Question

您好我有服务将数据发送到我的服务器：

import { Injectable} from '@angular/core';
import { Http, Response,Headers, RequestOptions } from '@angular/http';
import 'rxjs/add/operator/catch';
import 'rxjs/add/operator/map';
import { Observable } from 'rxjs/Observable';
import { Transaction } from './transaction'

@Injectable()
export class TransactionSenderService{
    constructor(private http:Http){}
    private url = 'http://localhost:3000/transaction/save/';

sendTransaction(ta: Transaction) : Observable<Boolean>{
    let bodyString = JSON.stringify(ta);
    let headers      = new Headers({ 'Content-Type': 'application/json' }); // ... Set content type to JSON
    let options       = new RequestOptions({ headers: headers }); // Create a request option
    return this.http.post(this.url,bodyString,options)
    .map(this.extractData)
    .catch(this.handleError);
}
 private extractData(res: Response) {
    let body = <Boolean>res.json();
    return body || {};
}
private handleError(error: Response | any) {
    // In a real world app, you might use a remote logging infrastructure
    let errMsg: string;
    if (error instanceof Response) {
        const body = error.json() || '';
        const err = body.error || JSON.stringify(body);
        errMsg = `${error.status} - ${error.statusText || ''} ${err}`;
    } else {
        errMsg = error.message ? error.message : error.toString();
    }
    console.error(errMsg);
    return Observable.throw(errMsg);
}

}

并在我的express.js部分：

app.post('/transaction/save/', (req, res)=>{
  var ta = req.body.ta;
  res.send("done");
})

app.listen(3000, function () {
  console.log('Example app listening on port 3000!')
});

问题是我的请求没有被发送？我无法在浏览器的网络选项卡中看到任何内容。我在express.js中也有断点，所以我看到没有收到任何东西。如果我是从Postman发送的，那么它正在运行。控制台中没有异常/错误。我做错了什么？

@UPDATE

我被要求放在这里，我打电话给这个发送：

export class MainComponent implements OnChanges, OnInit, OnDestroy {
  isModalVisible: Boolean;
  transactions: Transaction[];
  selectedTa: number;

  constructor(private transactionSenderService: TransactionSenderService) {}


  ngOnInit() {

  }
  ngOnChanges(changes: SimpleChanges) {
    alert("Wykrywam Zmiany");
  }
  ngOnDestroy(){
        // prevent memory leak when component destroyed
    this.subscription.unsubscribe();
  }
  myValueChange(event: any) {
    console.log(event);
  }
  clearTa(): void {
    this.transactionSenderService.sendTransaction(this.transactions[this.selectedTa])     
  }      
}

我删除了不必要的代码。这个片段正在运行。我可以一步一步地看到我要进入send方法。如果我将observable更改为toPromise而不是发送请求，请执行更多操作。为什么呢？

Answer 1

您需要订阅observable来发出请求，更改您拨打电话的地方。

this.transactionSenderService.sendTransaction(this.transactions[this.selectedTa]).subscribe(resp => {

});

邮寄请求未发送

1 个答案: