角色中的通用http错误处理

问题描述

为本机Angular http类提供了一个AuthHttp包装器，它自动包含http授权标头与每个请求。在我的服务中，我通常会像这样调用一个后端api。

  getThings（）：Observable< Thing []> {
 return this.http.get（environment.apiEndpoint +'/ things'）
 .map（res => res.json（）。data）
 .catch（res => ; this.handleError（res））; 
} 
  

包含错误处理程序，如

  private handleError（error：Response | any）{
 let errMsg：string; 
 if（error instanceof Response）{
 const body = error.json（）|| ; 
 const err = body.error || JSON.stringify（主体）; 
 errMsg =`$ {error.status}  -  $ {error.statusText || ''} $ {err}`; 
} else {
 errMsg = error.message？ error.message：error.toString（）; 
} 
 //如果JWT过期打开一个新窗口再次登录
 if（errMsg.indexOf（'No JWT present or has expired'）！== -1）{
 window.open（environment.apiEndpoint +'/ loginToApp？expired'，'_blank'，'height = 570，width = 520'）; 
} 
 console.error（error）; 
 return Observable.throw（errMsg）; 
} 
  

我在所有的服务中重复使用handleError方法，我想知道如果有办法让这个DRY。有没有办法为所有http请求定义一个通用的错误处理程序？

如果可能，我想避免每次调用catch。有没有办法扩展http类来自动捕获每个请求的错误，然后在特殊情况下，我可以逐个添加自定义捕获逻辑？

I可以从另一个文件导出方法，并将其导入我的每个服务，但我认为必须有一个更好的方法。感谢任何建议。

更新：我结束了从Angle2-jwt扩展AuthHttp类。

<$ p $来自'@ angular / http'的p> import {Http，RequestOptions，Response，Request，RequestOptionsArgs};

import {Observable} from'rxjs / Observable';
import'rxjs / add / operator / catch';
import'rxjs / add / observable / throw';

import {AuthHttp，AuthConfig} from'angular2-jwt';

export class ApiHttp extends AuthHttp {

public request（url：string | Request，options？：RequestOptionsArgs）：Observable< Response> {
return super.request（url，options）.catch（res => this.handleError（res））;
}

private handleError（error：Response | any）{
//错误处理然后重新抛出错误
return Observable.throw（error）;
}
}


解决方案

你可以像AuthHTTP Wrapper一样创建CustomAuthHttp的定制服务。喜欢wrapper添加标题，在CustomAuthHttp中可以捕获错误。然后在你的代码中注入CustomAuthHttp而不是AuthHTTP并使用。

  @Injectable（）
 export class CustomAuthHttp {
 
构造函数（私有http：AuthHttpWrapper）{} 
 
 get（url：string）{
 return this.http.get（url）
 .catch res => this.handleError（res））; 
} 
 
 private handleError（error：Response | any）{
 //你的代码
 return Observable.throw（''）; 
} 
} 
  

angular2-jwt provides an AuthHttp wrapper for the native Angular http class that automatically includes the http authorization header with each request. In my services I am usually calling a backend api like this

  getThings(): Observable<Thing[]> {
    return this.http.get(environment.apiEndpoint + '/things')
                    .map(res => res.json().data)
                    .catch(res => this.handleError(res));
  }

with an error handler like

private handleError(error: Response | any) {
  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();
  }
  // If JWT is expired open a new window to log in again
  if (errMsg.indexOf('No JWT present or has expired') !== -1) {
    window.open(environment.apiEndpoint + '/loginToApp?expired', '_blank', 'height=570,width=520');
  }
  console.error(error);
  return Observable.throw(errMsg);
}

I keep repeating the handleError method in all my services and I would like to know if there is a way to make this DRY. Is there a way to define a generic error handler for all http requests?

I'd like to avoid having to call catch each time if possible. Is there a way to extend the http class to automatically catch errors on each request and then in special situations I can add custom catch logic on a case by case basis?

I could export the method from another file and import it in each of my services but I think there has got to be a better way. Thanks for any suggestions.

UPDATE: I ended up extending the AuthHttp class from angular2-jwt.

import { Http, RequestOptions, Response, Request, RequestOptionsArgs } from '@angular/http';

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/catch';
import 'rxjs/add/observable/throw';

import { AuthHttp, AuthConfig } from 'angular2-jwt';

export class ApiHttp extends AuthHttp {

  public request(url: string | Request, options?: RequestOptionsArgs): Observable<Response> {
    return super.request(url, options).catch(res => this.handleError(res));
  }

  private handleError(error: Response | any) {
    // error handling then rethrow the error
    return Observable.throw(error);
  }
}

解决方案

You can create custom service CustomAuthHttp like AuthHTTP Wrapper. Like wrapper adds header, in CustomAuthHttp you can catch error. Then in your code inject CustomAuthHttp instead of AuthHTTP and use.

@Injectable()
export class CustomAuthHttp {

  constructor(private http: AuthHttpWrapper) { }

  get(url: string) {
    return this.http.get(url)
      .catch(res => this.handleError(res));
  }

  private handleError(error: Response | any) {
    // your code
    return Observable.throw('');
  }
}

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