@vara/custom-logic-sdk/src/route-handlers/fn-executor.js

Server Side JavaScript SDK for Custom Business Logic

/**
 * Created by stevenchin on 2/1/17.
 */

const _ = require('lodash');

const clFnRegistry = require('../services/fn-registry');
const customError = require('../services/custom-error');
const fnExecutorSvc = require('../services/fn-executor-svc');
const ApplicationErrors = require('../constants/application-errors.json');
const logSvc = require('../services/log-svc');

const CUSTOM_LOGIC = require('../constants/constants').CUSTOM_LOGIC;

const { ResourceNotFoundError, InternalError } = ApplicationErrors;

async function clFnExecutor(req, res, next) {
  const logPrefix = 'RouteHandler#clFnExecutor';

  const clFunctionName = _.get(req, 'params.name');
  const clFunction = clFnRegistry.getAPIResponder(clFunctionName);
  const requestedClProtocolVersion = req.get(CUSTOM_LOGIC.PROTOCOL.PROTOCOL_VERSION_REQ_HEADER) || CUSTOM_LOGIC.PROTOCOL.VERSIONS.LATEST;

  const logCtx = {
    clFunctionName,
    registeredClProtocolVersion: _.get(clFunction, 'config.clProtocolVersion'),
    requestedClProtocolVersion,
  };

  // To execute the custom logic function:
  //  1) it must exist in the registry
  //  2) its protocol version must match the current protocol version or the one sent by the platform
  if (!clFunction || _.get(clFunction, 'config.clProtocolVersion') !== requestedClProtocolVersion) {
    const resourceNotFoundErr = customError(
      ResourceNotFoundError.name,
     `Custom Logic Function: ${clFunctionName} with protocol version: ${requestedClProtocolVersion} was not found`);

    logSvc.logWarning(resourceNotFoundErr, logCtx, logPrefix);
    return next(resourceNotFoundErr);
  }

  try {
    // Attempt to build the necessary inputs for the custom logic function based on the protocol version
    const { context, done } = fnExecutorSvc.buildClFnParams(requestedClProtocolVersion, req, res, next);

    return await fnExecutorSvc.execHandler(clFunction.handler, context, done);
  } catch (err) {

    // handle cases where a protocol handler could not be found for the custom logic protocol specified
    if (err.name === ResourceNotFoundError.name) {
      logSvc.logWarning(err, logCtx, logPrefix);
      return next(err);
    }

    const internalErr = customError(InternalError.name, null, { innerError: err });
    logSvc.logError(internalErr, logCtx, logPrefix, `Custom Logic Function: ${clFunctionName} failed;`);
    return next(internalErr);
  }
}

module.exports = clFnExecutor;