在控制器中更改 ASP.NET Core 2.0 标识连接字符串

Question

我正在创建一个基于多租户结构的 Web 应用程序。因此，每个用户请求都会根据主机名将该用户锁定为特定租户（每个租户使用不同的数据库。）我可以设置一般上下文的连接字符串，但我现在不知道如何更改连接ASP.NET Core 2.0 Identity 对象的字符串。

我看到他们让我们这样做的默认方式是在 StartUp.cs 中设置 UseAuthentication()。然后当调用控制器时，DI 会设置 UserManager 和 SignInManager 对象。我假设我需要在每个控制器构造函数中创建新的 UserManager 和 SignInManager 对象，并为该租户传递特定的连接字符串（根本不使用 DI。）

对此有什么想法吗？

澄清：

我希望弄清楚是否可以通过依赖注入将传递的身份对象的数据库连接字符串更改为控制器。

Answer 1

// Startup class of asp.net core 2
public void ConfigureServices(IServiceCollection services)
{
    services.AddMultitenancy<Tenant, TenantResolver>();

    string accountsConnection = configuration.GetConnectionString("AccountsConnectionString");

    services.AddScoped<LicenseManager>();
    services.AddScoped<AccountManager>();


    services.AddEntityFrameworkSqlServer()
        .AddDbContext<AccountsContext>(options =>
        {
            options.UseSqlServer(accountsConnection);
        })
        .AddDbContext<MasterDataContext>(options => options.UseSqlServer(masterdataConnection))
        .AddDbContext<DataContext>();

    services.AddMvc();
}

// Tenantresolver which get's the connectionstring from the claims. (seperate file/class)
// On authentication i create several claims with one claim with the connectionstring per user. 
// I use a seperate accounts database where all the tenants are saved which each of them has his own connectionstring
public class TenantResolver : MemoryCacheTenantResolver<Tenant>
{
    private readonly AccountsContext Context;

    public TenantResolver(AccountsContext context, IMemoryCache cache, ILoggerFactory logger)
        :base(cache, logger)
    {
        Context = context;
    }

    protected override string GetContextIdentifier(HttpContext context)
    {
        return context.User.Claims.Where(r => r.Type == ClaimTypes.AccountIdType).Select(s => s.Value).SingleOrDefault();
    }

    protected override IEnumerable<string> GetTenantIdentifiers(TenantContext<Tenant> context)
    {
        return new[] { context.Tenant.Tenant_Id.ToString() };
    }

    protected override Task<TenantContext<Tenant>> ResolveAsync(HttpContext context)
    {
        TenantContext<Tenant> tenantContext = null;

        string claim = context.User.Claims.Where(r => r.Type == ClaimTypes.AccountIdType).Select(s => s.Value).SingleOrDefault();

        var tenant = Context.Accounts
                .Where(q => q.IsActive == true && q.Account_Id.ToString() == claim)
                .Select(s => new Tenant(s.Account_Id, s.DataStore.DatabaseConnection))
                .FirstOrDefault();

        if (tenant != null)
        {
            tenantContext = new TenantContext<Tenant>(tenant);
        }

        return Task.FromResult(tenantContext);
    }
}

// Tenant class where i save the info needed.
public class Tenant
{
    public Tenant(
        Guid tenant_id,
        string database_ConnectionString)
    {
        Tenant_Id = tenant_id;
        Database_ConnectionString = database_ConnectionString;
    }

    public Guid Tenant_Id { get; set; }
    public string Database_ConnectionString { get; set; }
}

// DbContext class which uses the tenant and links the connectionstring to the current tenant.
public class DataContext : DbContext
{
    private readonly Tenant Tenant;

    public DataContext(DbContextOptions<DataContext> options, Tenant tenant)
        : base(options)
    {
        this.Tenant = tenant;
    }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        if (Tenant != null)
        {
            optionsBuilder.UseSqlServer(Tenant.Database_ConnectionString);
        }

        base.OnConfiguring(optionsBuilder);
    }
}