将图片上传到 oData 网络服务

Question

在我的 oData 网络服务中，我有一个名为 Ware 的业务对象。此 Ware 有一个名为 Picture 的 Image 类型的属性。当我想使用 HttpClient 在 UWP 应用程序中获取图片时，我只需调用 http://localhost:8797/Data/Ware(2)/Picture。代码如下：

    using (var client = new HttpClient(handler))
    {
        client.BaseAddress = new Uri(DataServiceAddress + "Data/");
        client.DefaultRequestHeaders.Clear();
        client.DefaultRequestHeaders.Accept.Clear();
        using (HttpResponseMessage message = await client.GetAsync(url))
        {
            message.EnsureSuccessStatusCode();
            var content = (StreamContent)message.Content;
            return await content.ReadAsByteArrayAsync();
        }
    }

这是按预期工作的，return我把图片作为数组的字节。现在我想通过 'PUT' 上传新的 Picture。我试过下面的代码：

    public static async Task PutImage(string url, byte[] image)
    {
         var handler = new HttpClientHandler { UseDefaultCredentials = true };
         using (var client = new HttpClient(handler))
         {
            client.BaseAddress = new Uri(DataServiceAddress + "Data/");
            client.DefaultRequestHeaders.Clear();
            client.DefaultRequestHeaders.Accept.Clear();
            using (var ms = new MemoryStream(image))
            {
                using (var message = await client.PutAsync(url, httpContent))
                {
                    message.EnsureSuccessStatusCode();
                }
            }
        }
    }

然后当我调用 PutImage("Ware(2)/Picture", myFile.toByteArray()) 时，我会收到 Bad Request 响应。有趣的是，当我用 Postman 尝试 PUT 时，它工作正常。正如您在下图中看到的，我得到了 204 结果并且我的图片已成功更改。

Screenshot: Postman is successful sending the file with a 'PUT' verb to the odata server

谁能帮我解决这个问题？

这是 Postman 生成的代码：

    PUT /Data/Ware(2)/Picture HTTP/1.1
    Host: localhost:8797
    Authorization: Basic QWRtaW46
    Cache-Control: no-cache
    Postman-Token: 37827f09-8841-7ccb-c462-d488ef4c4e9d

    undefined

我做了很多谷歌搜索。但没有希望。 :(

Answer 1

终于搞定了:)

   public static async Task PutImage(string url, byte[] image)
   {
        var httpContent = new ByteArrayContent(image);

        var handler = new HttpClientHandler { UseDefaultCredentials = true };
        using (var client = new HttpClient(handler))
        {
            client.BaseAddress = new Uri(DataServiceAddress + "Data/");
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("*/*"));
            client.DefaultRequestHeaders.AcceptEncoding.Add(new StringWithQualityHeaderValue("gzip"));
            client.DefaultRequestHeaders.AcceptEncoding.Add(new StringWithQualityHeaderValue("deflate"));

            using (var request = new HttpRequestMessage(HttpMethod.Put, url) { Content = httpContent })
            {

                httpContent.Headers.ContentType = new MediaTypeHeaderValue("text/plain");
                using (var message = await client.SendAsync(request))
                {
                    message.EnsureSuccessStatusCode();
                }
            }
        }
    }

一切正常。

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