[Issue #193] Integrate OAuth2 Authentication into Core Repository

core/src/main/java/org/jsmart/zerocode/core/httpclient/oauth2/OAuth2HttpClient.java

@@ -0,0 +1,83 @@
+package org.jsmart.zerocode.core.httpclient.oauth2;
+
+import java.util.Map;
+import java.util.Timer;
+
+import org.jsmart.zerocode.core.httpclient.BasicHttpClient;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.inject.Inject;
+import com.google.inject.name.Named;
+
+import org.apache.http.client.methods.RequestBuilder;
+
+/**
+ * @author santhoshTpixler
+ *
+ */
+
+
+/*
+ * Note: This implementation supports the OAuth2.0 with refresh_token
+ * 
+ * Reference: https://tools.ietf.org/html/rfc6749#page-11
+ * 
+ * 
+ *  1. The refresh_token, access_token URL, client_id and client_secret
+ *  	should be generated by the user and stored in the properties file 
+ *  	mentioned in the @TargetEnv("host.properties").
+ *  2. For generating the refresh token REST Client such as Insomnia (https://insomnia.rest/) can 
+ *  	be used. 
+ *  
+ *  Note: Postman cannot be used as it does not show the refresh token.
+ */
+public class OAuth2HttpClient extends BasicHttpClient {
+
+	private static final Logger LOGGER = LoggerFactory.getLogger(OAuth2HttpClient.class);
+
+	/*
+	 * Properties to be fetched from the host.properties
+	 */
+	private static final String CLIENT_ID = "client_id";
+	private static final String CLIENT_SECRET = "client_secret";
+	private static final String REFRESH_TOKEN = "refresh_token";
+	private static final String ACCOUNTS_URL = "accounts_url";
+
+	/*
+	 * If the Authorization header contains the replacement value as specified by the 
+	 * below constant, then it is replaced with the valid access token
+	 */
+	private static final String ACCESS_TOKEN_REPLACEMENT_VALUE = "DIY";
+	/*
+	 * Time interval in which the accessToken should be renewed
+	 */
+	private static final long REFRESH_INTERVAL = 3540000;
+
+	private OAuth2Impl oauth2 = null;
+
+	@Inject
+	public OAuth2HttpClient(@Named(CLIENT_ID) String clientId, @Named(CLIENT_SECRET) String clientSecret,
+			@Named(REFRESH_TOKEN) String refreshToken, @Named(ACCOUNTS_URL) String accountsURL) {
+		this.oauth2 = new OAuth2Impl(clientId, clientSecret, refreshToken, accountsURL);
+		Timer timer = new Timer();
+		timer.schedule(oauth2, 0, REFRESH_INTERVAL);
+		synchronized (oauth2) {
+			try {
+				oauth2.wait();
+			} catch (InterruptedException e) {
+				Thread.currentThread().interrupt();
+			}
+		}
+	}
+
+	@Override
+	public RequestBuilder handleHeaders(Map<String, Object> headers, RequestBuilder requestBuilder) {
+		String authorization = (String) headers.get("Authorization");
+		if (authorization != null && authorization.equals(ACCESS_TOKEN_REPLACEMENT_VALUE)) {
+			headers.put("Authorization", oauth2.getAccessToken());
+			LOGGER.info("Token injected into header.");
+		}
+		return super.handleHeaders(headers, requestBuilder);
+	}
+}

core/src/main/java/org/jsmart/zerocode/core/httpclient/oauth2/OAuth2Impl.java

@@ -0,0 +1,108 @@
+package org.jsmart.zerocode.core.httpclient.oauth2;
+
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.TimerTask;
+
+import org.apache.http.NameValuePair;
+import org.apache.http.client.entity.UrlEncodedFormEntity;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClients;
+import org.apache.http.message.BasicNameValuePair;
+import org.json.JSONObject;
+import org.json.JSONTokener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * @author santhoshTpixler
+ *
+ */
+
+/*
+ * Note: This implementation supports the OAuth2.0 with refresh_token
+ * 
+ * Reference: https://tools.ietf.org/html/rfc6749#page-11
+ */
+public class OAuth2Impl extends TimerTask {
+	private String clienId;
+	private String clientSecret;
+	private String refreshToken;
+	private String accessTokenURL;
+
+	private String accessToken;
+	private static final Logger LOGGER = LoggerFactory.getLogger(OAuth2Impl.class);
+
+	public OAuth2Impl(String clientId, String clientSecret, String refreshToken, String accountsUrl) {
+		this.clienId = clientId;
+		this.clientSecret = clientSecret;
+		this.refreshToken = refreshToken;
+		this.accessTokenURL = accountsUrl;
+	}
+
+	@Override
+	public void run() {
+		generateToken();
+	}
+
+	public synchronized String getAccessToken() {
+		return accessToken;
+
+	}
+
+	private synchronized void setAccessToken(String token) {
+		this.accessToken = "Bearer " + token;
+	}
+
+	/**
+	 * Makes a POST request to the accessTokenURL to fetch the accesstoken
+	 */
+	private synchronized void generateToken() {
+		try (CloseableHttpClient client = HttpClients.createDefault()) {
+
+
+			StringBuilder URL = new StringBuilder(accessTokenURL);
+			URL.append('?');
+			URL.append("refresh_token=" + refreshToken);
+			URL.append("&client_id=" + clienId);;
+			URL.append("&client_secret=" + clientSecret);
+			URL.append("&grant_type=refresh_token");
+			HttpPost post = new HttpPost(URL.toString());
+
+
+			/*
+			 * Below code was not compatible with simulator. In production kindly make 
+			 * use of the below code.
+			 */
+
+			/*
+			 * List<NameValuePair> nameValuePairs = new ArrayList<>(4);
+			 * nameValuePairs.add(new BasicNameValuePair("refresh_token", refreshToken));
+			 * nameValuePairs.add(new BasicNameValuePair("client_secret", clientSecret));
+			 * nameValuePairs.add(new BasicNameValuePair("client_id", clienId));
+			 * nameValuePairs.add(new BasicNameValuePair("grant_type", "refresh_token"));
+			 * post.setEntity(new UrlEncodedFormEntity(nameValuePairs));
+			 */
+
+			JSONObject jsonRespone = null;
+			try (CloseableHttpResponse response = client.execute(post);) {
+				try (InputStream stream = response.getEntity().getContent()) {
+					jsonRespone = new JSONObject(new JSONTokener(stream));
+				}
+			}
+			if (accessToken == null) {
+				setAccessToken(jsonRespone.getString("access_token"));
+				this.notifyAll();
+			} else {
+				setAccessToken(jsonRespone.getString("access_token"));
+			}
+		} catch (Exception e) {
+			LOGGER.error("Cannot fetch access token from IAM", e);
+		}
+
+	}
+
+}