什麼是多租戶

網上有好多解釋，有些上升到了架構設計，讓你覺得似乎非常高深莫測，特別是目前流行的ABP架構中就有提到多租戶（IMustHaveTenant），其實說的簡單一點就是再每一張資料庫的表中新增一個TenantId的欄位，用於區分屬於不同的租戶（或是說不同的使用者組）的資料。關鍵是現實的方式必須對開發人員來說是透明的，不需要關注這個欄位的資訊，由後臺或是封裝在基類中實現資料的篩選和更新。

基本原理

從新使用者註冊時就必須指定使用者的TenantId,我的例子是用CompanyId,公司資訊做為TenantId,哪些使用者屬於不同的公司，每個使用者將來只能修改和查詢屬於本公司的資料。

接下來就是使用者登入的時候獲取使用者資訊的時候把TenantId儲存起來，asp.net mvc（不是 core） 是通過 Identity 2.0實現的認證和授權，這裡需要重寫部分程式碼來實現。

最後使用者對資料查詢/修改/新增時把使用者資訊中TenantId，這裡就需要設定一個Filter(過濾器)和每次SaveChange的插入TenantId

如何實現

第一步，擴充套件 Asp.net Identity user 屬性，必須新增一個TenantId欄位,根據Asp.net Mvc 自帶的專案模板修改IdentityModels.cs 這個檔案

 1   // You can add profile data for the user by adding more properties to your ApplicationUser class, please visit http://go.microsoft.com/fwlink/?LinkID=317594 to learn more.
 2   public class ApplicationUser : IdentityUser
 3   {
 4     public async Task<ClaimsIdentity> GenerateUserIdentityAsync(UserManager<ApplicationUser> manager, string authenticationType)
 5     {
 6       // Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
 7       var userIdentity = await manager.CreateIdentityAsync(this, authenticationType);
 8       // Add custom user claims here
 9       userIdentity.AddClaim(new Claim("http://schemas.microsoft.com/identity/claims/tenantid", this.TenantId.ToString()));
10       userIdentity.AddClaim(new Claim("CompanyName", this.CompanyName));
11       userIdentity.AddClaim(new Claim("EnabledChat", this.EnabledChat.ToString()));
12       userIdentity.AddClaim(new Claim("FullName", this.FullName));
13       userIdentity.AddClaim(new Claim("AvatarsX50", this.AvatarsX50));
14       userIdentity.AddClaim(new Claim("AvatarsX120", this.AvatarsX120));
15       return userIdentity;
16     }
17     public async Task<ClaimsIdentity> GenerateUserIdentityAsync(UserManager<ApplicationUser> manager)
18     {
19       // Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
20       var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);
21       // Add custom user claims here
22       return userIdentity;
23     }
24 
25     [Display(Name = "全名")]
26     public string FullName { get; set; }
27     [Display(Name = "性別")]
28     public int Gender { get; set; }
29     public int AccountType { get; set; }
30     [Display(Name = "所屬公司")]
31     public string CompanyCode { get; set; }
32     [Display(Name = "公司名稱")]
33     public string CompanyName { get; set; }
34     [Display(Name = "是否線上")]
35     public bool IsOnline { get; set; }
36     [Display(Name = "是否開啟聊天功能")]
37     public bool EnabledChat { get; set; }
38     [Display(Name = "小頭像")]
39     public string AvatarsX50 { get; set; }
40     [Display(Name = "大頭像")]
41     public string AvatarsX120 { get; set; }
42     [Display(Name = "租戶ID")]
43     public int TenantId { get; set; }
44   }
45 
46 
47 
48   public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
49   {
50     public ApplicationDbContext()
51         : base("DefaultConnection", throwIfV1Schema: false) => Database.SetInitializer<ApplicationDbContext>(null);
52 
53     public static ApplicationDbContext Create() => new ApplicationDbContext();
54 
55 
56   }

　　第二步 修改註冊使用者的程式碼，註冊新使用者的時候需要選擇所屬的公司資訊

 1  [HttpPost]
 2     [AllowAnonymous]
 3     [ValidateAntiForgeryToken]
 4     public async Task<ActionResult> Register(AccountRegistrationModel viewModel)
 5     {
 6       var data = this._companyService.Queryable().Select(x => new ListItem() { Value = x.Id.ToString(), Text = x.Name });
 7       this.ViewBag.companylist = data;
 8 
 9       // Ensure we have a valid viewModel to work with
10       if (!this.ModelState.IsValid)
11       {
12         return this.View(viewModel);
13       }
14 
15       // Try to create a user with the given identity
16       try
17       {
18         // Prepare the identity with the provided information
19         var user = new ApplicationUser
20         {
21           UserName = viewModel.Username,
22           FullName = viewModel.Lastname + "." + viewModel.Firstname,
23           CompanyCode = viewModel.CompanyCode,
24           CompanyName = viewModel.CompanyName,
25           TenantId=viewModel.TenantId,
26           Email = viewModel.Email,
27           AccountType = 0
28           
29         };
30         var result = await this.UserManager.CreateAsync(user, viewModel.Password);
31 
32         // If the user could not be created
33         if (!result.Succeeded)
34         {
35           // Add all errors to the page so they can be used to display what went wrong
36           this.AddErrors(result);
37 
38           return this.View(viewModel);
39         }
40 
41         // If the user was able to be created we can sign it in immediately
42         // Note: Consider using the email verification proces
43         await this.SignInAsync(user, true);
44 
45         return this.RedirectToLocal();
46       }
47       catch (DbEntityValidationException ex)
48       {
49         // Add all errors to the page so they can be used to display what went wrong
50         this.AddErrors(ex);
51 
52         return this.View(viewModel);
53       }
54     }

第三步 讀取登入使用者的TenantId 在使用者查詢和新增修改時把TenantId插入到表中,這裡需要引用

Z.EntityFramework.Plus，這個是免費開源的一個類庫，功能強大

 1  public StoreContext()
 2         : base("Name=DefaultConnection") {
 3       //獲取登入使用者資訊,tenantid
 4       var claimsidentity = (ClaimsIdentity)HttpContext.Current.User.Identity;
 5       var tenantclaim = claimsidentity?.FindFirst("http://schemas.microsoft.com/identity/claims/tenantid");
 6       var tenantid = Convert.ToInt32(tenantclaim?.Value);
 7       //設定當對Work物件進行查詢時預設新增過濾條件
 8       QueryFilterManager.Filter<Work>(q => q.Where(x => x.TenantId == tenantid));
 9       //設定當對Order物件進行查詢時預設新增過濾條件
10       QueryFilterManager.Filter<Order>(q => q.Where(x => x.TenantId == tenantid));
11     }
12 
13  public override Task<int> SaveChangesAsync(CancellationToken cancellationToken)
14     {
15       var currentDateTime = DateTime.Now;
16       var claimsidentity = (ClaimsIdentity)HttpContext.Current.User.Identity;
17       var tenantclaim = claimsidentity?.FindFirst("http://schemas.microsoft.com/identity/claims/tenantid");
18       var tenantid = Convert.ToInt32(tenantclaim?.Value);
19       foreach (var auditableEntity in this.ChangeTracker.Entries<Entity>())
20       {
21         if (auditableEntity.State == EntityState.Added || auditableEntity.State == EntityState.Modified)
22         {
23           //auditableEntity.Entity.LastModifiedDate = currentDateTime;
24           switch (auditableEntity.State)
25           {
26             case EntityState.Added:
27               auditableEntity.Property("LastModifiedDate").IsModified = false;
28               auditableEntity.Property("LastModifiedBy").IsModified = false;
29               auditableEntity.Entity.CreatedDate = currentDateTime;
30               auditableEntity.Entity.CreatedBy = claimsidentity.Name;
31               auditableEntity.Entity.TenantId = tenantid;
32               break;
33             case EntityState.Modified:
34               auditableEntity.Property("CreatedDate").IsModified = false;
35               auditableEntity.Property("CreatedBy").IsModified = false;
36               auditableEntity.Entity.LastModifiedDate = currentDateTime;
37               auditableEntity.Entity.LastModifiedBy = claimsidentity.Name;
38               auditableEntity.Entity.TenantId = tenantid;
39               //if (auditableEntity.Property(p => p.Created).IsModified || auditableEntity.Property(p => p.CreatedBy).IsModified)
40               //{
41               //    throw new DbEntityValidationException(string.Format("Attempt to change created audit trails on a modified {0}", auditableEntity.Entity.GetType().FullName));
42               //}
43               break;
44           }
45         }
46       }
47       return base.SaveChangesAsync(cancellationToken);
48     }
49 
50     public override int SaveChanges()
51     {
52       var currentDateTime = DateTime.Now;
53       var claimsidentity =(ClaimsIdentity)HttpContext.Current.User.Identity;
54       var tenantclaim = claimsidentity?.FindFirst("http://schemas.microsoft.com/identity/claims/tenantid");
55       var tenantid = Convert.ToInt32(tenantclaim?.Value);
56       foreach (var auditableEntity in this.ChangeTracker.Entries<Entity>())
57       {
58         if (auditableEntity.State == EntityState.Added || auditableEntity.State == EntityState.Modified)
59         {
60           auditableEntity.Entity.LastModifiedDate = currentDateTime;
61           switch (auditableEntity.State)
62           {
63             case EntityState.Added:
64               auditableEntity.Property("LastModifiedDate").IsModified = false;
65               auditableEntity.Property("LastModifiedBy").IsModified = false;
66               auditableEntity.Entity.CreatedDate = currentDateTime;
67               auditableEntity.Entity.CreatedBy = claimsidentity.Name;
68               auditableEntity.Entity.TenantId = tenantid;
69               break;
70             case EntityState.Modified:
71               auditableEntity.Property("CreatedDate").IsModified = false;
72               auditableEntity.Property("CreatedBy").IsModified = false;
73               auditableEntity.Entity.LastModifiedDate = currentDateTime;
74               auditableEntity.Entity.LastModifiedBy = claimsidentity.Name;
75               auditableEntity.Entity.TenantId = tenantid;
76               break;
77           }
78         }
79       }
80       return base.SaveChanges();
81     }

經過以上3步就實現一個簡單的多租戶查詢資料的功能。

希望對大家有