受欢迎的博客标签

StackExchange.Redis-How to add Generic List to Redis?

Published

For example, if I have a model called Customer

public class Customer
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string Address1 { get; set; }
        public string City { get; set; }
        public string State { get; set; }
    }

Example:

var customers = new List<Customer>();

StackExchange.Redis is a raw client - it talks in Redis terms only. 

 created 2 extension methods, which help me serialize/deserialize complex type for Redis database.

public static class RedisUtils
{
    //Serialize in Redis format:
    public static HashEntry[] ToHashEntries(this object obj)
    {
        PropertyInfo[] properties = obj.GetType().GetProperties();
        return properties
            .Where(x=> x.GetValue(obj)!=null) // <-- PREVENT NullReferenceException
            .Select(property => new HashEntry(property.Name, property.GetValue(obj)
            .ToString())).ToArray();
    }

    //Deserialize from Redis format
    public static T ConvertFromRedis<T>(this HashEntry[] hashEntries)
    {
        PropertyInfo[] properties = typeof(T).GetProperties();
        var obj = Activator.CreateInstance(typeof(T));
        foreach (var property in properties)
        {
            HashEntry entry = hashEntries.FirstOrDefault(g => g.Name.ToString().Equals(property.Name));
            if (entry.Equals(new HashEntry())) continue;
            property.SetValue(obj, Convert.ChangeType(entry.Value.ToString(), property.PropertyType));
        }
        return (T)obj;
    }
}

Usage:

var customer = new Customer
{
//Initialization
};

Db.HashSet("customer", customer.ToHashEntries());
Customer result = Db.HashGetAll("customer").ConvertFromRedis<Customer>();

Assert.AreEqual(customer.FirstName, result.FirstName);
Assert.AreEqual(customer.LastName, result.LastName);
Assert.AreEqual(customer.Address1, result.Address1);

 

 option:

AzureredisDb.Cache is СonnectionMultiplexer.Connect and GetDatabase();

public static class StackExchangeRedisExtensions
{

    public static T Get<T>(string key)
    {
        var connect = AzureredisDb.Cache;
        var r = AzureredisDb.Cache.StringGet(key);
        return Deserialize<T>(r);
    }

    public static List<T> GetList<T>(string key)
    {                       
        return (List<T>)Get(key);
    }

    public static void SetList<T>(string key, List<T> list)
    {
        Set(key, list);
    }

    public static object Get(string key)
    {
        return Deserialize<object>(AzureredisDb.Cache.StringGet(key));
    }

    public static void Set(string key, object value)
    {
        AzureredisDb.Cache.StringSet(key, Serialize(value));
    }

    static byte[] Serialize(object o)
    {
        if (o == null)
        {
            return null;
        }

        BinaryFormatter binaryFormatter = new BinaryFormatter();
        using (MemoryStream memoryStream = new MemoryStream())
        {
            binaryFormatter.Serialize(memoryStream, o);
            byte[] objectDataAsStream = memoryStream.ToArray();
            return objectDataAsStream;
        }
    }

    static T Deserialize<T>(byte[] stream)
    {
        if (stream == null)
        {
            return default(T);
        }

        BinaryFormatter binaryFormatter = new BinaryFormatter();
        using (MemoryStream memoryStream = new MemoryStream(stream))
        {
            T result = (T)binaryFormatter.Deserialize(memoryStream);
            return result;
        }
    }
}

 

如果你仅仅为了缓存存一批量的 List<Customer> 数据, 那么自己封装一个ListGet() 和 ListSet()方法吧。

我对比过使用 List 和 String 两种类型存储。

Redis 的List类型和 .NET领域还有所不同,实际上,它是一个双向队列,可以左右插入值。

所以如果是批量数据插入 那么必须一个个插入, 代码比较简单如下:

//封装的ListSet
public void ListSet<T>(string key, List<T> value)
{
        .....
       //下面的database 是redis的数据库对象.
        foreach (var single in value)
        {
                var s = ConvertJson(single); //序列化
                database.ListRightPush(key, s); //要一个个的插入
        }
}

//封装的ListGet
public void ListGet<T>(string key)
{
       ...
       //ListRange返回的是一组字符串对象
       //需要逐个反序列化成实体
       var vList = database.ListRange(key) ;  
       List<T> result = new List<T>();
       foreach (var item in vList)
       {
           var model = ConvertObj<T>(item); //反序列化
           result.Add(model);
       }
       return result;
}