使用Web Api CreateResponse <Content>()和CreateResponse()之间有什么区别吗？

Question

鉴于以下内容:

    [HttpGet]
    [ActionName("GetContent")]
    public HttpResponseMessage GetContent(int id)
    {
        Content content = _uow.Contents.GetById(id);
        if (content == null)
        {
            var message = string.Format("Content with id = {0} not found", id);
            return Request.CreateErrorResponse(HttpStatusCode.NotFound, message);
        }
        else
        {
            return Request.CreateResponse(HttpStatusCode.OK, content);
        }
    }

和:

    [HttpGet]
    [ActionName("GetContent")]
    public HttpResponseMessage GetContent(int id)
    {
        try
        {
            Content content = _uow.Contents.GetById(id);
            if (content == null)
            {
                throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.NotFound));
            }
            return Request.CreateResponse<Content>(HttpStatusCode.OK, content);
        }
        catch (Exception ex)
        {
            return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ex);
        } 

    }

我见过两种编码风格.一个使用例外,另一个不使用.一个使用CreateResponse <>和另一个CreateResponse().有人能说出使用这些有什么优点/缺点吗？据我所知,第二种方法似乎看起来更完整但是真的需要使用try/catch来做这么简单的事情吗？

Answer 1

抛出的主要好处HttpResponseException是当你的action方法返回一个模型类型而不是一个HttpResponseMessage.例如:

public Product Get(int id) 
{
    Product p = _GetProduct(id);
    if (p == null)
    {
        throw new HttpResponseException(HttpStatusCode.NotFound);
    }
    return p;
}

这相当于以下内容:

public HttpResponseMessage Get(int id) 
{
    Product p = _GetProduct(id);
    if (p == null)
    {
        return Request.CreateResponse(HttpStatusCode.NotFound);
    }
    return Request.CreateResponse(HttpStatusCode.OK, p);
}

选择任何一种风格都可以.

您不应该抓住HttpResponseExceptions,因为重点是Web API管道捕获它们并将它们转换为HTTP响应.在您的第二个代码示例中,当您确实希望客户端接收Not Found(404)时,Not Found错误会被捕获并变为Bad Request错误.

更长的回答:

CreateResponsevs CreateResponse<T>与使用无关HttpResponseException.

CreateResponse 返回没有邮件正文的HTTP响应:

public HttpResponseMessage Get()
{
    return Request.CreateResponse(HttpStatusCode.NotFound);
}

CreateResponse<T> 获取类型为T的对象并将该对象写入HTTP响应的主体:

public HttpResponseMessage Get()
{
    Product product = new Product();
    // Serialize product in the response body
    return Request.CreateResponse<Product>(HttpStatusCode.OK, product);  
}

下一个示例完全相同,但使用类型推断省略泛型类型参数:

public HttpResponseMessage Get()
{
    Product product = new Product();
    // Serialize product in the response body
    return Request.CreateResponse(HttpStatusCode.OK, product);  
}

该CreateErrorResponse方法创建一个HTTP响应,其响应主体是一个HttpError对象.这里的想法是使用通用消息格式进行错误响应.通话CreateErrorResponse与此基本相同:

HttpError err = new HttpError( ... )
// Serialize err in the response.
return Request.CreateResponse(HttpStatusCode.BadRequest, err);