Fix issue when string parsing in proxy

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

@@ -19,9 +19,13 @@
 package io.entgra.device.mgt.core.ui.request.interceptor.util;
 
 import com.fasterxml.jackson.core.JsonFactory;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.JsonMappingException;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.google.gson.Gson;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
@@ -62,8 +66,11 @@ import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.InputStreamReader;
 import java.io.PrintWriter;
+import java.io.Reader;
 import java.math.BigInteger;
+import java.nio.charset.StandardCharsets;
 import java.security.KeyManagementException;
 import java.security.KeyStoreException;
 import java.security.NoSuchAlgorithmException;
@@ -93,10 +100,6 @@ public class HandlerUtil {
     public static ProxyResponse execute(ClassicHttpRequest httpRequest) throws IOException {
 
         try (CloseableHttpClient client = getHttpClient()) {
-
-            JsonFactory jsonFactory = new JsonFactory();
-            ObjectMapper objectMapper = new ObjectMapper(jsonFactory);
-
             return client.execute(httpRequest, response -> {
                 final HttpEntity responseEntity = response.getEntity();
                 ProxyResponse handlerResponse = new ProxyResponse();
@@ -109,8 +112,7 @@ public class HandlerUtil {
                             HandlerConstants.INTERNAL_ERROR_CODE));
                     return handlerResponse;
                 }
-                try (InputStream inputStream = responseEntity.getContent()) {
-                    JsonNode responseData = objectMapper.readTree(inputStream);
+                JsonNode responseData = getResponseData(responseEntity);
                 if (statusCode == HttpStatus.SC_OK || statusCode == HttpStatus.SC_CREATED) {
                     handlerResponse.setCode(statusCode);
                     handlerResponse.setData(responseData);
@@ -143,7 +145,6 @@ public class HandlerUtil {
                 handlerResponse
                         .setExecutorResponse(HandlerConstants.EXECUTOR_EXCEPTION_PREFIX + getStatusKey(statusCode));
                 return handlerResponse;
-                }
             });
         }
     }
@@ -748,4 +749,45 @@ public class HandlerUtil {
     public static String generateStateToken() {
         return new BigInteger(130, new SecureRandom()).toString(32);
     }
+
+    /**
+     * Get response data and convert data into a json tree
+     * @param responseEntity Incoming {@link HttpEntity}
+     * @return {@link JsonNode} consists with response data content
+     * @throws IOException Throws when IO exception encountered
+     */
+    public static JsonNode getResponseData(HttpEntity responseEntity) throws IOException {
+        JsonFactory jsonFactory = new JsonFactory();
+        ObjectMapper objectMapper = new ObjectMapper(jsonFactory);
+        JsonNode finalNode;
+        try (InputStream inputStream = responseEntity.getContent()) {
+            String content = getResponseAsString(inputStream);
+            try {
+                finalNode = objectMapper.readTree(content);
+            } catch (JsonProcessingException e) {
+                ObjectNode objectNode = objectMapper.createObjectNode();
+                objectNode.put("message", content);
+                finalNode = objectMapper.valueToTree(objectNode);
+            }
+        }
+        return finalNode;
+    }
+
+    /**
+     * Get response content as a string
+     * @param inputStream Incoming response content as a stream
+     * @return String content of the incoming response
+     * @throws IOException Throws when IO exception encountered
+     */
+    public static String getResponseAsString(InputStream inputStream) throws IOException {
+        char []buffer = new char[8192];
+        StringBuilder stringBuilder = new StringBuilder();
+        try (Reader reader = new InputStreamReader(inputStream, StandardCharsets.UTF_8)) {
+            int charsRead;
+            while ((charsRead = reader.read(buffer, 0, buffer.length)) > 0) {
+                stringBuilder.append(buffer, 0, charsRead);
+            }
+        }
+        return stringBuilder.toString();
+    }
 }