HTTP with fetch

Jint.Workflows ships an opt-in, browser-compatible fetch — the standard WHATWG API for HTTP from JavaScript. The entire request/response is journaled as a single step, so replays return the buffered response without hitting the network.

Opt-in registration

fetch is not registered by default. Workflows that don't call EnableFetch cannot make HTTP calls — fetch(...) is undefined.

var http = new HttpClient();

var workflow = new WorkflowEngine()
    .EnableFetch(b => b
        .UseHttpClient(http)
        .UseDefaultTimeout(TimeSpan.FromSeconds(30)));

For IHttpClientFactory users:

.UseHttpClient(factory.CreateClient("jint-workflows"))

Standard fetch API

const res = await fetch('https://api.example.com/orders', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ sku: 'WIDGET' })
});

if (!res.ok) throw new Error(`HTTP ${res.status}`);

const data = await res.json();

Response exposes: ok, status, statusText, url, redirected, headers, bodyUsed, .text(), .json(), and .clone(). Header keys are lowercased on the response.

Non-2xx responses do not throw — res.ok is false and you handle it. This matches WHATWG semantics.

Retries

Attach a Foundatio policy to retry transient failures:

using Foundatio.Resilience;

var policy = new ResiliencePolicyBuilder()
    .WithMaxAttempts(5)
    .WithExponentialDelay(TimeSpan.FromSeconds(1))
    .WithJitter()
    .WithShouldRetry((n, ex) => ex is HttpRequestException or TaskCanceledException)
    .Build();

workflow.EnableFetch(b => b
    .UseHttpClient(http)
    .UseDefaultPolicy(policy));

Replay

Each await fetch(...) is a single journaled step. On replay, the response is reconstructed from the journal — .json() and .text() return the cached body. No network call is made.

Supported subset

Supported today:

• fetch(url, init) with string URL
• init.method, init.headers (plain object, case-insensitive), init.body (string or pre-stringified)
• init.signal → CancellationToken
• Response.ok, status, statusText, url, redirected, headers, bodyUsed
• Response.text(), .json(), .clone()

Not yet:

• Request / Response / Headers constructors (use plain objects)
• .blob(), .formData(), .arrayBuffer()
• Streaming body, multipart upload
• mode, credentials, cache, referrer, integrity, keepalive