正文转自:http://www.cnblogs.com/hantianwei/p/5723959.html

 

前言

  Asp.net Core
改变了事先的封闭,现在开源且开放,下面我们来所以Redis存储Session来开一个简短的测试,或者叫做中间件(middleware)。

  对于Session来说褒贬不一,很多丁直接说绝不为此,也起众多总人口以就此,这个呢从没断然的这义,个人觉得一旦不影什么还以得好实现的事物是可以就此的,现在未针对可免可用做表态,我们仅仅关注实现。

类库引用

  这个相对于事先的.net是有利了重重,需要以project.json中之dependencies节点中补充加如下内容:

    "StackExchange.Redis": "1.1.604-alpha",
    "Microsoft.AspNetCore.Session": "1.1.0-alpha1-21694"

Redis实现

此并非json自己实现,而是借https://github.com/aspnet/Caching/tree/dev/src/Microsoft.Extensions.Caching.Redis代码来实现,不知道为什么之前还有这个类库,而现在NUGET止没有了,为了不影响日后升级我的命名空间也用 Microsoft.Extensions.Caching.Redis

可以看到微软此发出四独八九不离十,其实我们才待三单,第四单拿过来反而会拧:

json 1😉

using System;
using System.Threading.Tasks;
using Microsoft.Extensions.Caching.Distributed;
using Microsoft.Extensions.Options;
using StackExchange.Redis;

namespace Microsoft.Extensions.Caching.Redis
{
    public class RedisCache : IDistributedCache, IDisposable
    {
        // KEYS[1] = = key
        // ARGV[1] = absolute-expiration - ticks as long (-1 for none)
        // ARGV[2] = sliding-expiration - ticks as long (-1 for none)
        // ARGV[3] = relative-expiration (long, in seconds, -1 for none) - Min(absolute-expiration - Now, sliding-expiration)
        // ARGV[4] = data - byte[]
        // this order should not change LUA script depends on it
        private const string SetScript = (@"
                redis.call('HMSET', KEYS[1], 'absexp', ARGV[1], 'sldexp', ARGV[2], 'data', ARGV[4])
                if ARGV[3] ~= '-1' then
                  redis.call('EXPIRE', KEYS[1], ARGV[3])
                end
                return 1");
        private const string AbsoluteExpirationKey = "absexp";
        private const string SlidingExpirationKey = "sldexp";
        private const string DataKey = "data";
        private const long NotPresent = -1;

        private ConnectionMultiplexer _connection;
        private IDatabase _cache;

        private readonly RedisCacheOptions _options;
        private readonly string _instance;

        public RedisCache(IOptions<RedisCacheOptions> optionsAccessor)
        {
            if (optionsAccessor == null)
            {
                throw new ArgumentNullException(nameof(optionsAccessor));
            }

            _options = optionsAccessor.Value;

            // This allows partitioning a single backend cache for use with multiple apps/services.
            _instance = _options.InstanceName ?? string.Empty;
        }

        public byte[] Get(string key)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }

            return GetAndRefresh(key, getData: true);
        }

        public async Task<byte[]> GetAsync(string key)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }

            return await GetAndRefreshAsync(key, getData: true);
        }

        public void Set(string key, byte[] value, DistributedCacheEntryOptions options)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }

            if (value == null)
            {
                throw new ArgumentNullException(nameof(value));
            }

            if (options == null)
            {
                throw new ArgumentNullException(nameof(options));
            }

            Connect();

            var creationTime = DateTimeOffset.UtcNow;

            var absoluteExpiration = GetAbsoluteExpiration(creationTime, options);

            var result = _cache.ScriptEvaluate(SetScript, new RedisKey[] { _instance + key },
                new RedisValue[]
                {
                        absoluteExpiration?.Ticks ?? NotPresent,
                        options.SlidingExpiration?.Ticks ?? NotPresent,
                        GetExpirationInSeconds(creationTime, absoluteExpiration, options) ?? NotPresent,
                        value
                });
        }

        public async Task SetAsync(string key, byte[] value, DistributedCacheEntryOptions options)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }

            if (value == null)
            {
                throw new ArgumentNullException(nameof(value));
            }

            if (options == null)
            {
                throw new ArgumentNullException(nameof(options));
            }

            await ConnectAsync();

            var creationTime = DateTimeOffset.UtcNow;

            var absoluteExpiration = GetAbsoluteExpiration(creationTime, options);

            await _cache.ScriptEvaluateAsync(SetScript, new RedisKey[] { _instance + key },
                new RedisValue[]
                {
                        absoluteExpiration?.Ticks ?? NotPresent,
                        options.SlidingExpiration?.Ticks ?? NotPresent,
                        GetExpirationInSeconds(creationTime, absoluteExpiration, options) ?? NotPresent,
                        value
                });
        }

        public void Refresh(string key)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }

            GetAndRefresh(key, getData: false);
        }

        public async Task RefreshAsync(string key)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }

            await GetAndRefreshAsync(key, getData: false);
        }

        private void Connect()
        {
            if (_connection == null)
            {
                _connection = ConnectionMultiplexer.Connect(_options.Configuration);
                _cache = _connection.GetDatabase();
            }
        }

        private async Task ConnectAsync()
        {
            if (_connection == null)
            {
                _connection = await ConnectionMultiplexer.ConnectAsync(_options.Configuration);
                _cache = _connection.GetDatabase();
            }
        }

        private byte[] GetAndRefresh(string key, bool getData)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }

            Connect();

            // This also resets the LRU status as desired.
            // TODO: Can this be done in one operation on the server side? Probably, the trick would just be the DateTimeOffset math.
            RedisValue[] results;
            if (getData)
            {
                results = _cache.HashMemberGet(_instance +

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