Merge branch 'master' into 'master'

Login cache improvements and Refresh token handling improvements

See merge request entgra/carbon-device-mgt!789

components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/config/ui/UIConfiguration.java

@@ -32,6 +32,7 @@ public class UIConfiguration {
     private List<String> scopes;
     private boolean isSsoEnable;
     private int sessionTimeOut;
+    private int loginCacheCapacity;
 
     @XmlElement(name = "AppRegistration", required=true)
     public AppRegistration getAppRegistration() {
@@ -69,4 +70,13 @@ public class UIConfiguration {
     public void setSessionTimeOut(int sessionTimeOut) {
         this.sessionTimeOut = sessionTimeOut;
     }
+
+    @XmlElement(name = "LoginCacheCapacity")
+    public int getLoginCacheCapacity() {
+        return loginCacheCapacity;
+    }
+
+    public void setLoginCacheCapacity(int loginCacheCapacity) {
+        this.loginCacheCapacity = loginCacheCapacity;
+    }
 }

components/ui-request-interceptor/io.entgra.ui.request.interceptor/src/main/java/io/entgra/ui/request/interceptor/InvokerHandler.java

@@ -18,9 +18,6 @@
 
 package io.entgra.ui.request.interceptor;
 
-import com.google.gson.JsonElement;
-import com.google.gson.JsonObject;
-import com.google.gson.JsonParser;
 import io.entgra.ui.request.interceptor.beans.AuthData;
 import io.entgra.ui.request.interceptor.util.HandlerConstants;
 import io.entgra.ui.request.interceptor.util.HandlerUtil;
@@ -43,7 +40,6 @@ import org.apache.http.client.methods.HttpRequestBase;
 import org.apache.http.cookie.SM;
 import org.apache.http.entity.ContentType;
 import org.apache.http.entity.InputStreamEntity;
-import org.apache.http.entity.StringEntity;
 import org.apache.http.entity.mime.HttpMultipartMode;
 import org.apache.http.entity.mime.MultipartEntityBuilder;
 import org.apache.http.entity.mime.content.InputStreamBody;
@@ -84,7 +80,7 @@ public class InvokerHandler extends HttpServlet {
                 ProxyResponse proxyResponse = HandlerUtil.execute(postRequest);
 
                 if (HandlerConstants.TOKEN_IS_EXPIRED.equals(proxyResponse.getExecutorResponse())) {
-                    proxyResponse = retryRequestWithRefreshedToken(req, resp, postRequest);
+                    proxyResponse = HandlerUtil.retryRequestWithRefreshedToken(req, resp, postRequest, apiEndpoint);
                     if (proxyResponse == null) {
                         return;
                     }
@@ -112,15 +108,19 @@ public class InvokerHandler extends HttpServlet {
                 getRequest.setHeader(HttpHeaders.AUTHORIZATION, HandlerConstants.BEARER + authData.getAccessToken());
                 ProxyResponse proxyResponse = HandlerUtil.execute(getRequest);
                 if (HandlerConstants.TOKEN_IS_EXPIRED.equals(proxyResponse.getExecutorResponse())) {
-                    proxyResponse = retryRequestWithRefreshedToken(req, resp, getRequest);
+                    proxyResponse = HandlerUtil.retryRequestWithRefreshedToken(req, resp, getRequest, apiEndpoint);
                     if (proxyResponse == null) {
                         return;
                     }
                 }
                 if (proxyResponse.getExecutorResponse().contains(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX)) {
-                    log.error("Error occurred while invoking the GET API endpoint.");
+                    if (proxyResponse.getCode() == HttpStatus.SC_UNAUTHORIZED) {
-                    HandlerUtil.handleError(resp, proxyResponse);
+                        proxyResponse = HandlerUtil.retryRequestWithRefreshedToken(req, resp, getRequest, apiEndpoint);
-                    return;
+                    } else {
+                        log.error("Error occurred while invoking the GET API endpoint.");
+                        HandlerUtil.handleError(resp, proxyResponse);
+                        return;
+                    }
                 }
                 HandlerUtil.handleSuccess(resp, proxyResponse);
             }
@@ -138,7 +138,7 @@ public class InvokerHandler extends HttpServlet {
                 headRequest.setHeader(HttpHeaders.AUTHORIZATION, HandlerConstants.BEARER + authData.getAccessToken());
                 ProxyResponse proxyResponse = HandlerUtil.execute(headRequest);
                 if (HandlerConstants.TOKEN_IS_EXPIRED.equals(proxyResponse.getExecutorResponse())) {
-                    proxyResponse = retryRequestWithRefreshedToken(req, resp, headRequest);
+                    proxyResponse = HandlerUtil.retryRequestWithRefreshedToken(req, resp, headRequest, apiEndpoint);
                     if (proxyResponse == null) {
                         return;
                     }
@@ -165,7 +165,7 @@ public class InvokerHandler extends HttpServlet {
                 ProxyResponse proxyResponse = HandlerUtil.execute(putRequest);
 
                 if (HandlerConstants.TOKEN_IS_EXPIRED.equals(proxyResponse.getExecutorResponse())) {
-                    proxyResponse = retryRequestWithRefreshedToken(req, resp, putRequest);
+                    proxyResponse = HandlerUtil.retryRequestWithRefreshedToken(req, resp, putRequest, apiEndpoint);
                     if (proxyResponse == null) {
                         return;
                     }
@@ -193,7 +193,7 @@ public class InvokerHandler extends HttpServlet {
                 deleteRequest.setHeader(HttpHeaders.AUTHORIZATION, HandlerConstants.BEARER + authData.getAccessToken());
                 ProxyResponse proxyResponse = HandlerUtil.execute(deleteRequest);
                 if (HandlerConstants.TOKEN_IS_EXPIRED.equals(proxyResponse.getExecutorResponse())) {
-                    proxyResponse = retryRequestWithRefreshedToken(req, resp, deleteRequest);
+                    proxyResponse = HandlerUtil.retryRequestWithRefreshedToken(req, resp, deleteRequest, apiEndpoint);
                     if (proxyResponse == null) {
                         return;
                     }
@@ -304,7 +304,7 @@ public class InvokerHandler extends HttpServlet {
             apiEndpoint = System.getProperty("iot.reporting.webapp.host");
             if (StringUtils.isBlank(apiEndpoint)){
                 log.error("Reporting Endpoint is not defined in the iot-server.sh properly.");
-                handleError(resp, HttpStatus.SC_INTERNAL_SERVER_ERROR);
+                HandlerUtil.handleError(resp, HttpStatus.SC_INTERNAL_SERVER_ERROR);
                 return false;
             }
         }
@@ -312,125 +312,22 @@ public class InvokerHandler extends HttpServlet {
         HttpSession session = req.getSession(false);
         if (session == null) {
             log.error("Unauthorized, You are not logged in. Please log in to the portal");
-            handleError(resp, HttpStatus.SC_UNAUTHORIZED);
+            HandlerUtil.handleError(resp, HttpStatus.SC_UNAUTHORIZED);
             return false;
         }
 
         authData = (AuthData) session.getAttribute(HandlerConstants.SESSION_AUTH_DATA_KEY);
         if (authData == null) {
             log.error("Unauthorized, Access token not found in the current session");
-            handleError(resp, HttpStatus.SC_UNAUTHORIZED);
+            HandlerUtil.handleError(resp, HttpStatus.SC_UNAUTHORIZED);
             return false;
         }
 
         if (req.getMethod() == null) {
             log.error("Bad Request, Request method is empty");
-            handleError(resp, HttpStatus.SC_BAD_REQUEST);
+            HandlerUtil.handleError(resp, HttpStatus.SC_BAD_REQUEST);
             return false;
         }
         return true;
     }
-
-    /**
-     * Retry request again after refreshing the access token
-     *
-     * @param req incoming {@link HttpServletRequest}
-     * @param resp resp {@link HttpServletResponse}
-     * @param httpRequest subclass of {@link HttpRequestBase} related to the current request.
-     * @return {@link ProxyResponse} if successful and <code>null</code> if failed.
-     * @throws IOException If an error occurs when try to retry the request.
-     */
-    private ProxyResponse retryRequestWithRefreshedToken(HttpServletRequest req, HttpServletResponse resp,
-                                                                HttpRequestBase httpRequest) throws IOException {
-        if (refreshToken(req, resp)) {
-            httpRequest.setHeader(HttpHeaders.AUTHORIZATION, HandlerConstants.BEARER + authData.getAccessToken());
-            ProxyResponse proxyResponse = HandlerUtil.execute(httpRequest);
-            if (proxyResponse.getExecutorResponse().contains(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX)) {
-                log.error("Error occurred while invoking the API after refreshing the token.");
-                HandlerUtil.handleError(resp, proxyResponse);
-                return null;
-            }
-            return proxyResponse;
-        }
-        return null;
-    }
-
-    /***
-     * This method is responsible to get the refresh token
-     *
-     * @param req {@link HttpServletRequest}
-     * @param resp {@link HttpServletResponse}
-     * @return If successfully renew tokens, returns TRUE otherwise return FALSE
-     * @throws IOException If an error occurs while witting error response to client side or invoke token renewal API
-     */
-    private static boolean refreshToken(HttpServletRequest req, HttpServletResponse resp)
-            throws IOException {
-        if (log.isDebugEnabled()) {
-            log.debug("refreshing the token");
-        }
-        HttpPost tokenEndpoint = new HttpPost(
-                apiEndpoint + HandlerConstants.TOKEN_ENDPOINT);
-        HttpSession session = req.getSession(false);
-        if (session == null) {
-            log.error("Couldn't find a session, hence it is required to login and proceed.");
-            handleError(resp, HttpStatus.SC_UNAUTHORIZED);
-            return false;
-        }
-
-        StringEntity tokenEndpointPayload = new StringEntity(
-                "grant_type=refresh_token&refresh_token=" + authData.getRefreshToken() + "&scope=PRODUCTION",
-                ContentType.APPLICATION_FORM_URLENCODED);
-
-        tokenEndpoint.setEntity(tokenEndpointPayload);
-        String encodedClientApp = authData.getEncodedClientApp();
-        tokenEndpoint.setHeader(HttpHeaders.AUTHORIZATION, HandlerConstants.BASIC +
-                                             encodedClientApp);
-        tokenEndpoint.setHeader(HttpHeaders.CONTENT_TYPE, ContentType.APPLICATION_FORM_URLENCODED.toString());
-
-        ProxyResponse tokenResultResponse = HandlerUtil.execute(tokenEndpoint);
-        if (tokenResultResponse.getExecutorResponse().contains(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX)) {
-            log.error("Error occurred while refreshing access token.");
-            HandlerUtil.handleError(resp, tokenResultResponse);
-            return false;
-        }
-
-        JsonParser jsonParser = new JsonParser();
-        JsonElement jTokenResult = jsonParser.parse(tokenResultResponse.getData());
-
-        if (jTokenResult.isJsonObject()) {
-            JsonObject jTokenResultAsJsonObject = jTokenResult.getAsJsonObject();
-            AuthData newAuthData = new AuthData();
-
-            newAuthData.setAccessToken(jTokenResultAsJsonObject.get("access_token").getAsString());
-            newAuthData.setRefreshToken(jTokenResultAsJsonObject.get("refresh_token").getAsString());
-            newAuthData.setScope(jTokenResultAsJsonObject.get("scope").getAsString());
-            newAuthData.setClientId(authData.getClientId());
-            newAuthData.setClientSecret(authData.getClientSecret());
-            newAuthData.setEncodedClientApp(authData.getEncodedClientApp());
-            newAuthData.setUsername(authData.getUsername());
-            authData = newAuthData;
-            session.setAttribute(HandlerConstants.SESSION_AUTH_DATA_KEY, newAuthData);
-            return true;
-        }
-
-        log.error("Error Occurred in token renewal process.");
-        handleError(resp, HttpStatus.SC_INTERNAL_SERVER_ERROR);
-        return false;
-    }
-
-    /**
-     * Handle error requests
-     *
-     * @param resp {@link HttpServletResponse}
-     * @param errorCode HTTP error status code
-     * @throws IOException If error occurred when trying to send the error response.
-     */
-    private static void handleError(HttpServletResponse resp, int errorCode)
-            throws IOException {
-        ProxyResponse proxyResponse = new ProxyResponse();
-        proxyResponse.setCode(errorCode);
-        proxyResponse.setExecutorResponse(
-                HandlerConstants.EXECUTOR_EXCEPTION_PREFIX + HandlerUtil.getStatusKey(errorCode));
-        HandlerUtil.handleError(resp, proxyResponse);
-    }
 }

components/ui-request-interceptor/io.entgra.ui.request.interceptor/src/main/java/io/entgra/ui/request/interceptor/LoginHandler.java

@@ -24,7 +24,7 @@ import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
 import com.google.gson.JsonSyntaxException;
 import io.entgra.ui.request.interceptor.beans.AuthData;
-import io.entgra.ui.request.interceptor.cache.LoginCacheManager;
+import io.entgra.ui.request.interceptor.cache.LoginCache;
 import io.entgra.ui.request.interceptor.cache.OAuthApp;
 import io.entgra.ui.request.interceptor.cache.OAuthAppCacheKey;
 import io.entgra.ui.request.interceptor.exceptions.LoginException;
@@ -39,7 +39,6 @@ import org.apache.http.entity.ContentType;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.protocol.HTTP;
 import io.entgra.ui.request.interceptor.beans.ProxyResponse;
-import org.json.JSONString;
 
 import javax.servlet.annotation.MultipartConfig;
 import javax.servlet.annotation.WebServlet;
@@ -80,10 +79,9 @@ public class LoginHandler extends HttpServlet {
             httpSession.setMaxInactiveInterval(sessionTimeOut);
 
             // Check if OAuth app cache exists. If not create a new application.
-            LoginCacheManager loginCacheManager = new LoginCacheManager();
+            LoginCache loginCache = HandlerUtil.getLoginCache(httpSession);
-            loginCacheManager.initializeCacheManager();
             OAuthAppCacheKey oAuthAppCacheKey = new OAuthAppCacheKey(HandlerConstants.PUBLISHER_APPLICATION_NAME, username);
-            OAuthApp oAuthApp = loginCacheManager.getOAuthAppCache(oAuthAppCacheKey);
+            OAuthApp oAuthApp = loginCache.getOAuthAppCache(oAuthAppCacheKey);
 
             if (oAuthApp == null) {
                 HttpPost apiRegEndpoint = new HttpPost(gatewayUrl + HandlerConstants.APP_REG_ENDPOINT);
@@ -111,8 +109,6 @@ public class LoginHandler extends HttpServlet {
                         clientSecret = jClientAppResultAsJsonObject.get("client_secret").getAsString();
                         encodedClientApp = Base64.getEncoder()
                                 .encodeToString((clientId + HandlerConstants.COLON + clientSecret).getBytes());
-
-                        oAuthAppCacheKey = new OAuthAppCacheKey(HandlerConstants.PUBLISHER_APPLICATION_NAME, username);
                         oAuthApp = new OAuthApp(
                                 HandlerConstants.PUBLISHER_APPLICATION_NAME,
                                 username,
@@ -120,7 +116,7 @@ public class LoginHandler extends HttpServlet {
                                 clientSecret,
                                 encodedClientApp
                         );
-                        loginCacheManager.addOAuthAppToCache(oAuthAppCacheKey, oAuthApp);
+                        loginCache.addOAuthAppToCache(oAuthAppCacheKey, oAuthApp);
                     }
 
                     if (getTokenAndPersistInSession(req, resp, clientId, clientSecret, encodedClientApp, scopes)) {

components/ui-request-interceptor/io.entgra.ui.request.interceptor/src/main/java/io/entgra/ui/request/interceptor/SsoLoginHandler.java

@@ -23,7 +23,7 @@ import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
 import com.google.gson.JsonSyntaxException;
-import io.entgra.ui.request.interceptor.cache.LoginCacheManager;
+import io.entgra.ui.request.interceptor.cache.LoginCache;
 import io.entgra.ui.request.interceptor.cache.OAuthApp;
 import io.entgra.ui.request.interceptor.cache.OAuthAppCacheKey;
 import io.entgra.ui.request.interceptor.util.HandlerConstants;
@@ -81,9 +81,9 @@ public class SsoLoginHandler extends HttpServlet {
 
     private JsonObject uiConfigJsonObject;
     private HttpSession httpSession;
-
+    private LoginCache loginCache;
-    private LoginCacheManager loginCacheManager;
     private OAuthApp oAuthApp;
+    private OAuthAppCacheKey oAuthAppCacheKey;
 
     @Override
     protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
@@ -99,13 +99,23 @@ public class SsoLoginHandler extends HttpServlet {
             baseContextPath = req.getContextPath();
             applicationName = baseContextPath.substring(1, baseContextPath.indexOf("-ui-request-handler"));
 
-            // Check if oauth app cache is available
+            String iotsCorePort = System.getProperty(HandlerConstants.IOT_CORE_HTTPS_PORT_ENV_VAR);
-            loginCacheManager = new LoginCacheManager();
+            if (HandlerConstants.HTTP_PROTOCOL.equals(req.getScheme())) {
-            loginCacheManager.initializeCacheManager();
+                iotsCorePort = System.getProperty(HandlerConstants.IOT_CORE_HTTP_PORT_ENV_VAR);
-            oAuthApp = loginCacheManager.getOAuthAppCache(
+            }
-                    new OAuthAppCacheKey(applicationName, adminUsername)
+            gatewayUrl = req.getScheme() + HandlerConstants.SCHEME_SEPARATOR + System.getProperty(HandlerConstants.IOT_GW_HOST_ENV_VAR)
-            );
+                    + HandlerConstants.COLON + HandlerUtil.getGatewayPort(req.getScheme());
+            iotsCoreUrl = req.getScheme() + HandlerConstants.SCHEME_SEPARATOR + System.getProperty(HandlerConstants.IOT_CORE_HOST_ENV_VAR)
+                    + HandlerConstants.COLON + iotsCorePort;
+
+            // Fetch ui config and persists in session
+            String uiConfigUrl = iotsCoreUrl + HandlerConstants.UI_CONFIG_ENDPOINT;
+            uiConfigJsonObject = HandlerUtil.getUIConfigAndPersistInSession(uiConfigUrl, gatewayUrl, httpSession, resp);
 
+            // Retrieving login cache and do a DCR if the cache is not available.
+            loginCache = HandlerUtil.getLoginCache(httpSession);
+            oAuthAppCacheKey = new OAuthAppCacheKey(applicationName, adminUsername);
+            oAuthApp = loginCache.getOAuthAppCache(oAuthAppCacheKey);
             if (oAuthApp == null) {
                 dynamicClientRegistration(req, resp);
             }
@@ -143,19 +153,6 @@ public class SsoLoginHandler extends HttpServlet {
      */
     private void dynamicClientRegistration(HttpServletRequest req, HttpServletResponse resp) {
         try {
-            String iotsCorePort = System.getProperty(HandlerConstants.IOT_CORE_HTTPS_PORT_ENV_VAR);
-
-            if (HandlerConstants.HTTP_PROTOCOL.equals(req.getScheme())) {
-                iotsCorePort = System.getProperty(HandlerConstants.IOT_CORE_HTTP_PORT_ENV_VAR);
-            }
-
-            gatewayUrl = req.getScheme() + HandlerConstants.SCHEME_SEPARATOR + System.getProperty(HandlerConstants.IOT_GW_HOST_ENV_VAR)
-                    + HandlerConstants.COLON + HandlerUtil.getGatewayPort(req.getScheme());
-            iotsCoreUrl = req.getScheme() + HandlerConstants.SCHEME_SEPARATOR + System.getProperty(HandlerConstants.IOT_CORE_HOST_ENV_VAR)
-                    + HandlerConstants.COLON + iotsCorePort;
-            String uiConfigUrl = iotsCoreUrl + HandlerConstants.UI_CONFIG_ENDPOINT;
-
-            uiConfigJsonObject = HandlerUtil.getUIConfigAndPersistInSession(uiConfigUrl, gatewayUrl, httpSession, resp);
             JsonArray tags = uiConfigJsonObject.get("appRegistration").getAsJsonObject().get("tags").getAsJsonArray();
             JsonArray scopes = uiConfigJsonObject.get("scopes").getAsJsonArray();
             sessionTimeOut = Integer.parseInt(String.valueOf(uiConfigJsonObject.get("sessionTimeOut")));
@@ -191,9 +188,8 @@ public class SsoLoginHandler extends HttpServlet {
                 }
 
                 // cache the oauth app credentials
-                OAuthAppCacheKey oAuthAppCacheKey = new OAuthAppCacheKey(applicationName, adminUsername);
                 oAuthApp = new OAuthApp(applicationName, adminUsername, clientId, clientSecret, encodedClientApp);
-                loginCacheManager.addOAuthAppToCache(oAuthAppCacheKey, oAuthApp);
+                loginCache.addOAuthAppToCache(oAuthAppCacheKey, oAuthApp);
             }
 
             // Get the details of the registered application

components/ui-request-interceptor/io.entgra.ui.request.interceptor/src/main/java/io/entgra/ui/request/interceptor/UserHandler.java

@@ -76,9 +76,13 @@ public class UserHandler extends HttpServlet {
             ProxyResponse tokenStatus = HandlerUtil.execute(tokenEndpoint);
 
             if (tokenStatus.getExecutorResponse().contains(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX)) {
-                log.error("Error occurred while invoking the API to get token status.");
+                if (tokenStatus.getCode() == HttpStatus.SC_UNAUTHORIZED) {
-                HandlerUtil.handleError(resp, tokenStatus);
+                    tokenStatus = HandlerUtil.retryRequestWithRefreshedToken(req, resp, tokenEndpoint, serverUrl);
-                return;
+                } else {
+                    log.error("Error occurred while invoking the API to get token status.");
+                    HandlerUtil.handleError(resp, tokenStatus);
+                    return;
+                }
             }
             String tokenData = tokenStatus.getData();
             if (tokenData == null) {

components/ui-request-interceptor/io.entgra.ui.request.interceptor/src/main/java/io/entgra/ui/request/interceptor/cache/LoginCache.java

@@ -18,25 +18,19 @@
 
 package io.entgra.ui.request.interceptor.cache;
 
-import io.entgra.ui.request.interceptor.util.HandlerConstants;
+import java.util.LinkedHashMap;
-
-import javax.cache.Cache;
-import javax.cache.CacheManager;
-import javax.cache.Caching;
 
 /**
  * Contains necessary functions to manage oAuth app cache during login handling
  */
-public class LoginCacheManager {
+public class LoginCache {
 
-    private CacheManager cacheManager = null;
+    private final LinkedHashMap<OAuthAppCacheKey, OAuthApp> cache;
-    private Cache<OAuthAppCacheKey, OAuthApp> cache = null;
+    private final int capacity;
 
-    /**
+    public LoginCache(int capacity) {
-     * Initialize the cache manager if it is not already initialized
+        this.capacity = capacity;
-     */
+        this.cache = new LinkedHashMap<>(capacity);
-    public void initializeCacheManager() {
-        cacheManager = Caching.getCacheManagerFactory().getCacheManager(HandlerConstants.LOGIN_CACHE);
     }
 
     /**
@@ -46,7 +40,9 @@ public class LoginCacheManager {
      * @param oAuthApp         - The value of the cache which contains OAuth app data
      */
     public void addOAuthAppToCache(OAuthAppCacheKey oAuthAppCacheKey, OAuthApp oAuthApp) {
-        cache = cacheManager.getCache(HandlerConstants.LOGIN_CACHE);
+        if (cache.size() == capacity) {
+            cache.remove(cache.entrySet().iterator().next().getKey());
+        }
         cache.put(oAuthAppCacheKey, oAuthApp);
     }
 
@@ -57,7 +53,13 @@ public class LoginCacheManager {
      * @return - Returns OAuthApp object
      */
     public OAuthApp getOAuthAppCache(OAuthAppCacheKey oAuthAppCacheKey) {
-        cache = cacheManager.getCache(HandlerConstants.LOGIN_CACHE);
+        OAuthApp oAuthApp = cache.get(oAuthAppCacheKey);
-        return cache.get(oAuthAppCacheKey);
+        if (oAuthApp != null) {
+            if (cache.size() == capacity) {
+                cache.remove(oAuthAppCacheKey);
+                cache.put(oAuthAppCacheKey, oAuthApp);
+            }
+        }
+        return oAuthApp;
     }
 }

components/ui-request-interceptor/io.entgra.ui.request.interceptor/src/main/java/io/entgra/ui/request/interceptor/util/HandlerConstants.java

@@ -55,7 +55,7 @@ public class HandlerConstants {
     public static final String PASSWORD_GRANT_TYPE = "password";
     public static final String JWT_BEARER_GRANT_TYPE = "urn:ietf:params:oauth:grant-type:jwt-bearer";
     public static final String PRODUCTION_KEY = "PRODUCTION";
-    public static final String LOGIN_CACHE = "LOGIN_CACHE";
+    public static final String LOGIN_CACHE_CAPACITY_KEY = "loginCacheCapacity";
 
     public static final String SCHEME_SEPARATOR = "://";
     public static final String COLON = ":";

components/ui-request-interceptor/io.entgra.ui.request.interceptor/src/main/java/io/entgra/ui/request/interceptor/util/HandlerUtil.java

@@ -23,13 +23,17 @@ import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
+import io.entgra.ui.request.interceptor.beans.AuthData;
+import io.entgra.ui.request.interceptor.cache.LoginCache;
 import org.apache.commons.lang.StringUtils;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.http.Consts;
+import org.apache.http.HttpHeaders;
 import org.apache.http.HttpResponse;
 import org.apache.http.HttpStatus;
 import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpPost;
 import org.apache.http.client.methods.HttpRequestBase;
 import org.apache.http.conn.ssl.NoopHostnameVerifier;
 import org.apache.http.entity.ContentType;
@@ -60,6 +64,9 @@ import java.io.StringWriter;
 public class HandlerUtil {
 
     private static final Log log = LogFactory.getLog(HandlerUtil.class);
+    private static LoginCache loginCache = null;
+    private static boolean isLoginCacheInitialized = false;
+    private static AuthData authData;
 
     /***
      *
@@ -166,9 +173,11 @@ public class HandlerUtil {
 
 
     /***
+     * Handle error requests.
      *
      * @param resp {@link HttpServletResponse}
-     * Return Error Response.
+     * @param proxyResponse {@link ProxyResponse}
+     * @throws IOException If error occurred when trying to send the error response.
      */
     public static void handleError(HttpServletResponse resp, ProxyResponse proxyResponse) throws IOException {
         Gson gson = new Gson();
@@ -188,6 +197,22 @@ public class HandlerUtil {
         }
     }
 
+    /**
+     * Handle error requests with custom error codes.
+     *
+     * @param resp {@link HttpServletResponse}
+     * @param errorCode HTTP error status code
+     * @throws IOException If error occurred when trying to send the error response.
+     */
+    public static void handleError(HttpServletResponse resp, int errorCode)
+            throws IOException {
+        ProxyResponse proxyResponse = new ProxyResponse();
+        proxyResponse.setCode(errorCode);
+        proxyResponse.setExecutorResponse(
+                HandlerConstants.EXECUTOR_EXCEPTION_PREFIX + HandlerUtil.getStatusKey(errorCode));
+        HandlerUtil.handleError(resp, proxyResponse);
+    }
+
     /***
      *
      * @param resp {@link HttpServletResponse}
@@ -400,4 +425,136 @@ public class HandlerUtil {
 
         return stringOutput;
     }
+
+    /***
+     * Search a key from a given json string object.
+     *
+     * @param jsonObjectString - json object in string format.
+     * @param key - the key to be searched.
+     * @return string value of the key value.
+     */
+    private static String searchFromJsonObjectString(String jsonObjectString, String key) {
+        JsonParser jsonParser = new JsonParser();
+        JsonElement jsonElement = jsonParser.parse(jsonObjectString);
+        JsonObject jsonObject = jsonElement.getAsJsonObject();
+        return jsonObject.get(key).getAsString();
+    }
+
+    /***
+     * Initializes the login cache.
+     *
+     * @param httpSession - current active HttpSession.
+     */
+    private static void initializeLoginCache(HttpSession httpSession) {
+        String uiConfig = httpSession.getAttribute(HandlerConstants.UI_CONFIG_KEY).toString();
+        int capacity = Integer.parseInt(searchFromJsonObjectString(uiConfig, HandlerConstants.LOGIN_CACHE_CAPACITY_KEY));
+        loginCache = new LoginCache(capacity);
+    }
+
+    /***
+     * Retrieves login cache and initializes if its not done already.
+     *
+     * @param httpSession - current active HttpSession.
+     */
+    public static LoginCache getLoginCache(HttpSession httpSession) {
+        if (!isLoginCacheInitialized || loginCache == null) {
+            isLoginCacheInitialized = true;
+            initializeLoginCache(httpSession);
+        }
+        return loginCache;
+    }
+
+    /**
+     * Retry request again after refreshing the access token
+     *
+     * @param req incoming {@link HttpServletRequest}
+     * @param resp resp {@link HttpServletResponse}
+     * @param httpRequest subclass of {@link HttpRequestBase} related to the current request.
+     * @return {@link ProxyResponse} if successful and <code>null</code> if failed.
+     * @throws IOException If an error occurs when try to retry the request.
+     */
+    public static ProxyResponse retryRequestWithRefreshedToken(HttpServletRequest req, HttpServletResponse resp,
+                                                               HttpRequestBase httpRequest, String apiEndpoint) throws IOException {
+        if (refreshToken(req, resp, apiEndpoint)) {
+            HttpSession session = req.getSession(false);
+            if (session == null) {
+                log.error("Unauthorized, You are not logged in. Please log in to the portal");
+                handleError(resp, HttpStatus.SC_UNAUTHORIZED);
+                return null;
+            }
+            httpRequest.setHeader(HttpHeaders.AUTHORIZATION, HandlerConstants.BEARER + authData.getAccessToken());
+            ProxyResponse proxyResponse = HandlerUtil.execute(httpRequest);
+            if (proxyResponse.getExecutorResponse().contains(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX)) {
+                log.error("Error occurred while invoking the API after refreshing the token.");
+                HandlerUtil.handleError(resp, proxyResponse);
+                return null;
+            }
+            return proxyResponse;
+        }
+        return null;
+    }
+
+    /***
+     * This method is responsible to get the refresh token
+     *
+     * @param req {@link HttpServletRequest}
+     * @param resp {@link HttpServletResponse}
+     * @return If successfully renew tokens, returns TRUE otherwise return FALSE
+     * @throws IOException If an error occurs while witting error response to client side or invoke token renewal API
+     */
+    private static boolean refreshToken(HttpServletRequest req, HttpServletResponse resp, String gatewayUrl)
+            throws IOException {
+        if (log.isDebugEnabled()) {
+            log.debug("refreshing the token");
+        }
+        HttpPost tokenEndpoint = new HttpPost(
+                gatewayUrl + HandlerConstants.TOKEN_ENDPOINT);
+        HttpSession session = req.getSession(false);
+        if (session == null) {
+            log.error("Couldn't find a session, hence it is required to login and proceed.");
+            handleError(resp, HttpStatus.SC_UNAUTHORIZED);
+            return false;
+        }
+
+        authData = (AuthData) session.getAttribute(HandlerConstants.SESSION_AUTH_DATA_KEY);
+        StringEntity tokenEndpointPayload = new StringEntity(
+                "grant_type=refresh_token&refresh_token=" + authData.getRefreshToken() + "&scope=PRODUCTION",
+                ContentType.APPLICATION_FORM_URLENCODED);
+
+        tokenEndpoint.setEntity(tokenEndpointPayload);
+        String encodedClientApp = authData.getEncodedClientApp();
+        tokenEndpoint.setHeader(HttpHeaders.AUTHORIZATION, HandlerConstants.BASIC +
+                encodedClientApp);
+        tokenEndpoint.setHeader(HttpHeaders.CONTENT_TYPE, ContentType.APPLICATION_FORM_URLENCODED.toString());
+
+        ProxyResponse tokenResultResponse = HandlerUtil.execute(tokenEndpoint);
+        if (tokenResultResponse.getExecutorResponse().contains(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX)) {
+            log.error("Error occurred while refreshing access token.");
+            HandlerUtil.handleError(resp, tokenResultResponse);
+            return false;
+        }
+
+        JsonParser jsonParser = new JsonParser();
+        JsonElement jTokenResult = jsonParser.parse(tokenResultResponse.getData());
+
+        if (jTokenResult.isJsonObject()) {
+            JsonObject jTokenResultAsJsonObject = jTokenResult.getAsJsonObject();
+            AuthData newAuthData = new AuthData();
+
+            newAuthData.setAccessToken(jTokenResultAsJsonObject.get("access_token").getAsString());
+            newAuthData.setRefreshToken(jTokenResultAsJsonObject.get("refresh_token").getAsString());
+            newAuthData.setScope(jTokenResultAsJsonObject.get("scope").getAsString());
+            newAuthData.setClientId(authData.getClientId());
+            newAuthData.setClientSecret(authData.getClientSecret());
+            newAuthData.setEncodedClientApp(authData.getEncodedClientApp());
+            newAuthData.setUsername(authData.getUsername());
+            authData = newAuthData;
+            session.setAttribute(HandlerConstants.SESSION_AUTH_DATA_KEY, newAuthData);
+            return true;
+        }
+
+        log.error("Error Occurred in token renewal process.");
+        handleError(resp, HttpStatus.SC_INTERNAL_SERVER_ERROR);
+        return false;
+    }
 }

features/device-mgt/org.wso2.carbon.device.mgt.basics.feature/src/main/resources/conf/mdm-ui-config.xml

@@ -22,6 +22,8 @@
     <EnableSSO>true</EnableSSO>
     <!-- session time out in seconds -->
     <SessionTimeOut>3600</SessionTimeOut>
+    <!--  maximum number of login cache entries  -->
+    <LoginCacheCapacity>10000</LoginCacheCapacity>
     <AppRegistration>
         <Tags>
             <Tag>application_management</Tag>