Microsoft.AspNet.Identity.EntityFramework/IdentityDbContext.cs

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Common;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Data.Entity.Infrastructure.Annotations;
using System.Data.Entity.Validation;
using System.Data.SqlClient;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq;

namespace Microsoft.AspNet.Identity.EntityFramework
{
/// <summary>
///     Default db context that uses the default entity types
/// </summary>
public class IdentityDbContext :
IdentityDbContext<IdentityUser, IdentityRole, string, IdentityUserLogin, IdentityUserRole, IdentityUserClaim>
{
/// <summary>
///     Default constructor which uses the DefaultConnection
/// </summary>
public IdentityDbContext()
: this("DefaultConnection")
{
}

/// <summary>
///     Constructor which takes the connection string to use
/// </summary>
/// <param name="nameOrConnectionString"></param>
public IdentityDbContext(string nameOrConnectionString)
: base(nameOrConnectionString)
{
}

/// <summary>
///     Constructs a new context instance using the existing connection to connect to a database, and initializes it from
///     the given model.  The connection will not be disposed when the context is disposed if contextOwnsConnection is
///     false.
/// </summary>
/// <param name="existingConnection">An existing connection to use for the new context.</param>
/// <param name="model">The model that will back this context.</param>
/// <param name="contextOwnsConnection">
///     Constructs a new context instance using the existing connection to connect to a
///     database, and initializes it from the given model.  The connection will not be disposed when the context is
///     disposed if contextOwnsConnection is false.
/// </param>
public IdentityDbContext(DbConnection existingConnection, DbCompiledModel model, bool contextOwnsConnection)
: base(existingConnection, model, contextOwnsConnection)
{
}
}

/// <summary>
///     DbContext which uses a custom user entity with a string primary key
/// </summary>
/// <typeparam name="TUser"></typeparam>
public class IdentityDbContext<TUser> :
IdentityDbContext<TUser, IdentityRole, string, IdentityUserLogin, IdentityUserRole, IdentityUserClaim>
where TUser : IdentityUser
{
/// <summary>
///     Default constructor which uses the DefaultConnection
/// </summary>
public IdentityDbContext()
: this("DefaultConnection")
{
}

/// <summary>
///     Constructor which takes the connection string to use
/// </summary>
/// <param name="nameOrConnectionString"></param>
public IdentityDbContext(string nameOrConnectionString)
: this(nameOrConnectionString, true)
{
}

/// <summary>
///     Constructor which takes the connection string to use
/// </summary>
/// <param name="nameOrConnectionString"></param>
/// <param name="throwIfV1Schema">Will throw an exception if the schema matches that of Identity 1.0.0</param>
public IdentityDbContext(string nameOrConnectionString, bool throwIfV1Schema)
: base(nameOrConnectionString)
{
if (throwIfV1Schema && IsIdentityV1Schema(this))
{
throw new InvalidOperationException(IdentityResources.IdentityV1SchemaError);
}
}

/// <summary>
///     Constructs a new context instance using the existing connection to connect to a database, and initializes it from
///     the given model.  The connection will not be disposed when the context is disposed if contextOwnsConnection is
///     false.
/// </summary>
/// <param name="existingConnection">An existing connection to use for the new context.</param>
/// <param name="model">The model that will back this context.</param>
/// <param name="contextOwnsConnection">
///     Constructs a new context instance using the existing connection to connect to a
///     database, and initializes it from the given model.  The connection will not be disposed when the context is
///     disposed if contextOwnsConnection is false.
/// </param>
public IdentityDbContext(DbConnection existingConnection, DbCompiledModel model, bool contextOwnsConnection)
: base(existingConnection, model, contextOwnsConnection)
{
}

internal static bool IsIdentityV1Schema(DbContext db)
{
var originalConnection = db.Database.Connection as SqlConnection;
// Give up and assume its ok if its not a sql connection
if (originalConnection == null)
{
return false;
}

if (db.Database.Exists())
{
using (var tempConnection = new SqlConnection(originalConnection.ConnectionString))
{
tempConnection.Open();
return
VerifyColumns(tempConnection, "AspNetUsers", "Id", "UserName", "PasswordHash", "SecurityStamp",
"Discriminator") &&
VerifyColumns(tempConnection, "AspNetRoles", "Id", "Name") &&
VerifyColumns(tempConnection, "AspNetUserRoles", "UserId", "RoleId") &&
VerifyColumns(tempConnection, "AspNetUserClaims", "Id", "ClaimType", "ClaimValue", "User_Id") &&
VerifyColumns(tempConnection, "AspNetUserLogins", "UserId", "ProviderKey", "LoginProvider");
}
}

return false;
}

[SuppressMessage("Microsoft.Security", "CA2100:Review SQL queries for security vulnerabilities",
Justification = "Reviewed")]
internal static bool VerifyColumns(SqlConnection conn, string table, params string[] columns)
{
var tableColumns = new List<string>();
using (
var command =
new SqlCommand("SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS where TABLE_NAME=@Table", conn))
{
command.Parameters.Add(new SqlParameter("Table", table));
using (var reader = command.ExecuteReader())
{
while (reader.Read())
{
// Add all the columns from the table
tableColumns.Add(reader.GetString(0));
}
}
}
// Make sure that we find all the expected columns
return columns.All(tableColumns.Contains);
}
}

/// <summary>
///     IdentityDbContext of IdentityUsers
/// </summary>
/// <typeparam name="TUser"></typeparam>
/// <typeparam name="TRole"></typeparam>
/// <typeparam name="TKey"></typeparam>
/// <typeparam name="TUserLogin"></typeparam>
/// <typeparam name="TUserRole"></typeparam>
/// <typeparam name="TUserClaim"></typeparam>
public class IdentityDbContext<TUser, TRole, TKey, TUserLogin, TUserRole, TUserClaim> : DbContext
where TUser : IdentityUser<TKey, TUserLogin, TUserRole, TUserClaim>
where TRole : IdentityRole<TKey, TUserRole>
where TUserLogin : IdentityUserLogin<TKey>
where TUserRole : IdentityUserRole<TKey>
where TUserClaim : IdentityUserClaim<TKey>
{
/// <summary>
///     Default constructor which uses the "DefaultConnection" connectionString
/// </summary>
public IdentityDbContext()
: this("DefaultConnection")
{
}

/// <summary>
///     Constructor which takes the connection string to use
/// </summary>
/// <param name="nameOrConnectionString"></param>
public IdentityDbContext(string nameOrConnectionString)
: base(nameOrConnectionString)
{
}

/// <summary>
///     Constructs a new context instance using the existing connection to connect to a database, and initializes it from
///     the given model.  The connection will not be disposed when the context is disposed if contextOwnsConnection is
///     false.
/// </summary>
/// <param name="existingConnection">An existing connection to use for the new context.</param>
/// <param name="model">The model that will back this context.</param>
/// <param name="contextOwnsConnection">
///     Constructs a new context instance using the existing connection to connect to a
///     database, and initializes it from the given model.  The connection will not be disposed when the context is
///     disposed if contextOwnsConnection is false.
/// </param>
public IdentityDbContext(DbConnection existingConnection, DbCompiledModel model, bool contextOwnsConnection)
: base(existingConnection, model, contextOwnsConnection)
{
}

/// <summary>
///     EntitySet of Users
/// </summary>
public virtual IDbSet<TUser> Users { get; set; }

/// <summary>
///     EntitySet of Roles
/// </summary>
public virtual IDbSet<TRole> Roles { get; set; }

/// <summary>
///     If true validates that emails are unique
/// </summary>
public bool RequireUniqueEmail { get; set; }

/// <summary>
///     Maps table names, and sets up relationships between the various user entities
/// </summary>
/// <param name="modelBuilder"></param>
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
if (modelBuilder == null)
{
throw new ArgumentNullException("modelBuilder");
}

// Needed to ensure subclasses share the same table
var user = modelBuilder.Entity<TUser>()
.ToTable("AspNetUsers");
user.HasMany(u => u.Roles).WithRequired().HasForeignKey(ur => ur.UserId);
user.HasMany(u => u.Claims).WithRequired().HasForeignKey(uc => uc.UserId);
user.HasMany(u => u.Logins).WithRequired().HasForeignKey(ul => ul.UserId);
user.Property(u => u.UserName)
.IsRequired()
.HasMaxLength(256)
.HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute("UserNameIndex") { IsUnique = true }));

// CONSIDER: u.Email is Required if set on options?
user.Property(u => u.Email).HasMaxLength(256);

modelBuilder.Entity<TUserRole>()
.HasKey(r => new { r.UserId, r.RoleId })
.ToTable("AspNetUserRoles");

modelBuilder.Entity<TUserLogin>()
.HasKey(l => new { l.LoginProvider, l.ProviderKey, l.UserId })
.ToTable("AspNetUserLogins");

modelBuilder.Entity<TUserClaim>()
.ToTable("AspNetUserClaims");

var role = modelBuilder.Entity<TRole>()
.ToTable("AspNetRoles");
role.Property(r => r.Name)
.IsRequired()
.HasMaxLength(256)
.HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute("RoleNameIndex") { IsUnique = true }));
role.HasMany(r => r.Users).WithRequired().HasForeignKey(ur => ur.RoleId);
}

/// <summary>
///     Validates that UserNames are unique and case insenstive
/// </summary>
/// <param name="entityEntry"></param>
/// <param name="items"></param>
/// <returns></returns>
protected override DbEntityValidationResult ValidateEntity(DbEntityEntry entityEntry,
IDictionary<object, object> items)
{
if (entityEntry != null && entityEntry.State == EntityState.Added)
{
var errors = new List<DbValidationError>();
var user = entityEntry.Entity as TUser;
//check for uniqueness of user name and email
if (user != null)
{
if (Users.Any(u => String.Equals(u.UserName, user.UserName)))
{
errors.Add(new DbValidationError("User",
String.Format(CultureInfo.CurrentCulture, IdentityResources.DuplicateUserName, user.UserName)));
}
if (RequireUniqueEmail && Users.Any(u => String.Equals(u.Email, user.Email)))
{
errors.Add(new DbValidationError("User",
String.Format(CultureInfo.CurrentCulture, IdentityResources.DuplicateEmail, user.Email)));
}
}
else
{
var role = entityEntry.Entity as TRole;
//check for uniqueness of role name
if (role != null && Roles.Any(r => String.Equals(r.Name, role.Name)))
{
errors.Add(new DbValidationError("Role",
String.Format(CultureInfo.CurrentCulture, IdentityResources.RoleAlreadyExists, role.Name)));
}
}
if (errors.Any())
{
return new DbEntityValidationResult(entityEntry, errors);
}
}
return base.ValidateEntity(entityEntry, items);
}
}
}

上面的代码出自：
https://www.symbolsource.org/MyGet/Metadata/aspnetwebstacknightly/Project/Microsoft.AspNet.Identity.EntityFramework/2.0.0-rtm-140221/Release/Default/Microsoft.AspNet.Identity.EntityFramework/Microsoft.AspNet.Identity.EntityFramework/IdentityDbContext.cs?ImageName=Microsoft.AspNet.Identity.EntityFramework
想查看Microsoft.AspNet.Identity.EntityFramework.dll中IdentityDbContext的源码，却发现Github上Identity的代码和实际调用的dll里面的结构不一致。

找到如上代码，留文备用。