How to Implement Rate Limiting for ChatGPT API Calls in C#?

 Rate limiting can be implemented by tracking the number of API calls made and adding delays if necessary. Here's an example:

using System;
using System.Net.Http;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Newtonsoft.Json;

namespace ChatGPTExample
{
    class Program
    {
        private static readonly string apiKey = "YOUR_API_KEY_HERE";
        private static readonly string endpoint = "https://api.openai.com/v1/completions";
        private static int requestCount = 0;
        private static readonly int requestLimit = 60; // Example limit
        private static readonly TimeSpan timeWindow = TimeSpan.FromMinutes(1);
        private static DateTime windowStart = DateTime.UtcNow;

        static async Task Main(string[] args)
        {
            string prompt = "Explain the significance of machine learning in modern technology.";
            var response = await GetChatGPTResponseWithRateLimiting(prompt);
            Console.WriteLine(response);
        }

        public static async Task<string> GetChatGPTResponseWithRateLimiting(string prompt)
        {
            if (requestCount >= requestLimit)
            {
                var delay = timeWindow - (DateTime.UtcNow - windowStart);
                if (delay > TimeSpan.Zero)
                {
                    Console.WriteLine($"Rate limit reached. Waiting for {delay.TotalSeconds} seconds.");
                    await Task.Delay(delay);
                }
                requestCount = 0;
                windowStart = DateTime.UtcNow;
            }

            requestCount++;

            using (var httpClient = new HttpClient())
            {
                httpClient.DefaultRequestHeaders.Add("Authorization", $"Bearer {apiKey}");

                var requestBody = new
                {
                    model = "text-davinci-003",
                    prompt = prompt,
                    max_tokens = 150
                };

                var content = new StringContent(JsonConvert.SerializeObject(requestBody), Encoding.UTF8, "application/json");
                var response = await httpClient.PostAsync(endpoint, content);
                response.EnsureSuccessStatusCode();

                var responseBody = await response.Content.ReadAsStringAsync();
                dynamic result = JsonConvert.DeserializeObject(responseBody);
                return result.choices[0].text;
            }
        }
    }
}

This example checks the number of requests made within a time window and adds a delay if the limit is reached, ensuring that you stay within the API usage limits.

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