[ZEPPELIN-6366] Separate WebSocket max message size into a dedicated REST API

### What is this PR for?
Currently, configuration data is fetched through both REST API and WebSocket channels. However, the WebSocket path does not perform permission checks, and the only required data from it is the WebSocket max message size. 

I extracted the websocket max message size field into a dedicated REST API, to improve security and simplify configuration handling.

### What type of PR is it?
Improvement

### Todos
* [ ] #5060

### What is the Jira issue?
* Open an issue on Jira https://issues.apache.org/jira/browse/ZEPPELIN/6366

### How should this be tested?
- Check the configuration page (/configuration)
- Check the notebook page (/notebook/{notebook_id})

### Screenshots (if appropriate)

### Questions:
* Does the license files need to update? N
* Is there breaking changes for older versions? Y
* Does this needs documentation? N


Closes #5099 from seung-00/feature/ZEPPELIN-6366.

Signed-off-by: ChanHo Lee <chanholee@apache.org>

Author: seung-00

conf/shiro.ini.template

@@ -123,6 +123,7 @@ admin = *
 /api/interpreter/setting/restart/** = authc
 /api/interpreter/** = authc, roles[admin]
 /api/notebook-repositories/** = authc, roles[admin]
+/api/configurations/client/** = anon
 /api/configurations/** = authc, roles[admin]
 /api/credential/** = authc, roles[admin]
 /api/admin/** = authc, roles[admin]

zeppelin-integration/src/test/java/org/apache/zeppelin/integration/ZeppelinIT.java

@@ -334,6 +334,7 @@ void testAngularRunParagraph() throws Exception {
 
       // Click on 1 paragraph to trigger z.runParagraph() function
 
+      ZeppelinITUtils.sleep(1000, false);
       clickAndWait(By.xpath(getParagraphXPath(1) + "//div[@id=\"angularRunParagraph\"]"));
 
       waitForParagraph(2, "FINISHED");

zeppelin-server/src/main/java/org/apache/zeppelin/rest/ConfigurationsRestApi.java

@@ -46,6 +46,21 @@ public ConfigurationsRestApi(
     this.configurationService = configurationService;
   }
 
+  @GET
+  @Path("client")
+  @ZeppelinApi
+  public Response getClientConfigurations() {
+    try {
+        int maxMessageSize = configurationService.getWsMaxMessageSize();
+
+        return new JsonResponse<>(Status.OK, "", Map.of(
+                "wsMaxMessageSize", maxMessageSize
+        )).build();
+        } catch (Exception e) {
+        return new JsonResponse<>(Status.INTERNAL_SERVER_ERROR, "Fail to get max message size", e).build();
+    }
+  }
+
   @GET
   @Path("all")
   @ZeppelinApi

zeppelin-server/src/main/java/org/apache/zeppelin/service/ConfigurationService.java

@@ -43,6 +43,10 @@ public Map<String, String> getAllProperties(ServiceContext context,
     return properties;
   }
 
+  public int getWsMaxMessageSize() {
+    return Integer.parseInt(zConf.getWebsocketMaxTextMessageSize());
+  }
+
   public Map<String, String> getPropertiesWithPrefix(String prefix,
                                                      ServiceContext context,
                                                      ServiceCallback<Map<String, String>> callback)

zeppelin-web-angular/projects/zeppelin-sdk/src/interfaces/message-common.interface.ts

@@ -29,6 +29,10 @@ export interface Ticket {
   roles: string;
 }
 
+export interface ClientConfigurations {
+  wsMaxMessageSize: number;
+}
+
 export interface ConfigurationsInfo {
   configurations: {
     'zeppelin.war.tempdir': string;

zeppelin-web-angular/src/app/pages/workspace/notebook/action-bar/action-bar.component.ts

@@ -29,7 +29,14 @@ import { NzModalService } from 'ng-zorro-antd/modal';
 import { MessageListener, MessageListenersManager } from '@zeppelin/core';
 import { TRASH_FOLDER_ID_TOKEN } from '@zeppelin/interfaces';
 import { MessageReceiveDataTypeMap, Note, OP, RevisionListItem } from '@zeppelin/sdk';
-import { MessageService, NotebookService, NoteStatusService, SaveAsService, TicketService } from '@zeppelin/services';
+import {
+  ConfigurationService,
+  MessageService,
+  NotebookService,
+  NoteStatusService,
+  SaveAsService,
+  TicketService
+} from '@zeppelin/services';
 import { NoteCreateComponent, ShortcutComponent } from '@zeppelin/share';
 
 @Component({
@@ -189,11 +196,12 @@ export class NotebookActionBarComponent extends MessageListenersManager implemen
     });
   }
 
-  exportNote() {
+  async exportNote() {
     if (!this.ticketService.configuration) {
       throw new Error('Configuration is not loaded');
     }
-    const sizeLimit = +this.ticketService.configuration['zeppelin.websocket.max.text.message.size'];
+
+    const sizeLimit = await this.configurationService.fetchWsMaxMessageSize();
     const jsonContent = JSON.stringify(this.note);
     if (jsonContent.length > sizeLimit) {
       this.nzModalService.confirm({
@@ -324,6 +332,7 @@ export class NotebookActionBarComponent extends MessageListenersManager implemen
     @Inject(TRASH_FOLDER_ID_TOKEN) public TRASH_FOLDER_ID: string,
     private nzModalService: NzModalService,
     private ticketService: TicketService,
+    private configurationService: ConfigurationService,
     private nzMessageService: NzMessageService,
     private router: Router,
     private cdr: ChangeDetectorRef,

zeppelin-web-angular/src/app/services/configuration.service.ts

@@ -13,8 +13,10 @@
 import { HttpClient } from '@angular/common/http';
 import { Injectable } from '@angular/core';
 
+import { Observable } from 'rxjs';
+import { ClientConfigurations } from '@zeppelin/sdk';
+import { BaseUrlService } from '@zeppelin/services/base-url.service';
 import { BaseRest } from './base-rest';
-import { BaseUrlService } from './base-url.service';
 
 @Injectable({
   providedIn: 'root'
@@ -27,7 +29,13 @@ export class ConfigurationService extends BaseRest {
     super(baseUrlService);
   }
 
-  getAll() {
+  fetchWsMaxMessageSize(): Promise<number> {
+    const configurations = this.http.get<ClientConfigurations>(this.restUrl`/configurations/client`);
+
+    return configurations.toPromise().then(config => config.wsMaxMessageSize);
+  }
+
+  getAll(): Observable<{ [p: string]: string }> {
     return this.http.get<{ [key: string]: string }>(this.restUrl`/configurations/all`);
   }
 }

zeppelin-web-angular/src/app/share/note-import/note-import.component.html

@@ -28,7 +28,7 @@
       <p class="ant-upload-text">Click or drag JSON file to this area to upload</p>
       <p class="ant-upload-hint">
         JSON file size cannot exceed
-        <strong class="tips warning">{{ maxLimit | humanizeBytes }}</strong>
+        <strong class="tips warning">{{ wsMaxLimit | humanizeBytes }}</strong>
       </p>
     </nz-upload>
   </nz-tab>

zeppelin-web-angular/src/app/share/note-import/note-import.component.ts

@@ -12,9 +12,8 @@
 
 import { HttpClient } from '@angular/common/http';
 import { ChangeDetectionStrategy, ChangeDetectorRef, Component, OnInit } from '@angular/core';
-import { MessageService, TicketService } from '@zeppelin/services';
+import { ConfigurationService, MessageService, TicketService } from '@zeppelin/services';
 
-import { get } from 'lodash';
 import { NzModalRef } from 'ng-zorro-antd/modal';
 import { NzUploadFile } from 'ng-zorro-antd/upload';
 
@@ -32,7 +31,7 @@ export class NoteImportComponent extends MessageListenersManager implements OnIn
   importUrl?: string;
   errorText?: string;
   importLoading = false;
-  maxLimit = get(this.ticketService.configuration, ['zeppelin.websocket.max.text.message.size'], null);
+  wsMaxLimit?: number;
 
   @MessageListener(OP.IMPORT_NOTE)
   noteImported(_: MessageReceiveDataTypeMap[OP.IMPORT_NOTE]) {
@@ -59,7 +58,7 @@ export class NoteImportComponent extends MessageListenersManager implements OnIn
 
   beforeUpload = (file: NzUploadFile): boolean => {
     this.errorText = '';
-    if (file.size !== undefined && this.maxLimit && file.size > Number.parseInt(this.maxLimit, 10)) {
+    if (file.size !== undefined && this.wsMaxLimit && file.size > this.wsMaxLimit) {
       this.errorText = 'File size limit Exceeded!';
     } else {
       const reader = new FileReader();
@@ -102,12 +101,15 @@ export class NoteImportComponent extends MessageListenersManager implements OnIn
   constructor(
     public messageService: MessageService,
     private ticketService: TicketService,
+    private configurationService: ConfigurationService,
     private cdr: ChangeDetectorRef,
     private nzModalRef: NzModalRef,
     private httpClient: HttpClient
   ) {
     super(messageService);
   }
 
-  ngOnInit() {}
+  async ngOnInit() {
+    this.wsMaxLimit = await this.configurationService.fetchWsMaxMessageSize();
+  }
 }

zeppelin-web/src/app/notebook/notebook.controller.js

@@ -267,30 +267,29 @@ function NotebookCtrl($scope, $route, $routeParams, $location, $rootScope,
     return note && note.path ? note.path.split('/')[1] === TRASH_FOLDER_ID : false;
   };
 
-  // Export notebook
-  let limit = 0;
+  $scope.exportNote = function() {
+    $http.get(baseUrlSrv.getRestApiBase() + '/configurations/client').then(function(response) {
+      const limit = response.data.body.wsMessageMaxSize;
 
-  websocketMsgSrv.listConfigurations();
-  $scope.$on('configurationsInfo', function(scope, event) {
-    limit = event.configurations['zeppelin.websocket.max.text.message.size'];
-  });
+      let jsonContent = JSON.stringify($scope.note, null, 2);
 
-  $scope.exportNote = function() {
-    let jsonContent = JSON.stringify($scope.note, null, 2);
-    if (jsonContent.length > limit) {
-      BootstrapDialog.confirm({
-        closable: true,
-        title: 'Note size exceeds importable limit (' + limit + ')',
-        message: 'Do you still want to export this note?',
-        callback: function(result) {
-          if (result) {
-            saveAsService.saveAs(jsonContent, $scope.note.name + '_' + $scope.note.id, 'zpln');
-          }
-        },
-      });
-    } else {
-      saveAsService.saveAs(jsonContent, $scope.note.name + '_' + $scope.note.id, 'zpln');
-    }
+      if (jsonContent.length > limit) {
+        BootstrapDialog.confirm({
+          closable: true,
+          title: 'Note size exceeds importable limit (' + limit + ')',
+          message: 'Do you still want to export this note?',
+          callback: function(result) {
+            if (result) {
+              saveAsService.saveAs(jsonContent, $scope.note.name + '_' + $scope.note.id, 'zpln');
+            }
+          },
+        });
+      } else {
+        saveAsService.saveAs(jsonContent, $scope.note.name + '_' + $scope.note.id, 'zpln');
+      }
+    }).catch(function(err) {
+      console.error('Error while fetching max message size', err);
+    });
   };
 
   // Export nbformat