Spring Boot with redirecting with single page angular2

Question

I have a single page Angular app with Spring Boot. It looks like the following:

src
  main
  java
    controller
       HomeController
       CustomerController
       OtherController
  webapp
    js/angular-files.js
    index.html

Spring boot correctly defaults to webapp folder and serves index.html file.

What I am looking to do is:

1. For every local REST request not starting with /api overwrite and redirect to default webapp/index.html. I plan to serve anything /api to the spring controllers.

2. Is there a way to prefix all controllers with API so that I do not have to write API every time? e.g.

   @RequestMapping("/api/home") can write shorthand in code @RequestMapping("/home")

or

@RequestMapping("/api/other-controller/:id") can write shorthand  @RequestMapping("/other-controller/:id")

I'm looking for every API request, e.g. 1) http://localhost:8080/api/home keep API with API and resolve to correct controller and return JSON, however if someone enters a URL like http:///localhost/some-url or http:///localhost/some-other/123/url then it will serve the index.html page and keep the URL.

Alternative ways to do it: try adding #ErrorViewResolver: Springboot/Angular2 - How to handle HTML5 urls?

Answer 1

For every local REST request not starting with /api overwrite and redirect to default webapp/index.html. I plan to serve anything /api to the spring controllers.

Update 15/05/2017

Let me re-phrase your query for other readers. (Correct me, if misunderstood)

Background
Using Spring Boot and Serving static resources from classpath

Requirement
All 404 non api requests should be redirected to index.html.

NON API - means Requests in which URL doesn't start with /api.
API - 404 should throw 404 as usual.

Sample Response
/api/something - will throw 404
/index.html - will server index.html
/something - will redirect to index.html

My Solution

Let the Spring MVC throw exceptions, if any handler is not available for the given resource.

Add following to application.properties

spring.mvc.throw-exception-if-no-handler-found=true
spring.resources.add-mappings=false

Add a ControllerAdvice as follows

@ControllerAdvice
public class RedirectOnResourceNotFoundException {

    @ExceptionHandler(value = NoHandlerFoundException.class)
    public Object handleStaticResourceNotFound(final NoHandlerFoundException ex, HttpServletRequest req, RedirectAttributes redirectAttributes) {
        if (req.getRequestURI().startsWith("/api"))
            return this.getApiResourceNotFoundBody(ex, req);
        else {
            redirectAttributes.addFlashAttribute("errorMessage", "My Custom error message");
            return "redirect:/index.html";
        }
    }

    private ResponseEntity<String> getApiResourceNotFoundBody(NoHandlerFoundException ex, HttpServletRequest req) {
        return new ResponseEntity<>("Not Found !!", HttpStatus.NOT_FOUND);
    }
}

You can customize the error message as you like.

Is there a way to prefix all controllers with api so that I do not have to write api every time.

For this, you can create a BaseController and set the RequestMapping path to /api

Example

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RequestMapping("/api")
public abstract class BaseController {}

And extend this BaseController and make sure you do not annotate child class with @RequestMapping

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class FirstTestController extends BaseController {
    @RequestMapping(path = "/something")
    public String sayHello() {
        return "Hello World !!";
    }

}

Previous Answer

You can create a Filter which redirects to /index.html if request path doesn't startsWith /api.

// CODE REMOVED. Check Edit History If you want.

Answer 2

If you're tired of trying to solve this problem by following so many conflicting solutions - look here!!

After hours upon hours trying to follow all the scattered advice from dozens of stack overflow and blog posts, I've finally found the minimum PURE spring boot + angular 6 application to always redirect to index.html after a refresh on a non-root page WHILE maintaining all your REST API endpoint paths. No @EnableWebMvc, no @ControllerAdvice, no changes to application.properties, no custom ResourceHandlerRegistry modifications, just simplicity:

Very important pre-requisite

You *must* include the output of ng build into Spring's resources/static folder. You can accomplish this via the maven-resources-plugin. Learn here: Copying multiple resource directories to independent target directories with maven

Code

@Controller
@SpringBootApplication
public class MyApp implements ErrorController {

    public static void main(String[] args) {
        SpringApplication.run(MyApp.class, args);
    }

    private static final String PATH = "/error";

    @RequestMapping(value = PATH)
    public String error() {
        return "forward:/index.html";
    }

    @Override
    public String getErrorPath() {
        return PATH;
    }
}

Reasoning

• Including the output of ng-build into resources/static at build time allows spring view redirects ("forward:/index.html") to succeed. It seems spring cannot redirect to anything outside of the resources folder so if you're trying to access pages at the root of the site, it won't work.
• With default functionality (i.e. no additions of @EnableWebMvc or changes to application.properties) navigating to / automatically serves the index.html (iff it was included in the resources/static folder) so no need to make changes there.
• With default functionality (as stated above), any error encountered in a spring boot app routes to /error and implementing ErrorController overrides that behavior to - you guessed it - route to index.html which allows Angular to take over the routing.

Remarks

• Don't settle for the HashLocationStrategy to get over this problem as it is not recommended by Angular: https://angular.io/guide/router#which-strategy-is-best

Answer 3

Try this instead

@SpringBootApplication
@Controller
class YourSpringBootApp { 

    // Match everything without a suffix (so not a static resource)
    @RequestMapping(value = "/**/{path:[^.]*}")       
    public String redirect() {
        // Forward to home page so that route is preserved.(i.e forward:/intex.html)
        return "forward:/";
    }
}

Answer 4

@Controller
public class RedirectController {
    /*
     * Redirects all routes to FrontEnd except: '/', '/index.html', '/api', '/api/**'
     */
    @RequestMapping(value = "{_:^(?!index\\.html|api).*$}")
    public String redirectApi() {
        return "forward:/";
    }
}

Answer 5

The solution that works to me is to overwrite the BasicErrorController of Spring Boot:

@Component
public class CustomErrorController extends BasicErrorController {

    public CustomErrorController(ErrorAttributes errorAttributes) {
        super(errorAttributes, new ErrorProperties());
    }

    @RequestMapping(produces = "text/html")
    @Override
    public ModelAndView errorHtml(HttpServletRequest request, HttpServletResponse response) {
        HttpStatus status = getStatus(request);
        if (status == HttpStatus.NOT_FOUND) {
            return new ModelAndView("forward:/");
        } else {
            return super.errorHtml(request, response);
        }
    }
}

The method errorHtml only intercepts not found requests and is transparent for responses 404 (not found) from the api.

Answer 6

Most reasonable solution, imho, for Spring Boot 2+ (code is in Kotlin):

@Component
class ForwardErrorsToIndex : ErrorViewResolver {
   override fun resolveErrorView(request: HttpServletRequest?, 
                              status: HttpStatus?, 
                              model: MutableMap<String, Any>?): ModelAndView {
      return ModelAndView("forward:/index.html")
   }
}

Answer 7

Too late on this thread, but thought it might help someone

Tried many solutions, but this looked pretty straight forward and great to me

import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.resource.PathResourceResolver;
 
import java.io.IOException;
 
@Configuration
public class MvcConfiguration implements WebMvcConfigurer {
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/**")
                .addResourceLocations("classpath:/static/")
                .resourceChain(true)
                .addResolver(new PathResourceResolver() {
                    @Override
                    protected Resource getResource(String resourcePath, Resource location) throws IOException {
                        Resource requestedResource = location.createRelative(resourcePath);
 
                        return requestedResource.exists() && requestedResource.isReadable() ? requestedResource
                                : new ClassPathResource("/static/index.html");
                    }
                });
    }
}

Credits: https://keepgrowing.in/java/springboot/make-spring-boot-surrender-routing-control-to-angular/

Answer 8

For whole application, you can add context path in application.properties

server.contextPath=/api

It will append "/api" to every requested URL after http://localhost:8080/api/home

For Redirection,

@Override
public void addViewControllers(ViewControllerRegistry registry) {
    registry.addRedirectViewController("/", "/home");
    registry.setOrder(Ordered.HIGHEST_PRECEDENCE);
    super.addViewControllers(registry);
}

Put this bunch of code in WebMVCConfig.java

Answer 9

In the @Configuration bean you can add a ServletRegistrationBean to make the spring server for the /api/* resquest only, then in the Controller you don't need to add it.

@Bean
public ServletRegistrationBean dispatcherRegistration() {
    ServletRegistrationBean registration = new ServletRegistrationBean(
            dispatcherServlet());
    registration.addUrlMappings("/api/*");
    registration.setLoadOnStartup(1);
    registration.setName("mvc-dispatcher");
    return registration;
}

Answer 10

Ok, let's start with the simple part of your question:

Is there a way to prefix all controllers with api so that I do not have to write api every time?

The answer is yes, just mark your controller with a "global" @RequestMapping annotation, for example:

@RestController
@RequestMapping("/api")
public class ApiController{

   @RequestMapping("/hello") 
   public String hello(){
      return "hello simple controller";
   }

   @RequestMapping("/hello2") 
   public String hello2(){
      return "hello2 simple controller";
   }
}

In the example above you can invoke hello method with this URL: /api/hello

and the second method with this URL: /api/hello2

This is how I didn't have to mark each method with /api prefix.

Now, to the more complex part of your question:

is how to achieve a redirect if the request doesn't start with /api prefix?

You can do it by returning an HTTP status code (302) of Redirect, after all, angularJs "speaks" REST natively, thus you can't force a redirect from Java/Spring code like you use to.

Then just return an HTTP message with the status code of 302, and on your angularJS do the actual redirection.

For example:

On AngularJS:

var headers = {'Content-Type':'application/json', 'Accept':'application/json'}

var config = {
    method:'GET'
    url:'http://localhost:8080/hello',
    headers:headers
};

http(config).then(
    function onSuccess(response){
        if(response.status == 302){
            console.log("Redirect");
            $location("/")
        }
}, function onError(response){
    console.log("An error occured while trying to open a new game room...");
});

On Spring:

@RestController
@RequestMapping("/api")
public class ApiController{

   @RequestMapping("/hello") 
   public ResponseEntity<String> hello(){
      HttpHeaders header = new HttpHeaders();
      header.add("Content-Type", "application/json");
      return new ResponseEntity<String>("", header, HttpStatus.FOUND);
   }
}

of course, you'll need to custom it to your project.

Answer 11

All you need to try is put the index.html to src/main/resources/static/

See Example: https://github.com/reflexdemon/shop/tree/master/src/main/resources/static

In my package.josn I try to copy it to this location.

See PackageJSON: https://github.com/reflexdemon/shop/blob/master/package.json#L14