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
}

这个 - 给客户：

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 的断点处停止）。

由于有一个byte 数组，我不想将其序列化为 JSON，而是希望将其作为二进制数据发布以减少网络流量（类似于application/octet-stream）。

如何做到这一点？

我尝试过使用MultipartFormDataContent，但似乎我无法理解MultipartFormDataContent 将如何匹配控制器方法的签名。

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，指定要使用“application/bson”作为“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();
    }
}

Answer 2

我将Byte Array 转换为Base64 String 来发帖：

await client.PostAsJsonAsync( apiUrl,  
    new  {
        message = "",
        content = Convert.ToBase64String(yourByteArray),
    }
);

接收者可以通过以下方式将Base64 String 转换回Byte Array：

string base64Str = (string)postBody.content;
byte[] fileBytes = Convert.FromBase64String(base64Str);

Answer 3

我使用 Json.NET 库创建了这个通用的跨平台方法来支持 BSON 格式，以便我们以后可以更轻松地重用它。它在 Xamarin 平台上也能正常工作。

public static async HttpResponseMessage PostBsonAsync<T>(string url, T data)
{
    using (var client = new HttpClient())
    {
        //Specifiy 'Accept' header As BSON: to ask server to return data as BSON format
        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(
                new MediaTypeWithQualityHeaderValue("application/bson"));

        //Specify 'Content-Type' header: to tell server which format of the data will be posted
        //Post data will be as Bson format                
        var bSonData = HttpExtensions.SerializeBson<T>(data);
        var byteArrayContent = new ByteArrayContent(bSonData);
        byteArrayContent.Headers.ContentType = new MediaTypeHeaderValue("application/bson");

        var response = await client.PostAsync(url, byteArrayContent);

        response.EnsureSuccessStatusCode();

        return response;
    }
}

帮助将数据序列化为 BSON 格式的方法：

public static byte[] SerializeBson<T>(T obj)
{
    using (MemoryStream ms = new MemoryStream())
    {
        using (BsonWriter writer = new BsonWriter(ms))
        {
            JsonSerializer serializer = new JsonSerializer();
            serializer.Serialize(writer, obj);
        }

        return ms.ToArray();
    }
}

然后你可以像这样使用 Post 方法：

var response = await PostBsonAsync<SamplePostRequest>("api/SomeData/Incoming", requestData);

Answer 4

仅供参考，用于 protobuf 序列化以请求正文帖子

        LoginRequest loginRequest = new LoginRequest()
        {
            Code = "UserId",
            Password = "myPass",
            CMToken = "eIFt4lYTKGU:APA91bFZPe3XCDL2r1JUJuEQLlN3FoeFw9ULpw8ljEavNdo9Lc_-Qua4w9pTqdOFLTb92Kf03vyWBqkcvbBfYEno4NQIvp21kN9sldDt40eUOdy0NgMRXf2Asjp6FhOD1Kmubx1Hq7pc",
        };
        byte[] rawBytes = ProtoBufSerializer.ProtoSerialize<LoginRequest>(loginRequest);

        var client = new HttpClient();
        client.BaseAddress = new Uri("http://localhost:9000/");
        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(
            new MediaTypeWithQualityHeaderValue("application/x-protobuf"));

        //var bSonData = HttpExtensions.SerializeBson<T>(data);
        var byteArrayContent = new ByteArrayContent(rawBytes);
        byteArrayContent.Headers.ContentType = new MediaTypeHeaderValue("application/x-protobuf");

        var result = client.PostAsync("Api/Login", byteArrayContent).Result;

        Console.WriteLine(result.IsSuccessStatusCode);