Skip to main content

Using Redis distributed cache in dotnet core with helper extension methods

Redis cache is out process cache provider for a distributed environment. It is popular in Azure Cloud solution, but it also has a standalone application to operate upon in case of small enterprises application.

How to install Redis Cache on a local machine?
Redis can be used as a local cache server too on our local machines.

At first install, Chocolatey https://chocolatey.org/, to make installation of Redis easy. Also, the version under Chocolatey supports more commands and compatible with Official Cache package from Microsoft.
After Chocolatey installation hit choco install redis-64.
Once the installation is done, we can start the server by running redis-server.

Distributed Cache package and registration
dotnet core provides IDistributedCache interface which can be overrided with our own implementation. That is one of the beauties of dotnet core, having DI implementation at heart of framework.

There is already nuget package available to override IDistributedCache i:e Microsoft.Extensions.Caching.Redis.

To use we need to register service by using an extension method from the package.

 services.AddDistributedRedisCache(options =>  
 {  
   options.Configuration = Configuration["<Redis connection string>"];  
   options.InstanceName = "<prefix name for easy identification (optional)>:";  
 });

How to use Redis Cache based on IDistributedCache?
Since Redis cache registration is done, we can use IDistributedCache reference in the constructor to utilize Redis.
Default distributed cache option.
Default options from IDistributedCache
The image on the right side provide all options from IDistrubutedCache. Also, you can see I have used it on constructor to get an instance from DI. This is a Disposable implementation so if you are you are not using DI then disposing of the object needs to be taken care explicitly.

As you can see from function names, these are pretty basic to use. The idea is to extend the APIs with C# extension methods through which we can take care of serialization and deserialization of any object too.

In the extension method, I am going to use GetOrSetCacheAsync which would take care of getting or setting of value automatically in the cache, if the cache is available in Redis than it would get from it else it would save in Redis and get the value, we would see how to use shortly.

The GetOrSetCacheAsync function backed by GetCacheValueAsync to get from Redis and to save StoreValueAsync. These all are generic version. Here is the whole implementation of Extension methods.

 /// <summary>  
 /// Extension methods for caching.  
 /// </summary>  
 public static class CacheExtension  
 {  
   /// <summary>  
   /// Gets or set cache asynchronous.  
   /// </summary>  
   /// <typeparam name="TResult">The type of the result.</typeparam>  
   /// <param name="cache">The distributed cache interface.</param>  
   /// <param name="key">The key for storing cache.</param>  
   /// <param name="storingItem">The storing item.</param>  
   /// <param name="cacheRule">The cache rule.</param>  
   /// <returns>  
   /// The result for stored item.  
   /// </returns>  
   public static async Task<TResult> GetOrSetCacheAsync<TResult>(this IDistributedCache cache, string key,  
     Func<TResult> storingItem, DistributedCacheEntryOptions cacheRule = null)  
     where TResult : class  
   {  
     var cachedValue = await cache.GetCacheValueAsync<TResult>(key);  
     if (cachedValue == null)  
     {  
       return await cache.StoreValueAsync(key, storingItem, cacheRule);  
     }  
     return cachedValue;  
   }  
   /// <summary>  
   /// Gets the cache value asynchronous.  
   /// </summary>  
   /// <typeparam name="TResult">The type of the result.</typeparam>  
   /// <param name="cache">The cache.</param>  
   /// <param name="key">The key for caching.</param>  
   /// <param name="storingItem">The storing item.</param>  
   /// <returns>Value of cached item.</returns>  
   public static async Task<TResult> GetCacheValueAsync<TResult>(this IDistributedCache cache, string key)  
       where TResult : class  
   {  
     if (IsNullOrEmpty(key))  
     {  
       throw new ArgumentNullException(nameof(key));  
     }  
     var cachedValue = await cache.GetStringAsync(key.ToLower(CultureInfo.InvariantCulture));  
     if (IsNullOrEmpty(cachedValue))  
     {  
       return null;  
     }  
     return JsonConvert.DeserializeObject<TResult>(cachedValue);  
   }  
   /// <summary>  
   /// Stores the value in cache.  
   /// </summary>  
   /// <typeparam name="TResult">The type of the result.</typeparam>  
   /// <param name="cache">The cache.</param>  
   /// <param name="key">The key for caching.</param>  
   /// <param name="storingItem">The storing item.</param>  
   /// <param name="cacheRule">The cache rule.</param>  
   /// <returns>  
   /// Value of caching item.  
   /// </returns>  
   /// <exception cref="ArgumentNullException">key</exception>  
   public static async Task<TResult> StoreValueAsync<TResult>(this IDistributedCache cache, string key,  
     Func<TResult> storingItem, DistributedCacheEntryOptions cacheRule = null)  
     where TResult : class  
   {  
     if (IsNullOrEmpty(key))  
     {  
       throw new ArgumentNullException(nameof(key));  
     }  
     var storingValue = storingItem();  
     if (storingValue != null && storingValue != default(TResult))  
     {  
       var redisKey = key.ToLower(CultureInfo.InvariantCulture);  
       var value = JsonConvert.SerializeObject(storingValue);  
       if (cacheRule != null)  
       {  
         await cache.SetStringAsync(redisKey, value, cacheRule);  
       }  
       else  
       {  
         await cache.SetStringAsync(redisKey, value);  
       }  
     }  
     return storingValue;  
   }  
 }

You can add your own implementation based on a need basis.

How to use created extension methods?
The best way to show this is through Unit Test class, so here is the code which utilizes and explains whole custom extension methods.

 [TestClass]  
 public class RedisCacheTest  
 {  
   private readonly IDistributedCache CacheStore;  
   public RedisCacheTest()  
   {  
     CacheStore = new RedisCache(new RedisCacheOptions  
     {  
       Configuration = "localhost:6379",  
       InstanceName = "Test:"  
     });  
   }  
   // INFO: Gets or sets the value based on request.  
   //    If it is first call it would save the value in Redis   
   //    and for second call onwards it would just receive the value from cache.  
   // WARNING: If we use same method to update value in cache again, it would not save.   
   //     Check OverWriteCache() and StoresCacheOnce() function  
   [TestMethod]  
   public async Task CacheStoreIsSame()  
   {  
     await CacheStore.GetOrSetCacheAsync("key", () =>  
     {  
       // Do some sort of process and return object.  
       return new RedisStoreClass("value");  
     });  
     var val = await CacheStore.GetCacheValueAsync<RedisStoreClass>("key");  
     Assert.IsTrue(val.Name == "value");  
   }  
   // INFO: Expiration test after 1 millisecond delay.  
   [TestMethod]  
   public async Task CacheExpire()  
   {  
     var cacheKey = "cache:expiration:test";  
     await CacheStore.GetOrSetCacheAsync(cacheKey,  
       () => new RedisStoreClass("value"), new DistributedCacheEntryOptions  
       {  
         AbsoluteExpirationRelativeToNow = TimeSpan.FromMilliseconds(100)  
       });  
     await Task.Delay(101);  
     var cachedValue = await CacheStore.GetCacheValueAsync<RedisStoreClass>(cacheKey);  
     Assert.IsNull(cachedValue);  
   }  
   // INFO: Overwriting cache.  
   [TestMethod]  
   public async Task OverWriteCache()  
   {  
     var cacheKey = "cache:overwrite";  
     await CacheStore.GetOrSetCacheAsync(cacheKey, () => new RedisStoreClass("value"));  
     await CacheStore.StoreValueAsync(cacheKey, () => new RedisStoreClass("value2"));  
     var cachedValue = await CacheStore.GetCacheValueAsync<RedisStoreClass>(cacheKey);  
     Assert.AreEqual(cachedValue.Name, "value2");  
   }  
   [TestMethod]  
   public async Task RemoveCache()  
   {  
     var cacheKey = "cache:remove";  
     await CacheStore.GetOrSetCacheAsync(cacheKey,  
       () => new RedisStoreClass("value"));  
     await Task.Delay(10000);  
     await CacheStore.RemoveAsync(cacheKey);  
     var cachedValue = await CacheStore.GetCacheValueAsync<RedisStoreClass>(cacheKey);  
     Assert.IsNull(cachedValue);  
   }  
   // INFO: Case insensitive check  
   [TestMethod]  
   public async Task CaseInsensitiveKey()  
   {  
     var cacheKey = "cache:InsensitiveKey";  
     await CacheStore.GetOrSetCacheAsync(cacheKey,  
       () => new RedisStoreClass("value"));  
     var val = await CacheStore.GetCacheValueAsync<RedisStoreClass>(cacheKey.ToUpperInvariant());  
     Assert.IsNotNull(val);  
   }  
   // INFO: If we use GetOrSetCacheAsync multiple times, new value won't be saved.  
   [TestMethod]  
   public async Task StoresCacheOnce()  
   {  
     var cacheKey = "cache:StoreOnce";  
     await CacheStore.GetOrSetCacheAsync(cacheKey,  
       () => new RedisStoreClass("value"));  
     await CacheStore.GetOrSetCacheAsync(cacheKey,  
       () => new RedisStoreClass("value2"));  
     var val = await CacheStore.GetCacheValueAsync<RedisStoreClass>(cacheKey);  
     Assert.AreEqual(val.Name, "value");  
   }  
 }  
 internal class RedisStoreClass  
 {  
   public string Name { get; set; }  
   public RedisStoreClass(string name)  
   {  
     Name = name;  
   }  
 }

Please note that to make it simple, I have not used disposed on RedisCache instance.




Labels:

Comments

  1. Jindo29 October 2019 at 20:36

    Dear Sir
    how can I delete all redis cache with some pattern key

    Example: I have 3 key like this
    Key 1: :User:1 (1: is dynamic)
    Key 2: :User:2 (2: is dynamic)
    Key 3: :Role:1
    -> how can I delete key 1 and 2

    ReplyDelete
    Replies
    1. Vikash Kumar24 August 2020 at 20:29

      So, sorry for really late..... reply. You might not need now but adding here if it can help someone else.
      You can create an extension method to remove, which can loop and look for your provided pattern to delete.

      Delete
  2. komala12 October 2021 at 16:19

    Thanks a lot, you made it really easy to understand
    Cucumber BDD Online Training
    BDD Cucumber Training in Bangalore

    ReplyDelete

Post a Comment

Popular posts from this blog

Elegantly dealing with TimeZones in MVC Core / WebApi

In any new application handling TimeZone/DateTime is mostly least priority and generally, if someone is concerned then it would be handled by using DateTime.UtcNow on codes while creating current dates and converting incoming Date to UTC to save on servers. Basically, the process is followed by saving DateTime to UTC format in a database and keep converting data to native format based on user region or single region in the application's presentation layer. The above is tedious work and have to be followed religiously. If any developer misses out the manual conversion, then that area of code/view would not work. With newer frameworks, there are flexible ways to deal/intercept incoming or outgoing calls to simplify conversion of TimeZones. These are steps/process to achieve it. 1. Central code for storing user's state about TimeZone. Also, central code for conversion logic based on TimeZones. 2. Dependency injection for the above class to ...
4 comments
Read more

Trim text in MVC Core through Model Binder

Trimming text can be done on client side codes, but I believe it is most suitable on MVC Model Binder since it would be at one place on infrastructure level which would be free from any manual intervention of developer. This would allow every post request to be processed and converted to a trimmed string. Let us start by creating Model binder using Microsoft.AspNetCore.Mvc.ModelBinding; using System; using System.Threading.Tasks; public class TrimmingModelBinder : IModelBinder { private readonly IModelBinder FallbackBinder; public TrimmingModelBinder(IModelBinder fallbackBinder) { FallbackBinder = fallbackBinder ?? throw new ArgumentNullException(nameof(fallbackBinder)); } public Task BindModelAsync(ModelBindingContext bindingContext) { if (bindingContext == null) { throw new ArgumentNullException(nameof(bindingContext)); } var valueProviderResult = bindingContext.ValueProvider.GetValue(bin...
2 comments
Read more

Handling JSON DateTime format on Asp.Net Core

This is a very simple trick to handle JSON date format on AspNet Core by global settings. This can be applicable for the older version as well. In a newer version by default, .Net depends upon Newtonsoft to process any JSON data. Newtonsoft depends upon Newtonsoft.Json.Converters.IsoDateTimeConverter class for processing date which in turns adds timezone for JSON data format. There is a global setting available for same that can be adjusted according to requirement. So, for example, we want to set default formatting to US format, we just need this code. services.AddMvc() .AddJsonOptions(options => { options.SerializerSettings.DateTimeZoneHandling = "MM/dd/yyyy HH:mm:ss"; });
1 comment
Read more

Centralized model validation both for MVC/WebApi and SPA client-side validation using FluentValidation

Validation is one of the crucial parts of any application. It has to validate on both client side and server side requests. What are target features or implementation from this article? Model validation for any given model. Centralized/One code for validation on both server-side and client-side. Automatic validation of model without writing any extra codes on/under actions for validation.  NO EXTRA/ANY codes on client-side to validate any form. Compatible with SPA. Can be compatible with any client-side validation framework/library. Like Angular Reactive form validation or any jquery validation libraries. Tools used in the implementation? FluentValidation : I feel DataAnnotation validation are excellent and simple to use, but in case of complex validation or writing any custom validations are always tricker and need to write a lot of codes to achieve whereas FluentValidations are simple even in case of complex validation. Generally, we need to validate inc...
1 comment
Read more

Architecture solution composting Repository Pattern, Unit Of Work, Dependency Injection, Factory Pattern and others

Project architecture is like garden, we plant the things in certain order and eventually they grow in similar manner. If things are planted well then they will all look(work) great and easier to manage. If they grow as cumbersome it would difficult to maintain and with time more problems would be happening in maintenance. There is no any fixed or known approach to decide project architecture and specially with Agile Methodology. In Agile Methodology, we cannot predict how our end products will look like similarly we cannot say a certain architecture will fit well for entire development lifespan for project. So, the best thing is to modify the architecture as per our application growth. I understand that it sounds good but will be far more problematic with actual development. If it is left as it is then more problems will arise with time. Just think about moving plant vs a full grown tree. Coming to technical side, In this article, I will be explaining about the various techniques ...
Post a Comment
Read more

Blazor 0.5.0 Interop JavaScript from C# and C# to JavaScript call

Blazor provides two-way communication from JS to C# and C# to JS which is called Interop. The version upgrade to Blazor 0.5.0 changed the approach in interactions between cshtml and JS files. The newer version simplifies JS calling by avoiding pre-registration of JS function. In this article, we would see how to call a JS method by passing multiple parameters from cshtml and parameterized call from JS to cshtml. The scenario that is used in this article has a Kendo AutoComplete to search book and populate information based on the selection. An example of a call to JS from cshtml await JSRuntime.Current.InvokeAsync<string>( "searchBook.Init", "#SearchTitle", new DotNetObjectRef(this)); Takeaways from the above example: - JSRuntime.Current give environment to execute out-process JS. - InvokeAsync is a function that would allow executing the JS function. - The searchBook.Init is a JS function call, we would see it in details in the second sec...
Post a Comment
Read more

LDAP with ASP.Net Identity Core in MVC with project.json

Lightweight Directory Access Protocol (LDAP), the name itself explain it. An application protocol used over an IP network to access the distributed directory information service. The first and foremost thing is to add references for consuming LDAP. This has to be done by adding reference from Global Assembly Cache (GAC) into project.json "frameworks": { "net461": { "frameworkAssemblies": { "System.DirectoryServices": "4.0.0.0", "System.DirectoryServices.AccountManagement": "4.0.0.0" } } }, These  System.DirectoryServices  and  System.DirectoryServices.AccountManagement  references are used to consume LDAP functionality. It is always better to have an abstraction for irrelevant items in consuming part. For an example, the application does not need to know about PrincipalContext or any other dependent items from those two references to make it extensible. So, we can begin wi...
Post a Comment
Read more

Channel, ChannelReader and ChannelWriter to manage data streams in multi-threading environment

I came across Channel class while working with SignalR which looks really interesting. By looking into NuGet packages ( https://www.nuget.org/packages/System.Threading.Channels ), it seems just 4 months old. The Channel class provides infrastructure to have multiple reads and write simuletensely through it's Reader and Writer properties. This is where it is handy in case of SignalR where data streaming needs to be done but is not just limited to that but wherever something needs to be read/write/combination of both in a multi-threading environment. In my case with SignalR, I had to stream stock data at a regular interval of time. public ChannelReader<StockData> StreamStock() { var channel = Channel.CreateUnbounded<StockData>(); _stockManager.OnStockData = stockData => { channel.Writer.TryWrite(stockData); }; return channel.Reader; } The SignalR keeps return type of ChannelReader<StockData> open so that whatev...
Post a Comment
Read more

A wrapper implementation for Kendo Grid usage

A wrapper implementation for any heavily used item is always a good practice. Whatever is not written by us and used at a lot of places should be wrapped within specific functionality to keep it future proof and easily changeable. This also encourages DRY principle to keep our common setting at a central place. Kendo UI items are enormous in configuration, one of an issue I find people keep repeating codes for Kendo Grid configuration. They have built very flexible system to have any configuration, but in most of the cases, we do not need all of those complicated configuration. We would try to see a simpler configuration of same. The actual core implementation is bit complex, but we do not have to bother about it once done since the focus is just on usage only. I recommend doing this practice for as simple as jQuery events, form handling or as simple as any notification system. This just won't make things simple but makes codes much more manageable, easy understand, read or open f...
Post a Comment
Read more