README.md

Oz.SimpleRateLimiter

SimpleRateLimiter is.. well.. just that. A short, sweet and to the point rate limiter (with interrupt-ability!). Implement it however you like. Use it in a loop or implement it into a delegate handler. Create a derivative of your favorite class and use it in otherwise pointless overrides that just point back to base. Whatever you want.

Example

Here's a more than pointless ConsoleApp demonstrating exactly how this works.

using Oz.RateLimiting;

internal static async Task Main() {
    // create a new limiter @ 5 requests per 1 second
    var rateLimiter = new SimpleRateLimiter(5, new TimeSpan(0, 0, 0, 1));
    var cancellationToken = new CancellationToken();
    
    // try spamming the console
    for (int i = 1; i <= 10; i++) {
        // wait for any potential hold times 
        if (await rateLimiter.WaitForAvailabilityAsync(cancellationToken)) {
            // we're safe to continue
            Console.WriteLine($"Request #{i} - DateTime.Now: {DateTime.Now}");
        }
    }
}

Usage

Import the namespace

using Oz.RateLimiting;

Establish a rate limit

Let's get setup for 200 requests per hour.

var rateLimiter = new SimpleRateLimiter(200, new TimeSpan(0, 1));

Or if maybe this is easier to read. Albeit, definitely less efficient.

var now = DateTime.Now;
var oneMinuteFromNow = now.AddHours(1);
var oneMinuteWindow = oneMinuteFromNow - now;

var rateLimiter = new SimpleRateLimiter(200, oneMinuteWindow);

Abiding by the rate limit

Let's make some API calls to jsonplaceholder (a free, fake API for testing).

var cancellationToken = new CancellationToken();
var httpClient = new HttpClient();
for (int i = 1; i <= 5000; i++) {
    var request = new HttpRequestMessage(HttpMethod.Get,
        $"https://jsonplaceholder.typicode.com/photos/{i}");
    if (rateLimiter.WaitForAvailabilityAsync(cancellationToken)) {
        var response = await client.SendAsync(request);
    }
}