Separating jhipster back-end and front-end into two projects?

2022-09-03 02:16:39

I'm trying jhipster with token-based authentication. It works perfectly.

Now, I want to run back-end and front-end code on different domains. How can I do this?


This is what I tried:

  1. Run yo jhipster and select token-based authentication option:

    Welcome to the JHipster Generator
    
    ? (1/13) What is the base name of your application? jhipster
    ? (2/13) What is your default Java package name? com.mycompany.myapp
    ? (3/13) Do you want to use Java 8? Yes (use Java 8)
    ? (4/13) Which *type* of authentication would you like to use? Token-based authentication (stateless, with a token)
    ? (5/13) Which *type* of database would you like to use? SQL (H2, MySQL, PostgreSQL)
    ? (6/13) Which *production* database would you like to use? MySQL
    ? (7/13) Which *development* database would you like to use? H2 in-memory with Web console
    ? (8/13) Do you want to use Hibernate 2nd level cache? Yes, with ehcache (local cache, for a single node)
    ? (9/13) Do you want to use clustered HTTP sessions? No
    ? (10/13) Do you want to use WebSockets? No
    ? (11/13) Would you like to use Maven or Gradle for building the backend? Maven (recommended)
    ? (12/13) Would you like to use Grunt or Gulp.js for building the frontend? Grunt (recommended)
    ? (13/13) Would you like to use the Compass CSS Authoring Framework? No
    
    ...
    
    I'm all done. Running bower install & npm install for you
    ^C
    
  2. Make two copies of the project as jhipster/backend and jhipster/frontend

  3. Delete unnecessary files from back-end and front-end

    rm -rf backend/.bowerrc
    rm -rf backend/.jshintrc
    rm -rf backend/bower.json
    rm -rf backend/Gruntfile.js
    rm -rf backend/package.json
    rm -rf backend/src/main/webapp
    rm -rf backend/src/test/javascript
    
    rm -rf frontend/pom.xml
    rm -rf frontend/src/main/java
    rm -rf frontend/src/main/resources
    rm -rf frontend/src/test/gatling
    rm -rf frontend/src/test/java
    rm -rf frontend/src/test/resources
    
  4. Make changes in code to completely remove backend/frontend dependency

    • frontend/Gruntfile.js

      ...
      var parseVersionFromPomXml = function() {
          return '1.2.2.RELEASE';
      };
      ...
      browserSync: { ..., proxy: "localhost:8081" }
      
    • frontend/src/main/webapp/scripts/app/app.js

      angular.module('jhipsterApp', [...])
      .constant('API_URL', 'http://localhost:8080/')
      .run( ... )
      
    • frontend/src/main/webapp/scripts/**/*.service.js

      angular.module('jhipsterApp').factory(..., API_URL) {
          return $http.post(API_URL + 'api/authenticate', ...);
      }
      
      angular.module('jhipsterApp').factory('Account', function Account($resource, API_URL) {
          return $resource(API_URL + 'api/account', {}, {...});
      }
      
      // Make similar changes in all service files.
      
    • backend/pom.xml

      Remove yeoman-maven-plugin

    • backend/src/main/java/com/mycompany/myapp/SimpleCORSFilter.java

      // Copied from here: https://spring.io/guides/gs/rest-service-cors/
      
      @Component
      public class SimpleCORSFilter implements Filter {
          public void doFilter(...) {
              ...
              response.setHeader("Access-Control-Allow-Origin", "*");
              ...
          }
      }
      
  5. Run

    • Terminal Tab #1: BACKEND

      cd backend
      mvn spring-boot:run
      
      ...
      [INFO] com.mycompany.myapp.Application - Started Application in 11.529 seconds (JVM running for 12.079)
      [INFO] com.mycompany.myapp.Application - Access URLs:
      ----------------------------------------------------------
              Local:          http://127.0.0.1:8080
              External:       http://192.168.56.1:8080
      ----------------------------------------------------------
      
    • Terminal Tab #2: FRONTEND

      cd frontend/src/main/webapp
      npm install -g http-server
      http-server
      
      Starting up http-server, serving ./ on: http://0.0.0.0:8081
      Hit CTRL-C to stop the server
      
    • Terminal Tab #3: GRUNT

      cd frontend
      bower install
      npm install
      grunt serve
      
      ...
      [BS] Proxying: http://localhost:8081
      [BS] Access URLs:
       -------------------------------------
             Local: http://localhost:3000
          External: http://10.34.16.128:3000
       -------------------------------------
                UI: http://localhost:3001
       UI External: http://10.34.16.128:3001
       -------------------------------------
      
  6. Browse http://localhost:3000/#/login

    Enter as username:passwordadmin:admin

    Our BACKEND tab reads:

    [DEBUG] com.mycompany.myapp.security.Http401UnauthorizedEntryPoint - Pre-authenticated entry point called. Rejecting access
    

Apparently, I'm doing something wrong. What is it?


答案 1

When requests fail due to CORS, there is no visible error on the backend. The HTTP request actually succeeds, but is blocked on the front-end side by javascript. A message like this one will appear in the JS console.

XMLHttpRequest cannot load http://localhost:8080/api/authenticate. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:9000' is therefore not allowed access.

The error message you're seeing is actually related to authentication. When you enable CORS, your JS will send ''pre-flight'' requests using the HTTP OPTIONS method. JHipster isn't configured to allow the OPTIONS method globally. I ran into this exact same problem myself while doing the same thing you did. The fix is very simple: just add this line to your immediately preceding (before) the first entry.com.mycompany.config.SecurityConfigurationantMatchers

.antMatchers(org.springframework.http.HttpMethod.OPTIONS, "/api/**").permitAll()

This will explicitly allow all requests with the OPTIONS method. The OPTIONS method is used in CORS as a way to read all of the headers and see what HTTP methods are allowed in the CORS request.

Finally, in your SimpleCORSFilter class, you should also add these headers:

response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
response.setHeader("Access-Control-Max-Age", "86400"); // 24 Hours
response.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept, x-auth-token");

答案 2

Separating frontend and backend in JHipster application is quite simple. Please follow the steps mentioned below if you want to setup frontend and backend applications separately and individually using JHipster:

  1. Create two directories for frontend and backend applications

    • mkdir frontend
    • mkdir backend
  2. change your directory to frontend and run the JHipster command to create just frontend module

    • cd frontend
    • jhipster --skip-server --db=sql --auth=jwt
    • if all works fine, run npm start command to run your frontend application.

    I'm using mysql for db and JWT for auth and if you want to use websockets you add: "--websocket=spring-websocket"

  3. Now, change your directory to the backend and run JHipster command to create just backend module

    • cd .. //as we are ing backend directory currently
    • cd backend
    • jhipster --skip-client
    • Run your backend application as you run your spring boot application

Now, your frontend and backend application are running separately and individually and frontend is coordinating with the backend application via REST API calls.


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