Google Authentication get user profile picture

Question

If user is authenticated via google, I need to get his profile picture.

If user is authenticated via facebook I get his profile picture with this code:

var info = await _signInManager.GetExternalLoginInfoAsync();
var identifier = info.Principal.FindFirstValue(ClaimTypes.NameIdentifier); 
var picture = $"https://graph.facebook.com/{identifier}/picture"; // 3

So, which code I need to use in 3 line for getting user's profile picture in case user is authenticated via google?

Answer 1

Accessing user profile picture, full solution.

Stack:
Asp Net Identity 4 v4 + Asp Net Identity + Google People Api

Steps

1. Preparation

1.1 I'm using default HttpClient to generate HTTP requests to Google API
1.2 Install NUGET System.Net.Http.Json to ease serialization. 1.3 Use a [json to c#] tool, to create a DTO like this:

/// <summary>
    /// 🟡 official docs.
    /// https://developers.google.com/people/api/rest/v1/people#Person.Photo
    /// </summary>
    public class PeopleApiPhotos    {
        
        public string resourceName { get; set; } 
        public string etag { get; set; } 
        public List<Photo> photos { get; set; }
        
        public class Source    {
            public string type { get; set; } 
            public string id { get; set; } 
        }

        public class Metadata    {
            public bool primary { get; set; } 
            public Source source { get; set; } 
        }

        public class Photo    {
            public Metadata metadata { get; set; } 
            public string url { get; set; } 
        }
    }

2. Identity Server: when users confirms external info data, send http get request, to retrieve avatar picture url:

Identity Server with Asp Net Identity > Login > OnPostConfirmationAsync: FULL METHOD

public async Task < IActionResult > OnPostConfirmationAsync(string returnUrl = null) {
  returnUrl = returnUrl ? ?Url.Content("~/");
  // Get the information about the user from the external login provider
  var info = await _signInManager.GetExternalLoginInfoAsync();
  if (info == null) {
    ErrorMessage = "Error loading external login information during confirmation.";
    return RedirectToPage("./Login", new {
      ReturnUrl = returnUrl
    });
  }

  // try to get profile picture
  string pictureUri = string.Empty;

  if (info.LoginProvider.ToLower() == "google") {
    var httpClient = _httpClientFactory.CreateClient();
    string peopleApiKey = _configuration["GoogleApiKey:PeopleApiKey"];;
    var googleAccountId = info.Principal.FindFirstValue(ClaimTypes.NameIdentifier);
    var photosResponse = await httpClient.GetFromJsonAsync < PeopleApiPhotos > (
    $ "https://people.googleapis.com/v1/people/{googleAccountId}?personFields=photos&key={peopleApiKey}");
    pictureUri = photosResponse ? .photos.FirstOrDefault() ? .url;
  }

  if (ModelState.IsValid) {
    // Cria usuário
    var user = new AppUser {
      UserName = Input.Email,
      Email = Input.Email,
      FirstName = Input.FirstName,
      LastName = Input.LastName,
      ProfilePictureUrl = pictureUri
    };

    var result = await _userManager.CreateAsync(user);
    if (result.Succeeded) {
      result = await _userManager.AddLoginAsync(user, info);
      if (result.Succeeded) {
        _logger.LogInformation("User created an account using {Name} provider.", info.LoginProvider);

        var userId = await _userManager.GetUserIdAsync(user);
        var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
        code = WebEncoders.Base64UrlEncode(Encoding.UTF8.GetBytes(code));
        var callbackUrl = Url.Page("/Account/ConfirmEmail", pageHandler: null, values: new {
          area = "Identity",
          userId = userId,
          code = code
        },
        protocol: Request.Scheme);

        await _emailSender.SendEmailAsync(Input.Email, "Confirm your email", $ "Please confirm your account by <a href='{HtmlEncoder.Default.Encode(callbackUrl)}'>clicking here</a>.");

        // If account confirmation is required, we need to show the link if we don't have a real email sender
        if (_userManager.Options.SignIn.RequireConfirmedAccount) {
          return RedirectToPage("./RegisterConfirmation", new {
            Email = Input.Email
          });
        }

        await _signInManager.SignInAsync(user, isPersistent: false, info.LoginProvider);

        return LocalRedirect(returnUrl);
      }
    }
    foreach(var error in result.Errors) {
      ModelState.AddModelError(string.Empty, error.Description);
    }
  }

  ProviderDisplayName = info.ProviderDisplayName;
  ReturnUrl = returnUrl;
  return Page();
}

2.1 Identity Server with Asp Net Identity > Login > OnPostConfirmationAsync: HIGHLIGHT:

❗️ this is only a little part from full method above.

Checks if external provider is Google, and use [NameIdentifier] and [Google Api Key] to reach People Endpoint.

// try to get profile picture
string pictureUri = string.Empty;

if (info.LoginProvider.ToLower() == "google") {
  var httpClient = _httpClientFactory.CreateClient();
// ApiKey can get generated in [Google Developers Console](https://console.developers.google.com/apis/credentials).
  string peopleApiKey = _configuration["GoogleApiKey:PeopleApiKey"];;
  var googleAccountId = info.Principal.FindFirstValue(ClaimTypes.NameIdentifier);
  var photosResponse = await httpClient.GetFromJsonAsync < PeopleApiPhotos > (
  $ "https://people.googleapis.com/v1/people/{googleAccountId}?personFields=photos&key={peopleApiKey}");
  pictureUri = photosResponse ? .photos.FirstOrDefault() ? .url;
}

3. Identity Server > Profile Service Implementation:

public async Task GetProfileDataAsync(ProfileDataRequestContext context) {
  var sub = context.Subject.GetSubjectId();
  var user = await _userManager.FindByIdAsync(sub);
  var principal = await _claimsFactory.CreateAsync(user);

  var claims = principal.Claims.ToList();

  claims.Add(new Claim(JwtClaimTypes.GivenName, user.FirstName));
  claims.Add(new Claim(JwtClaimTypes.FamilyName, user.LastName));

  // Insert a new claim, that gets ProfilePictureUrl persisted in my app user in database.
  claims.Add(new Claim(JwtClaimTypes.Picture, user.ProfilePictureUrl));

  context.IssuedClaims = claims;
}

4. Acessing profile user in ReactJS Frontend:

To get user profile data in frontend, i'm using OidcClient-js

// here i'm using oidc-client.js
// user object is loaded with user full data.
let profilePictureUrl = user.profile.picture;

---

Thanks to @DaImTo response.