如何在 Angular 中的 httpClient 调用中生成错误？

Question

我的 Angular 应用程序中有以下搜索功能的方法，我想测试错误部分。但是，它不会命中错误块。和订阅有关系吗？或者我应该使用什么方法或途径？

this.searchGetCall(text).subscribe((res) => {

    res = undefined; //test: added to create error

    console.log('res', res.constructor());

    this.isSearching = false;

    this.apiResponse = res;

  }, (err) => {

    debugger; //cannot hit this block

    this.isSearching = false;

    console.log('error', err);

  });

searchGetCall(term: string) {

  if (term === '') {

    return of([]);

  }

  return this.httpClient.get('http://www.omdbapi.com/?s=' + term + '&apikey=' + APIKEY, { params: PARAMS.set('search', term) });

}

Answer 1

据我了解，您想在 'res = undefined; 行抛出异常；//测试：添加以创建错误'。为此目的使用 try catch。(err) 块用于处理 http 错误。例如，在 C# 中，在操作结果中键入以下内容：&nbsp; &nbsp;[HttpGet("Get/{id}")]&nbsp; &nbsp; public async Task<ActionResult<UserDto>> Get(long id)&nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; ServiceResult<IEnumerable<UserBo>> result = await serviceManager.User_Service.FindAsync(filterCriteria);&nbsp; &nbsp; &nbsp; &nbsp; if (result.Success)&nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; userBo = result.Data.FirstOrDefault();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (userBo == null)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return NotFound();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; else&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ServiceResult<bool> resultAutorized = await GetAutorizedUserStatusById(userBo);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (!resultAutorized.Success || !resultAutorized.Data)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return BadRequest("unauthorized access");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; UserDto userDto = UserBo.ConvertToDto(userBo);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return userDto;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; else&nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return BadRequest(result.Error);&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;.FirstOrDefaultAsync();&nbsp; &nbsp; }注意这一行： return BadRequest("未经授权的访问");

Answer 2

这不像try/catch。订阅错误块的到达取决于 HTTP 代码状态（403,404,500 等），而不是脚本执行错误。您的测试只是使脚本崩溃，而不是模拟 HTTP 错误代码。

Answer 3

我假设您的 searchGetCall 是一个网络请求，并且它返回一个可观察值。当您的 Web 请求返回 http 状态代码错误时，您的错误块将被执行。