Using Webhook Callbacks for Commands in n8n

This guide demonstrates how to use webhooks to get real-time status updates for your FetchMedia commands in n8n. Using webhooks is more efficient than polling, as FetchMedia will notify you instantly when a command is complete.

We will create two separate workflows:

1. Webhook Handler: A workflow that listens for incoming webhook calls from FetchMedia.

2. Command Creator: A workflow that sends the request to create a command, telling FetchMedia where to send the webhook.

Prerequisites

• An n8n account.

• A FetchMedia API Key.

• A publicly accessible n8n instance. If you are using n8n's cloud version, your webhook URLs are already public. If you are self-hosting, you may need a tool like ngrok to expose your local n8n instance to the internet during testing.

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Part 1: The Waiting Stage

The workflow adds a "wait" step to your n8n process, pausing execution until a specific webhook from FetchMedia is received.

Step 1: Create a Workflow with a Wait Node

1. Create a new, empty workflow in n8n.

2. Add a Wait node. This node will pause your workflow until it receives a specific signal.

3. Configure the Wait node:

   • Mode: On Webhook Call

   • The webhook URL will be generated at run time. It can be referenced with the $execution.resumeUrl variable. Send it somewhere before getting to the Wait node. More info

Step 2: Check the Status with an "If" node

Now we can use the webhook data to direct our workflow after the wait.

1. Add an If node and connect it to the Wait node's output.

2. Configure the "If" node to check if the command was successful.

   • Value 1: {{$json.body.status}}

   • Operation: Equal

   • Value 2: success

The true branch will now execute only if the status is success. All other statuses will go to the false branch.

Step 3: Handle the Result and Activate

You can now add further actions based on the result.

• From the true output, you could save the results to a database or send a "success" notification.

• From the false output, you could add another "If" node to check if the status is failed and then send an error alert.

Part 2: The Command Creator Workflow

Step 2: Configure the HTTP Request Node

1. Add an HTTP Request node.

2. Configure it to create a command:

   • Method: POST

   • URL: https://api.fetchmedia.io/v1/commands

   • Authentication: Header Auth (Use your FetchMedia API Key credentials).

   • Body Content Type: JSON

   • Body:

     {
       "ffmpeg_command": "ffmpeg -i {{in_1}} -c:v copy -c:a copy {{out_1}}",
       "input_files": {
         "in_1": "https://www3.cde.ca.gov/download/rod/big_buck_bunny.mp4"
       },
       "output_files": {
         "out_1": "output.mp4"
       },
       "webhook": "{{ $execution.resumeUrl }}" # From the Wait node
     }
     

     Keep in mind the $execution.resumeUrl you copied from your Wait node in Part 1.

Step 3: Run the Workflow

Execute this workflow manually. It will send a request to FetchMedia to create a new command. Once that command finishes processing, FetchMedia will automatically send a notification to your webhook URL, which will trigger the Wait node from part 1 and will contiune the workflow.

You have now successfully set up a webhook-driven process to manage your FetchMedia commands!