JSON-Validator

index.js

addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request));
});

const API_URL = 'https://dummyjson.com/test';
const POSTMARK_URL = 'https://api.postmarkapp.com/email';
const POSTMARK_API_KEY = '';
const EMAIL_PAYLOAD_TEMPLATE = {
  "From": "[email protected]",
  "To": "[email protected]",
  "Subject": "API Validation Failed",
  "TextBody": ''
};

/**
 * Main handler for the fetch event.
 * @param {Request} request - The incoming request object.
 * @returns {Promise<Response>}
 */
async function handleRequest(request) {
  try {
    const response = await fetch(API_URL);
    if (!response.ok) {
      throw new Error(`Failed to fetch API data: ${response.statusText}`);
    }

    const data = await response.json();
    const validationError = validateJson(data);

    if (validationError) {
      await sendEmailAlert(validationError);
      return new Response('Validation failed. Email alert sent.', { status: 200 });
    }

    return new Response('Validation successful.', { status: 200 });

  } catch (error) {
    console.error('Error during request handling:', error);
    return new Response(`Error: ${error.message}`, { status: 500 });
  }
}

/**
 * Validates the JSON data from the API response.
 * @param {Object} data - The JSON data to validate.
 * @returns {string|null} - An error message if validation fails, otherwise null.
 */
function validateJson(data) {
  if (!data || typeof data !== 'object' || !data.requiredField) {
    return 'Validation failed: requiredField is missing.';
  }
  return null;
}

/**
 * Sends an email alert using the Postmark API.
 * @param {string} errorMessage - The error message to include in the email body.
 * @returns {Promise<void>}
 */
async function sendEmailAlert(errorMessage) {
  const emailPayload = { ...EMAIL_PAYLOAD_TEMPLATE, TextBody: `The API response validation failed with the following error: ${errorMessage}` };

  const requestOptions = {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'X-Postmark-Server-Token': POSTMARK_API_KEY
    },
    body: JSON.stringify(emailPayload)
  };

  const response = await fetch(POSTMARK_URL, requestOptions);

  if (!response.ok) {
    const errorText = await response.text();
    throw new Error(`Failed to send email alert: ${response.statusText} - ${errorText}`);
  }
}