Problem with fetching data from Spring Boot API endpoint using Java Script

Question

I work on web application and encountered an issue with fetching data from an endpoint using Java Script. If I type endpoint adres in a browser it works perfectly fine but somehow it does not work in the script. The response.ok is returns False.

Here is script:

(function() {

    function requestAuthorization() {
        let response = fetch("http://localhost:8080/authorizationData")
            .then(response => response.json());

        if (response.ok) {
            let json = response.json();
            alert(json);
        } else {
            alert("HTTP response not ok");
        }
    }

    requestAuthorization();

})();

Here is controller:

@RestController
class AuthController {

    private final AuthService service;

    AuthController(AuthService service) throws IOException {
        this.service = service;
    }

    @GetMapping("/authorizationData")
    public ResponseEntity<AuthData> authorize() throws IOException {
        return ResponseEntity.ok(service.getAuthData());
    }
}

Here is service:

@Service
class AuthService {

    private final ObjectMapper mapper;

    AuthService(ObjectMapper mapper) {
        this.mapper = mapper;
    }

    public AuthData getAuthData() throws IOException {
        String resourcePath = "data/applicationSettings.json";
        InputStream resource = new ClassPathResource(resourcePath).getInputStream();
        return mapper.readValue(resource, AuthData.class);
    }
}

What is wrong? If You have any other advice regarding my work I will be pleased to hear it.

EDIT

The script and and HTML file which runs it are both located in static directory in classpath.

Answer 1

You should be doing it like this:

// mark your function as async
async function requestAuthorization() {
    // always try using const rather than let
    const response = await fetch("http://localhost:8080/authorizationData");

    if (response.ok) {
        const json = response.json();
        alert(json);
    } else {
        alert("HTTP response not ok");
    }
}