CODEWITHSUNDEEP
asp.net-coredependency-injectionblazor-server-sidelazycache
David Thielen
David Thielen

Reputation: 32986

Is there an advantage to using LazyCache as a service?

LazyService describes how to use it directly or as a service. I'm still somewhat new to the whole concept of Dependency Injection and so I'm curious.

Calling it directly (not going the DI route) is a lot simpler & easier. So why would you instead go the DI approach? The document it as an option so I'm guessing there are advantages and I'd like to understand them.

The only advantage that occurred to me is you can then use a different library. But the use of LazyService is built around GetOrAddAsync() and I don't think any replacement would have that.

Upvotes: 0

Views: 191

Answers (1)

Md Farid Uddin Kiron
Md Farid Uddin Kiron

Reputation: 22495

Calling it directly (not going the DI route) is a lot simpler & easier. So why would you instead go the DI approach?

Using LazyCache as a service provides several benefits over directly instantiating and using it. While it might seem simpler to use it directly without dependency injection (DI), the DI approach has notable advantages that align with modern software development best practices. Here's why:

LazyCache offers a generic, developer-friendly API and ensures thread safety. This means your cached delegates are only executed once, even in highly concurrent scenarios, making it a robust choice for applications that need consistent and performant caching.

For example, using the GetOrAddAsync method ensures that the expensive delegate is executed only once per cache miss, no matter how many concurrent requests are made:

public async Task<string> GetUserDetailsAsync(int userId)
{
    
    return await _cache.GetOrAddAsync($"UserDetails_{userId}", async () => 
    {
        // Simulate a time-consuming operation, e.g., database or API call
        return await GetDetailsFromDatabaseAsync(userId);
    });
}

By injecting LazyCache as a service, you decouple your code from a specific caching library implementation. This makes your application more flexible and easier to maintain. For example, if you later decide to use a different caching library or even an external caching service like Redis or Memcached, you can do so without modifying the consuming code.

Within your service you could do that:

public class UserService
{
    private readonly IAppCache _cache;

    public UserService(IAppCache cache)
    {
        _cache = cache;
    }

    public async Task<string> GetUserDetailsAsync(int userId)
    {
        return await _cache.GetOrAddAsync($"UserDetails_{userId}", async () => 
        {
            // Simulate a data fetch
            return await GetDetailsFromDatabaseAsync(userId);
        });
    }
}

In addition, Using DI allows you to easily mock the caching behavior during unit testing, enabling better test coverage and ensuring that caching logic is tested without relying on the actual caching implementation.

While it might seem simpler to call LazyCache directly, using it as a service with dependency injection provides flexibility, maintainability, and testability, all of which are crucial for scalable, modern applications. By injecting LazyCache, you future-proof your application against changes in caching requirements or libraries.

Upvotes: 0

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