Proper way to get current User ID in Entity Framework Core
asp.net-core asp.net-identity entity-framework-core
Question
There are a bunch of different answers floating around here for the different RC's of ASP.NET Core on how to get the ID of the currently logged in user. I wanted to ask the definite question here. Please note that project.json now has "Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.0.0"
With RC1, you could do something like this:
using Microsoft.AspNet.Identity;
using System.Security.Claims;
User.GetUserId();
But with the newly released version 1 of EF Core, Microsoft.AspNet.Identity is not the right version.
There was suggestions to use UserManager, which seems like a lot just to get the currently logged in user:
private Task<ApplicationUser> GetCurrentUserAsync() => _userManager.GetUserAsync(HttpContext.User);
var user = await GetCurrentUserAsync();
var userId = user?.Id;
Another method that I found was:
private readonly UserManager<ApplicationUser> _userManager;
_userManager.GetUserId(User)
So with ASP.NET Core 1 RTM and EF Core 1 with the following libraries in project.json, what is the proper way to get the id of the currently logged in user?
"Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.0.0",
"Microsoft.AspNetCore.Mvc": "1.0.0",
Accepted Answer
ASP.NET Core Identity is injected via DI in the startup.cs - as such you just have to inject UserManager via a constructor
UserManager<ApplicationUser> userManager
You can then use the following in methods
_userManager.GetUserId(User);
That's the way its used in the Sample Web Application when you create a new ASP.NET Core 1 project with Individual User Account.
Popular Answer
If you are accessing this from withing the Controller, then using UserManager to get the user ID is pretty inefficient as you are making a round trip to the database. If you are using ClaimsIdentity, you can do something like this to get the user id:
var claimsIdentity = (ClaimsIdentity)this.User.Identity;
var claim = claimsIdentity.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier);
var userId = claim.Value;
This method just reads the user ID which is already present in the cookie, which in turn is automatically deserialized and stored in a ClaimsIdentity instance.
I use this helper class:
public static class UserHelpers
{
public static string GetUserId(this IPrincipal principal)
{
var claimsIdentity = (ClaimsIdentity)principal.Identity;
var claim = claimsIdentity.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier);
return claim.Value;
}
}
So getting a user ID becomes:
var userId = this.User.GetUserId();
If, for some reason, the required claim is not present in the Claims colleciton, you can easily add it when creating the user's ClaimsIdentity:
public class ApplicaionUser : IdentityUser
{
public async Task<ClaimsIdentity> GenerateUserIdentityAsync(UserManager<User> manager)
{
var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);
userIdentity.AddClaim(new Claim(ClaimTypes.NameIdentifier, this.UserId));
return userIdentity;
}
}
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