c# - 使用 HttpClient 将字节数组发布到 Web API 服务器

Question

我想将此数据发布到 Web API 服务器:

public sealed class SomePostRequest
{
    public int Id { get; set; }
    public byte[] Content { get; set; }
}

将此代码用于服务器:

[Route("Incoming")]
[ValidateModel]
public async Task<IHttpActionResult> PostIncomingData(SomePostRequest requestData)
{
    // POST logic here
}

还有这个 - 对于客户:

var client = new HttpClient();
client.BaseAddress = new Uri("http://localhost:25001/");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(
    new MediaTypeWithQualityHeaderValue("application/json"));

var content = new FormUrlEncodedContent(new Dictionary<string, string>
{
    { "id", "1" },
    { "content", "123" }
});

var result = await client.PostAsync("api/SomeData/Incoming", content);
result.EnsureSuccessStatusCode();

一切正常(至少，调试器在 PostIncomingData 中的断点处停止)。

因为有一个 byte 数组，我不想将它序列化为 JSON，而是想将它作为二进制数据发布以减少网络流量(类似于 application/octet-流).

如何实现？

我试过使用 MultipartFormDataContent，但看起来我就是无法理解，MultipartFormDataContent 将如何匹配 Controller 方法的签名。

例如，将内容替换为:

var content = new MultipartFormDataContent();
content.Add(new FormUrlEncodedContent(new Dictionary<string, string> { { "id", "1" } }));

var binaryContent = new ByteArrayContent(new byte[] { 1, 2, 3 });
binaryContent.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
content.Add(binaryContent, "content");

var result = await client.PostAsync("api/SomeData/Incoming", content);
result.EnsureSuccessStatusCode();

导致错误 415(“不支持的媒体类型”)。

Answer 1

WebAPI v2.1 及更高版本 supports BSON (Binary JSON) out of the box ，甚至还包含一个 MediaTypeFormatter。这意味着您可以以二进制格式发布整个消息。

如果你想使用它，你需要在WebApiConfig中设置它:

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        config.Formatters.Add(new BsonMediaTypeFormatter());
    }
}

现在，您可以在客户端使用相同的 BsonMediaTypeFormatter 来序列化您的请求:

public async Task SendRequestAsync()
{
    var client = new HttpClient
    {
        BaseAddress = new Uri("http://www.yourserviceaddress.com");
    };

    // Set the Accept header for BSON.
    client.DefaultRequestHeaders.Accept.Clear();
    client.DefaultRequestHeaders.Accept.Add(
            new MediaTypeWithQualityHeaderValue("application/bson"));

    var request = new SomePostRequest
    {
        Id = 20,
        Content = new byte[] { 2, 5, 7, 10 }
    };

    // POST using the BSON formatter.
    MediaTypeFormatter bsonFormatter = new BsonMediaTypeFormatter();
    var result = await client.PostAsync("api/SomeData/Incoming", request, bsonFormatter);

    result.EnsureSuccessStatusCode();
}

或者，您可以使用 Json.NET 将您的类序列化为 BSON。然后，指定您要使用“application/bson”作为您的“Content-Type”:

public async Task SendRequestAsync()
{   
    using (var stream = new MemoryStream())
    using (var bson = new BsonWriter(stream))
    {
        var jsonSerializer = new JsonSerializer();

        var request = new SomePostRequest
        {
            Id = 20,
            Content = new byte[] { 2, 5, 7, 10 }
        };

        jsonSerializer.Serialize(bson, request);

        var client = new HttpClient
        {
            BaseAddress = new Uri("http://www.yourservicelocation.com")
        };

        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(
                new MediaTypeWithQualityHeaderValue("application/bson"));

        var byteArrayContent = new ByteArrayContent(stream.ToArray());
        byteArrayContent.Headers.ContentType = new MediaTypeHeaderValue("application/bson");

        var result = await client.PostAsync(
                "api/SomeData/Incoming", byteArrayContent);

        result.EnsureSuccessStatusCode();
    }
}