ama-team / voxengine-sdk

var C = require('./_common')

var Q = C.Query

var H = C.Headers

var Slf4j = require('../logger').slf4j.Slf4j

/**

 * Provides client configuration defaults.

 *

 * @returns {BasicHttpClientSettings}

 */

function getDefaults () {

  return {

    url: '',

    retryOnNetworkError: true,

    throwOnServerError: true,

    retryOnServerError: true,

    throwOnClientError: true,

    retryOnClientError: false,

    throwOnNotFound: false,

    retryOnNotFound: false,

    retries: 4,

    logger: {}

  }

}

/**

 * Internal response type, used to simplify processing path finding.

 *

 * RS is an abbreviation from ResponseStatus

 *

 * @enum

 * @readonly

 */

var RS = {

  NetworkError: 'NetworkError',

  ServerError: 'ServerError',

  ClientError: 'ClientError',

  NotFound: 'NotFound',

  Ok: 'Ok',

/**

 * @typedef {Object} BasicHttpClientSettings

 *

 * @property {string} url

 * @property {boolean} retryOnNetworkError

 * @property {boolean} throwOnServerError

 * @property {boolean} retryOnServerError

 * @property {boolean} throwOnClientError

 * @property {boolean} retryOnClientError

 * @property {boolean} throwOnNotFound

 * @property {boolean} retryOnNotFound

 * @property {string} methodOverrideHeader

 * @property {HeaderBag} headers Headers to be used on every request.

 * @property {int} retries Maximum number of retries allowed for request.

 * @property {LoggerOptions} logger Logger instance or context and/or name.

 */

/**

 * @class

 *

 * @implements IHttpClient

 *

 * @param {BasicHttpClientSettings|object} [settings]

 * @param {netHttpRequestAsync} [transport]

 */

function BasicHttpClient (settings, transport) {

  transport = transport || Net.httpRequestAsync

  settings = settings || {}

  var defaults = getDefaults()

  var logger = Slf4j.factory(setting('logger'), 'ama-team.voxengine-sdk.http.basic')

  var self = this

  var requests = 0

  function fetch (source, key, def) {

    return source[key] !== undefined ? source[key] : def

  }

  function setting (key, def) {

    return fetch(settings, key, fetch(defaults, key, def))

  }

  function shouldRetry (status, attempt) {

    // number of attempts = 1 + number of retries, so it's 'greater than' rather than 'greater or equal to'

    // comparison

    return attempt <= setting('retries') && setting('retryOn' + status, false)

  }

  function shouldThrow (status) {

    return status === RS.NetworkError || setting('throwOn' + status, false)

  }

  function performThrow (status, request, response) {

    // yes, i'm counting bytes and switch is more expensive

    if (status === RS.ServerError) {

      throw new C.ServerErrorException('Server returned erroneous response', request, response)

    } else if (status === RS.ClientError) {

      throw new C.ClientErrorException('Client has performed an invalid request', request, response)

    } else if (status === RS.NotFound) {

      throw new C.NotFoundException('Requested resource hasn\'t been found', request, response)

    }

    // get exception with specified code, otherwise use default one

    var ErrorClass = C.codeExceptionIndex[response.code] || C.NetworkException

    throw new ErrorClass(null, response.code, request, response)

  }

  /**

   * Executes HTTP request.

   *

   * @param {HttpRequest} request

   * @return {Promise.<(HttpResponse|Error)>}

   */

  function execute (request) {

    var message

    if (!request.method) {

      message = 'Request method hasn\'t been specified'

      return Promise.reject(new C.InvalidConfigurationException(message))

    }

    var id = request.id = request.id || ++requests

    request.method = request.method.toUpperCase()

    if (['POST', 'GET'].indexOf(request.method) === -1 && !setting('methodOverrideHeader')) {

      message = 'Tried to execute non-GET/POST request without specifying methodOverrideHeader in settings'

      return Promise.reject(new C.InvalidConfigurationException(message))

    }

    request.query = Q.normalize(request.query)

    request.headers = H.normalize(request.headers)

    var url = request.url = setting('url') + (request.url || '')

    logger.debug('Executing request #{} `{} {}`', request.id, request.method, url)

    return executionLoop(request, 1)

      .then(function (response) {

        logger.debug('Request #{} `{} {}` got response with code {}', id,

          request.method, url, response.code)

        return response

      }, function (e) {

        logger.debug('Request #{} `{} {}` resulted in error {}', id,

          request.method, url, e.name)

        throw e

      })

  }

  function executionLoop (request, attempt) {

    var qs = Q.encode(request.query)

    var url = request.url + (qs.length > 0 ? '?' + qs : '')

    var opts = new Net.HttpRequestOptions()

    var method = ['HEAD', 'GET'].indexOf(request.method) === -1 ? 'POST' : 'GET'

    var headers = H.override(setting('headers', {}), request.headers)

    if (method !== request.method) {

      headers[setting('methodOverrideHeader')] = [request.method]

    }

    opts.method = method

    opts.postData = request.payload

    opts.headers = H.encode(headers)

    logger.trace('Executing request #{} `{} {}`, attempt #{}', request.id, request.method, url, attempt)

    return transport(url, opts).then(function (raw) {

      var response = {code: raw.code, headers: H.decode(raw.headers), payload: raw.text}

      var status = RS.fromCode(response.code)

      var toRetry = shouldRetry(status, attempt)

      var toThrow = !toRetry && shouldThrow(status)

      logger.trace('Request #{} `{} {}` (attempt #{}) ended with code `{}` / status `{}`, (retry: {}, throw: {})',

        request.id, request.method, url, attempt, response.code, status, toRetry, toThrow)

      if (toRetry) {

        return executionLoop(request, attempt + 1)

      }

      if (toThrow) {

        performThrow(status, request, response)

      }

      response.request = request

      return response

    })

  }

  function request (method, url, query, payload, headers) {

    return execute({url: url, method: method, headers: headers, query: query, payload: payload})

  }

  // noinspection JSUnusedGlobalSymbols

  this.execute = execute

  this.request = request

  var methods = ['get', 'head']

  methods.forEach(function (method) {

    self[method] = function (url, query, headers) {

      return request(method, url, query, null, headers)

    }

  })

  methods = ['post', 'put', 'patch', 'delete']

  methods.forEach(function (method) {

    self[method] = function (url, payload, headers, query) {

      return request(method, url, query, payload, headers)

    }

  })

  /**

   * Perform GET request.

   *

   * @function BasicHttpClient#get

   *

   * @param {string} url

   * @param {QueryBag} [query]

   * @param {HeaderBag} [headers]

   *

   * @return {HttpResponsePromise}

   */

  /**

   * Perform HEAD request.

   *

   * @function BasicHttpClient#head

   *

   * @param {string} url

   * @param {QueryBag} [query]

   * @param {HeaderBag} [headers]

   *

   * @return {HttpResponsePromise}

   */

  /**

   * Perform POST request.

   *

   * @function BasicHttpClient#post

   *

   * @param {string} url

   * @param {string} [payload]

   * @param {HeaderBag} [headers]

   *

   * @return {HttpResponsePromise}

   */

  /**

   * Perform PUT request.

   *

   * @function BasicHttpClient#put

   *

   * @param {string} url

   * @param {string} [payload]

   * @param {HeaderBag} [headers]

   *

   * @return {HttpResponsePromise}

   */

  /**

   * Perform PATCH request.

   *

   * @function BasicHttpClient#patch

   *

   * @param {string} url

   * @param {string} [payload]

   * @param {HeaderBag} [headers]

   *

   * @return {HttpResponsePromise}

   */

  /**

   * Perform DELETE request.

   *

   * @function BasicHttpClient#delete

   *

   * @param {string} url

   * @param {string} [payload]

   * @param {HeaderBag} [headers]

   *

   * @return {HttpResponsePromise}

   */

}

BasicHttpClient.getDefaults = getDefaults

module.exports = {

  Client: BasicHttpClient,

  /** @deprecated */

  getDefaults: getDefaults

}