Cloudflare Worker integration

npm install fauna

import { Client, fql, FaunaError, ServiceError } from 'fauna';

// This interface defines the structure of the environment variables that get passed in.
export interface Env {
  FAUNA_SECRET: string;
}

export default {
   async fetch(request, env, ctx): Promise<Response> {
      // 1. Initialize a new Fauna client using the secret from the environment.
      const client = new Client({ secret: env.FAUNA_SECRET });

      // Extract the email from the query string. Otherwise, use an email address that's
      // in the Fauna sample data.
        const url = new URL(request.url);
      const email = url.searchParams.get('email') || "alice.appleseed@example.com";

      try {
         // 2. Execute an FQL query to retrieve data from Fauna.
         //    In this example, it queries 'Customer.byEmail(...)' for a particular user.
         //    'first()' ensures only the first matching result is returned as email has
         //    a unique constraint on it in this collection.
         const getData = await client.query(
                fql`Customer.byEmail(${email}).first()`
            );

         // 3. Return the retrieved data as a JSON response.
         return new Response(JSON.stringify(getData), { status: 200 });
      } catch (error) {
         // 4. Handle Fauna-specific errors separately from other errors.
            if (error instanceof FaunaError) {
            // If it's a service error (e.g., a problem with the query or the Fauna service itself),
            // log the Fauna queryInfo summary to the console for debugging.
                if (error instanceof ServiceError) {
                    console.error(error.queryInfo?.summary);
                } else {
               // Otherwise, return a generic error response for Fauna errors.
                    return new Response("Error " + error, { status: 500 });
                }
            }
         // 5. For any other error, return a less specific message
         //    to prevent leaking internal error details to the caller.
            return new Response('An error occurred, ' + error.message, { status: 500 });
        }
   },
} satisfies ExportedHandler<Env>;