http服务器如何响应404,在httpclient中检测来自服务器的http 404响应

我在从api检测404响应状态时遇到问题。如果您查看图像,您将看到chrome正确地记录了请求的404响应状态。问题是Angular的HTTP客户端报告的状态代码是“0”。我在这里做错什么了…?

代码:

checkNameTaken(clientId: string, name: string): Observable {

const baseUrl = this.configService.configBs.getValue().apiBaseUrl;

return this.http.get(`${baseUrl}/Rules/${clientId}/${name}`)

.pipe(

catchError( error => {

if ( !(error.error instanceof ErrorEvent)) {

// The backend returned an unsuccessful response code.

// The response body may contain clues as to what went wrong,

if (error.status === '404') {

return of(true);

}

console.error(

`Backend returned code ${error.status}, ` +

`body was: ${error.error}`);

}

return of(false);

}),

map(rule => rule ? true : false)

);

}

这是chrome的网络标签:

Request URL: http://localhost:57067/api/Rules/C7000050/tests

Request Method: GET

Status Code: 404 Not Found

Remote Address: [::1]:57067

Referrer Policy: no-referrer-when-downgrade

知道为什么当服务器返回404时error.status总是返回0吗?运行角度7.2.0

将代码更新为:

checkNameTaken(clientId: string, name: string): Observable {

const baseUrl = this.configService.configBs.getValue().apiBaseUrl;

return this.http.get(`${baseUrl}/Rules/${clientId}/${name}`)

.pipe(

catchError( error => {

if ( !(error.error instanceof ErrorEvent)) {

// The backend returned an unsuccessful response code.

// The response body may contain clues as to what went wrong,

if (error.status === 404) {

return of(true);

}

console.error(

`Backend returned code ${error.status}, ` +

`body was: ${error.error}`);

}

return of(false);

}),

map(rule => rule ? true : false)

);

}

当服务器返回404时,error.status始终为0。