Question: Issue Fetching Updated RAW Data from GitHub Gist Using HttpClient

Question

Hi, I’m working on a C project where I fetch a JSON file from a GitHub Gist using HttpClient. However, even after updating the Gist, the HttpClient.GetStringAsync() method keeps returning the old data. I suspect this issue might be related to caching.

Here’s the code I’m using:

using System;

using System.Net.Http;

using System.Threading.Tasks;

class Program

{

static async Task Main(string[] args)

{

    string gistRawUrl = "https://gist.githubusercontent.com/username/gistid/raw";

    try

    {

        using (HttpClient client = new HttpClient())

        {

            string content = await client.GetStringAsync(gistRawUrl);

            Console.WriteLine("Gist content:");

            Console.WriteLine(content);

        }

    }

    catch (Exception ex)

    {

        Console.WriteLine($"An error occurred: {ex.Message}");

    }

}

}

Problem

1. Updates I make to the Gist are not reflected in the RAW URL response.

2. The application always returns the old version of the data.

How can I address this caching issue effectively?  

Thanks in advance!

Answer 1

Hi @fatih uyanık , Welcome to Microsoft Q&A,

You can try adding cache-control headers to your HTTP requests to instruct servers and intermediaries not to cache responses.

using System;
using System.Net.Http;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        string gistRawUrl = "https://gist.githubusercontent.com/username/gistid/raw";

        try
        {
            using (HttpClient client = new HttpClient())
            {
                // Add cache-busting headers
                client.DefaultRequestHeaders.Add("Cache-Control", "no-cache");
                client.DefaultRequestHeaders.Add("Pragma", "no-cache");

                // Append a timestamp to the URL as a query parameter to bypass cache
                string urlWithTimestamp = $"{gistRawUrl}?_={DateTimeOffset.UtcNow.ToUnixTimeMilliseconds()}";

                string content = await client.GetStringAsync(urlWithTimestamp);

                Console.WriteLine("Gist content:");
                Console.WriteLine(content);
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"An error occurred: {ex.Message}");
        }
    }
}

Best Regards,

Jiale

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