c# - ASP.NET Core 2.2 在 DbContext 中获取 userId

Question

我是 ASP.NET Core 的新手。我想使用 Entity Framework Core 和 ASP.NET Identity 创建 ASP.NET Core 2.2 WebAPI。此外，我想使用 JWT 通过 token 来保护对该 WebAPI 的访问。

我已成功将用户插入数据库并从我的 API 取回 token ，并且 token 身份验证正在运行。

但是，我还想软删除数据库记录并跟踪谁删除/更新/添加了记录。测试表是 Countries，其中字段只有 Title 和 Description。

到目前为止，我已经颠倒了互联网，但没有帮助:(

Las 我试过的是(userId 是 null):

• 在 startup.cs 中:

  services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
  

• 在我的 AppDbContext.cs 中

  public class AppDbContext : IdentityDbContext<AppUser>{
  
      public AppDbContext(DbContextOptions options) : base(options)
      {
      }
  
      public DbSet<AppUser> AppUsers { get; set; }
  
      public DbSet<Country> Countries { get; set; } // just for testing
  
      protected override void OnModelCreating(ModelBuilder builder)
      {
          base.OnModelCreating(builder);
  
          // TODO - IGNORE THIS
          //builder.Entity<AppUser>().Property<bool>("IsDeleted");
          //builder.Entity<AppUser>().HasQueryFilter(m => EF.Property<bool>(m, "IsDeleted") == false);
      }
  
      public override async Task<int> SaveChangesAsync(CancellationToken cancellationToken = default(CancellationToken))
      {
          CheckBeforeSaving();
          return (await base.SaveChangesAsync(true, cancellationToken).ConfigureAwait(false));
      }
  
      private void CheckBeforeSaving()
      {
          var httpContextAccessor = this.GetService<IHttpContextAccessor>();
          var userId = httpContextAccessor?.HttpContext.User.FindFirstValue(ClaimTypes.NameIdentifier);
  
          foreach (var entry in ChangeTracker.Entries())
          {
              switch (entry.State)
              {
                  case EntityState.Detached:
                      break;
                  case EntityState.Unchanged:
                      break;
                  case EntityState.Deleted:
                      entry.State = EntityState.Modified;
                      entry.CurrentValues["IsDeleted"] = true;
                      entry.CurrentValues["DeletedBy"] = userId;
                      entry.CurrentValues["Deleted"] = DateTime.Now;
                      break;
                  case EntityState.Modified:
                      entry.CurrentValues["UpdatedBy"] = userId;
                      entry.CurrentValues["Updated"] = DateTime.Now;
                      break;
                  case EntityState.Added:
                      entry.CurrentValues["IsDeleted"] = false;
                      entry.CurrentValues["CreatedBy"] = userId;
                      entry.CurrentValues["Created"] = DateTime.Now;
                      entry.CurrentValues["Description"] = userId;
                      break;
                  default:
                      break;
              }
          }
      }}}
  

Answer 1

尝试将 IHttpContextAccessor 直接注入(inject)到 ApplicationDbContext 中:

public class ApplicationDbContext : IdentityDbContext<AppUser>
{
    private readonly IHttpContextAccessor _httpContextAccessor;
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options, IHttpContextAccessor httpContextAccessor)
        : base(options)
    {
        _httpContextAccessor= httpContextAccessor;
    }

    //other methods

   private void CheckBeforeSaving()
   {        
     var userId = _httpContextAccessor?.HttpContext.User.FindFirstValue(ClaimTypes.NameIdentifier);
     //...
   }
}