Fix app manager access token creating issue

components/application-mgt/org.wso2.carbon.device.application.mgt.common/src/main/java/org/wso2/carbon/device/application/mgt/common/ProxyResponse.java

@@ -0,0 +1,42 @@
+package org.wso2.carbon.device.application.mgt.common;
+
+/* Copyright (c) 2019, Entgra (Pvt) Ltd. (http://www.entgra.io) All Rights Reserved.
+ *
+ * Entgra (Pvt) Ltd. licenses this file to you under the Apache License,
+ * Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+public class ProxyResponse {
+
+    private int code;
+    private String url;
+    private String data;
+    private String executorResponse;
+
+    public int getCode() { return code; }
+
+    public void setCode(int code) { this.code = code; }
+
+    public String getUrl() { return url; }
+
+    public void setUrl(String url) { this.url = url; }
+
+    public String getData() { return data; }
+
+    public void setData(String data) { this.data = data; }
+
+    public String getExecutorResponse() { return executorResponse; }
+
+    public void setExecutorResponse(String executorResponse) { this.executorResponse = executorResponse; }
+}

components/application-mgt/org.wso2.carbon.device.application.mgt.handler/src/main/java/org/wso2/carbon/device/application/mgt/handler/InvokerHandler.java

@@ -23,7 +23,6 @@ import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.apache.http.HttpResponse;
 import org.apache.http.HttpStatus;
 import org.apache.http.client.methods.HttpDelete;
 import org.apache.http.client.methods.HttpGet;
@@ -32,9 +31,10 @@ import org.apache.http.client.methods.HttpPut;
 import org.apache.http.client.methods.HttpRequestBase;
 import org.apache.http.entity.ContentType;
 import org.apache.http.entity.StringEntity;
+import org.wso2.carbon.device.application.mgt.common.ProxyResponse;
 import org.wso2.carbon.device.application.mgt.handler.beans.AuthData;
 import org.wso2.carbon.device.application.mgt.handler.util.HandlerConstants;
-
+import org.wso2.carbon.device.application.mgt.handler.util.HandlerUtil;
 
 import javax.servlet.annotation.MultipartConfig;
 import javax.servlet.annotation.WebServlet;
@@ -43,16 +43,12 @@ import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
 import java.io.IOException;
-import java.io.PrintWriter;
 
 import static java.net.HttpURLConnection.HTTP_BAD_REQUEST;
-import static java.net.HttpURLConnection.HTTP_INTERNAL_ERROR;
 import static java.net.HttpURLConnection.HTTP_UNAUTHORIZED;
 import static org.wso2.carbon.device.application.mgt.handler.util.HandlerUtil.execute;
-import static org.wso2.carbon.device.application.mgt.handler.util.HandlerUtil.retrieveResponseString;
 
-@MultipartConfig
+@MultipartConfig @WebServlet("/invoke")
-@WebServlet("/invoke")
 public class InvokerHandler extends HttpServlet {
     private static final Log log = LogFactory.getLog(LoginHandler.class);
     private static final long serialVersionUID = -6508020875358160165L;
@@ -60,174 +56,171 @@ public class InvokerHandler extends HttpServlet {
     private static String apiEndpoint;
     private static String method;
     private static String serverUrl;
+    private static String platform;
+
+    @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) {
+        try {
+            if (!validateRequest(req, resp)) {
+                return;
+            }
+            HttpRequestBase executor = constructExecutor(req);
+            if (executor == null) {
+                resp.sendError(HTTP_BAD_REQUEST, "Bad Request, method: " + method + " is not supported");
+                return;
+            }
+            executor.setHeader(HandlerConstants.AUTHORIZATION_HEADER_KEY, "Bearer " + authData.getAccessToken());
+
+            ProxyResponse proxyResponse = execute(executor);
+            if (HandlerConstants.TOKEN_IS_EXPIRED.equals(proxyResponse.getExecutorResponse())) {
+                if (!refreshToken(req, resp)) {
+                    return;
+                }
+                executor.setHeader(HandlerConstants.AUTHORIZATION_HEADER_KEY, "Bearer " + authData.getAccessToken());
+                proxyResponse = execute(executor);
+                if (proxyResponse.getExecutorResponse().contains(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX)) {
+                    log.error("Error occurred while invoking the API after refreshing the token.");
+                    HandlerUtil.handleError(req, resp, serverUrl, platform, proxyResponse);
+                    return;
+                }
+            }
+
+            if (proxyResponse.getExecutorResponse().contains(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX)) {
+                log.error("Error occurred while invoking the API endpoint.");
+                HandlerUtil.handleError(req, resp, serverUrl, platform, proxyResponse);
+                return;
+            }
+
+            HandlerUtil.handleSuccess(req, resp, serverUrl, platform, proxyResponse);
+
+        } catch (IOException e) {
+            log.error("Error occured when processing invoke call.", e);
+        }
+    }
+
+    /***
+     *
+     * @param req {@link HttpServletRequest}
+     * @return {@link HttpRequestBase} if method equals to either GET, POST, PUT or DELETE otherwise returns NULL.
+     */
+    private HttpRequestBase constructExecutor(HttpServletRequest req) {
+        String payload = req.getParameter("payload");
+        String contentType = req.getParameter("content-type");
+        if (contentType == null || contentType.isEmpty()) {
+            contentType = ContentType.APPLICATION_JSON.toString();
+        }
+
+        HttpRequestBase executor;
+        if (HttpGet.METHOD_NAME.equalsIgnoreCase(method)) {
+            executor = new HttpGet(serverUrl + HandlerConstants.API_COMMON_CONTEXT + apiEndpoint);
+        } else if (HttpPost.METHOD_NAME.equalsIgnoreCase(method)) {
+            executor = new HttpPost(serverUrl + HandlerConstants.API_COMMON_CONTEXT + apiEndpoint);
+            StringEntity payloadEntity = new StringEntity(payload, ContentType.create(contentType));
+            ((HttpPost) executor).setEntity(payloadEntity);
+        } else if (HttpPut.METHOD_NAME.equalsIgnoreCase(method)) {
+            executor = new HttpPut(serverUrl + HandlerConstants.API_COMMON_CONTEXT + apiEndpoint);
+            StringEntity payloadEntity = new StringEntity(payload, ContentType.create(contentType));
+            ((HttpPut) executor).setEntity(payloadEntity);
+        } else if (HttpDelete.METHOD_NAME.equalsIgnoreCase(method)) {
+            executor = new HttpDelete(serverUrl + HandlerConstants.API_COMMON_CONTEXT + apiEndpoint);
+        } else {
+            return null;
+        }
+        return executor;
+    }
+
+    /***
+     *
+     * @param req {@link HttpServletRequest}
+     * @param resp {@link HttpServletResponse}
+     * @return If request is a valid one, returns TRUE, otherwise return FALSE
+     * @throws IOException If and error occurs while witting error response to client side
+     */
+    private static boolean validateRequest(HttpServletRequest req, HttpServletResponse resp) throws IOException {
+        HttpSession session = req.getSession(false);
+        if (session == null) {
+            resp.sendError(HTTP_UNAUTHORIZED, "Unauthorized, You are not logged in. Please log in to the portal");
+            return false;
+        }
+        authData = (AuthData) session.getAttribute(HandlerConstants.SESSION_AUTH_DATA_KEY);
+        platform = (String) session.getAttribute(HandlerConstants.PLATFORM);
+        if (authData == null) {
+            resp.sendError(HTTP_UNAUTHORIZED, "Unauthorized, Access token couldn't found in the current session");
+            return false;
+        }
+
+        apiEndpoint = req.getParameter("api-endpoint");
+        method = req.getParameter("method");
+        serverUrl = req.getScheme() + "://" + req.getServerName() + ":" + req.getServerPort();
+        if (apiEndpoint == null || method == null) {
+            resp.sendError(HTTP_BAD_REQUEST, "Bad Request, Either api-endpoint or method is empty");
+            return false;
+        }
+        return true;
+    }
+
+    /***
+     *
+     * @param req {@link HttpServletRequest}
+     * @param resp {@link HttpServletResponse}
+     * @return If successfully renew tokens, returns TRUE otherwise return FALSE
+     * @throws IOException If and error occurs while witting error response to client side or invoke token renewal API
+     */
+    private static boolean refreshToken(HttpServletRequest req, HttpServletResponse resp) throws IOException {
+        log.debug("refreshing the token");
+        HttpPost tokenEndpoint = new HttpPost(
+                serverUrl + HandlerConstants.API_COMMON_CONTEXT + 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.");
+            ProxyResponse proxyResponse = new ProxyResponse();
+            proxyResponse.setCode(HttpStatus.SC_UNAUTHORIZED);
+            proxyResponse.setExecutorResponse(
+                    HandlerConstants.EXECUTOR_EXCEPTION_PREFIX + HandlerUtil.getStatusKey(HttpStatus.SC_UNAUTHORIZED));
+            HandlerUtil.handleError(req, resp, serverUrl, platform, proxyResponse);
+            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("Authorization", "Basic " + encodedClientApp);
+        tokenEndpoint.setHeader("Content-Type", ContentType.APPLICATION_FORM_URLENCODED.toString());
+
+        ProxyResponse tokenResultResponse = execute(tokenEndpoint);
+        if (tokenResultResponse.getExecutorResponse().contains(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX)) {
+            log.error("Error occurred while refreshing access token.");
+            HandlerUtil.handleError(req, resp, serverUrl, platform, 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;
+        }
 
-//    @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) {
+        log.error("Error Occurred in token renewal process.");
-//        try {
+        ProxyResponse proxyResponse = new ProxyResponse();
-//            if (!validateRequest(req, resp)) {
+        proxyResponse.setCode(HttpStatus.SC_INTERNAL_SERVER_ERROR);
-//                return;
+        proxyResponse.setExecutorResponse(
-//            }
+                HandlerConstants.EXECUTOR_EXCEPTION_PREFIX + HandlerUtil.getStatusKey(HttpStatus.SC_INTERNAL_SERVER_ERROR));
-//
+        HandlerUtil.handleError(req, resp, serverUrl, platform, proxyResponse);
-//            HttpRequestBase executor = constructExecutor(req);
+        return false;
-//            if (executor == null) {
+    }
-//                resp.sendError(HTTP_BAD_REQUEST, "Bad Request, method: " + method + " is not supported");
-//                return;
-//            }
-//            String accessToken = authData.getAccessToken();
-//            executor.setHeader("Authorization", "Bearer " + accessToken);
-//
-//            String result = execute(executor, HttpStatus.SC_OK);
-//
-////            unauthorized
-////            if (response == null) {
-////                resp.sendError(HTTP_INTERNAL_ERROR, "Empty response retried for the API call.");
-////                return;
-////            }
-//
-////            int responseCode = response.getStatusLine().getStatusCode();
-////            String result = retrieveResponseString(response);
-//
-//            if (responseCode == HttpStatus.SC_UNAUTHORIZED && (result.contains("Access token expired") || result
-//                    .contains("Invalid input. Access token validation failed"))) {
-//                if (!refreshToken(req, resp)) {
-//                    return;
-//                }
-//                response = execute(executor);
-//                if (response == null) {
-//                    resp.sendError(HTTP_INTERNAL_ERROR, "Empty response retried for the token renewal API call.");
-//                    return;
-//                }
-//                responseCode = response.getStatusLine().getStatusCode();
-//                result = retrieveResponseString(response);
-//            }
-//            if (responseCode != HttpStatus.SC_OK && responseCode != HttpStatus.SC_CREATED) {
-//                resp.sendError(responseCode, "Error response retrieved for the API call.");
-//                return;
-//            }
-//            try (PrintWriter writer = resp.getWriter()) {
-//                writer.write(result);
-//            }
-//        } catch (IOException e) {
-//            log.error("Error occured when processing invoke call.", e);
-//        }
-//    }
-//
-//    /***
-//     *
-//     * @param req {@link HttpServletRequest}
-//     * @return {@link HttpRequestBase} if method equals to either GET, POST, PUT or DELETE otherwise returns NULL.
-//     */
-//    private HttpRequestBase constructExecutor(HttpServletRequest req) {
-//        String payload = req.getParameter("payload");
-//        String contentType = req.getParameter("content-type");
-//        if (contentType == null || contentType.isEmpty()) {
-//            contentType = ContentType.APPLICATION_JSON.toString();
-//        }
-//
-//        HttpRequestBase executor;
-//        if (HttpGet.METHOD_NAME.equalsIgnoreCase(method)) {
-//            executor = new HttpGet(serverUrl + HandlerConstants.API_COMMON_CONTEXT + apiEndpoint);
-//        } else if (HttpPost.METHOD_NAME.equalsIgnoreCase(method)) {
-//            executor = new HttpPost(serverUrl + HandlerConstants.API_COMMON_CONTEXT + apiEndpoint);
-//            StringEntity payloadEntity = new StringEntity(payload, ContentType.create(contentType));
-//            ((HttpPost) executor).setEntity(payloadEntity);
-//        } else if (HttpPut.METHOD_NAME.equalsIgnoreCase(method)) {
-//            executor = new HttpPut(serverUrl + HandlerConstants.API_COMMON_CONTEXT + apiEndpoint);
-//            StringEntity payloadEntity = new StringEntity(payload, ContentType.create(contentType));
-//            ((HttpPut) executor).setEntity(payloadEntity);
-//        } else if (HttpDelete.METHOD_NAME.equalsIgnoreCase(method)) {
-//            executor = new HttpDelete(serverUrl + HandlerConstants.API_COMMON_CONTEXT + apiEndpoint);
-//        } else {
-//            return null;
-//        }
-//        return executor;
-//    }
-//
-//    /***
-//     *
-//     * @param req {@link HttpServletRequest}
-//     * @param resp {@link HttpServletResponse}
-//     * @return If request is a valid one, returns TRUE, otherwise return FALSE
-//     * @throws IOException If and error occurs while witting error response to client side
-//     */
-//    private static boolean validateRequest(HttpServletRequest req, HttpServletResponse resp) throws IOException {
-//        HttpSession session = req.getSession(false);
-//        if (session == null) {
-//            resp.sendError(HTTP_UNAUTHORIZED, "Unauthorized, You are not logged in. Please log in to the portal");
-//            return false;
-//        }
-//        authData = (AuthData) session.getAttribute(HandlerConstants.SESSION_AUTH_DATA_KEY);
-//        if (authData == null) {
-//            resp.sendError(HTTP_UNAUTHORIZED, "Unauthorized, Access token couldn't found in the current session");
-//            return false;
-//        }
-//
-//        apiEndpoint = req.getParameter("api-endpoint");
-//        method = req.getParameter("method");
-//
-//        serverUrl = req.getScheme() + "://" + req.getServerName() + ":" + req.getServerPort();
-//        if (apiEndpoint == null || method == null) {
-//            resp.sendError(HTTP_BAD_REQUEST, "Bad Request, Either api-endpoint or method is empty");
-//            return false;
-//        }
-//        return true;
-//    }
-//
-//    /***
-//     *
-//     * @param req {@link HttpServletRequest}
-//     * @param resp {@link HttpServletResponse}
-//     * @return If successfully renew tokens, returns TRUE otherwise return FALSE
-//     * @throws IOException If and error occurs while witting error response to client side or invoke token renewal API
-//     */
-//    private static boolean refreshToken(HttpServletRequest req, HttpServletResponse resp) throws IOException {
-//        log.debug("refreshing the token");
-//        HttpPost tokenEndpoint = new HttpPost(
-//                serverUrl + HandlerConstants.API_COMMON_CONTEXT + HandlerConstants.TOKEN_ENDPOINT);
-//        HttpSession session = req.getSession(false);
-//        if (session == null) {
-//            resp.sendError(HTTP_UNAUTHORIZED, "Session is expired. Please log in to the server.");
-//            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("Authorization", "Basic " + encodedClientApp);
-//        tokenEndpoint.setHeader("Content-Type", ContentType.APPLICATION_FORM_URLENCODED.toString());
-//
-//        HttpResponse response = execute(tokenEndpoint);
-//        if (response == null) {
-//            resp.sendError(HTTP_INTERNAL_ERROR,
-//                    "Internal Server Error, response of the token refresh API call is null.");
-//            return false;
-//        } else if ((response.getStatusLine().getStatusCode() != HttpStatus.SC_OK)) {
-//            resp.sendError(response.getStatusLine().getStatusCode(),
-//                    "Error occured while getting new access token by using refresh token.");
-//            return false;
-//        }
-//        String tokenResult = retrieveResponseString(response);
-//        JsonParser jsonParser = new JsonParser();
-//
-//        JsonElement jTokenResult = jsonParser.parse(tokenResult);
-//        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;
-//        }
-//        return false;
-//    }
 }

components/application-mgt/org.wso2.carbon.device.application.mgt.handler/src/main/java/org/wso2/carbon/device/application/mgt/handler/LoginHandler.java

@@ -22,16 +22,16 @@ import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
 import com.google.gson.JsonSyntaxException;
+import org.apache.commons.lang.StringUtils;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-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.entity.ContentType;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.protocol.HTTP;
-import org.wso2.carbon.device.application.mgt.common.config.UIConfiguration;
+import org.wso2.carbon.device.application.mgt.common.ProxyResponse;
 import org.wso2.carbon.device.application.mgt.handler.beans.AuthData;
 import org.wso2.carbon.device.application.mgt.handler.exceptions.LoginException;
 import org.wso2.carbon.device.application.mgt.handler.util.HandlerConstants;
@@ -50,8 +50,7 @@ import java.util.Base64;
 
 import static org.wso2.carbon.device.application.mgt.handler.util.HandlerUtil.execute;
 
-@MultipartConfig
+@MultipartConfig @WebServlet("/login")
-@WebServlet("/login")
 public class LoginHandler extends HttpServlet {
     private static final Log log = LogFactory.getLog(LoginHandler.class);
     private static final long serialVersionUID = 9050048549140517002L;
@@ -61,10 +60,8 @@ public class LoginHandler extends HttpServlet {
     private static String platform;
     private static String serverUrl;
     private static String uiConfigUrl;
-    private static JsonObject uiConfig;
 
-    @Override
+    @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) {
-    protected void doPost(HttpServletRequest req, HttpServletResponse resp) {
         try {
             validateLoginRequest(req, resp);
             DeviceManagementConfig deviceManagementConfig = DeviceConfigurationManager.getInstance()
@@ -82,25 +79,38 @@ public class LoginHandler extends HttpServlet {
 
             HttpGet uiConfigEndpoint = new HttpGet(uiConfigUrl);
             JsonParser jsonParser = new JsonParser();
-            String uiConfigJsonString = execute(uiConfigEndpoint,HttpStatus.SC_OK);
+            ProxyResponse uiConfigResponse = execute(uiConfigEndpoint);
-            if (uiConfigJsonString.contains(HandlerConstants.EXECUTOR_XCEPTIO_PRFIX)){
+            String executorResponse = uiConfigResponse.getExecutorResponse();
+            if (!StringUtils.isEmpty(executorResponse) && executorResponse
+                    .contains(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX)) {
                 log.error("Error occurred while getting UI configurations by invoking " + uiConfigUrl);
-                handleErrorResponse(resp, uiConfigJsonString);
+                HandlerUtil.handleError(req, resp, serverUrl, platform, uiConfigResponse);
+                return;
             }
 
-            JsonElement uiConfigJsonElement = jsonParser.parse(uiConfigJsonString);
+            String uiConfig = uiConfigResponse.getData();
-            JsonObject uiConfigAsJsonObject = null ;
+            if (uiConfig == null){
+                log.error("UI config retrieval is failed, and didn't find UI configuration for App manager.");
+                HandlerUtil.handleError(req, resp, serverUrl, platform, null);
+                return;
+            }
+            JsonElement uiConfigJsonElement = jsonParser.parse(uiConfigResponse.getData());
+            JsonObject uiConfigJsonObject = null;
             if (uiConfigJsonElement.isJsonObject()) {
-                uiConfigAsJsonObject = uiConfigJsonElement.getAsJsonObject();
+                uiConfigJsonObject = uiConfigJsonElement.getAsJsonObject();
+                httpSession.setAttribute(HandlerConstants.UI_CONFIG_KEY, uiConfigJsonObject);
+                httpSession.setAttribute(HandlerConstants.PLATFORM, serverUrl);
             }
-            if (uiConfigAsJsonObject == null) {
+            if (uiConfigJsonObject == null) {
-                resp.sendRedirect(serverUrl + "/" + platform + HandlerConstants.DEFAULT_ERROR_CALLBACK);
+                log.error(
+                        "Either UI config json element is not an json object or converting rom json element to json object is failed.");
+                HandlerUtil.handleError(req, resp, serverUrl, platform, null);
                 return;
             }
 
-            boolean isSsoEnable = uiConfigAsJsonObject.get("isSsoEnable").getAsBoolean();
+            boolean isSsoEnable = uiConfigJsonObject.get("isSsoEnable").getAsBoolean();
-            JsonArray tags = uiConfigAsJsonObject.get("appRegistration").getAsJsonObject().get("tags").getAsJsonArray();
+            JsonArray tags = uiConfigJsonObject.get("appRegistration").getAsJsonObject().get("tags").getAsJsonArray();
-            JsonArray scopes = uiConfigAsJsonObject.get("scopes").getAsJsonArray();
+            JsonArray scopes = uiConfigJsonObject.get("scopes").getAsJsonArray();
 
             if (isSsoEnable) {
                 log.debug("SSO is enabled");
@@ -112,18 +122,19 @@ public class LoginHandler extends HttpServlet {
                 apiRegEndpoint.setHeader(HTTP.CONTENT_TYPE, ContentType.APPLICATION_JSON.toString());
                 apiRegEndpoint.setEntity(constructAppRegPayload(tags));
 
-                String clientAppResult = execute(apiRegEndpoint, HttpStatus.SC_CREATED);
+                ProxyResponse clientAppResponse = execute(apiRegEndpoint);
+                String clientAppResult = clientAppResponse.getData();
 
-                if (!clientAppResult.isEmpty() && persistTokenInSession(req, resp, clientAppResult, scopes)) {
+                if (!StringUtils.isEmpty(clientAppResult) && getTokenAndPersistInSession(req, resp,
-                    resp.sendRedirect(
+                        clientAppResponse.getData(), scopes)) {
-                            serverUrl + "/" + platform + uiConfigAsJsonObject.get(HandlerConstants.LOGIN_RESPONSE_KEY)
+                    ProxyResponse proxyResponse = new ProxyResponse();
-                                    .getAsJsonObject().get("successCallback").getAsString());
+                    proxyResponse.setCode(HttpStatus.SC_OK);
+                    proxyResponse.setUrl(serverUrl + "/" + platform + uiConfigJsonObject.get(HandlerConstants.LOGIN_RESPONSE_KEY)
+                            .getAsJsonObject().get("successCallback").getAsString());
+                    HandlerUtil.handleSuccess(req, resp, serverUrl, platform, proxyResponse);
                     return;
                 }
-                resp.sendRedirect(
+                HandlerUtil.handleError(req, resp, serverUrl, platform, null);
-                        serverUrl + "/" + platform + uiConfigAsJsonObject.get(HandlerConstants.LOGIN_RESPONSE_KEY)
-                                .getAsJsonObject().get(HandlerConstants.FAILURE_CALLBACK_KEY).getAsJsonObject()
-                                .get(HandlerUtil.getStatusKey(HandlerConstants.INTERNAL_ERROR_CODE)).getAsString());
             }
         } catch (IOException e) {
             log.error("Error occured while sending the response into the socket. ", e);
@@ -141,11 +152,9 @@ public class LoginHandler extends HttpServlet {
      * @param scopes - scopes defied in the application-mgt.xml
      * @throws LoginException - login exception throws when getting token result
      */
-    private boolean persistTokenInSession(HttpServletRequest req, HttpServletResponse resp, String clientAppResult,
+    private boolean getTokenAndPersistInSession(HttpServletRequest req, HttpServletResponse resp,
-            JsonArray scopes) throws LoginException {
+            String clientAppResult, JsonArray scopes) throws LoginException {
         JsonParser jsonParser = new JsonParser();
-        String tokenResult;
-
         try {
             JsonElement jClientAppResult = jsonParser.parse(clientAppResult);
             if (jClientAppResult.isJsonObject()) {
@@ -155,26 +164,37 @@ public class LoginHandler extends HttpServlet {
                 String encodedClientApp = Base64.getEncoder()
                         .encodeToString((clientId + ":" + clientSecret).getBytes());
 
-                tokenResult = getTokenResult(encodedClientApp, scopes, resp);
+                ProxyResponse tokenResultResponse = getTokenResult(encodedClientApp, scopes);
 
-                if (tokenResult != null) {
+                if (tokenResultResponse.getExecutorResponse().contains(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX)) {
-                    JsonElement jTokenResult = jsonParser.parse(tokenResult);
+                    log.error("Error occurred while invoking the API to get token data.");
-                    if (jTokenResult.isJsonObject()) {
+                    HandlerUtil.handleError(req, resp, serverUrl, platform, tokenResultResponse);
-                        JsonObject jTokenResultAsJsonObject = jTokenResult.getAsJsonObject();
+                    return false;
-                        HttpSession session = req.getSession(false);
+                }
-                        if (session == null) {
+                String tokenResult = tokenResultResponse.getData();
-                            return false;
+                if (tokenResult == null){
-                        }
+                    log.error("Invalid token response is received.");
-                        AuthData authData = new AuthData();
+                    HandlerUtil.handleError(req, resp, serverUrl, platform, tokenResultResponse);
-                        authData.setClientId(clientId);
+                    return false;
-                        authData.setClientSecret(clientSecret);
+                }
-                        authData.setEncodedClientApp(encodedClientApp);
+
-                        authData.setAccessToken(jTokenResultAsJsonObject.get("access_token").getAsString());
+                JsonElement jTokenResult = jsonParser.parse(tokenResult);
-                        authData.setRefreshToken(jTokenResultAsJsonObject.get("refresh_token").getAsString());
+                if (jTokenResult.isJsonObject()) {
-                        authData.setScope(jTokenResultAsJsonObject.get("scope").getAsString());
+                    JsonObject jTokenResultAsJsonObject = jTokenResult.getAsJsonObject();
-                        session.setAttribute(HandlerConstants.SESSION_AUTH_DATA_KEY, authData);
+                    HttpSession session = req.getSession(false);
-                        return true;
+                    if (session == null) {
+                        return false;
                     }
+                    AuthData authData = new AuthData();
+                    authData.setClientId(clientId);
+                    authData.setClientSecret(clientSecret);
+                    authData.setEncodedClientApp(encodedClientApp);
+                    authData.setAccessToken(jTokenResultAsJsonObject.get("access_token").getAsString());
+                    authData.setRefreshToken(jTokenResultAsJsonObject.get("refresh_token").getAsString());
+                    authData.setScope(jTokenResultAsJsonObject.get("scope").getAsString());
+                    session.setAttribute(HandlerConstants.SESSION_AUTH_DATA_KEY, authData);
+                    return true;
+
                 }
             }
             return false;
@@ -246,50 +266,27 @@ public class LoginHandler extends HttpServlet {
      *
      * @param encodedClientApp - Base64 encoded clientId:clientSecret.
      * @param scopes - Scopes which are retrieved by reading application-mgt configuration
-     * @param resp - {@link HttpServletResponse}
      * @return Invoke token endpoint and return the response as string.
      * @throws IOException IO exception throws if an error occured when invoking token endpoint
      */
-    private String getTokenResult(String encodedClientApp, JsonArray scopes, HttpServletResponse resp)
+    private ProxyResponse getTokenResult(String encodedClientApp, JsonArray scopes) throws IOException {
-            throws IOException, LoginException {
-
-            HttpPost tokenEndpoint = new HttpPost(serverUrl + HandlerConstants.TOKEN_ENDPOINT);
-            tokenEndpoint.setHeader("Authorization", "Basic " + encodedClientApp);
-            tokenEndpoint.setHeader("Content-Type", ContentType.APPLICATION_FORM_URLENCODED.toString());
-            String scopeString = getScopeString(scopes);
-
-            if (scopeString != null) {
-                scopeString = scopeString.trim();
-            }
 
-            StringEntity tokenEPPayload = new StringEntity(
+        HttpPost tokenEndpoint = new HttpPost(serverUrl + HandlerConstants.TOKEN_ENDPOINT);
-                    "grant_type=password&username=" + username + "&password=" + password + "&scope=" + scopeString,
+        tokenEndpoint.setHeader("Authorization", "Basic " + encodedClientApp);
-                    ContentType.APPLICATION_FORM_URLENCODED);
+        tokenEndpoint.setHeader("Content-Type", ContentType.APPLICATION_FORM_URLENCODED.toString());
-            tokenEndpoint.setEntity(tokenEPPayload);
+        String scopeString = getScopeString(scopes);
 
-            String tokenResult = execute(tokenEndpoint, HttpStatus.SC_OK);
+        if (scopeString != null) {
+            scopeString = scopeString.trim();
+        } else {
+            scopeString = "default";
+        }
 
-            if (tokenResult.contains(HandlerConstants.EXECUTOR_XCEPTIO_PRFIX)) {
+        StringEntity tokenEPPayload = new StringEntity(
-                log.error("Error occurred while getting token data by invoking " + serverUrl
+                "grant_type=password&username=" + username + "&password=" + password + "&scope=" + scopeString,
-                        + HandlerConstants.TOKEN_ENDPOINT);
+                ContentType.APPLICATION_FORM_URLENCODED);
-                handleErrorResponse(resp, tokenResult);
+        tokenEndpoint.setEntity(tokenEPPayload);
-            }
-            return tokenResult;
-    }
 
-    /***
+        return execute(tokenEndpoint);
-     *
-     * @param resp {@link HttpServletResponse}
-     * corresponding error page.
-     * @throws LoginException If an {@link IOException} occurs when redirecting to corresponding error page.
-     */
-    private void handleErrorResponse(HttpServletResponse resp, String respMessage) throws LoginException {
-        try {
-            resp.sendRedirect(serverUrl + uiConfig.get(HandlerConstants.LOGIN_RESPONSE_KEY).getAsJsonObject()
-                    .get(HandlerConstants.FAILURE_CALLBACK_KEY).getAsJsonObject()
-                    .get(respMessage.split(HandlerConstants.EXECUTOR_XCEPTIO_PRFIX)[0]).getAsString());
-        } catch (IOException e) {
-            throw new LoginException("Error occured while redirecting to corresponding error page. ", e);
-        }
     }
 }

components/application-mgt/org.wso2.carbon.device.application.mgt.handler/src/main/java/org/wso2/carbon/device/application/mgt/handler/util/HandlerConstants.java

@@ -28,11 +28,16 @@ public class HandlerConstants {
     public static final String TAGS_KEY = "tags";
     public static final String APP_NAME_KEY = "applicationName";
     public static final String SESSION_AUTH_DATA_KEY = "application-mgt";
+    public static final String AUTHORIZATION_HEADER_KEY = "Authorization";
+    public static final String UI_CONFIG_KEY = "ui-config";
+    public static final String PLATFORM = "platform";
+    public static final String SERVER_HOST = "server-host";
     public static final String DEFAULT_ERROR_CALLBACK = "/pages/error/default";
     public static final String LOGIN_RESPONSE_KEY = "loginResponse";
-    public static final String FAILURE_CALLBACK_KEY = "FailureCallback";
+    public static final String FAILURE_CALLBACK_KEY = "failureCallback";
     public static final String API_COMMON_CONTEXT = "/api";
-    public static final String EXECUTOR_XCEPTIO_PRFIX = "ExecutorException-";
+    public static final String EXECUTOR_EXCEPTION_PREFIX = "ExecutorException-";
+    public static final String TOKEN_IS_EXPIRED = "ACCESS_TOKEN_IS_EXPIRED";
 
     public static final int INTERNAL_ERROR_CODE = 500;
     public static final long TIMEOUT = 300;

components/application-mgt/org.wso2.carbon.device.application.mgt.handler/src/main/java/org/wso2/carbon/device/application/mgt/handler/util/HandlerUtil.java

@@ -17,9 +17,8 @@
 
 package org.wso2.carbon.device.application.mgt.handler.util;
 
-import com.google.gson.JsonElement;
+import com.google.gson.Gson;
 import com.google.gson.JsonObject;
-import com.google.gson.JsonParser;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.http.HttpResponse;
@@ -28,16 +27,19 @@ import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPost;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClients;
-import org.wso2.carbon.device.application.mgt.handler.exceptions.LoginException;
+import org.wso2.carbon.device.application.mgt.common.ProxyResponse;
 
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.HttpSession;
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.io.PrintWriter;
 
 public class HandlerUtil {
 
     private static final Log log = LogFactory.getLog(HandlerUtil.class);
-    private static JsonObject uiConfigAsJsonObject;
 
     /***
      *
@@ -46,9 +48,9 @@ public class HandlerUtil {
      * @return response as string
      * @throws IOException IO exception returns if error occurs when executing the httpMethod
      */
-    public static <T> String execute(T httpMethod, int expectedStatusCode) throws IOException {
+    public static <T> ProxyResponse execute(T httpMethod) throws IOException {
-        HttpResponse response = null;
         try (CloseableHttpClient client = HttpClients.createDefault()) {
+            HttpResponse response = null;
             if (httpMethod instanceof HttpPost) {
                 HttpPost method = (HttpPost) httpMethod;
                 response = client.execute(method);
@@ -57,46 +59,50 @@ public class HandlerUtil {
                 response = client.execute(method);
             }
 
+            ProxyResponse proxyResponse = new ProxyResponse();
             if (response == null) {
-                return HandlerConstants.EXECUTOR_XCEPTIO_PRFIX + getStatusKey(HandlerConstants.INTERNAL_ERROR_CODE);
+                proxyResponse.setCode(HandlerConstants.INTERNAL_ERROR_CODE);
+                proxyResponse.setExecutorResponse(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX + getStatusKey(
+                        HandlerConstants.INTERNAL_ERROR_CODE));
+                return proxyResponse;
             } else {
                 int statusCode = response.getStatusLine().getStatusCode();
-                if ( statusCode != expectedStatusCode) {
+                try (BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()))) {
-                    return HandlerConstants.EXECUTOR_XCEPTIO_PRFIX + getStatusKey(statusCode);
+                    StringBuilder result = new StringBuilder();
-                } else {
+                    String line;
-                    try (BufferedReader rd = new BufferedReader(
+                    while ((line = rd.readLine()) != null) {
-                            new InputStreamReader(response.getEntity().getContent()))) {
+                        result.append(line);
-                        StringBuilder result = new StringBuilder();
+                    }
-                        String line;
+
-                        while ((line = rd.readLine()) != null) {
+                    String jsonString = result.toString();
-                            result.append(line);
+                    if (statusCode == HttpStatus.SC_OK || statusCode == HttpStatus.SC_CREATED) {
+                        proxyResponse.setCode(statusCode);
+                        proxyResponse.setData(jsonString);
+                        proxyResponse.setExecutorResponse("SUCCESS");
+                        return proxyResponse;
+                    } else if (statusCode == HttpStatus.SC_UNAUTHORIZED) {
+                        if (jsonString.contains("Access token expired") || jsonString
+                                .contains("Invalid input. Access token validation failed")) {
+                            proxyResponse.setCode(statusCode);
+                            proxyResponse.setExecutorResponse("ACCESS_TOKEN_IS_EXPIRED");
+                            return proxyResponse;
+                        } else {
+                            proxyResponse.setCode(statusCode);
+                            proxyResponse.setData(jsonString);
+                            proxyResponse.setExecutorResponse(
+                                    HandlerConstants.EXECUTOR_EXCEPTION_PREFIX + getStatusKey(statusCode));
+                            return proxyResponse;
                         }
-                        return result.toString();
                     }
+                    proxyResponse.setCode(statusCode);
+                    proxyResponse
+                            .setExecutorResponse(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX + getStatusKey(statusCode));
+                    return proxyResponse;
                 }
             }
         }
     }
 
-    /***
-     *
-     * @param response {@link HttpResponse}
-     * @return {@link String} get the response payload by using Entity of the response
-     * @throws IOException if error occurs while reading the content of the response or reading {@link BufferedReader}
-     * object
-     */
-    public static String retrieveResponseString (HttpResponse response) throws  IOException{
-        try (BufferedReader rd = new BufferedReader(
-                new InputStreamReader(response.getEntity().getContent()))) {
-            StringBuilder result = new StringBuilder();
-            String line;
-            while ((line = rd.readLine()) != null) {
-                result.append(line);
-            }
-            return result.toString();
-        }
-    }
-
     /***
      *
      * @param statusCode Provide status code, e.g:- 400, 401, 500 etc
@@ -106,28 +112,28 @@ public class HandlerUtil {
         String statusCodeKey;
 
         switch (statusCode) {
-        case 500:
+        case HttpStatus.SC_INTERNAL_SERVER_ERROR:
             statusCodeKey = "internalServerError";
             break;
-        case 400:
+        case HttpStatus.SC_BAD_REQUEST:
             statusCodeKey = "badRequest";
             break;
-        case 401:
+        case HttpStatus.SC_UNAUTHORIZED:
             statusCodeKey = "unauthorized";
             break;
-        case 403:
+        case HttpStatus.SC_FORBIDDEN:
             statusCodeKey = "forbidden";
             break;
-        case 404:
+        case HttpStatus.SC_NOT_FOUND:
             statusCodeKey = "notFound";
             break;
-        case 405:
+        case HttpStatus.SC_METHOD_NOT_ALLOWED:
             statusCodeKey = "methodNotAllowed";
             break;
-        case 406:
+        case HttpStatus.SC_NOT_ACCEPTABLE:
             statusCodeKey = "notAcceptable";
             break;
-        case 415:
+        case HttpStatus.SC_UNSUPPORTED_MEDIA_TYPE:
             statusCodeKey = "unsupportedMediaType";
             break;
         default:
@@ -137,33 +143,68 @@ public class HandlerUtil {
         return statusCodeKey;
     }
 
+
     /***
      *
-     * @param uiConfigUrl - JSON string of the UI configuration
+     * @param resp {@link HttpServletResponse}
-     * @return - True returns if UI config load is succeeded and False returns if it fails. Further, if call ie
+     * Return Error Response.
-     * succeeded assign values for uiConfigAsJsonObject static variable.
-     * @throws LoginException IO exception could occur if an error occured when invoking end point for getting UI
-     * configs
      */
-    public static JsonObject loadUiConfig(String uiConfigUrl) throws LoginException {
+    public static void handleError(HttpServletRequest req, HttpServletResponse resp, String serverUrl,
-        try {
+            String platform, ProxyResponse proxyResponse) throws IOException {
-            if (uiConfigAsJsonObject != null) {
+
-                return uiConfigAsJsonObject;
+        HttpSession httpSession = req.getSession(true);
-            }
+        Gson gson = new Gson();
-            HttpGet uiConfigEndpoint = new HttpGet(uiConfigUrl);
+        if (proxyResponse == null){
-            JsonParser jsonParser = new JsonParser();
+            proxyResponse = new ProxyResponse();
-            String uiConfig = execute(uiConfigEndpoint,HttpStatus.SC_OK);
+            proxyResponse.setCode(HttpStatus.SC_INTERNAL_SERVER_ERROR);
-
+            proxyResponse.setExecutorResponse(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX + HandlerUtil
-            JsonElement uiConfigJsonElement = jsonParser.parse(uiConfig);
+                    .getStatusKey(HandlerConstants.INTERNAL_ERROR_CODE));
-            if (uiConfigJsonElement.isJsonObject()) {
+        }
-                uiConfigAsJsonObject = uiConfigJsonElement.getAsJsonObject();
+
-                return uiConfigAsJsonObject;
+        resp.setStatus(proxyResponse.getCode());
+        resp.setContentType("application/json");
+        resp.setCharacterEncoding("UTF-8");
+
+        if (httpSession != null) {
+            JsonObject uiConfig = (JsonObject) httpSession.getAttribute(HandlerConstants.UI_CONFIG_KEY);
+            if (uiConfig == null){
+                proxyResponse.setUrl(serverUrl + "/" + platform + HandlerConstants.DEFAULT_ERROR_CALLBACK);
+            } else{
+                proxyResponse.setUrl(serverUrl + uiConfig.get(HandlerConstants.LOGIN_RESPONSE_KEY).getAsJsonObject()
+                        .get(HandlerConstants.FAILURE_CALLBACK_KEY).getAsJsonObject()
+                        .get(proxyResponse.getExecutorResponse().split(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX)[1])
+                        .getAsString());
             }
+        } else {
+            proxyResponse.setUrl(serverUrl + "/" + platform + HandlerConstants.DEFAULT_ERROR_CALLBACK);
+        }
+
+        proxyResponse.setExecutorResponse(null);
+        try (PrintWriter writer = resp.getWriter()) {
+            writer.write(gson.toJson(proxyResponse));
+        }
+    }
+
+    /***
+     *
+     * @param resp {@link HttpServletResponse}
+     * Return Success Response.
+     */
+    public static void handleSuccess(HttpServletRequest req, HttpServletResponse resp, String serverUrl,
+            String platform, ProxyResponse proxyResponse) throws IOException {
+        if (proxyResponse == null){
+            handleError(req,resp,serverUrl,platform,proxyResponse);
+            return;
+        }
 
-        } catch (IOException e) {
+        Gson gson = new Gson();
-            throw new LoginException("Error occured while getting UI configs. ", e);
+        resp.setStatus(proxyResponse.getCode());
+        resp.setContentType("application/json");
+        resp.setCharacterEncoding("UTF-8");
+        proxyResponse.setExecutorResponse(null);
+        try (PrintWriter writer = resp.getWriter()) {
+            writer.write(gson.toJson(proxyResponse));
         }
-        return null;
     }
 
 }