ClientCredentialProvider.java

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.AuthConstants;
import com.microsoft.graph.auth.BaseAuthentication;
import com.microsoft.graph.auth.enums.NationalCloud;
import com.microsoft.graph.authentication.IAuthenticationProvider;
import com.microsoft.graph.http.IHttpRequest;
import com.microsoft.graph.httpcore.ICoreAuthenticationProvider;

import okhttp3.Request;

public class ClientCredentialProvider extends BaseAuthentication implements IAuthenticationProvider, ICoreAuthenticationProvider{
	
	/*
	 * Client credential provider instance using client secret
	 * 
	 * @param clientId Client ID of application
	 * @param scopes Scopes that application need to access protected resources
	 * @param clientSecret Client secret of application
	 * @param tenant The tenant GUID or friendly name format or common
	 * 
	 */
	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 void authenticateRequest(IHttpRequest request) {
		String accessToken = getAcccessToken();
		request.addHeader(AuthConstants.AUTHORIZATION_HEADER, AuthConstants.BEARER + accessToken);
	}
	
	@Override
	public Request authenticateRequest(Request request) {
		String accessToken = getAcccessToken();
		return request.newBuilder().addHeader(AuthConstants.AUTHORIZATION_HEADER, AuthConstants.BEARER + accessToken).build();
	}
	
	String getAcccessToken() {
		String accessToken = "";
		try {
			long duration = System.currentTimeMillis() - getStartTime();
			if(getResponse()!=null && duration>0 && duration< getResponse().getExpiresIn()*1000) {
				accessToken = getResponse().getAccessToken();
			} else {
				OAuthClientRequest authRequest = getTokenRequestMessage();
				accessToken = getAccessTokenNewRequest(authRequest);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return accessToken;
	}
	
	/*
	 * Create the token request message
	 * 
	 * @return The token request message
	 */
	OAuthClientRequest getTokenRequestMessage() throws OAuthSystemException {
		String tokenUrl = getAuthority() + AuthConstants.TOKEN_ENDPOINT;
		TokenRequestBuilder token = OAuthClientRequest.
				tokenLocation(tokenUrl)
				.setClientId(getClientId())
				.setGrantType(GrantType.CLIENT_CREDENTIALS)
				.setScope(getScopesAsString()); 
		if(getClientSecret() != null) {
			token.setClientSecret(getClientSecret());
		}
		return token.buildBodyMessage();
	}
	
	/*
	 * Call using request to get response containing access token
	 * 
	 * @param request The request to execute
	 * @return The access token in response
	 */
	String getAccessTokenNewRequest(OAuthClientRequest request) throws OAuthSystemException, OAuthProblemException {
		OAuthClient oAuthClient = new OAuthClient(new URLConnectionClient());
		setStartTime(System.currentTimeMillis()); 
		setResponse(oAuthClient.accessToken(request)); 
		return getResponse().getAccessToken();
	}
}