Angular - SpringBoot - CORS (unknown url): 0 Unknown Error

Question

I have a pretty simple Angular 6 service that calls a Spring Boot service. Here is how it looks like in Angular :

getData(user, numberOfRequests, graphDepth, max): Observable<String> {
    var headers = new Headers();
    var body = {    "user" : user,
                    "numberofRequests" : numberOfRequests,
                    "graphDepth" : graphDepth,
                    "max" : max };
    headers.append('Content-Type', 'application/x-www-form-urlencoded');    
    return this.http.post<String>('http://XX.XX.XXX.XXX:8083/collect', body, httpOptions);
}

Here is the server side :

@CrossOrigin(origins = "*")
    @RequestMapping(value = "/collect", method = RequestMethod.POST, produces = "application/json; charset=UTF-8")
    @ResponseBody
    public String startServices(@RequestBody UserParameters parameters) {
        LOGGER.info("Calling for data");
        String jsonOutput = collect.getData(parameters);
        LOGGER.info("Data ready to be served");
        return jsonOutput;
    }

It works well when both application run locally or when they run on 2 different VMs. But when I deploy on a cloud service I get something that seems to be a CORS error :

 Reason: CORS request did not succeed

error: error { target: XMLHttpRequest, isTrusted: true, lengthComputable: false, … }
headers: Object { normalizedNames: Map(0), lazyUpdate: null, headers: Map(0) }
 message: "Http failure response for (unknown url): 0 Unknown Error"
 name: "HttpErrorResponse"
 ok: false
 status: 0
 statusText: "Unknown Error"
 url: null

This error happens when the webapp and the backend run on the same VM or in two separate VM with 2 different IP...

Do you know what could cause that problem ? How can it be a CORS error ? And do you know how can I try to fix it ?

Thanks!

Liviu · Accepted Answer · 2018-12-18 16:08:55Z

1

try:

httpOptions = {
    headers : new HttpHeaders({'Content-Type', 'application/x-www-form-urlencoded'})
};

return this.http.post<String>('http://XX.XX.XXX.XXX:8083/collect', body, httpOptions);

How do you link the headers to the httpOptions?

For me that works.

answered Dec 18, 2018 at 16:08

Liviu

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2 Comments

GrinnS Over a year ago

Actually I had this on my class :

const httpOptions = {     headers: new HttpHeaders({       'Content-Type':  'application/json',       'Authorization': 'my-auth-token'     })   };

Your modification bring the same issue...

Liviu Over a year ago

Oh ok. You could also try some more changes: In the Security configuration class (extends WebSecurityConfigurerAdapter), in the method configure(HttSecurity httpSecurity) try this: http.cors().disable(); maybe even http.csrf().disable(); I hope this helps

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