Callbacks

Callbacks are how you can get notified when a workflow is done

Overview

In your nextjs server side, where you run your endpoint, you can queue a run and pass a webhook url to it.

Full Stack Demo

See how the callback works in a NextJS app

src/app/api/run/route.tsx

import { cd } from "client";

export async function POST(request: Request) {
    const { deploymentId } = await request.json();

    const headersList = headers();
    const host = headersList.get("host") || "";
    const protocol = headersList.get("x-forwarded-proto") || "";
    let endpoint = `${protocol}://${host}`;

    const { runId } = await cd.run.deployment.queue({
        deploymentId: deploymentId,
        webhook: `${endpoint}/api/webhook`,
    });
}

Make sure you have a route that can handle the webhook. For the response body, check the docs here

src/app/api/webhook/route.tsx

import { WorkflowRunWebhookBody$inboundSchema as WebhookParser } from "comfydeploy/models/components";
import { NextResponse } from "next/server";

export async function POST(request: Request) {
    const parseData = WebhookParser.safeParse(
      await request.json(),
    );

    if (!parseData.success) {
      return NextResponse.json({ message: "error" }, { status: 400 });
    }

    const data = parseData.data;

    const { status, runId, outputs } = data;

    // Do your things
    console.log(status, runId, outputs);

    // Return success to ComfyDeploy
    return NextResponse.json({ message: "success" }, { status: 200 });
}

Enforcing Webhook Security

To enhance the security of your webhook endpoint, you can implement a secret token verification using the jose library, which is compatible with edge environments. This method uses a shared secret to generate and verify signatures for each webhook request.

Here’s how to modify your code to include this security measure:

src/app/api/run/route.tsx

import * as jose from 'jose';
import { cd } from "client";

const WEBHOOK_SECRET = process.env.WEBHOOK_SECRET; // Store this securely, e.g., in environment variables

export async function POST(request: Request) {
    // ... existing code ...

    const timestamp = Date.now().toString();
    const secret = new TextEncoder().encode(WEBHOOK_SECRET);
    const signature = await new jose.SignJWT({ deploymentId })
        .setProtectedHeader({ alg: 'HS256' })
        .setIssuedAt(timestamp)
        .sign(secret);

    const { runId } = await client.run.queue({
        deploymentId: deploymentId,
        webhook: `${endpoint}/api/webhook?timestamp=${timestamp}&signature=${encodeURIComponent(signature)}`,
    });
}

Then, update your webhook handler to verify the signature:

src/app/api/webhook/route.tsx

import { WorkflowRunWebhookBody$inboundSchema as WebhookParser } from "comfydeploy/models/components";
import { NextResponse } from "next/server";
import * as jose from 'jose';

const WEBHOOK_SECRET = process.env.WEBHOOK_SECRET;
const MAX_TIMESTAMP_DIFF = 60 * 60 * 1000; // 1 hour

export async function POST(request: Request) {
    const url = new URL(request.url);
    const timestamp = url.searchParams.get('timestamp');
    const signature = url.searchParams.get('signature');

    if (!timestamp || !signature) {
        return NextResponse.json({ message: "Missing query parameters" }, { status: 400 });
    }

    // Check if the timestamp is recent
    if (Math.abs(Date.now() - parseInt(timestamp)) > MAX_TIMESTAMP_DIFF) {
        return NextResponse.json({ message: "Timestamp too old" }, { status: 400 });
    }

    // const body = await request.json();
    const secret = new TextEncoder().encode(WEBHOOK_SECRET);

    try {
        const { payload } = await jose.jwtVerify(signature, secret, {
            algorithms: ['HS256'],
        });

        if (payload.deploymentId !== body.deploymentId) {
            throw new Error('Deployment ID mismatch');
        }

        if (payload.iat !== parseInt(timestamp)) {
            throw new Error('Timestamp mismatch');
        }
    } catch (error) {
        return NextResponse.json({ message: "Invalid signature" }, { status: 401 });
    }

    const parseData = WebhookParser.safeParse(
      await request.json(),
    );

    if (!parseData.success) {
      return NextResponse.json({ message: "error" }, { status: 400 });
    }

    const data = parseData.data;

    const { status, runId, outputs } = data;

    // Do your things
    console.log(status, runId, outputs);

    // Return success to ComfyDeploy
    return NextResponse.json({ message: "success" }, { status: 200 });
}