Angular 2对预检请求的响应未通过访问控制检查:没有"Access-Control-Allow-Origin"标头

问题描述

我是Angular2的新手.而且我正在尝试将POST方法调用到.net核心API中.它与Postman正常工作.但是，当我从angular 2服务中调用它时，会出现错误.

I'm new to Angular2. And I'm trying to call POST method to my .net core API.It's working fine with Postman.But when I call it from my angular 2 service it gives an error.

这是我的api.service.ts

import { Injectable } from '@angular/core';
import { environment } from '../../../environments/environment';
import { Headers, Http, Response, URLSearchParams } from '@angular/http';
import { Observable } from 'rxjs/Rx';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';

import { JwtService } from './jwt.service';

@Injectable()
export class ApiService {
  constructor(
    private http: Http,
    private jwtService: JwtService
  ) {}

  private setHeaders(): Headers {
    const headersConfig = {
      'Content-Type': 'application/json',
      'Accept': 'application/json',
      'Access-Control-Allow-Origin': '*'
    };

    if (this.jwtService.getToken()) {
      headersConfig['Authorization'] = `Token ${this.jwtService.getToken()}`;
    }
    return new Headers(headersConfig);
  }

  post(path: string, body: Object = {}): Observable<any> {

    return this.http.post(
      `${environment.api_url}${path}`,
        JSON.stringify(body),
        { headers: this.setHeaders() }
    )
    .catch(this.formatErrors)
    .map((res: Response) => res.json());
  }

身体价值

.net核心API方法

.net core API mothod

推荐答案

这是CORS问题.发生这种情况是因为您试图从其他主机请求资源.您的API需要正确回答这些OPTIONS请求，否则浏览器将阻止该请求.

That's a CORS issue. It happens because you are trying to request a resource from a different host. Your API needs to answer those OPTIONS requests properly otherwise the browser is going to block the request.

https://developer.mozilla.org/zh-CN/docs/Web/HTTP/CORS

CORS保护未在邮递员中实现，因此您的请求在此可以正常工作.

CORS protection isn't implemented in postman so your request works fine there.

如果您的后端要在生产环境中的同一主机上运行，​​则还可以使用webpack/angular cli的代理支持: https://github.com/angular/angular -cli/blob/master/docs/documentation/stories/proxy.md

You can also use webpack / angular cli's proxy support if your backend is going to run on the same host in production:https://github.com/angular/angular-cli/blob/master/docs/documentation/stories/proxy.md

这篇关于Angular 2对预检请求的响应未通过访问控制检查:没有"Access-Control-Allow-Origin"标头的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！