如何从ReactJS + Redux应用程序正确进行REST调用？

Question

我正在使用ReactJS + Redux，以及Express和Webpack。有一个内置的API，我希望能够从客户端进行REST调用-
GET，POST，PUT，DELETE。

使用Redux架构的方式和正确方法是什么？就简化程序，动作创建者，存储和反应路线而言，任何有关流程的良好示例都将非常有帮助。

先感谢您！

Answer 1

最简单的方法是使用redux-thunkpackage进行操作。这个软件包是一个redux中间件，因此，首先，您应该将其连接到redux：

import { createStore, applyMiddleware } from 'redux';
import thunk from 'redux-thunk';
import rootReducer from './reducers/index';

const store = createStore(
  rootReducer,
  applyMiddleware(thunk)
);

这使您可以将async动作与常规sync动作一起分派。让我们创建其中之一：

// actions.js

export function fetchTodos() {
  // Instead of plain objects, we are returning function.
  return function(dispatch) {
    // Dispatching REQUEST action, which tells our app, that we are started requesting todos.
    dispatch({
      type: 'FETCH_TODOS_REQUEST'
    });
    return fetch('/api/todos')
      // Here, we are getting json body(in our case it will contain `todos` or `error` prop, depending on request was failed or not) from server response
      // And providing `response` and `body` variables to the next chain.
      .then(response => response.json().then(body => ({ response, body })))
      .then(({ response, body }) => {
        if (!response.ok) {
          // If request was failed, dispatching FAILURE action.
          dispatch({
            type: 'FETCH_TODOS_FAILURE',
            error: body.error
          });
        } else {
          // When everything is ok, dispatching SUCCESS action.
          dispatch({
            type: 'FETCH_TODOS_SUCCESS',
            todos: body.todos
          });
        }
      });
  }
}

我更喜欢在呈现和容器组件上分离React组件。本文完美地描述了这种方法。

接下来，我们应该创建TodosContainer组件，该组件将为演示Todos组件提供数据。在这里，我们正在使用react-redux库：

// TodosContainer.js

import React, { Component } from 'react';
import { connect } from 'react-redux';
import { fetchTodos } from '../actions';

class TodosContainer extends Component {
  componentDidMount() {
    // When container was mounted, we need to start fetching todos.
    this.props.fetchTodos();
  }

  render() {
    // In some simple cases, it is not necessary to create separate `Todos` component. You can put todos markup directly here.
    return <Todos items={this.props.todos} />
  }
}

// This function is used to convert redux global state to desired props.
function mapStateToProps(state) {
  // `state` variable contains whole redux state.
  return {
    // I assume, you have `todos` state variable.
    // Todos will be available in container component as `this.props.todos`
    todos: state.todos
  };
}

// This function is used to provide callbacks to container component.
function mapDispatchToProps(dispatch) {
  return {
    // This function will be available in component as `this.props.fetchTodos`
    fetchTodos: function() {
      dispatch(fetchTodos());
    }
  };
}

// We are using `connect` function to wrap our component with special component, which will provide to container all needed data.
export default connect(mapStateToProps, mapDispatchToProps)(TodosContainer);

另外，如果要显示加载程序/错误消息，则应创建todosReducer，将处理FETCH_TODOS_SUCCESS操作以及其他2个操作。

// reducers.js

import { combineReducers } from 'redux';

const INITIAL_STATE = {
  items: [],
  isFetching: false,
  error: undefined
};

function todosReducer(state = INITIAL_STATE, action) {
  switch (action.type) {
    case 'FETCH_TODOS_REQUEST':
      // This time, you may want to display loader in the UI.
      return Object.assign({}, state, {
        isFetching: true
      });
    case 'FETCH_TODOS_SUCCESS':
      // Adding derived todos to state
      return Object.assign({}, state, {
        isFetching: false,
        todos: action.todos
      });
    case 'FETCH_TODOS_FAILURE':
      // Providing error message to state, to be able display it in UI.
      return Object.assign({}, state, {
        isFetching: false,
        error: action.error
      });
    default:
      return state;
  }
}

export default combineReducers({
  todos: todosReducer
});

对于其它操作喜欢CREATE，UPDATE，DELETE没有什么特别的，他们正在实施方式相同。