Angular HTTP不起作用并且没有引发错误 [英] Angular http get not working and no error thrown

问题描述

围绕此主题有很多疑问，但我找不到合适的解决方案.我在控制台上看不到任何错误，这就是为什么它非常令人困惑的原因.

There are lot questions around this topic but I could not find a suitable solution. I am not able to see any error on the console, which is why its very confusing.

这是我的服务文件代码

   findVariantById(id: string):Observable<Evaluation[]>  {

    const endPoint = 'Evalution/Get'
    let params = new URLSearchParams();
    params.set('key', '1234'); //For example API key would come into picture
    params.set('id', id);
    params.set('format', 'json');
    params.set('callback', 'JSONP_CALLBACK');
    // this much code gets called but nothing on Network tab. 
    return this.http.get(this.apiUrl + endPoint, { search: params })
         .map<Evaluation[]>(this.extractData)
        .catch<Evaluation[]>(this.handleError);
} 

这是我的调用服务的组件文件代码

    evaluation(id: string) {
        this.searchService.findVariantById(id)
            .subscribe(
            evaluations => this.evaluations = evaluations,
            error => this.errorMessage = <any>error);
    }        

和型号

  export interface Evaluation {
    QuestionId: string;
    QuestionText: string;
    questionResponse: Array<Object>
  }

我已经包括了相同的依赖项

   import { Observable } from 'rxjs/Observable';
   import 'rxjs/add/operator/map';
   import 'rxjs/add/operator/catch';
    import 'rxjs/add/operator/toPromise';

我正在使用"@ angular/core":〜2.2.1"和"rxjs":"5.0.0-beta.12" . 任何帮助都将受到高度赞赏.谢谢

I am using "@angular/core": "~2.2.1", and "rxjs": "5.0.0-beta.12". Any kind of help is highly appreciated. Thank you

更新:切换到Angular:4.0.1后，Http.Get和Post给出了错误

Update: After switching to Angular:4.0.1, Http.Get and Post gave error as

提供的参数与呼叫目标的任何签名都不匹配.

Supplied parameters do not match any signature of call target.

因此，我进行了以下更改.而且效果很好.

So I made following changes. And it worked perfectly.

  return this.http.get(this.apiUrl + endPoint, { search: params })
        .map(this.extractData)
        .catch(this.handleError); 

推荐答案

此错误是由于伪造HTTP请求的虚假后端提供程序引起的.

This error was due to a Fake Backend Provider which Mocks HTTP requests.

我已按照以下教程使用Fake Backend Provider进行登录和注册.
有关更多信息: http://jasonwatmore.com/post/2016/09/29/angular-2-user-registration-and-login-example-tutorial

I have used Fake Backend Provider to perform Login and registration, as per following tutorial.
More info on: http://jasonwatmore.com/post/2016/09/29/angular-2-user-registration-and-login-example-tutorial

通过从app.module.ts删除其依赖项，它解决了我的问题.

By removing its dependencies from app.module.ts,it solved my problem.

这篇关于Angular HTTP不起作用并且没有引发错误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IT屋！