request-plus/src/index.js

advanced promisified http client with retries, EventEmitter, cache-manager, prom-client and logging

'use strict';
const requestPromise = require('request-promise-any');
const wrappers = {
  defaults: require('./defaultsDecorator'),
  event: require('./eventDecorator'),
  retry: require('./retryDecorator'),
  cache: require('./cacheDecorator'),
  prom: require('./promDecorator'),
  log: require('./logDecorator'),
};

/**
 * @param {Object} [factoryOptions]
 * @param {Object} [factoryOptions.event]
 * @param {Object} [factoryOptions.retry]
 * @param {Object} [factoryOptions.cache]
 * @param {Object} [factoryOptions.prom]
 * @param {Function} [factoryOptions.requestPromise] - alternative request-promise implementation
 * @return {Function} - same API as request, but with .plus object set
 */

class RequestPlus {
  constructor(wrapped, ancestor) {
    for (let key in ancestor) {
      this[key] = ancestor[key];
    }
    this.wrapped = wrapped;
  }

  wrap(decorator, opts) {
    if (typeof decorator === 'string') {
      if (!wrappers[decorator]) {
        throw new Error('unknown request-plus wrapper: ' + decorator);
      }
      decorator = wrappers[decorator];
    }
    const newReplaced = decorator(this.wrapped, opts);
    newReplaced.plus = new RequestPlus(newReplaced, this.wrapped.plus);
    return newReplaced;
  }
}

function me(factoryOpts) {
  const requester = factoryOpts && factoryOpts.requestPromise || requestPromise;

  function replaced(uri, requestOptions, callback) {
    return requester(uri, requestOptions, callback);
  }

  replaced.plus = new RequestPlus(replaced);

  if (factoryOpts) {
    for (let wrapperName of Object.keys(wrappers)) {
      if (factoryOpts[wrapperName]) {
        replaced = replaced.plus.wrap(wrappers[wrapperName], factoryOpts[wrapperName]);
      }
    }
    return replaced;
  }

  return replaced;
};

me.registerWrapper = function(wrapperName, wrapper) {
  wrappers[wrapperName] = wrapper;
};

me.unregisterWrapper = function(wrapperName) {
  delete wrappers[wrapperName];
};

module.exports = me;