使用Enablebuffering多次读取Asp Net Core 3.0 请求体 读取Request.Body流

原文:使用Enablebuffering多次读取Asp Net Core 请求体

使用Enablebuffering多次读取Asp Net Core 请求体

1 .Net Core 2.X时代

使用EnableRewind倒带

public IActionResult Index()
{
    Request.EnableRewind();
    using (var reader = new StreamReader(Request.Body))
    {
        var body = reader.ReadToEnd();
        // Do something
        Request.Body.Seek(0, SeekOrigin.Begin);
        body = reader.ReadToEnd();
    }
    // More code
    return View("Index");
}

2 .NET Core 3.0时代

因为.NET Core 3.0 preview 6以后（6还是可以使用的）， Microsoft.AspNetCore.Http.Internal不再是公有方法. 所以EnableRewind不能使用。

使用Enablebuffering

 public async Task<IActionResult> Index()
 {
    Request.EnableBuffering();
    using (var reader = new StreamReader(Request.Body, encoding: Encoding.UTF8))
    {
        var body = reader.ReadToEndAsync();
        // Do some processing with body…
        // Reset the request body stream position so the next middleware can read it
        Request.Body.Position = 0;
    }
    return View();
 }

 // 默认不支持同步方法：ReadToEnd()
 // 需要设置AllowSynchronousIO=true;
 // System.InvalidOperationException: 'Synchronous operations are disallowed. Call ReadAsync or set AllowSynchronousIO to true instead.' 
如:

  public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.ConfigureKestrel((context, options) =>
                    {
                        options.AllowSynchronousIO = true;
                        //设置应用服务器Kestrel请求体最大为50MB
                        options.Limits.MaxRequestBodySize = ;
                    });
                    webBuilder.UseStartup<Startup>();
                });

3. 参考

1. Reading request body in ASP.NET Core

2. EnableRewind 源码

3. Rereading Asp Net Core Request Bodies With Enablebuffering