoft/graph/auth/confidentialClient/ClientCredentialProvider.java

@@ -0,0 +1,70 @@
+package com.microsoft.graph.auth.confidentialClient;
+
+import java.util.List;
+
+import org.apache.oltu.oauth2.client.OAuthClient;
+import org.apache.oltu.oauth2.client.URLConnectionClient;
+import org.apache.oltu.oauth2.client.request.OAuthClientRequest;
+import org.apache.oltu.oauth2.client.request.OAuthClientRequest.TokenRequestBuilder;
+import org.apache.oltu.oauth2.common.exception.OAuthProblemException;
+import org.apache.oltu.oauth2.common.exception.OAuthSystemException;
+import org.apache.oltu.oauth2.common.message.types.GrantType;
+
+import com.microsoft.graph.auth.BaseAuthentication;
+import com.microsoft.graph.auth.enums.NationalCloud;
+import com.microsoft.graph.httpcore.IAuthenticationProvider;
+
+public class ClientCredentialProvider extends BaseAuthentication implements IAuthenticationProvider{
+	
+	public ClientCredentialProvider(String clientId,
+			List<String> scopes,
+			String clientSecret,
+			String tenant,
+			NationalCloud nationalCloud) {
+		super(	scopes, 
+				clientId,
+				GetAuthority(nationalCloud == null? NationalCloud.Global: nationalCloud, tenant),
+				null,
+				nationalCloud == null? NationalCloud.Global: nationalCloud,
+				tenant,
+				clientSecret);
+	}
+	
+	@Override
+	public String getAccessToken() {
+		if(super.response != null) {
+			long duration = System.currentTimeMillis() - super.startTime;
+			if(duration > 0 && duration < super.response.getExpiresIn()*1000) {
+				return super.response.getAccessToken();
+			}
+		}
+		String accessToken = null;
+		try {
+			OAuthClientRequest request = getTokenRequestMessage();
+			accessToken = getAccessTokenNewRequest(request);
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+		return accessToken;
+	}
+	
+	protected OAuthClientRequest getTokenRequestMessage() throws OAuthSystemException {
+		String tokenUrl = super.authority + "/oauth2/v2.0/token";
+		TokenRequestBuilder token = OAuthClientRequest.
+				tokenLocation(tokenUrl)
+				.setClientId(super.ClientId)
+				.setGrantType(GrantType.CLIENT_CREDENTIALS)
+				.setScope(getScopesAsString()); 
+		if(super.ClientSecret != null) {
+			token.setClientSecret(this.ClientSecret);
+		}
+		return token.buildBodyMessage();
+	}
+	
+	protected String getAccessTokenNewRequest(OAuthClientRequest request) throws OAuthSystemException, OAuthProblemException {
+		OAuthClient oAuthClient = new OAuthClient(new URLConnectionClient());
+		super.startTime = System.currentTimeMillis();
+		super.response = oAuthClient.accessToken(request);
+		return super.response.getAccessToken();
+	}
+}

src/test/java/com/microsoft/graph/auth/confidentialClient/ClientCredentialProviderTests.java

@@ -0,0 +1,41 @@
+package com.microsoft.graph.auth.confidentialClient;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.apache.oltu.oauth2.common.exception.OAuthSystemException;
+import org.junit.Test;
+
+import com.microsoft.graph.auth.enums.NationalCloud;
+import com.microsoft.graph.httpcore.IAuthenticationProvider;
+
+public class ClientCredentialProviderTests {
+	public static String CLIENT_ID = "CLIENT_ID";
+	public static String SCOPE = "https://graph.microsoft.com/.default";
+	public static List<String > SCOPES = Arrays.asList(SCOPE);
+	public static String CLIENT_SECRET = "CLIENT_SECRET";
+	public static String CLIENT_ASSERTION = "CLIENT_ASSERTION";
+	public static String TENANT = "TENANT_GUID_OR_DOMAIN_NAME";
+	public static NationalCloud NATIONAL_CLOUD = NationalCloud.Global;
+	
+	@Test
+	public void createInstanceClientSecretTest() {
+		IAuthenticationProvider authenticationProvider = new ClientCredentialProvider(CLIENT_ID, SCOPES, CLIENT_SECRET, TENANT, NATIONAL_CLOUD);
+		assertNotNull(authenticationProvider);
+	}
+	
+	@Test
+	public void getTokenRequestMessageTest() throws OAuthSystemException {
+		ClientCredentialProvider authenticationProvider = new ClientCredentialProvider(CLIENT_ID, SCOPES, CLIENT_SECRET, TENANT, NATIONAL_CLOUD);
+		String expected = "grant_type=client_credentials&scope=https%3A%2F%2Fgraph.microsoft.com%2F.default+&client_secret=CLIENT_SECRET&client_id=CLIENT_ID";
+		String actual = authenticationProvider.getTokenRequestMessage().getBody();
+		String expectedLocationUri = "https://login.microsoftonline.com/TENANT_GUID_OR_DOMAIN_NAME/oauth2/v2.0/token";
+		String actualLocationUri = authenticationProvider.getTokenRequestMessage().getLocationUri();
+		assertEquals(expected, actual);
+		assertEquals(expectedLocationUri, actualLocationUri);
+	}
+	
+}