Program.cs

using System.Net.Http.Json;
using YsfInstall;

var token = Environment.GetEnvironmentVariable("GITHUB_TOKEN")!;
var repoUrl = Environment.GetEnvironmentVariable("GITHUB_REPOSITORY_URL")!;
Console.WriteLine($"Url:{repoUrl}");
Console.WriteLine($"Token:{token.Substring(0, 10)}...");
var handler = new HttpClientHandler()
{
    AllowAutoRedirect = false
};

var httpClient = new HttpClient(handler)
{
    Timeout = TimeSpan.FromMinutes(20)
};

var req = new HttpRequestMessage(HttpMethod.Get, $"{repoUrl}/actions/artifacts");
req.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("token", token);
req.Headers.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/vnd.github+json"));
req.Headers.UserAgent.Add(new System.Net.Http.Headers.ProductInfoHeaderValue("GitHubApiClient", "1.0"));

Console.WriteLine("Getting artifacts...");
var httpRes = await httpClient.SendAsync(req);
if (httpRes is null)
{
    Console.WriteLine("Failed to get artifacts");
    return;
}

if (!httpRes.IsSuccessStatusCode)
{
    Console.WriteLine($"Failed response code: {httpRes.StatusCode}");
    return;
}

var response = await httpRes.Content.ReadFromJsonAsync<GetArtifacts>();
if (null == response)
{
    Console.WriteLine("Failed to parse artifacts response");
    return;
}

var namePrefix = Environment.GetEnvironmentVariable("ARTIFACT_NAME_PREFIX")!;
var branch = Environment.GetEnvironmentVariable("GITHUB_BRANCH");
var commit = Environment.GetEnvironmentVariable("GITHUB_COMMIT");
var artifact = response.Artifacts
    .Where(a => a.Name.StartsWith(namePrefix) && a.Expired == false)
    .Where(a => string.IsNullOrEmpty(branch) || a.WorkflowRun.HeadBranch == branch)
    .Where(a => string.IsNullOrEmpty(commit) || a.WorkflowRun.HeadSha == commit)
    .OrderByDescending(a => a.CreatedAt)
    .FirstOrDefault();
if (null == artifact)
{
    Console.WriteLine("No valid artifact found");
    return;
}

var downloadUrl = artifact.ArchiveDownloadUrl;
Console.WriteLine($"Downloading artifact {artifact.Name} from {downloadUrl}");
var req2 = new HttpRequestMessage(HttpMethod.Get, downloadUrl);
req2.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("token", token);
req2.Headers.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/vnd.github+json"));
req2.Headers.UserAgent.Add(new System.Net.Http.Headers.ProductInfoHeaderValue("GitHubApiClient", "1.0"));
var downloadResponse = await httpClient.SendAsync(req2);
if (downloadResponse.StatusCode == System.Net.HttpStatusCode.Redirect)
{
    downloadUrl = downloadResponse.Headers.Location!.ToString();
    Console.WriteLine($"Downloading artifact {artifact.Name} from redirect {downloadUrl}");
    downloadResponse = await httpClient.GetAsync(downloadUrl);
} else if (!downloadResponse.IsSuccessStatusCode)
{
    Console.WriteLine($"Failed to download artifact: {downloadResponse.StatusCode}");
    return;
}

var path = Environment.GetEnvironmentVariable("DOWNLOAD_PATH") ?? "/app/output";
var fileName = $"{artifact.Name}.zip";
var downloadPath = Path.Combine(path, fileName);
await using var fs = new FileStream(downloadPath, FileMode.Create, FileAccess.Write);
await downloadResponse.Content.CopyToAsync(fs);
Console.WriteLine($"Artifact downloaded to {downloadPath}");