@vara/custom-logic-sdk/src/services/fn-registry.js

Server Side JavaScript SDK for Custom Business Logic

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

const _ = require('lodash');
const Joi = require('joi');

const logSvc = require('./log-svc');
const customError = require('./custom-error');
const clFunctionConfigSchema = require('../validation-schemas/function-config');
const ApplicationErrors = require('../constants/application-errors.json');
const validationOpts = require('../constants/validation-opts');

const { ValidationError } = ApplicationErrors;

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

const { TYPES: CL_FN_TYPES } = CUSTOM_LOGIC.FUNCTIONS;
const { TYPES: CL_ACTION_TYPES } = CUSTOM_LOGIC.ACTIONS;

const registry = {
  apiResponders: {},
  actions: {},
};

const clFnRegistry = {};

/**
 * @throws ValidationError - thrown when the config param is invalid or the fn param is not a function
 * Adds a function along with its configurations to the registry.
 * @param config {Object} - configurations for custom logic function
 * @param fn {Function} - function to add to registry
 * @param opts {Object} - options to use when adding the fn to the registry
 */
clFnRegistry.add = function add(config = {}, fn, { isAction } = {}) {
  const errData = {
    typeofRegistryFn: typeof fn,
    config,
  };

  if (!_.isFunction(fn)) {
    throw customError(ValidationError.name, 'Only functions can be added to custom logic registry', errData);
  }

  if (!config || !_.isString(config.type)) {
    const validTypes = [CL_FN_TYPES.POST_HOOK, CL_FN_TYPES.PRE_HOOK, CL_FN_TYPES.STANDALONE, CL_ACTION_TYPES.CL_ACTION];
    throw customError(ValidationError.name, `Custom logic function config must contain a type property; Valid types are: ${validTypes}`, errData);
  }

  const fnTypeConfigValidationRes = Joi.validate(config, clFunctionConfigSchema[config.type], validationOpts.ALLOW_ADDITIONAL_PROPERTIES);
  if (fnTypeConfigValidationRes.error) {
    errData.details = fnTypeConfigValidationRes.error.details;
    throw customError(ValidationError.name, fnTypeConfigValidationRes.error.message, errData);
  }

  const registryPath = isAction ? 'actions' : 'apiResponders';
  if (registry[registryPath][config.name]) {
    logSvc.warn(`Function: ${config.name} already exists in registry, it will be replaced`);
  }

  registry[registryPath][config.name] = { config, handler: fn };
};

/**
 * Returns the api responder specified by name or null if the function was not found
 * @param name {String} - name of api responder to retrieve
 * @returns {Function|Null}
 */
clFnRegistry.getAPIResponder = function getAPIResponder(name) {
  return registry['apiResponders'][name] || null;
};

/**
 * Returns the custom logic action specified by name or null if the function was not found
 * @param name {String} - name of cl action to retrieve
 * @returns {Function|Null}
 */
clFnRegistry.getClAction = function getClAction(name) {
  return registry['actions'][name] || null;
};

/**
 * Returns a list of all registered custom logic functions
 * @returns {Array}
 */
clFnRegistry.getAll = function getAll() {
  const handlers = [];

  _.forOwn(registry, (fnType) => {
    _.forOwn(fnType, (handlerConfig) => {
      handlers.push(handlerConfig);
    });
  });

  return handlers;
};

module.exports = clFnRegistry;