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Autofac:如何在单实例作用域中使用每个请求依赖项?

autofac asp.net-web-api2 dependency-injection asp.net-web-api c#

0

Nikita · 技术社区 · 8 年前

有 IDbConnection 连接依赖项注册为 per-request 和 ApplicationOAuthProvider 注册为 single instance .

builder.Register(c => new SqlConnection(WebConfigUtils.DefaultConnectionString))
            .As<IDbConnection>()
            .InstancePerRequest();

builder.RegisterType<ApplicationOAuthProvider>()
            .As<IOAuthAuthorizationServerProvider>()
            .PropertiesAutowired()
            .SingleInstance();

需要在标识声明中存储用户权限。为此,我创建了GetRolePermissions命令,并在该命令中插入 IDB连接 实例。

public class GetRolePermissions
{
    public class Command: IRequest<List<string>>
    {
        public ICollection<AspNetUserRole> UserRoles { get; set; }
    }

    public class Handler : AsyncRequestHandler<Command, List<string>>
    {
        private IDbConnection databaseConnection;

        public Handler(IDbConnection databaseConnection)
        {
            this.databaseConnection = databaseConnection;
        }
    }
}

此命令是在 应用程序身份验证提供程序

public class ApplicationOAuthProvider : OAuthAuthorizationServerProvider
{
    private async Task<ClaimsIdentity> GenerateUserIdentityAsync(AspNetUser user, string authenticationType)
    {
        user.SecurityStamp = Guid.NewGuid().ToString();
        var identity = await mediator.Send(new GenerateUserIdentity.Command
        {
            AuthenticationType = authenticationType,
            User = user
        });

        List<string> permissions = null;
        permissions = await mediator.Send(new GetRolePermissions.Command { UserRoles = user.Roles });
        var permissionClaimValue = permissions != null && permissions.Count > 0
            ? permissions.Aggregate((resultString, permission) => resultString + "," + permission)
            : "";
        identity.AddClaim(new Claim(AuthenticationConstants.Gender, user.Gender.ToString()));
        identity.AddClaim(new Claim(AuthenticationConstants.Permissions, permissionClaimValue));
        return identity;
    }
}

permissions = await mediator.Send(new GetRolePermissions.Command { UserRoles = user.Roles }); -将错误抛出为 GetRolePermissions.Handler 需要注射 IDB连接 ,但当前的autofac范围 应用程序身份验证提供程序 是 "root" 而且没有 iDbConnection 已在此范围内注册。但它存在于 按请求 范围。

不想使用 perLifettime 因为我认为 dbConnection 应该在不必要时关闭我被认为是这样做的:

using(var scope = AutofacConfig.container.BeginLifiTime("AutofacWebRequest")) 
{
      permissions = await mediator.Send(new GetRolePermissions.Command { UserRoles = user.Roles });
}

但不能让这个解决方案起作用。我不知道如何正确地获取容器,目前它是AutofacConfig的静态变量,我手动设置的。

如何启用注入 IDB连接 进入这个 GetPermissions.Handler ?

1 回复 | 直到 8 年前

1

Alexander Leonov 8 年前

事实上, InstancePerLifetimeScope() 是你要找的解决方案。您只需要注入DbConnection 工厂生产自有产品( docs link 1 和 docs link 2 )DbConnection的实例,而不是DbConnection本身。

// registration

builder.RegisterType<SqlConnection>()
    .As<IDbConnection>()
    .WithParameter(new NamedParameter("connectionString", WebConfigUtils.DefaultConnectionString))
    .InstancePerLifetimeScope();

// usage

public class GetRolePermissions
{
    public class Command: IRequest<List<string>>
    {
        public ICollection<AspNetUserRole> UserRoles { get; set; }
    }

    public class Handler : AsyncRequestHandler<Command, List<string>>
    {
        private Func<Owned<IDbConnection>> _connectionFactory;

        public Handler(Func<Owned<IDbConnection>> connectionFactory)
        {
            _connectionFactory = connectionFactory;
        }

        // not really sure where your consuming code is, so just something off the top of my head
        public DontKnowYourResultType Handle(GetRolePermissions.Command cmd) {
            using (var ownedConnection = _connectionFactory()) {
                // ownedConnection.Value is the DbConnection you want
                // ... do your stuff with that connection
            } // and connection gets destroyed upon leaving "using" scope
        }
    }
}

它确实会更改请求作用域的子作用域的行为,但我不确定这是否是您的代码的问题-请尝试一下,它应该可以正常工作如果没有,你知道该问哪里。;)