我有一个ASP.NET Web API端点,其控制器操作定义如下：
[HttpPost] public HttpResponseMessage Post([FromBody] object text)
如果我的帖子请求正文包含纯文本(即不应该被解释为json,xml或任何其他特殊格式),那么我以为我可以在我的请求中包含以下标题：
Content-Type: text/plain
但是,我收到错误：
No MediaTypeFormatter is available to read an object of type 'Object' from content with media type 'text/plain'.
如果我将我的控制器操作方法签名更改为：
[HttpPost] public HttpResponseMessage Post([FromBody] string text)
我有一个稍微不同的错误信息：
No MediaTypeFormatter is available to read an object of type 'String' from content with media type 'text/plain'.
解决方法
实际上,Web API没有用于纯文本的MediaTypeFormatter是可惜的.这是我实现的.它也可以用于发布内容.
public class TextMediaTypeFormatter : MediaTypeFormatter
{
public TextMediaTypeFormatter()
{
SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/plain"));
}
public override Task<object> ReadFromStreamAsync(Type type,Stream readStream,HttpContent content,IFormatterLogger formatterLogger)
{
var taskCompletionSource = new TaskCompletionSource<object>();
try
{
var memoryStream = new MemoryStream();
readStream.CopyTo(memoryStream);
var s = System.Text.Encoding.UTF8.GetString(memoryStream.ToArray());
taskCompletionSource.SetResult(s);
}
catch (Exception e)
{
taskCompletionSource.SetException(e);
}
return taskCompletionSource.Task;
}
public override Task WriteToStreamAsync(Type type,object value,Stream writeStream,System.Net.TransportContext transportContext,System.Threading.CancellationToken cancellationToken)
{
var buff = System.Text.Encoding.UTF8.GetBytes(value.ToString());
return writeStream.WriteAsync(buff,buff.Length,cancellationToken);
}
public override bool CanReadType(Type type)
{
return type == typeof(string);
}
public override bool CanWriteType(Type type)
{
return type == typeof(string);
}
}
您需要通过以下类似的方式在HttpConfig中“注册”此格式化程序：
config.Formatters.Insert(0,new TextMediaTypeFormatter());
