IEnumerable - 如何管理 NotFound 错误

Question

我正在尝试找到一种在 IEnumerable 返回空对象或空数组时返回自定义错误消息的方法

    [HttpGet("All/{questionId}")]
    [ProducesResponseType(StatusCodes.Status200OK)]
    // [ProducesResponseType(StatusCodes.Status404NotFound)]
    [ProducesResponseType(typeof(ApiResponse), StatusCodes.Status404NotFound)]
    public async Task<IEnumerable<AnswerDto>> GetAnswers(string questionId)
    {
        var answers = await _context.Answers
            .Where(q => q.QuestionId == questionId)
            .ToListAsync();

        // something like this: if (!answers.Any()) return NotFound(new ApiResponse(404), "There are no answers for this question");

        var answersToReturn = _mapper.Map<IReadOnlyList<AnswerDto>>(answers);
        return answersToReturn;
    }

在我的 ApiResponse 类中：

private string GetDefaultMessageForStatusCode(int statusCode)
{
    return statusCode switch
    {
        . . .
        404 => "No item found",
        . . .
    };
}

这方面有什么帮助吗？

Answer 1

看看controller action return types。

ActionResult 有助于返回 HTTP 状态代码，并将生成带有适当 HTTP 状态代码的 Json 结果。

我已经稍微调整了你的代码以适应它 -

[HttpGet("All/{questionId}")]
    [ProducesResponseType(StatusCodes.Status200OK)]
    // [ProducesResponseType(StatusCodes.Status404NotFound)]
    [ProducesResponseType(typeof(ApiResponse), StatusCodes.Status404NotFound)]
    public async Task<IActionResult<IEnumerable<AnswerDto>>> GetAnswers(string questionId)
    {
        var answers = await _context.Answers
            .Where(q => q.QuestionId == questionId)
            .ToListAsync();

        if (!answers.Any()) return NotFound("There are no answers for this question");

        var answersToReturn = _mapper.Map<IReadOnlyList<AnswerDto>>(answers);
        return Ok(answersToReturn)