FetchCatch.Client 0.1.0

FetchCatch.Client

Typed .NET client for FetchCatch — a workflow engine for decision flows you author visually and call as an API.

dotnet add package FetchCatch.Client

For ASP.NET Core hosts, see also FetchCatch.AspNetCore for one-line DI registration.

Quick start

using FetchCatch.Client;

var fc = new FetchCatchClient(new FetchCatchOptions
{
    ApiKey = Environment.GetEnvironmentVariable("FETCHCATCH_API_KEY")!,
});

var result = await fc.EvaluateAsync<CheckoutInput, CheckoutDecision>(
    flowSlug: "checkout",
    input: new CheckoutInput { Amount = 100, UserId = "u-123" });

if (result.IsCompleted)
{
    Console.WriteLine($"Approved: {result.Decision!.Approved}");
}
else if (result.IsWaiting)
{
    // The flow paused at a wait_for_event node; render UI and resume later
    await fc.ResumeAsync(result.RunId, result.WaitingForEvent!, new { confirmed = true });
}

public record CheckoutInput(decimal Amount, string UserId);
public record CheckoutDecision(bool Approved, string? Reason);

Features

• Strongly-typed EvaluateAsync<TInput, TDecision> plus a JsonElement overload for dynamic schemas
• Resume waiting runs (ResumeAsync)
• Inspect runs (ListRunsAsync, GetRunAsync, GetRunStatsAsync) — same data backing the FetchCatch console dashboard
• Structured exception hierarchy: FetchCatchAuthException, FetchCatchNotFoundException, FetchCatchValidationException, FetchCatchRateLimitedException (with RetryAfter)
• Built-in exponential backoff for transient 5xx / network errors (toggleable)
• OpenTelemetry tracing via ActivitySource("FetchCatch.Client") — every call opens a span
• AOT- and trim-friendly on net8.0+ (<IsAotCompatible>true</IsAotCompatible>)
• Multi-targets net8.0 · net10.0 · netstandard2.0 (works with .NET Framework 4.7.2+)

Configuration

Streaming run history

var filter = new RunFilter
{
    Status = RunStatus.Failed,
    FromUtc = DateTime.UtcNow.AddHours(-1),
};

await foreach (var run in fc.ListRunsAsync(filter, ct))
{
    logger.LogWarning("{Flow} failed: {Error}", run.FlowSlug, run.Error);
}

ListRunsAsync returns IAsyncEnumerable<FlowRunListItem> and auto-pages via the server's cursor — you never see a cursor token in your code.

Stats dashboard

var stats = await fc.GetRunStatsAsync(
    fromUtc: DateTime.UtcNow.AddDays(-1),
    toUtc:   DateTime.UtcNow);

Console.WriteLine($"{stats.Completed}/{stats.Total} succeeded · p95 {stats.P95Ms}ms");
foreach (var top in stats.TopFlows)
    Console.WriteLine($"  {top.FlowSlug}: {top.Total} runs ({top.Failed} failed)");

ASP.NET Core

Install FetchCatch.AspNetCore and one line of registration gives you IFetchCatchClient via DI with IHttpClientFactory, options validation, and tracing:

builder.Services.AddFetchCatch(builder.Configuration);  // binds "FetchCatch" section

Status

0.x. The HTTP API (/v1/...) is stable; SDK surface may evolve before 1.0. Pin a version in production.

License

MIT. © FetchCatch.