Day 16 of 30-Day .NET Challenge: In-Memory Caching

Challenges are hard when the database resides in a remote machine or experiencing heavy load. The in-memory caching acts as a better implementation to avoid performance bottlenecks.

Introduction

One of the major issues in an application's performance is the time it takes to respond from external data sources mostly databases. Challenges are hard when the database resides in a remote machine or experiencing heavy load. The in-memory caching acts as a better implementation to avoid performance bottlenecks.

Learning Objectives

How to use in-memory caching
Key benefits

Prerequisites for Developers

Basic understanding of C# programming language.

30 Day .Net Challenge

Getting Started

Usually, developers directly fetch information or data directly from the database. It is quite straightforward and simple approach but can lead to performance issues when the database is under a heavy load which impacts application performance and hampers UI experience

    public Product GetProductById(int id)
    {
        // Fetching product data from the database every time
        var product = _dbContext.Products.FirstOrDefault(p => p.Id == id);
        return product;
    }

How to implement in-memory caching

In-memory caching involves temporarily storing frequently accessed data in the memory of the application server, drastically reducing the need to retrieve data from the database for each request.

    private static MemoryCache _cache = new MemoryCache(new MemoryCacheOptions());

    public Product GetProductById(int id)
    {
        // Fetching product data from the cache if available
        if (!_cache.TryGetValue(id, out Product product))
        {
            product = _dbContext.Products.FirstOrDefault(p => p.Id == id);
            _cache.Set(id, product, TimeSpan.FromMinutes(30));
        }
        return product;
    }

To use MemoryCache, you need to add the Microsoft.Extensions.Caching.Memory package to your project.

    dotnet add package Microsoft.Extensions.Caching.Memory

Create a class InMemoryCache with function named GetProductById which returns a class object of type Product

    public static class InMemoryCache
    {
        private static MemoryCache _cache = new MemoryCache(new MemoryCacheOptions());
        private static ProductRepository _productRepository = new ProductRepository();
        public static Product GetProductById(int id)
        {
            if (!_cache.TryGetValue(id, out Product product))
            {
                Console.WriteLine("Fetching from database...");
                product = _productRepository.GetProductById(id);
                _cache.Set(id, product, TimeSpan.FromMinutes(30)); // Cache for 30 minutes
            }
            else
            {
                Console.WriteLine("Fetching from cache...");
            }

            return product;
        }
    }

Simulate the ProductRepository and relevant Product class

    // Simulating a product repository
    public class ProductRepository
    {
        public Product GetProductById(int id)
        {
            // Simulate database access
            return new Product { Id = id, Name = $"Product {id}" };
        }
    }

    public class Product
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }

Call from the main method as follows and relevant console output showcasing data fetched from memory.

    #region Day 16: In-Memory Cache

    Console.WriteLine("Fetching product with ID 1 for the first time:");
    var product = InMemoryCache.GetProductById(1);
    Console.WriteLine($"Product Name: {product.Name}\n");

    Console.WriteLine("Fetching product with ID 1 again:");
    product = InMemoryCache.GetProductById(1); // This time, it should come from the cache
    Console.WriteLine($"Product Name: {product.Name}\n");

    #endregion