Distributed Cache in .NET: How to Configure and Use Redis

Article: Distributed Cache in .NET: How to Configure and Use Redis

This repository provides a hands-on guide and reference implementation for integrating Redis as a Distributed Cache layer into a .NET Web API.

The project demonstrates how to achieve near-instantaneous response times by moving the workload of fetching heavy datasets (1,000+ records) from a simulated database to an in-memory cache, highlighting the significant performance gap between a Cache Miss and a Cache Hit.

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What This Project Covers

• Generic Cache Repository Pattern: Implementing ICacheRepository<T> to decouple business logic from the caching provider.
• Double Invalidation Strategy: Maintaining data consistency by clearing both individual keys and collection keys on data updates.
• Performance Benchmarking: Comparison of response times between database fetching and Redis retrieval.
• Serialization: Handling complex objects using JSON serialization for Redis storage.

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Concepts Overview

Cache-Aside Pattern

The application first checks the cache. If the data is missing (Cache Miss), it fetches it from the database and stores it in the cache for future requests.

Double Invalidation

To prevent "stale data" (showing old info after an update), this project implements a strategy where any write operation (POST, PUT, DELETE) automatically removes:

1. The specific item key (e.g., user:123)
2. The collection key (e.g., all_users_list)

This ensures that the next GET request is forced to fetch fresh data from the database.

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Tech Stack

• .NET 9 (Web API)
• Redis (Distributed Cache)
• StackExchange.Redis (Client library)
• Docker (Local environment)

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Environment Setup

Prerequisites

• .NET 9 SDK
• Docker Desktop

Step 1: Start Redis

Run the following command to start a local Redis instance:

docker run --name my-redis -d -p 6379:6379 redis

Step 2: Run the API

Navigate to the project directory and execute:

dotnet run --project src/RedisCache.Api/RedisCache.Api.csproj

The API will be available (typically) at: http://localhost:5000 (check your launchSettings.json).

About

This repository is part of my technical writing and learning notes.
If you found it useful, consider starring the repo and sharing feedback.

• Author: Joao Oliveira
• Blog: https://joaooliveira.net
• Topics: .NET, Redis, Distributed Systems, Caching Patterns

Contributing

Issues and pull requests are welcome.
If you plan a larger change, please open an issue first so we can align on scope.

License

Licensed under the MIT License. See the LICENSE file for details.