web3-provider-engine/dist/es5/subproviders/json-rpc-engine-middleware.js

A JavaScript library for composing Ethereum provider objects using middleware modules

"use strict";

function _typeof(o) { "@babel/helpers - typeof"; return _typeof = "function" == typeof Symbol && "symbol" == typeof Symbol.iterator ? function (o) { return typeof o; } : function (o) { return o && "function" == typeof Symbol && o.constructor === Symbol && o !== Symbol.prototype ? "symbol" : typeof o; }, _typeof(o); }
function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, _toPropertyKey(descriptor.key), descriptor); } }
function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); Object.defineProperty(Constructor, "prototype", { writable: false }); return Constructor; }
function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return _typeof(key) === "symbol" ? key : String(key); }
function _toPrimitive(input, hint) { if (_typeof(input) !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (_typeof(res) !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function"); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, writable: true, configurable: true } }); Object.defineProperty(subClass, "prototype", { writable: false }); if (superClass) _setPrototypeOf(subClass, superClass); }
function _setPrototypeOf(o, p) { _setPrototypeOf = Object.setPrototypeOf ? Object.setPrototypeOf.bind() : function _setPrototypeOf(o, p) { o.__proto__ = p; return o; }; return _setPrototypeOf(o, p); }
function _createSuper(Derived) { var hasNativeReflectConstruct = _isNativeReflectConstruct(); return function _createSuperInternal() { var Super = _getPrototypeOf(Derived), result; if (hasNativeReflectConstruct) { var NewTarget = _getPrototypeOf(this).constructor; result = Reflect.construct(Super, arguments, NewTarget); } else { result = Super.apply(this, arguments); } return _possibleConstructorReturn(this, result); }; }
function _possibleConstructorReturn(self, call) { if (call && (_typeof(call) === "object" || typeof call === "function")) { return call; } else if (call !== void 0) { throw new TypeError("Derived constructors may only return object or undefined"); } return _assertThisInitialized(self); }
function _assertThisInitialized(self) { if (self === void 0) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return self; }
function _isNativeReflectConstruct() { if (typeof Reflect === "undefined" || !Reflect.construct) return false; if (Reflect.construct.sham) return false; if (typeof Proxy === "function") return true; try { Boolean.prototype.valueOf.call(Reflect.construct(Boolean, [], function () {})); return true; } catch (e) { return false; } }
function _getPrototypeOf(o) { _getPrototypeOf = Object.setPrototypeOf ? Object.getPrototypeOf.bind() : function _getPrototypeOf(o) { return o.__proto__ || Object.getPrototypeOf(o); }; return _getPrototypeOf(o); }
var Subprovider = require('./subprovider.js');

// wraps a json-rpc-engine middleware in a subprovider interface
var JsonRpcEngineMiddlewareSubprovider = /*#__PURE__*/function (_Subprovider) {
  _inherits(JsonRpcEngineMiddlewareSubprovider, _Subprovider);
  var _super = _createSuper(JsonRpcEngineMiddlewareSubprovider);
  // take a constructorFn to call once we have a reference to the engine
  function JsonRpcEngineMiddlewareSubprovider(constructorFn) {
    var _this;
    _classCallCheck(this, JsonRpcEngineMiddlewareSubprovider);
    _this = _super.call(this);
    if (!constructorFn) throw new Error('JsonRpcEngineMiddlewareSubprovider - no constructorFn specified');
    _this._constructorFn = constructorFn;
    return _this;
  }

  // this is called once the subprovider has been added to the provider engine
  _createClass(JsonRpcEngineMiddlewareSubprovider, [{
    key: "setEngine",
    value: function setEngine(engine) {
      if (this.middleware) throw new Error('JsonRpcEngineMiddlewareSubprovider - subprovider added to engine twice');
      var blockTracker = engine._blockTracker;
      var middleware = this._constructorFn({
        engine: engine,
        provider: engine,
        blockTracker: blockTracker
      });
      if (!middleware) throw new Error('JsonRpcEngineMiddlewareSubprovider - _constructorFn did not return middleware');
      if (typeof middleware !== 'function') throw new Error('JsonRpcEngineMiddlewareSubprovider - specified middleware is not a function');
      this.middleware = middleware;
    }
  }, {
    key: "handleRequest",
    value: function handleRequest(req, provEngNext, provEngEnd) {
      var res = {
        id: req.id
      };
      this.middleware(req, res, middlewareNext, middlewareEnd);
      function middlewareNext(handler) {
        provEngNext(function (err, result, cb) {
          // update response object with result or error
          if (err) {
            delete res.result;
            res.error = {
              message: err.message || err
            };
          } else {
            res.result = result;
          }
          // call middleware's next handler (even if error)
          if (handler) {
            handler(cb);
          } else {
            cb();
          }
        });
      }
      function middlewareEnd(err) {
        if (err) return provEngEnd(err);
        provEngEnd(null, res.result);
      }
    }
  }]);
  return JsonRpcEngineMiddlewareSubprovider;
}(Subprovider);
module.exports = JsonRpcEngineMiddlewareSubprovider;