CODEWITHSUNDEEP
angular
Sallu
Sallu

Reputation: 489

What kind of JSON should return from the server in case of error in angular2

I am making my first angular2 app.

It gets login verification from the server. It posts username (email) and password to the server and in return it gets the USER OBJECT.

user.ts

export class User {
    constructor(
    public id: number,
    public email: string,
    public password: string,
    public token: string,
    public firstName: string,
    public lastName: string,
    public lastLogin: number,
    public credits: number,
    public isAdmin: number
    ) { }
}

Success json

 {"id":2,"email":"john.doe@google","password": "", "token":"37ee4a596d443aaf0308c0783bfdcf83","firstName":"John","lastName":"Doe","lastLogin":1486994085,"credits":0,"isAdmin":0}

Failure messages

 {"code":"empty","error":"Password is empty"}
 {"code":"auth-failed","error":"Login information not correct"}
 {"code":"auth-failed","error":"Invalid id\/token, please login again"}

Now when went to program my failure messages it got me thinking

My code is this, how will i handle failure in the angular2

    return this.http.get(url)
            .map(response => response.json() as User)
            .catch(this.handleError);

I guess I cannot use the response.json() as User cause it will crash app in case of error. What is the best practice? Should i change my json format for success also ?

Upvotes: 2

Views: 107

Answers (3)

Jim L
Jim L

Reputation: 2327

First, you should make sure you have the correct HTTP status code set on the response from the server (assuming you control the server). Then, you can set the content of the response to be whatever you want and then handle it however you like based on the status using the catch handler. 

return this.http.get(url)
        .map(response => response.json() as User)
        .catch(err => /* handle err*/);

More info on status codes:

If the server isn't setting the status codes, then you'd have to look at the raw data to see what you're getting (edit: hopefully this isn't the case as your server wouldn't be following the rules).

https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html

https://en.wikipedia.org/wiki/List_of_HTTP_status_codes

Upvotes: 1

Rossco
Rossco

Reputation: 3753

Just use res.json()

Like this:

login(){
        return this.http.get(url)
            .map(response => response.json());
}

Then for your function calling this http request like this:

    this._yourservice.login().subscribe(
        suc => {
            console.log(suc); // success json, if returned with http response status 200
        },
        err => {
            var res = JSON.parse(err._body);
            console.log(suc); // error json if returned with other http response status
        }
    );

Upvotes: 1

paul
paul

Reputation: 22001

If you return Http status codes other than 200 as part of the server response, then the angular 2 call to http.get will throw an exception, directing you handleError.

Upvotes: 0

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