How to make a post request using react redux?

问题

I have created a form with email, firstname, lastname details. Now I want to make a POST request to localhost:5000/api/users and want to store it in mongo database. How can I make use of redux ? I have implemented it using on reactjs only how can I make use of redux ? Note: I am using redux thunk.

Code:

import React, { Component } from 'react'
import './login.css'

export default class Login extends Component {

  constructor(props) {
    super(props)
    this.state = {
      firstName:'',
      lastName:'',
      email:''
    }

    this.onChangeHandler = this.onChangeHandler.bind(this)
    this.onSubmitHandler = this.onSubmitHandler.bind(this)
  }

  onChangeHandler(e){
    this.setState({ [e.target.name]: e.target.value })
  }

  onSubmitHandler(e){
    e.preventDefault();
    console.log(this.state)
  }

  render() {
    return (
      <div>
        <form onSubmit={this.onSubmitHandler}>
          <label>
            FirstName:
            <input type="text" name="firstName" value={this.state.firstName} onChange={this.onChangeHandler} />
          </label>

          <label>
            LastName:
            <input type="text" name="lastName" value={this.state.lastName} onChange={this.onChangeHandler} />
          </label>

          <label>
            Email:
            <input type="text" name="email" value={this.state.email} onChange={this.onChangeHandler} />
          </label>
          <button type="submit" className="btn btn-default">Submit</button>
        </form>
      </div>
    )
  }
}

loginAction.js:

import { ADD_USER } from './types';
import axios from 'axios';

export const userLoginRequest = () => dispatch => {
    axios.post(`localhost:5000/api/users`)
    .then( userdata => 
        dispatch({
            type: ADD_USER,
            payload: userdata
        })
    )
    .catch( error => {
        console.log(error);
    });
};

loginReducer.js:

import { ADD_USER } from '../actions/types';

const initialState = {
    firstName: '',
    lastName: '',
    email: ''
}


export default function (state = initialState, action) {
    switch (action.type) {
        case ADD_USER:
            return {
                ...state,
                items: action.payload
            };
        default:
            return state;
    }
}

I am not able to understand do I need to create 3 actions each one for firstname, lastname and email ? In that case what will be those 3 actions will it have 3 POST req in each of them ?

回答1:

I recommend you to have some insight about redux and redux-thunk. For making network requests you need to use middleware like redux-thunk or redux-saga;

Here are very basic examples of redux-thunk

//example 1
function myThunkActionCreator(someValue) {
    return (dispatch, getState) => {
        dispatch({type : "REQUEST_STARTED"});

        myAjaxLib.post("/someEndpoint", {data : someValue})
            .then(
                response => dispatch({type : "REQUEST_SUCCEEDED", payload : response}),
                error => dispatch({type : "REQUEST_FAILED", error : error})
            );    
    };
}

// example 2 for conditional dispatching based on state
const MAX_TODOS = 5;

function addTodosIfAllowed(todoText) {
    return (dispatch, getState) => {
        const state = getState();

        if(state.todos.length < MAX_TODOS) {
            dispatch({type : "ADD_TODO", text : todoText});
        }    
    }
}

Update

So the flow for posting the form data to the server using redux-thunk goes like so

When submit button is clicked and action gets dispatched let us suppose SAVE_USER_TO_SERVER and an object with all the user details (name, email etc) is passed to for eg postUserThunkCreator() (which is a thunk function like in examples above).
Then thunk makes a post request to the server and sends the data along with it. And on the server side it gets saved into the database and response is returned
Now myAjaxLib.post("/someEndpoint", {data : someValue}).then() in .then() function you can check for the response if successfull the dispatch another action for eg SAVE_USER_TO_SERVER_SUCCESS otherwise SAVE_USER_TO_SERVER_FALIURE;

*So as we can see that three actions are bieng dipatched in this work flow namely : SAVE_USER_TO_SERVER

SAVE_USER_TO_SERVER_SUCCESS

SAVE_USER_TO_SERVER_FALIURE

So I hope its clear to you that you to create three action mentioned above.

Your Question Do I need to create 3 actions each one for firstname, lastname and email ?

Answer: Not at all. Only three action mentioned above.

来源：https://stackoverflow.com/questions/53100829/how-to-make-a-post-request-using-react-redux

标签

reactjs