HttpClient.Cache

A lightweight in-memory cache for HttpClient

The Purpose

Working with high-load systems or with a system where it is important to have a good response time - the cache is a first citizen. This package contains lightweight, self-written, in-memory cache implementation to catch and store responses based on their status code. The configuration is pretty flexible and gives opportynity to set pair between cache time and response code.

How to install

dotnet add package Leefrost.HttpClient.Cache

Plans and TODOs:

• in-memory caching support
• distributed caching support

How to use

The code below caches 3 top-kind responses (OK, BadRequest, and InternalServerError) for a different time - 60/10/5 seconds. HttpClient will do 5 requests to the https://randomuser.me/api/ and do cache the responses for us.

The cache report will show us 1 miss (initial request) and 4 hits (so the response time will be 0)

const string url = "https://randomuser.me/api/";

//Setting the cache time for each required status
var cacheExpiration = new Dictionary<HttpStatusCode, TimeSpan>
{
    {HttpStatusCode.OK, TimeSpan.FromSeconds(60)},
    {HttpStatusCode.BadRequest, TimeSpan.FromSeconds(10)},
    {HttpStatusCode.InternalServerError, TimeSpan.FromSeconds(5)}
};

//Calling the API and cache the responses
var requestHandler = new HttpClientHandler();
var cacheHandler = new InMemoryCacheHandler(requestHandler, cacheExpiration);
using (var httpClient = new HttpClient(cacheHandler))
{
    for (int i = 1; i <= 5; ++i)
    {
        Console.Write($"Attempt {i}: {url}");

        var stopwatch = Stopwatch.StartNew();
        var result = await httpClient.GetAsync(url);
        Console.Write($" --> {result.StatusCode} ");
        stopwatch.Stop();
        
        Console.WriteLine($"Done in: {stopwatch.ElapsedMilliseconds} ms");
        await Task.Delay(TimeSpan.FromSeconds(1));
    }
    Console.WriteLine();
}

//Checking cache stats
var stats = cacheHandler.StatsProvider.GetReport();
Console.WriteLine($"Cache stats - total requests: {stats.Total.TotalRequests}");
Console.WriteLine($"--> Hits: {stats.Total.CacheHit} [{stats.Total.TotalHitsPercent}]");
Console.WriteLine($"--> Misses: {stats.Total.CacheMiss} [{stats.Total.TotalMissPercent}]");
Console.ReadLine();

Console will show next output:

Attempt 1: https://randomuser.me/api/ --> OK Done in: 681 ms
Attempt 2: https://randomuser.me/api/ --> OK Done in: 75 ms
Attempt 3: https://randomuser.me/api/ --> OK Done in: 0 ms
Attempt 4: https://randomuser.me/api/ --> OK Done in: 0 ms
Attempt 5: https://randomuser.me/api/ --> OK Done in: 0 ms

Cache stats - total requests: 5
--> Hits: 4 [0,8]
--> Misses: 1 [0,2]