auth0-pre-registerarion-check.js

/**
* Handler that will be called during the execution of a PreUserRegistration flow.
*
* @param {Event} event - Details about the context and user that is attempting to register.
* @param {PreUserRegistrationAPI} api - Interface whose methods can be used to change the behavior of the signup.
*/
const axios = require('axios');

exports.onExecutePreUserRegistration = async (event, api) => {

    const deviceSerialNumber = event.user?.user_metadata?.deviceSerialNumber;
    let isValidSN = false;

    const checkDeviceSN = async (deviceSerialNumber) => {
        const apiKey = event.secrets.API_KEY;
        const url = `https://api.example.com/v1/devices/${deviceSerialNumber}`;
        const headers = {
            'api-key': apiKey,
            'Content-Type': 'application/json'
        };
        const response = await axios.get(url, { headers });
        return response.data.isValid;
    }
  
    if(deviceSerialNumber){
      // make a http call to your api and check the device SN
      isValidSN = await checkDeviceSN(deviceSerialNumber);
    }
  
    if(!isValidSN){
        return api.access.deny('Invalid device serial number', 'You need to provide a valid device serial number')
    }

    api.user.setAppMetadata('deviceCheckPassed', true)
  
  };