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Pusher Webhooks

TL;DR

To integrate Pusher webhooks with ngrok:

  1. Launch your local webhook. npm start
  2. Launch ngrok. ngrok http 3000
  3. Configure Pusher webhooks with your ngrok URL.
  4. Secure your webhook requests with verification.

This guide covers how to use ngrok to integrate your localhost app with Pusher by using Webhooks. Pusher webhooks can be used to notify an external application whenever specific events occur in your Pusher channel.

By integrating ngrok with Pusher, you can:

  • Develop and test Pusher webhooks locally, eliminating the time in deploying your development code to a public environment and setting it up in HTTPS.
  • Inspect and troubleshoot requests from Pusher in real-time via the inspection UI and API.
  • Modify and Replay Pusher Webhook requests with a single click and without spending time reproducing events manually in your Pusher account.
  • Secure your app with Pusher validation provided by ngrok. Invalid requests are blocked by ngrok before reaching your app.

Step 1: Start your app​

For this tutorial, we'll use the sample NodeJS app available on GitHub.

To install this sample, run the following commands in a terminal:

git clone https://github.com/ngrok/ngrok-webhook-nodejs-sample.git
cd ngrok-webhook-nodejs-sample
npm install

This will get the project installed locally.

Now you can launch the app by running the following command:

npm start

The app runs by default on port 3000.

You can validate that the app is up and running by visiting http://localhost:3000. The application logs request headers and body in the terminal and responds with a message in the browser.

Step 2: Launch ngrok​

Once your app is running successfully on localhost, let's get it on the internet securely using ngrok!

  1. If you're not an ngrok user yet, just sign up for ngrok for free.

  2. Download the ngrok agent.

  3. Go to the ngrok dashboard and copy your Authtoken.
    Tip: The ngrok agent uses the auth token to log into your account when you start a tunnel.

  4. Start ngrok by running the following command:

    ngrok http 3000

  5. ngrok will display a URL where your localhost application is exposed to the internet (copy this URL for use with Pusher). ngrok agent running

Step 3: Integrate Pusher​

To register a webhook on your Pusher channel follow the instructions below:

  1. Access the Pusher dashboard, sign in using your Pusher account, and then click your channel name in the Channels tile.

    Tip: If you don't have a channel, create one with the name my-channel.

  2. On your channel page, click Webhooks on the left menu and then click Add webhook.

  3. On the Add new webhook popup, enter the URL provided by the ngrok agent to expose your application to the internet in the Webhook URL field (i.e. https://1a2b-3c4d-5e6f-7g8h-9i0j.sa.ngrok.io). URL to Publish

  4. Click Client events under the Event type section and then click Save.

  5. Repeat the previous 3 steps to create webhooks for the other Event type values.

Run Webhooks with Pusher and ngrok​

Pusher sends different request body contents depending on the event that is being triggered. You can trigger new calls from Pusher to your application by creating a client event test.

  1. On the Pusher dashboard, click Debug console on the left menu, expand the Event creator section, enter my-channel in the Channel field, enter my-event in the Event field, enter some text in the Data field, and then click Send event.

    Confirm your localhost app receives an event notification and logs both headers and body in the terminal.

Alternatively, you can verify any error occurring during webhook calls in Pusher:

  1. On the Pusher dashboard, click Error Logs on the left menu, and then click the Webhook errors tab. Webhook Logs

Note: On this page, Pusher only shows messages that couldn't be delivered for any reason.

Inspecting requests​

When you launch the ngrok agent on your local machine, you can see two links:

  • The URL to your app (it ends with ngrok-free.app for free accounts or ngrok.app for paid accounts when not using custom domains)
  • A local URL for the Web Interface (a.k.a Request Inspector).

The Request Inspector shows all the requests made through your ngrok tunnel to your localhost app. When you click on a request, you can see details of both the request and the response.

Seeing requests is an excellent way of validating the data sent to and retrieved by your app via the ngrok tunnel. That alone can save you some time dissecting and logging HTTP request and response headers, methods, bodies, and response codes within your app just to confirm you are getting what you expect.

To inspect Pusher's webhooks call, launch the ngrok web interface (i.e. http://127.0.0.1:4040), and then click one of the requests sent by Pusher.

From the results, review the response body, header, and other details:

ngrok Request Inspector

Replaying requests​

The ngrok Request Inspector provides a replay function that you can use to test your code without the need to trigger new events from Pusher. To replay a request:

  1. In the ngrok inspection interface (i.e. http://localhost:4040), select a request from Pusher.

  2. Click Replay to execute the same request to your application or select Replay with modifications to modify the content of the original request before sending the request.

  3. If you choose to Replay with modifications, you can modify any content from the original request. For example, you can modify the name field inside the body of the request.

  4. Click Replay.

Verify that your local application receives the request and logs the corresponding information to the terminal.

Secure webhook requests​

The ngrok signature webhook verification feature allows ngrok to assert that requests from your Pusher webhook are the only traffic allowed to make calls to your localhost app.

Note: This ngrok feature is limited to 500 validations per month on free ngrok accounts. For unlimited, upgrade to Pro or Enterprise.

This is a quick step to add extra protection to your application.

  1. On the Pusher dashboard, click App keys on the left menu, and then copy the value of the secret field that appears on the screen.

  2. Restart your ngrok agent by running the command, replacing {your webhook secret} with the value you have copied before:

    ngrok http 3000 --verify-webhook pusher --verify-webhook-secret {your webhook secret}

  3. Repeat the steps described in the Run Webhooks with Pusher and ngrok section.

Verify that your local application receives the request and logs information to the terminal.