Caption and render video from a Supabase Edge Function

supabase secrets set REELSDK_KEY=rk_live_xxx REELSDK_WEBHOOK_SECRET=whsec_xxx

supabase functions deploy render-captions
supabase functions deploy reelsdk-webhook --no-verify-jwt

import "jsr:@supabase/functions-js/edge-runtime.d.ts";

const REELSDK = "https://api.reelsdk.com";

Deno.serve(async (req) => {
  const { video_url } = await req.json();

  const res = await fetch(`${REELSDK}/v1/captions?wait=120`, {
    method: "POST",
    headers: {
      Authorization: `Bearer ${Deno.env.get("REELSDK_KEY")}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      video_url,
      style: "karaoke",
      webhook_url: `${Deno.env.get("SUPABASE_URL")}/functions/v1/reelsdk-webhook`,
    }),
  });

  const { job, error } = await res.json();
  if (!res.ok) return Response.json({ error }, { status: res.status });

  // On 200 the mp4 is ready; on 202 we let the webhook deliver it
  return Response.json({ id: job.id, status: job.status, video: job.outputs?.video ?? null });
});

import "jsr:@supabase/functions-js/edge-runtime.d.ts";
import { createClient } from "npm:@supabase/supabase-js@2";

const supabase = createClient(Deno.env.get("SUPABASE_URL")!, Deno.env.get("SUPABASE_SERVICE_ROLE_KEY")!);

Deno.serve(async (req) => {
  const body = await req.text();
  const signature = req.headers.get("Reel-Signature");
  if (!(await verifyReelSignature(signature, body, Deno.env.get("REELSDK_WEBHOOK_SECRET")!))) {
    return new Response("invalid signature", { status: 401 });
  }

  const job = JSON.parse(body);
  if (job.status === "succeeded") {
    // We answer right away and copy the mp4 into Storage in the background
    EdgeRuntime.waitUntil(saveToStorage(job.id, job.outputs.video));
  }
  return new Response("ok");
});

async function saveToStorage(id: string, url: string) {
  const video = await fetch(url);
  const { error } = await supabase.storage
    .from("videos")
    .upload(`${id}.mp4`, await video.blob(), { contentType: "video/mp4", upsert: true });
  if (error) console.error("storage upload failed", id, error.message);
}

async function verifyReelSignature(header: string | null, body: string, secret: string) {
  const parts = Object.fromEntries((header ?? "").split(",").map((part) => part.split("=")));
  const age = Math.abs(Date.now() / 1000 - Number(parts.t));
  if (!/^[0-9a-f]{64}$/i.test(parts.v1 ?? "") || !(age <= 300)) return false;

  const encoder = new TextEncoder();
  const key = await crypto.subtle.importKey(
    "raw",
    encoder.encode(secret),
    { name: "HMAC", hash: "SHA-256" },
    false,
    ["verify"],
  );
  const signature = Uint8Array.from(parts.v1.match(/../g), (pair: string) => parseInt(pair, 16));
  return crypto.subtle.verify("HMAC", key, signature, encoder.encode(`${parts.t}.${body}`));
}