Session of Asp.NetCore

• MVC 和 Asp.NetCore开发得差别在哪里？
• • ISession 声明最小化
  • 自带有的扩展方法
  • Session 的扩展.

MVC 和 Asp.NetCore开发得差别在哪里？

声明最小化，然后扩展方法增强API。以Session为例：

ISession 声明最小化

namespace Microsoft.AspNetCore.Http
{
    public interface ISession
    {
        //
        // Summary:
        //     A unique identifier for the current session. This is not the same as the session
        //     cookie since the cookie lifetime may not be the same as the session entry lifetime
        //     in the data store.
        string Id { get; }
        //
        // Summary:
        //     Indicate whether the current session has loaded.
        bool IsAvailable { get; }
        //
        // Summary:
        //     Enumerates all the keys, if any.
        IEnumerable<string> Keys { get; }

        //
        // Summary:
        //     Remove all entries from the current session, if any. The session cookie is not
        //     removed.
        void Clear();
        //
        // Summary:
        //     Store the session in the data store. This may throw if the data store is unavailable.
        Task CommitAsync(CancellationToken cancellationToken = default);
        //
        // Summary:
        //     Load the session from the data store. This may throw if the data store is unavailable.
        Task LoadAsync(CancellationToken cancellationToken = default);
        //
        // Summary:
        //     Remove the given key from the session if present.
        //
        // Parameters:
        //   key:
        void Remove(string key);
        //
        // Summary:
        //     Set the given key and value in the current session. This will throw if the session
        //     was not established prior to sending the response.
        //
        // Parameters:
        //   key:
        //
        //   value:
        void Set(string key, byte[] value);
        //
        // Summary:
        //     Retrieve the value of the given key, if present.
        //
        // Parameters:
        //   key:
        //
        //   value:
        bool TryGetValue(string key, out byte[] value);
    }
           

自带有的扩展方法

namespace Microsoft.AspNetCore.Http
{
    public static class SessionExtensions
    {
        public static byte[] Get(this ISession session, string key);
        public static int? GetInt32(this ISession session, string key);
        public static string GetString(this ISession session, string key);
        public static void SetInt32(this ISession session, string key, int value);
        public static void SetString(this ISession session, string key, string value);
    }
}
           

Session 的扩展.

1. 背景：我们发现系统默认提供的Session方法，仅能存储byte、string、int类型，很不灵活，我们想能存储任何对象，这个时候就需要我们自行扩展。

2. 利用Newtonsoft.Json进行扩展

   All session data must be serialized to enable a distributed cache scenario, even when using the in-memory cache. String and integer serializers are provided by the extension methods of ISession. Complex types must be serialized by the user using another mechanism, such as JSON.

扩展代码详见SessionExtensions中的Set和Get方法：

public static class SessionExtensions
    {
        public static void Set<T>(this ISession session, string key, T value)
        {
            session.SetString(key, JsonConvert.SerializeObject(value));
        }

        public static T Get<T>(this ISession session, string key)
        {
            var value = session.GetString(key);
            return value == null ? default(T) :
                                  JsonConvert.DeserializeObject<T>(value);
        }
    }