为什么我收到“无法读取未定义的属性‘有效负载’”

Question

我正在开发和应用程序进行搜索，当用户在输入框中键入时，发送一个帖子请求以检查数据库（猫鼬）以查看它是否存在，如果存在 响应将有效负载发送回具有匹配名称的客户端。当我在框中输入时，我得到 UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'payload' of undefined 从服务器。在 chrome 开发工具中，状态为待处理。根据我的研究， req.body.payload 其中 body 是属性。 我添加了 app.use(express.json() 并且我什至尝试过 const bodyParser = require('body-parser') app.use(bodyParser.urlencoded({ extended: false })) 

app.use(bodyParser.json())。 在我的路由上添加一个虚拟处理程序时，我确实从客户端收到了状态为 200 的请求。这是一个代码 sn-p。

My server.js

const press.Router();
const someProducts      = require('./liveSearch');
const getProducts        = 
require('.../../controllers/api/getProducts/getProducts')



const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost/productLiveSearch', 
{useNewUrlParser:
true, useUnifiedTopology: true, }); 
const db = mongoose.connection;
db.on('error', error => console.log(error));
db.once('open', () =>{
  console.log('Connected to Mongoose');

  const app = express();
  

  app.use(express.json());
  app.use(express.urlencoded({extended: true}));
  
      

  app.use(function(req,res,next){
    res.header("Access-Control-Allow-Origin", "*");
    res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
    res.header('Access-Control-Allow-Methods','POST, GET ,DELETE, PUT');
    next();
    });

});



const app = express();

app.options('/getProducts', cors()) // enable pre-flight 
app.use(cors({
  origin: [
    'http://localhost:4200'           ]
}))

 app.use('/', getProducts)
 app.use('/getProducts', getProducts);


 

app.get('/', function(req, res){
  res.send('hello world');
});




app.listen(process.env.Port|| 3000, () => {
    console.log("Server has started on Port 3000");

});

module.exports = router

 
  

my getProducts.js
var express = require('express');
const cors    = require('cors');
const someProducts      = require('../liveSearch');
var router = express.Router();

const bodyParser = require('body-parser')
const app = express();


// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: false })) 

// parse application/json
app.use(bodyParser.json())


router.get('/', function(req, res){
   res.send('GET route on things here.');
});

  
router.post('/getProducts', async(req,res) =>{
   console.log("Does it get to post");
   payload: req.body.payload;
   console.log("does it get pass")
   let search = await someProducts.find({name: {$regex: new RegExp('^'+payload+'.*',
   'i')}}).exec();
      //Limit search to 10
   search = search.slice(0, 10);
   //res.send("got a post request")
   res.send({payload:payload});
})



//export this router to use in our server.js
module.exports = router;

My post request is in my searchservice.ts

import { Injectable } from '@angular/core';
import{HttpClient, HttpHeaders} from '@angular/common/http';
import{map, catchError, tap} from 'rxjs/operators'
//import { Product } from '@app/models/product';
import { Observable } from 'rxjs';
import {MessengerService} from 'src/app/services/messenger.service';
import {productsUrl} from '@app/ui/header/api'
import { productUrl } from '@app/config/api';


export interface someProducts{
  _id: string,
  name: string
}


@Injectable({
  providedIn: 'root'
})
export class SearchService {


 
  constructor(private http:HttpClient, private messageService:MessengerService) { }
  
 
 
  searchProducts(query:string){
    console.log("Does it get  my  searchProducts");
    return this.http.post<{payload: Array<someProducts>}>(productsUrl, {payload:query}, {
     
     headers:new HttpHeaders({'Content-Type': 'application.json'}) 
           
    }).pipe(
       map(data =>data.payload)
     
    );
        
  }
  
}

    
Thanking You in Advance.
PH

Answer 1

我移动了 app.use(express.json()); app.use(express.urlencoded({extended: true}));

在我的 app.use('/', getProducts) 文件的底部更多 app.use('/getProducts', getProducts);

然后错误就消失了。

PDH