获取请求不符合Angular-Express

Question

我是MEAN堆栈的新手我希望从快递服务器（我用mongodb创建）中获取数据，当我点击按钮时，按钮点击功能被执行但请求未完成，数据库，服务器全部运行好吧，我在控制台什么都没有，这是我的客户端和服务器文件：

• 客户端（在http://localhost:3001上运行）

• 导入的模块并添加到ngModule中的导入

  

从“@ angular / http”导入{Http，Headers，HttpModule，Response，RequestOptions};

在构造函数中作为服务注入，然后： 模板：

<button md-button class="button1" (click)="newQues()">Submit</button>

课堂上：

newQues(){

  this.http.get('https://localhost:3000/')
                .map(this.extractData)
                .catch(this.handleError);  //these copied from angular2
                                           //official documentation          
}

private extractData(res: Response) {
let body = res.json();
console.log(body);  //not getting console nor error
return body.data || { };
}

服务器在端口3000上运行

app.get('/', function (req, res) {

   model.findOne({ id: 1}, function (err, data) {
   if (err) {
   console.log(err)
   } else {
   console.log(data);
   res.send(data);
}
})

请求时出现这些错误

整个服务器代码：

import * as express from "express";
var app = express();
import * as path from "path";
import * as mongoose from "mongoose";
import * as lodash from "lodash";
import * as morgan from "morgan";


app.use(express.static(path.join(__dirname, "./../client")));

var uriString = 'mongodb://localhost/quizapp';
mongoose.connect(uriString, function (err, res) {
if (err) {
console.log("Error occured while establishing connection " + err);
} else {
console.log("Connection successful ");
}
})

var schema = new mongoose.Schema({     //schema
question: String,
id: Number
})

var quizz = mongoose.model('Quiz', schema);  //creating model

var firstDoc = new quizz({
question: 'question 1',
id: 1
})
var secondDoc = new quizz({
question: 'question 2',
id: 2
})

var question_data = [firstDoc, secondDoc];

quizz.insertMany(question_data, function (err, res) {
if (err) {
console.log("Error occured while saving document object " + err)
} else {
console.log("Data Saved Successful");
}
})

app.get('/data', function(req, res) {
quizz.findOne({ id: 1}, function (err, data) {
 if (err) {
   console.log(err)
 } else {
   console.log(data);
   res.send(data);   //res.json
 }
 })
 })

当我路由到localhost时：3000 / data来自数据库的数据显示在窗口上，但是当从客户端请求该路由时（请参阅客户端代码this.http.get）发生错误（附图）

Answer 1

用于提取您必须订阅的数据。试试这种方式

export class SimpleHTTPComponent {
      data: Object;
      loading: boolean;

      constructor(public http: Http) {
      }

      makeRequest(): void {
        this.loading = true;
        this.http.request('http://jsonplaceholder.typicode.com/posts/1')
          .subscribe((res: Response) => {
            this.data = res.json();
            this.loading = false;
          });
      }
    }

我认为您没有将this与body一起使用。你的console.log应该是这样的。 console.log(this.body);