Fix Improper Error Handling in Gatsby

Improper error handling in Gatsby applications, particularly within 'gatsby-node.js' or during client-side hydration, often results in Information Disclosure. Leaking stack traces, file paths, or raw API responses provides attackers with a blueprint of your backend architecture. A secure implementation ensures that errors are caught, sanitized, and logged internally without exposing sensitive metadata to the client or public build logs.

The Vulnerable Pattern

exports.createPages = async ({ actions, graphql }) => {
  const result = await graphql(`{ allInternalSecrets { nodes { id, api_key } } }`);
  if (result.errors) {
    // VULNERABLE: Throwing raw error objects leaks internal schema and potential secrets to the build console/logs
    throw new Error(JSON.stringify(result.errors));
  }
};

The Secure Implementation

The vulnerable code directly stringifies the GraphQL error object, which often includes internal file paths, query structures, and sometimes even data snippets that should remain private. The secure version leverages Gatsby's 'reporter' API to provide a sanitized summary. It follows the principle of 'fail securely' by halting the build without spilling the guts of the system. In production frontend code, always wrap components in React Error Boundaries to catch runtime exceptions and display a generic 'Something went wrong' UI rather than the default crash screen.

exports.createPages = async ({ actions, graphql, reporter }) => {
  try {
    const result = await graphql(`{ allInternalData { nodes { id } } }`);
    if (result.errors) {
      // SECURE: Use Gatsby's reporter to log a sanitized message and stop the build safely
      reporter.panicOnBuild('Error fetching data for page creation. Check internal logs for details.');
      return;
    }
    // Page creation logic here...
  } catch (err) {
    // SECURE: Log the actual error to a private monitoring service, show generic error to build output
    reporter.error('A critical build-time error occurred. Reference: ' + Date.now());
  }
};