如何使用AWS Lambda Node.js服务器实施Braintree并生成带有承诺的客户端令牌？

我意识到这些lambda是异步函数，并且由于我们必须等待Braintree返回的响应，因此我们必须声明嵌套async/await语句的正确组合。

下面的代码是我通过正确的Promise链实现提交的最终实现，以正确处理async流程：

import * as dynamoDbLib from "./libs/dynamodb-lib";
import { success, failure } from "./libs/response-lib";
import braintree from "braintree";

export async function main(event, context) {
    /*
            All secrets are declared in the serverless template for the specific function
            and stored in AWS SecretsManger
    */
    // create a Braintree gateway
    let gateway = braintree.connect({
        environment: braintree.Environment.Sandbox, // either Sandbox or Production
        merchantId: process.env.merchantId, // these come from the Lambda's environmental variables
        publicKey: process.env.publicKey,
        privateKey: process.env.privateKey
    });

    /*************************************************
    * Braintree related functions based on documentation at
    * https://developers.braintreepayments.com/start/hello-server/node
    */
    /////////////////////////////////////
    // get a client token from Braintree and send it to the client
    /////////////////////////////////////
    const getClientToken = async (options = {}) => {
        console.log("Getting client token...");
        //console.log("hasOwnProps: ", options.hasOwnProperty("customerID") );

        let customerId = options && options.hasOwnProperty("customerID")
          ? options.customerID
          : null;

        console.log("This is customerID: ", customerId);

        return await gateway.clientToken.generate({});
    };

    /////////////////////////////////////
    // purchase an item using Braintree's transaction method
    /////////////////////////////////////
    const purchaseItem = async (purchaseInformation) => {
        /* console.log(
          "purchaseInformation: ",
          util.inspect(purchaseInformation, { showHidden: false, depth: null })
        ); */
        return await gateway.transaction.sale(
            {
                amount: purchaseInformation.amount,
                paymentMethodNonce: purchaseInformation.nonce,
                options: {
                    submitForSettlement: true
                }
            }
        );
    };

  /*************************************************
   * Enter here
   */
  // view the event that was received
  console.log("event: ", event);
  let result;

  // try to execute API calls
  try {
    switch (event.pathParameters.txnMethod) {
      case "get-client-token":
        // call getClientToken with the parsed version of optional body if present, otherwise call it with nothing
        await getClientToken(
            event.hasOwnProperty("body")
                ? JSON.parse(event.body) 
                : null)
            .then((res) => {
                //console.log("maybe result: ", res);
                //console.log("Maybe success/fail: ", typeof(res.success));
                //console.log("maybe token: ", res.clientToken);
                // Code here
                if(res.success.toString() === "true"){

                    //console.log("SUCCESS token: ", res.clientToken);
                    return context.succeed(success({
                        status: true,
                        clientToken: res.clientToken
                    }));
                } else {

                    return failure({
                        status: false,
                        error: "Braintree ClientToken Failure."
                    });
                }
            })
            .catch (err => {
                console.log("ERROR CAUGHT: ", err);

                return failure({
                  status: false,
                  error: "did it trigger 2: " + err
                });
            });
        break;

      case "purchase-item":
        console.log("purchasing item");
        const data = JSON.parse(event.body);
        await purchaseItem(data)
            .then((res) => {
                // Code here
                if(res.success === true){
                    console.log("~~~~~~~~~~~");
                    console.log("This is RES: ", res);
                    console.log("This is ERR>RES: ", res.ErrorResponse);
                    return context.succeed(success({
                        status: true,
                        TxnAuth: res
                    }));
                } else if (res.success === false) {
                    console.log("#################");
                    console.log(res.result);
                    return failure({
                        status: false,
                        error: "Error validating payment server information"
                    });
                } else {

                    return failure({
                        status: false,
                        error: "Braintree Server Failure."
                    });
                }
            })
            .catch (err => {
                console.log("ERROR CAUGHT: ", err);
                console.log("*********");
                return failure({
                    status: false,
                    error: "did it trigger 3pmt: " + err
                });
            });
        break;

      default:
        return failure({
          status: false,
          error: "invalid query string"
        });
        break;
    }
  } catch (error) {
    return failure({
      status: false,
      error: "API Call to Braintree Failed: " + error
    });
  }
}