Validate API Requests with Bearer Token Authentication and Airtable

This n8n workflow provides a robust solution for validating incoming API requests, specifically focusing on bearer token authentication. It leverages Airtable as a secure backend to store and manage authorized API keys, ensuring that only requests with valid tokens are processed.

What it does

This workflow automates the following steps:

1. Listens for API Requests: It acts as an API endpoint, waiting for incoming HTTP requests.
2. Extracts Bearer Token: Upon receiving a request, it extracts the Authorization header to retrieve the bearer token.
3. Validates Token against Airtable: It queries an Airtable base to check if the extracted bearer token exists and is marked as valid.
4. Conditional Processing:
   • If Valid: If the token is found and valid, the workflow proceeds to process the request (e.g., performing further actions, returning a success response).
   • If Invalid: If the token is not found or is invalid, the workflow immediately responds with an unauthorized error.
5. Responds to Request: It sends an appropriate HTTP response back to the client, indicating success or failure of the authentication.

Prerequisites/Requirements

To use this workflow, you will need:

• n8n Instance: A running n8n instance (cloud or self-hosted).
• Airtable Account: An Airtable account with a base and a table configured to store API keys.
  • The table should include a field for the bearer token (e.g., API Key) and a field to indicate its validity (e.g., Is Active, a checkbox or boolean field).
• Airtable Credentials: An Airtable API key for n8n to connect to your Airtable base.

Setup/Usage

1. Import the Workflow:

   • Download the provided JSON file.
   • In your n8n instance, click on "Workflows" in the left sidebar.
   • Click "New" and then "Import from JSON".
   • Paste the JSON content or upload the file.

2. Configure Credentials:

   • Airtable Node:
     • Click on the "Airtable" node.
     • Under "Credentials", select an existing Airtable credential or create a new one. You will need your Airtable API key.
     • Configure the "Base ID" and "Table Name" to match your Airtable setup where API keys are stored.
     • Ensure the "View" is set correctly if you have specific views.
     • Verify the "Filter By Formula" to match your token field (e.g., {API Key} = "{{ $json.token }}") and the validity field (e.g., AND({API Key} = "{{ $json.token }}", {Is Active} = TRUE())).

3. Configure Webhook Trigger:

   • Click on the "Webhook" node.
   • Note the "Webhook URL". This is the endpoint your API requests will be sent to.
   • Set the "HTTP Method" to the expected method for your API requests (e.g., POST, GET).

4. Configure Code Node (Token Extraction):

   • Click on the "Code" node.
   • This node extracts the bearer token from the Authorization header. Ensure the code correctly parses your expected header format. The default assumes a Bearer <token> format.

5. Configure If Node (Validation Logic):

   • Click on the "If" node.
   • The condition should check if the Airtable query returned any valid items. For example, {{ $json.length > 0 }} if the Airtable node outputs an array of matching records.

6. Configure Respond to Webhook Nodes:

   • Success Path:
     • Configure the "Respond to Webhook" node on the TRUE branch to return a 200 OK status and any relevant success data.
   • Failure Path:
     • Configure the "Respond to Webhook" node on the FALSE branch to return a 401 Unauthorized status and an appropriate error message.

7. Activate the Workflow:

   • Once configured, make sure to activate the workflow by toggling the "Active" switch in the top right corner of the n8n editor.

Now, any API requests sent to the Webhook URL with a valid bearer token in the Authorization header will pass through, while invalid ones will be rejected.