React无法从API访问Json Resposne

Question

In my website on login,i get a confirmation and a token which i need to store and pass as a property throughout all the pages.I am able to receive the token,but i am unable to store the value for the token and store it as a state value.

Here is the code i have tried so far.

import React from 'react'
import ReactDOM from 'react-dom'
import {Login_Submit_style,Login_button_style,Login_text_field_style,
password_style,para_login_style} from './style'

import Supers from 'superagent'

class Login extends React.Component
{
  constructor(props)
  {
    super(props);
    this.state={username:'',password:''}
    this.Login_data_password=this.Login_data_password.bind(this)
    this.Login_data_username=this.Login_data_username.bind(this)
    this.MainRedirect=this.MainRedirect.bind(this)
    this.api_call_login=this.api_call_login.bind(this)
  }

Login_data_username(e)
{
  this.setState({username:e.target.value})
}

Login_data_password(password)
{
  this.setState({password:password.target.value})
}

MainRedirect()
{
  window.location = '/main';
}

api_call_login()
{
  Supers.post('http://127.0.0.1:8000/user_ops/user_login/')
  .send({'username':this.state.username,'password':this.state.password})
  .then(response => response.json())
  .then(responseData=>{
    console.log(responseData);
  })
    }



render()
{
  return(
    <div style={{background:'yellow'}}>
      <div>
        <h1 style={{marginLeft:550}}>Login Page</h1>
        <div>
          <p style={para_login_style}><b>Username</b></p>
          <input type="text" style={Login_text_field_style} onChange={this.Login_data_username}/>
          <h2>{this.state.username}</h2>
        </div>
        <div>
          <p style={para_login_style} ><b>Password</b></p>
          <input type="password" style={password_style} onChange={this.Login_data_password}/>
        </div>
        <div>
          <button style = {Login_Submit_style} onClick={this.api_call_login}> Log in </button>
        </div>
      </div>
    </div>
  )
}
}

This is the Format in which i get the response: {"Successful_Login": "True", "token": "d278f30445aa0c37f274389551b4faafee50c1f2"}

So ideally i would like to store the values for both the keys returned from the json output.Adn when i use response.body,i am able to get the data in the above format.

Answer 1

I don't know if this will be helpful to you, but I'll try.

Things like XHR calls from a browser to an API are done asynchronously. What you get back is a promise that will execute a function you give it when the call to the API is completed. Your code rightly has a callback function.

However, I don't think that callback function can call setState, because I think (I might be wrong) React wouldn't like it.

I use Redux for React as a way of storing stuff that the rest of the app can just grab when it needs it. Better still, Redux is integrated into React in such a way that whenever this central database is updated, any component that pulls in a piece of data from it (via props) gets updated (re-rendered) automatically.

I think I should point you to the documentation for Redux for more information. There are alternatives to Redux, too.

Good luck, and ask more questions if you get stuck.

Answer 2

In order to set a new state with the values from a json response, I ideally call this.setState right in your promise response.

api_call_login()
{
  Supers.post('http://127.0.0.1:8000/user_ops/user_login/')
  .send({'username':this.state.username,'password':this.state.password})
  .then(response => response.json())
  .then(responseData=>{
    this.setState({ 
      Successful_Login: responseData.Successful_Login,
      token: responseData.token
  })
}

state will be updated when response arrives.

If possible try to use lowercase or camelCase to your keys.

Answer 3

It would be great if you could post link where we can see what exactly is going on, but the way I understand this you would have to add .set('Accept', 'application/json') in your request to get correct json. So, your code should be like:

Supers.post('http://127.0.0.1:8000/user_ops/user_login/')
      .send({'username':this.state.username,'password':this.state.password})
      .set('Accept', 'application/json')
      .then(response => response.json())
      .then(responseData=>{
            console.log(responseData);
})

Since I cannot test, you would have to look if it works. Alternatively, I would suggest you to try using superagent

Let me know if it helps!