Question

我开发了一个角度应用程序，需要从远程服务器中使用json数据。由于CORS问题，应用程序无法直接从该服务器获取数据。我的解决方案是开发一个＆＃34;代理＆＃34; web api读取并将json返回给我的应用程序。目前，这就是我正在做的事情：

public async Task<IActionResult> MyJson()
{
    const string jsonUrl = "url-of-remote-json";
    using (var client = new HttpClient())
    {
        using (var result = await client.GetAsync(jsonUrl))
        {
            if (result.IsSuccessStatusCode)
            {
                return new ObjectResult(JsonConvert.DeserializeObject(await result.Content.ReadAsStringAsync()));
            }
        }
    }

    return new ObjectResult(new { });
}

但是，我认为这远非被认为是一种有效的方式，因为我必须将json读取为字符串，然后使用JsonConvert包将其转换为对象以提供web api方法。因此，表现并不是很好。

我想知道是否有更简单/有效/更简单的方法来完成这项任务？

Answer 1

只需通过远程服务器的响应即可。看看编辑过的例子。

public async Task MyJson()//void if not async
{
    string jsonUrl = "url-to-json";
    HttpContext.Response.ContentType = "application/json";
    using (var client = new System.Net.WebClient())
    {
        try
        {
            byte[] bytes = await client.DownloadDataTaskAsync(jsonUrl);
            //write to response stream aka Response.Body
            await HttpContext.Response.Body.WriteAsync(bytes, 0, bytes.Length);
        }
        catch (Exception e)//404 or anything
        {
            HttpContext.Response.StatusCode = 400;//BadRequest
        }
        await HttpContext.Response.Body.FlushAsync();
        HttpContext.Response.Body.Close();
    }
}

按预期工作。

Answer 2

这是@ Alex代码的修改版本，使用HttpClient代替WebClient：

public async Task MyJson()//void if not async
{
    string jsonUrl = "url-to-json";
    HttpContext.Response.ContentType = "application/json";
    using (var client = new HttpClient())
    {
        try
        {
            byte[] bytes = await client.GetByteArrayAsync(jsonUrl);
            //write to response stream aka Response.Body
            await HttpContext.Response.Body.WriteAsync(bytes, 0, bytes.Length);
        }
        catch (Exception e)//404 or anything
        {
            HttpContext.Response.StatusCode = 400;//BadRequest
        }
        await HttpContext.Response.Body.FlushAsync();
        HttpContext.Response.Body.Close();
    }
}

这是我的实际代码：

    public async Task<IActionResult> MyJson()
    {
        const string jsonUrl = "url-to-json";
        HttpContext.Response.ContentType = "application/json";
        using (var client = new HttpClient())
        {
            try
            {
                byte[] bytes = await client.GetByteArrayAsync(jsonUrl);
                //write to response stream aka Response.Body
                await HttpContext.Response.Body.WriteAsync(bytes, 0, bytes.Length);
                await HttpContext.Response.Body.FlushAsync();
                HttpContext.Response.Body.Close();
            }
            catch (Exception e)
            {
                return new BadRequestResult();
            }
        }

        return new BadRequestResult();
    }

代理调用远程json以避免CORS问题

2 个答案: