CODEWITHSUNDEEP
angularnestedobservableconcatmap
MaynorSong
MaynorSong

Reputation: 640

How to use the first response from concatMap in the second request

I am trying to avoid the nested subscription in request to the backend. I need to login, then get a service token based on the response of the login, then get a encryption token based on the service token.

I have seen about concatMap but i am not sure how to use the first response in the second request or third 

  this.rest.CallLogin(this.data).pipe(
            concatMap(serviceToken => this.rest.GetServiceTicket(1stresponse.headers.get('Location'))),// dont know how to get the 1st response from CallLogin
            concatMap(tokenResponse => this.rest.getEncryptToken(serviceToken)),

        );

Upvotes: 0

Views: 1194

Answers (3)

MaynorSong
MaynorSong

Reputation: 640

I ended up using SwitchMap

 this.rest.CallLogin(this.data).pipe(
        switchMap((response: any) => {
        this.data.requestUrl = response.headers.get('Location');
        return this.rest.GetServiceTicket(this.data) // serviceticket
        }),
        switchMap((serviceticket) => {
            return this.rest.getEncryptToken(serviceticket.body) // tokenResponse
        }),
        //continue doing requests or stuff
        switchMap((tokenResponse) => {
            encryptToken = tokenResponse;
            ///...                
        }),

Upvotes: 0

Ludevik
Ludevik

Reputation: 7254

If i understood correctly then you only want to chain the calls and use the response header from the first response. For that you need to use observe on response in your first call:

this.rest.CallLogin(this.data, {observe: 'response'}).pipe(
    concatMap(loginResponse => this.rest.GetServiceTicket(loginResponse.headers.get('Location'))),
    concatMap(serviceTicket => this.rest.getEncryptToken(serviceTicket)),
);

Upvotes: -1

user
user

Reputation: 568

You can use flatMap in place of the nested subscriptions.

import { flatMap } from 'rxjs/operators';

this.rest.CallLogin(this.data).pipe(
        flatMap((serviceToken) => {
            //serviceToken is the response of first call
            return this.rest.GetServiceTicket(serviceToken.headers.get('Location'))
        }),
        map((tokenResponse) => {
            //tokenResponse is the response of second call
            this.rest.getEncryptToken(tokenResponse)
        });

Upvotes: 0

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