server.mjs

// Set default response headers as `const`
let DEFAULT_HEADERS = {
  "Access-Control-Allow-Origin": "*",
  "Access-Control-Allow-Credentials": true,
};

export const handler = async (event) => {
  
  // N.B. YOU SHOULD MAKE A _REAL_ APPLICATION WITH ERROR CHECKING
  // AND SOLID DEV PRACTICES. THIS IS A PROOF-OF-CONCEPT.
  //
  // IN OTHER WORDS...DON'T TRY THIS AT HOME!
  // 
  const body = JSON.parse(event.body);
  
  const url = "https://fp.keyri.com/v1/client";
  const ipAddress =  event.requestContext.identity.sourceIp;
  const Service_Encryption_Key = process.env.Service_Encryption_Key;
  const Service_Decryption_Key = process.env.Service_Decryption_Key;
  const API_Key = process.env.API_Key;
  
  //
  // BUILD THE PAYLOAD TO SEND TO THE KEYRI API
  //
  const sendBody = {
    ...body, 
    "userId": "undefined",
    "eventType": "visits",
    "metadata": {},
    ipAddress,
    headers: event.headers,
    API_Key,
    Service_Encryption_Key,
    Service_Decryption_Key
  };
  
  //
  // SEND THE PAYLOAD...
  //
  let returnData = await fetch(url, {
      method: 'POST', // Method itself
      headers: {'Content-Type': 'application/json'},
      body: JSON.stringify(sendBody)
  });
  
  let returnDataJson = await returnData.json();
  
  //
  // DONE. NOW DECIDE WHAT TO DO NEXT BASED ON
  // THE RESPONSE FROM THE KEYRI API
  //

  // Probably want to get fancier here - this'll do for demo purposes:
  let statusCode;
  if(returnDataJson?.riskSummary === "allow"){
    statusCode = 200;
  } else if(returnDataJson?.riskSummary === "warn"){
    statusCode = 302;
    DEFAULT_HEADERS = {...DEFAULT_HEADERS, "Location": "./bicycle_identification_adventure.html"}
  } else {
    statusCode = 400;
    DEFAULT_HEADERS = {...DEFAULT_HEADERS, "Location": "./blocked.html"}
  }
  
  return {
    statusCode,
    body: JSON.stringify(returnDataJson),
    headers: DEFAULT_HEADERS
  };

};