向Angular HttpClient添加一个HTTP头并不会发送这个头，为什么?

这是我的代码:

import { HttpClient, HttpErrorResponse, HttpHeaders } from '@angular/common/http';

logIn(username: string, password: string) {
    const url = 'http://server.com/index.php';
    const body = JSON.stringify({username: username,
                                 password: password});
    const headers = new HttpHeaders();
    headers.set('Content-Type', 'application/json; charset=utf-8');
    this.http.post(url, body, {headers: headers}).subscribe(
        (data) => {
            console.log(data);
        },
        (err: HttpErrorResponse) => {
            if (err.error instanceof Error) {
                console.log('Client-side error occured.');
            } else {
                console.log('Server-side error occured.');
            }
        }
    );
}

这里是网络调试:

Request Method:POST
Status Code:200 OK
Accept:application/json, text/plain, */*
Accept-Encoding:gzip, deflate
Accept-Language:en-US,en;q=0.8
Cache-Control:no-cache
Connection:keep-alive
Content-Length:46
Content-Type:text/plain

和数据存储在“请求有效载荷”，但在我的服务器没有收到POST值:

print_r($_POST);
Array
(
)

我相信错误来自于在POST期间没有设置头，我做错了什么?

当前回答

我用的是Angular 8，唯一对我有用的是:

  getCustomHeaders(): HttpHeaders {
    const headers = new HttpHeaders()
      .set('Content-Type', 'application/json')
      .set('Api-Key', 'xxx');
    return headers;
  }

2019-10-12 11:03:12

其他回答

带有错误处理和自定义报头的Angular 8 HttpClient服务示例

    import { Injectable } from '@angular/core';
    import { HttpClient, HttpHeaders, HttpErrorResponse } from '@angular/common/http';
    import { Student } from '../model/student';
    import { Observable, throwError } from 'rxjs';
    import { retry, catchError } from 'rxjs/operators';

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

      // API path
      base_path = 'http://localhost:3000/students';

      constructor(private http: HttpClient) { }

      // Http Options
      httpOptions = {
        headers: new HttpHeaders({
          'Content-Type': 'application/json'
        })
      }

      // Handle API errors
      handleError(error: HttpErrorResponse) {
        if (error.error instanceof ErrorEvent) {
          // A client-side or network error occurred. Handle it accordingly.
          console.error('An error occurred:', error.error.message);
        } else {
          // The backend returned an unsuccessful response code.
          // The response body may contain clues as to what went wrong,
          console.error(
            `Backend returned code ${error.status}, ` +
            `body was: ${error.error}`);
        }
        // return an observable with a user-facing error message
        return throwError(
          'Something bad happened; please try again later.');
      };


      // Create a new item
      createItem(item): Observable<Student> {
        return this.http
          .post<Student>(this.base_path, JSON.stringify(item), this.httpOptions)
          .pipe(
            retry(2),
            catchError(this.handleError)
          )
      }

      ....
      ....

点击这里查看完整的示例教程

2019-08-07 15:50:09

新的HttpHeader类的实例是不可变对象。调用类方法将返回一个新实例作为结果。所以基本上，你需要做以下事情:

let headers = new HttpHeaders();
headers = headers.set('Content-Type', 'application/json; charset=utf-8');

const headers = new HttpHeaders({'Content-Type':'application/json; charset=utf-8'});

更新:增加多个报头

let headers = new HttpHeaders();
headers = headers.set('h1', 'v1').set('h2','v2');

const headers = new HttpHeaders({'h1':'v1','h2':'v2'});

更新:接受HttpClient头和参数的对象映射

因为5.0.0-beta。现在可以跳过HttpHeaders对象的创建，直接传递一个对象映射作为参数。所以现在可以做以下事情:

http.get('someurl',{
   headers: {'header1':'value1','header2':'value2'}
});

2017-07-24 17:50:49

首先，您需要使用HttpClient添加HttpHeaders

import { HttpClient,HttpHeaders  } from '@angular/common/http';

构造函数应该如下所示。

constructor(private http: HttpClient) { }

然后你可以这样用

   let header = new HttpHeaders({ "Authorization": "Bearer "+token});

   const requestOptions = {  headers: header};                                                                                                                                                                            

    return this.http.get<any>(url, requestOptions)
        .toPromise()
        .then(data=> {
            //...
            return data;
    });

2020-08-27 06:00:02

我也在和这个斗争。我使用了一个拦截器，它捕获响应头，然后克隆头(因为头是不可变的对象)，然后发送修改后的头。https://angular.io/guide/http#intercepting-requests-and-responses

2021-02-22 10:08:00

我为此挣扎了很长一段时间。我使用的是Angular 6，我发现了这一点

let headers = new HttpHeaders();
headers = headers.append('key', 'value');

没有工作。但真正起作用的是

let headers = new HttpHeaders().append('key', 'value');

当你意识到它们是不可变的时候，这就说得通了。因此，创建了一个标题，你不能再添加它。我没试过，但我猜

let headers = new HttpHeaders();
let headers1 = headers.append('key', 'value');

也会起作用。

2018-08-27 04:17:47

向Angular HttpClient添加一个HTTP头并不会发送这个头，为什么?

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