我试图在中间件中读取正文以进行身份验证,但是当请求到达api控制器时,对象是空的,因为正在读取正文。有没有办法解决。我正在中间件中读这样的身体。
var buffer = new byte[ Convert.ToInt32( context.Request.ContentLength ) ];
await context.Request.Body.ReadAsync( buffer, 0, buffer.Length );
var body = Encoding.UTF8.GetString( buffer );
如果你正在使用application/x-www-form-urlencoded
或multipart/form-data
,你可以安全地多次调用context.Request.ReadFormAsync()
,因为它在后续调用中返回一个缓存的实例。
如果您使用的是其他内容类型,则必须手动缓冲请求,并通过MemoryStream
等可重绕的流替换请求正文。以下是使用内联中间件的方法(您需要在管道中尽快注册):
app.Use(next => async context => {
// Keep the original stream in a separate
// variable to restore it later if necessary.
var stream = context.Request.Body;
// Optimization: don't buffer the request if
// there was no stream or if it is rewindable.
if (stream == Stream.Null || stream.CanSeek) {
await next(context);
return;
}
try {
using (var buffer = new MemoryStream()) {
// Copy the request stream to the memory stream.
await stream.CopyToAsync(buffer);
// Rewind the memory stream.
buffer.Position = 0L;
// Replace the request stream by the memory stream.
context.Request.Body = buffer;
// Invoke the rest of the pipeline.
await next(context);
}
}
finally {
// Restore the original stream.
context.Request.Body = stream;
}
});
您还可以使用BufferingHelper.EnableRewind()
扩展,它是Microsoft.AspNet.Http
包的一部分:它基于类似的方法,但依赖于一个特殊的流,它开始缓冲内存中的数据,并在达到阈值时将所有内容假脱机到磁盘上的临时文件:
app.Use(next => context => {
context.Request.EnableRewind();
return next(context);
});
仅供参考:将来可能会将缓冲中间件添加到vNext。
PinPoint提到EnableRewind的用法
Startup.cs
using Microsoft.AspNetCore.Http.Internal;
Startup.Configure(...){
...
//Its important the rewind us added before UseMvc
app.Use(next => context => { context.Request.EnableRewind(); return next(context); });
app.UseMvc()
...
}
然后在你的中间件中你只是倒带并重读
private async Task GenerateToken(HttpContext context)
{
context.Request.EnableRewind();
string jsonData = new StreamReader(context.Request.Body).ReadToEnd();
...
}