Webflow Worker spam filter.

export default {
  async fetch(req, env) {
    if (req.method !== "POST") return new Response("method", { status: 405 });

    const form = await req.formData();
    const message = String(form.get("message") ?? "");
    const email = String(form.get("email") ?? "");

    let probability = 0;
    let ceiling = null;
    try {
      const resp = await fetch("https://api.siftfy.io/v1/predict", {
        method: "POST",
        headers: {
          "Content-Type": "application/json",
          "X-API-Key": env.SIFTFY_KEY,
        },
        body: JSON.stringify({ text: message }),
        signal: AbortSignal.timeout(2000),
      });
      if (resp.ok) {
        const data = await resp.json();
        probability = data.spam_probability;
        ceiling = data.max_confidence ?? null;
      }
    } catch {}

    // Forward unless the score is ABOVE the ceiling the response reports. A fixed
    // constant reads backwards here: 0.85 is never reached, so everything
    // forwards, spam included.
    if (ceiling === null || probability <= ceiling) {
      await env.DESTINATION.fetch("https://hooks.example.com/lead", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ email, message, probability }),
      });
    }
    return new Response("ok", { status: 200 });
  },
};