加入收藏 | 设为首页 | 会员中心 | 我要投稿 李大同 (https://www.lidatong.com.cn/)- 科技、建站、经验、云计算、5G、大数据,站长网!
当前位置: 首页 > 百科 > 正文

ajax – 模拟api in react redux-thunk项目返回undefined

发布时间:2020-12-16 01:37:15 所属栏目:百科 来源:网络整理
导读:我在redux世界中很新,还没有一个项目以 ducks方式构建.我试图理解它并使用它来制作一个模拟API,因为我还没有准备好后端.我正在使用遗留代码,我想弄清楚.有一个名为data的文件夹,它有一个duck和一个backendApi文件. Duck文件看起来像这样. 数据/ duck.jsx imp
我在redux世界中很新,还没有一个项目以 ducks方式构建.我试图理解它并使用它来制作一个模拟API,因为我还没有准备好后端.我正在使用遗留代码,我想弄清楚.有一个名为data的文件夹,它有一个duck和一个backendApi文件. Duck文件看起来像这样.

数据/ duck.jsx

import { createSelector } from 'reselect';
import { createReduxApi } from './backendApi';

const getDataContext = state => state.default.dataContext;

const backendReduxApi = createBackendReduxApi(getDataContext);

// Action creators
export const makeRestApiRequest = endpointName => backendReduxApi .makeRequestActionCreator(endpointName);

export const resetRestApi = endpointName => backendReduxApi .makeResetActionCreator(endpointName);

// Reducers
export const dataReducer = backendReduxApi .createReducer();

// Selectors
const getRestApiState = endpointName => backendReduxApi .getEndpointState(endpointName);
export const getRestApiData = endpointName => createSelector([getRestApiState(endpointName)],apiState => apiState.data);
export const getRestApiMeta = endpointName => createSelector([getRestApiState(endpointName)],apiState => apiState.meta);
export const getRestApiError = endpointName => createSelector([getRestApiState(endpointName)],apiState => apiState.error);
export const getRestApiStarted = endpointName => createSelector([getRestApiState(endpointName)],apiState => apiState.started);
export const getRestApiFinished = endpointName => createSelector([getRestApiState(endpointName)],apiState => apiState.finished);

backendApi.jsx文件如下所示:

数据/ backendApi.jsx

import ReduxRestApi from './rest/ReduxRestApi';

export const BackendApi = { // NOSONAR
  LANGUAGE_FILE: 'languageFile',EMPLOYEE: 'employee',};

const backendReduxApiBuilder = ReduxRestApi.build()
  /* /api */

  /* /api/employee */
  .withGet('/myproject/api/employee',BackendApi.EMPLOYEE)

  /* /language*/
  .withGet('/myproject/language/nb_NO.json',BackendApi.LANGUAGE_FILE)

export const createBackendReduxApi = restApiSelector => backendReduxApiBuilder
  .withRestApiSelector(restApiSelector)
  .create();

然后在data / rest文件夹中我有4个文件:ReduxRestApi,restConfig,RestDuck和restMethods.

数据/休息/ ReduxRestApi.jsx

import { combineReducers } from 'redux';
import { get,post,postAndOpenBlob } from './restMethods';
import RestDuck from './RestDuck';

class ReduxRestApi {
  constructor(endpoints,getRestApiState) {
    this.createReducer = this.createReducer.bind(this);
    this.getEndpoint = this.getEndpoint.bind(this);
    this.makeRequestActionCreator = this.makeRequestActionCreator.bind(this);
    this.makeResetActionCreator = this.makeResetActionCreator.bind(this);
    this.getEndpointState = this.getEndpointState.bind(this);
    this.ducks = endpoints.map(({ name,path,restMethod }) => new RestDuck(name,restMethod,getRestApiState));
  }

  createReducer() {
    const reducers = this.ducks
      .map(duck => ({ [duck.name]: duck.reducer }))
      .reduce((a,b) => ({ ...a,...b }),{});
    return combineReducers(reducers);
  }

  getEndpoint(endpointName) {
    return this.ducks.find(duck => duck.name === endpointName)
      || { actionCreators: {} };
  }

  makeRequestActionCreator(endpointName) {
    return this.getEndpoint(endpointName).actionCreators.execRequest;
  }

  makeResetActionCreator(endpointName) {
    return this.getEndpoint(endpointName).actionCreators.reset;
  }

  getEndpointState(endpointName) {
    return this.getEndpoint(endpointName).stateSelector;
  }

  static build() {
    class RestApiBuilder {
      constructor() {
        this.withGet = this.withGet.bind(this);
        this.withPost = this.withPost.bind(this);
        this.withPostAndOpenBlob = this.withPostAndOpenBlob.bind(this);
        this.withRestApiSelector = this.withRestApiSelector.bind(this);
        this.endpoints = [];
      }

      withGet(path,name) {
        this.endpoints.push({ path,name,restMethod: get });
        return this;
      }

      withPost(path,restMethod: post });
        return this;
      }

      withPostAndOpenBlob(path,restMethod: postAndOpenBlob });
        return this;
      }

      withRestApiSelector(restApiSelector) {
        this.restApiSelector = restApiSelector;
        return this;
      }

      create() {
        return new ReduxRestApi(
          this.endpoints,this.restApiSelector
        );
      }
    }

    return new RestApiBuilder();
  }
}

export default ReduxRestApi;

restConfig.jsx

import axios from 'axios';
import { removeErrorMessage,showErrorMessage } from '../../app/duck';
import { is401Error,isHandledError } from '../../app/ErrorTypes';

const isDevelopment = process.env.NODE_ENV === 'development';

const configureRequestInterceptors = (store) => {
  const onRequestAccepted = (config) => {
    store.dispatch(removeErrorMessage());
    return config;
  };

  const onRequestRejected = error => Promise.reject(error);

  axios.interceptors.request.use(onRequestAccepted,onRequestRejected);
};

const configureResponseInterceptors = (store) => {
  const onSuccessResponse = response => response;

  const onErrorResponse = (error) => {
    if (is401Error(error) && !isDevelopment) {
      window.location.reload();
    }
    if (!isHandledError(error)) {
      store.dispatch(showErrorMessage(error));
    }
    return Promise.reject(error);
  };

  axios.interceptors.response.use(onSuccessResponse,onErrorResponse);
};

const configureRestInterceptors = (store) => {
  configureRequestInterceptors(store);
  configureResponseInterceptors(store);
};

export default configureRestInterceptors;

数据/休息/ RestDuck.jsx

import { createSelector } from 'reselect';

import { get,getBlob,postAndOpenBlob,postBlob } from './restMethods';

/**
 * getMethodName
 * Helper function that maps given AJAX-method to a name
 *
 * Ex. getMethodName(getBlob) -> 'GET'
 */
const getMethodName = (restMethod) => {
  switch (restMethod) {
    case get:
    case getBlob:
      return 'GET';
    case post:
    case postBlob:
    case postAndOpenBlob:
      return 'POST';
    default:
      return '';
  }
};

/**
 * createRequestActionType
 * Helper function to generate actionType for actions related to AJAX calls
 *
 * Ex: createRequestActionType('fetchEmployee','ERROR',get,'/myproject/api/employee') -> '@@REST/fetchEmployee GET /myproject/api/employeeERROR'
 */
const createRequestActionType = (name,qualifier,restMethod = '',path = '') => [`@@REST/${name}`,getMethodName(restMethod),qualifier]
  .filter(s => s !== '')
  .join(' ');

/**
 * createRequestActionTypes
 * Helper function to generate ActionTypes for a given AJAX method and resource.
 *
 * Ex. createRequestActionType(fetchEmployee,'/myproject/api/employee') -> {
 *   reset: '@@REST GET /myproject/api/employee RESET',*   requestStarted: '@@REST GET /myproject/api/employee STARTED',*   requestError: '@@REST GET /myproject/api/employee ERROR',*   requestFinished: '@@REST GET /myproject/api/employee FINISHED',* }
 */
const createRequestActionTypes = (name,path) => ({
  reset: createRequestActionType(name,'RESET'),requestStarted: createRequestActionType(name,'STARTED',path),requestError: createRequestActionType(name,requestFinished: createRequestActionType(name,'FINISHED',path)
});

/**
 * createRequestThunk
 * Helper function that generates a thunk that performs an AJAX call specified by 'restMethod' and 'restEndpoint'
 *
 * When the thunk is running,the action 'requestStarted' will be dispatched immediately.
 * Then,it performs the AJAX call that returns a promise.
 *  If the call goes well,the action 'requestFinished' will be dispatched with data from the call.
 * If the call fails,the action 'requestError' is dispatched with the contents of the error.
 */
const createRequestThunk = (restMethod,restEndpoint,requestStarted,requestFinished,requestError) => (
  (params,options = {}) => (dispatch) => {
    dispatch(requestStarted(params,options));
    return restMethod(restEndpoint,params)
      .catch((error) => {
        const data = error.response && error.response.data ? error.response.data : error;
        dispatch(requestError(data));
        return Promise.reject(error);
      })
      .then((response) => {
        dispatch(requestFinished(response.data));
        return response;
      });
  }
);

/**
 * createRequestActionCreators
 * Helper function that creates action creators 'requestStarted','requestFinished' and 'requestError',* @see createRequestThunkCreator
 */
const createRequestActionCreators = (restMethod,actionTypes) => {
  const reset = () => ({ type: actionTypes.reset });
  const requestStarted = (params,options = {}) => ({ type: actionTypes.requestStarted,payload: { params,timestamp: Date.now() },meta: { options } });
  const requestFinished = data => ({ type: actionTypes.requestFinished,payload: data });
  const requestError = error => ({ type: actionTypes.requestError,payload: error });
  const execRequest = createRequestThunk(restMethod,requestError);
  return {
    reset,requestError,execRequest
  };
};

/**
 * createRequestReducer
 *
 * Helper function that creates a reducer for an AJAX call.
 * Reducer alters the state of the actions with the name defined by
 *   actionTypes.requestStarted
 *   actionTypes.requestFinished
 *   actionTypes.requestError
 */
const createRequestReducer = (restMethod,resourceName,actionTypes) => {
  const initialState = {
    data: undefined,meta: undefined,error: undefined,started: false,finished: false
  };

  return (state = initialState,action = {}) => {
    switch (action.type) {
      case actionTypes.requestStarted:
        return {
          ...initialState,data: action.meta.options.keepData ? state.data : initialState.data,started: true,meta: action.payload
        };
      case actionTypes.requestFinished:
        return {
          ...state,finished: true,data: action.payload
        };
      case actionTypes.requestError:
        return {
          ...state,error: action.payload
        };
      case actionTypes.reset:
        return {
          ...initialState
        };
      default:
        return state;
    }
  };
};

/**
 * RestDuck
 * Class that offers action types,action creators,reducers and selectors for an AJAX call.
 * @see createRequestActionTypes
 * @see createRequestActionCreators
 * @see createRequestReducer
 *
 * Ex.
 * const getEmployeeDuck = new RestDuck(execGetRequest,'employee',GET_EMPLOYEE_SERVER_URL);
 * // Action creators
 * export const fetchEmployee = getEmployeeDuck.actionCreators.execRequest;
 * // Reducer
 * export const dataReducer = combineReducers(
 *   ...,*   getEmployeeDuck.reducer,* }
 * // Selectors
 * export const getDataContext = state => state.default.dataContext;
 * export const getEmployeeData = getEmployeeDuck.selectors.getRequestData(getDataContext);
 * export const getEmployeeStarted = getEmployeeDuck.selectors.getRequestStarted(getDataContext);
 * ...
 */
class RestDuck {
  constructor(name,getApiContext) {
    this.restMethod = restMethod;
    this.name = name;
    this.path = path;
    this.getApiContext = getApiContext;
    this.$$duck = {}; // for class internal use
  }

  get actionTypes() {
    if (!this.$$duck.actionTypes) {
      this.$$duck.actionTypes = createRequestActionTypes(this.name,this.restMethod,this.path);
    }
    return this.$$duck.actionTypes;
  }

  get actionCreators() {
    if (!this.$$duck.actionCreators) {
      this.$$duck.actionCreators = createRequestActionCreators(this.restMethod,this.path,this.actionTypes);
    }
    return this.$$duck.actionCreators;
  }

  get reducer() {
    if (!this.$$duck.reducer) {
      this.$$duck.reducer = createRequestReducer(this.restMethod,this.name,this.actionTypes);
    }
    return this.$$duck.reducer;
  }

  get stateSelector() {
    return createSelector([this.getApiContext],restApiContext => restApiContext[this.name]);
  }
}

export default RestDuck;

数据/休息/ restMethods.jsx

import axios,{ CancelToken } from 'axios';

const openPreview = (data) => {
  if (window.navigator.msSaveOrOpenBlob) {
    window.navigator.msSaveOrOpenBlob(data);
  } else {
    window.open(URL.createObjectURL(data));
  }
};

const cancellable = (config) => {
  let cancel;
  const request = axios({
    ...config,cancelToken: new CancelToken((c) => { cancel = c; })
  });
  request.cancel = cancel;
  return request.catch(error => (axios.isCancel(error) ? Promise.reject(new Error(null)) : Promise.reject(error)));
};

const defaultHeaders = {
  'Cache-Control': 'no-cache',Pragma: 'no-cache',Expires: 0
};

const defaultPostHeaders = {
  'Content-Type': 'application/json'
};

export const get = (url,params,responseType = 'json') => cancellable({
  url,responseType,method: 'get',headers: {
    ...defaultHeaders
  }
});

export const post = (url,data,data: JSON.stringify(data),method: 'post',headers: {
    ...defaultHeaders,...defaultPostHeaders
  },cache: false
});

export const getBlob = (url,params) => get(url,'blob');

export const postBlob = (url,data) => post(url,'blob');

export const postAndOpenBlob = (url,data) => postBlob(url,data)
  .then((response) => {
    openPreview(response.data);
    return {
      ...response,data: 'blob opened as preview' // Don't waste memory by storing blob in state
    };
  });

我不知道在这个结构中如何放置以及如何模拟api调用.我正在考虑制作一个类似于这个one的模拟api,在那里我会模仿ajax调用并将它们存储在redux中,但是不知道如何在这种设置中执行此操作?

我尝试使用mockApi文件夹而不是使用restMethods来使用我将编写将解析mockData的promises的文件.这是我的尝试:

mockRestMethods

const employee = {
  name: 'Joe Doe'
}
const data = {
  employee 
};

export const get = item => new Promise((resolve) => {
  setTimeout(() => {
    resolve({ data: data[item] });
  },1000);
});

但是,如果我在RestDuck文件中的createRequestThunk函数内检查返回的内容作为response.data,我得到数据:undefined there.为什么,我做错了什么?

我可能有这个错误,但似乎你正在取代

export const get =(url,responseType =’json’)=>撤销({

with export const get = item =>新的Promise((resolve)=> {具有不同的API.

无论如何,您是否尝试在mock get函数中记录item的值.我猜它不是“员工”,这是数据中唯一的属性.

Yes,that was my goal,to replace the call that was pointing to the backend API,with the call where I would return the mock data. I have tried to log the value of the item,but I get undefined

好的,所以那里有很多抽象.我建议首先使用返回promise的版本替换get in data / rest / restMethods.jsx,让它工作,然后将其分解.这样你就不会立刻处理太多未知数.

(编辑:李大同)

【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容!

    推荐文章
      热点阅读