CODEWITHSUNDEEP
angularhttptypescriptangular5
Sahil Khanna
Sahil Khanna

Reputation: 4382

Read response headers from API response - Angular 5 + TypeScript

I'm triggering a HTTP request and I'm getting a valid response from it. The response also has a header X-Token that I wish to read. I'm trying the below code to read the headers, however, I get null as a result

this.currentlyExecuting.request = this.http.request(reqParams.type, reqParams.url, {
    body: reqParams.body,
    responseType: 'json',
    observe: 'response'
}).subscribe(
    (_response: any) => {
        // Also tried _response.headers.init();
        const header = _response.headers.get('X-Token');
        console.log(header);
        onComplete(_response.body);
     },
    _error => {
        onComplete({
            code: -1,
            message: Constants.WEBSERVICE_INTERNET_NOT_CONNNECTED
        });
    }
);

The response of the API, when checked in Chrome inspect, shows the header is present.

enter image description here

Upvotes: 121

Views: 253855

Answers (9)

Eternal21
Eternal21

Reputation: 4664

I had to do the following to get the headers to appear in SPA Angular application when GETting them from ASP.NET Core service:

var builder = WebApplication.CreateBuilder(args);

services.AddCors(options =>
{
    options.AddPolicy("MyExposeResponseHeadersPolicy",
        builder =>
        {
            builder.WithOrigins("https://*.example.com")
                   .WithExposedHeaders("x-custom-header");
        });
});

builder.Services.AddControllers();

var app = builder.Build();

Upvotes: 0

A.K.J.94
A.K.J.94

Reputation: 552

Try this simple code.

1. Components side code: to get both body and header property. Here there's a token in body and Authorization in the header.

loginUser() {
    this.userService.loginTest(this.loginCred).
    subscribe(res => {
        let output1 = res;
        console.log(output1.body.token);
        console.log(output1.headers.get('Authorization'));
    })
}

2. Service side code: sending login data in the body and observe the response in Observable any which be subscribed in the component side.

loginTest(loginCred: LoginParams): Observable<any> {
    const header1= {'Content-Type':'application/json',};
    const body =  JSON.stringify(loginCred);
    return this.http.post<any>(this.baseURL+'signin',body,{
        headers: header1,
        observe: 'response',
        responseType: 'json'
    });
}

Upvotes: 1

Lauris
Lauris

Reputation: 11

Angular 7 Service: 

    this.http.post(environment.urlRest + '/my-operation',body, { headers: headers, observe: 'response'});
Component:
    this.myService.myfunction().subscribe(
          (res: HttpResponse) => {
              console.log(res.headers.get('x-token'));
                }  ,
        error =>{
        })

Upvotes: 1

Hrishikesh Kale
Hrishikesh Kale

Reputation: 6548

Have you exposed the X-Token from server side using access-control-expose-headers? because not all headers are allowed to be accessed from the client side, you need to expose them from the server side

Also in your frontend, you can use new HTTP module to get a full response using {observe: 'response'} like 

http
  .get<any>('url', {observe: 'response'})
  .subscribe(resp => {
    console.log(resp.headers.get('X-Token'));
  });

Upvotes: 202

Trilok Pathak
Trilok Pathak

Reputation: 3101

As Hrishikesh Kale has explained we need to pass the Access-Control-Expose-Headers.

Here how we can do it in the WebAPI/MVC environment:

protected void Application_BeginRequest()
        {
            if (HttpContext.Current.Request.HttpMethod == "OPTIONS")
            {
                //These headers are handling the "pre-flight" OPTIONS call sent by the browser
                HttpContext.Current.Response.AddHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS");
                HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers", "*");
                HttpContext.Current.Response.AddHeader("Access-Control-Allow-Credentials", "true");
                HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", "http://localhost:4200");
                HttpContext.Current.Response.AddHeader("Access-Control-Expose-Headers", "TestHeaderToExpose");
                HttpContext.Current.Response.End();
            }
        }

Another way is we can add code as below in the webApiconfig.cs file.

config.EnableCors(new EnableCorsAttribute("", headers: "", methods: "*",exposedHeaders: "TestHeaderToExpose") { SupportsCredentials = true });

**We can add custom headers in the web.config file as below. *

<httpProtocol>
   <customHeaders>
      <add name="Access-Control-Expose-Headers" value="TestHeaderToExpose" />
   </customHeaders>
</httpProtocol>

we can create an attribute and decore the method with the attribute.

Happy Coding !!

Upvotes: 17

Root
Root

Reputation: 995

In my case in the POST response I want to have the authorization header because I was having the JWT Token in it. So what I read from this post is the header I we want should be added as an Expose Header from the back-end. So what I did was added the Authorization header to my Exposed Header like this in my filter class.

response.addHeader("Access-Control-Expose-Headers", "Authorization");
response.addHeader("Access-Control-Allow-Headers", "Authorization, X-PINGOTHER, Origin, X-Requested-With, Content-Type, Accept, X-Custom-header");
response.addHeader(HEADER_STRING, TOKEN_PREFIX + token); // HEADER_STRING == Authorization

And at my Angular Side

In the Component.

this.authenticationService.login(this.f.email.value, this.f.password.value)
  .pipe(first())
  .subscribe(
    (data: HttpResponse<any>) => {
      console.log(data.headers.get('authorization'));
    },
    error => {
      this.loading = false;
    });

At my Service Side.

return this.http.post<any>(Constants.BASE_URL + 'login', {username: username, password: password},
  {observe: 'response' as 'body'})
  .pipe(map(user => {
       return user;
  }));

Upvotes: 28

Gurudath BN
Gurudath BN

Reputation: 1411

You can get headers using below code

let main_headers = {}
this.http.post(url,
  {email: this.username, password: this.password},
  {'headers' : new HttpHeaders ({'Content-Type' : 'application/json'}), 'responseType': 'text', observe:'response'})
  .subscribe(response => {
    const keys = response.headers.keys();
    let headers = keys.map(key => {
      `${key}: ${response.headers.get(key)}`
        main_headers[key] = response.headers.get(key)
       }
      );
  });

later we can get the required header form the json object.

header_list['X-Token']

Upvotes: 2

Pritam Parker
Pritam Parker

Reputation: 111

You can get data from post response Headers in this way (Angular 6):

import { HttpClient, HttpHeaders, HttpResponse } from '@angular/common/http';

const httpOptions = {
  headers: new HttpHeaders({ 'Content-Type': 'application/json' }),
  observe: 'response' as 'response'
};

this.http.post(link,body,httpOptions).subscribe((res: HttpResponse<any>) => {
  console.log(res.headers.get('token-key-name'));
})

Upvotes: 11

user4676340
user4676340

Reputation:

You should use the new HttpClient. You can find more information here.

http
  .get<any>('url', {observe: 'response'})
  .subscribe(resp => {
    console.log(resp.headers.get('X-Token'));
  });

Upvotes: 22

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