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

Question

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>();

How would I added a List of Customer? How would I do this?

 using (var redis = ConnectionMultiplexer.Connect(this.redisServer))
            {
                var db = redis.GetDatabase();

                db.SetAdd(key, ?????);
}

I think SetAdd is the right method, but I can't see how to get my generic list of Customer (i.e. List into the format of RedisValue.

Marc Gravell · Accepted Answer · 2014-09-17 19:42:09Z

16

StackExchange.Redis is a raw client - it talks in Redis terms only. It does not attempt to be an ORM of any kind. It will, however, store any string or byte[] that you care to throw at it - which means you should have your choice of serializers. JSON would be a reasonable default (Jil is awesome), although we tend to use protocol-buffers ourselves (via protobuf-net).

It you intend to use list semantics, I strongly recommend starting with the List* commands - sets have different semantics to lists - sets are unordered and only store unique values; lists preserve order and allow duplicates.

answered Sep 17, 2014 at 19:42

Marc Gravell

1.1m273 gold badges2.6k silver badges3k bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Shane Over a year ago

Understood. So I would maybe serialize my generic list of Customers to Json (via newtonsoft or what not), then I could save as a string and just serialize/deserialize back and forth? I'll check out the List commands.

Marc Gravell Over a year ago

@Shane two options - if you want to use the list features of redis, serialize each object separately and send as separate list rows. If you just want "store my list, fetch my list" - then: serialize the list and use the String* redis functions. A redis "string" just means "a single value" - it doesn't need to be a string (if that makes sense)

Philip P. Over a year ago

OR, you could store objects like Customer as hashes, and then have sorted sets to group them into "lists". That's actually cool because you can have same customer be in different "lists" (entirely reasonable) and store them only once. And easy to move between "lists".

Andrey Gubal · Accepted Answer · 2016-04-25 14:04:30Z

May be it helps. I also faced the same question at the beginning of my diving into StackExchange.Redis. In my project I created 2 extension methods, which help me serialize/deserialize complex type for Redis database. You may extend them to your needs.

Methods:

    public static class RedisUtils
        {
//Serialize in Redis format:
            public static HashEntry[] ToHashEntries(this object obj)
            {
                PropertyInfo[] properties = obj.GetType().GetProperties();
                return properties.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);

Suppose Customer class asked by OP has a custom object of say Product. In that case can you please explain how to proceed?

von v. · Accepted Answer · 2015-08-17 10:39:57Z

An improvement to Andrey Gubal's answer, to handle nullable properties or null values:

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;
    }
}

Erçin Dedeoğlu · Accepted Answer · 2016-03-04 10:37:14Z

4

This is an option

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;
        }
    }
}

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

edited Mar 4, 2016 at 10:37

Erçin Dedeoğlu

5,4414 gold badges52 silver badges73 bronze badges

answered Mar 22, 2015 at 18:06

Andrey Fedorov

591 bronze badge

3 Comments

user585968 Over a year ago

Generally avoid code-only answers. Consider adding a description that helps to explain your code. Thanks

user585968 Over a year ago

@alex Code-only answers may fall under 'Very Low Quality' ...and are candidates for deletion....We've always touted that we aren't a code factory. We are the people who teach others to fish. Code-only answers only feed a person for a day. I'm pretty sure I've never seen a Learn c# book consisting of a sequence of code listings with no dialog in between

knocte Over a year ago

storing binary data is a really bad approach IMO

Collectives™ on Stack Overflow

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

4 Answers 4

3 Comments

1 Comment

Comments

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

3 Comments

1 Comment

Comments

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related