ASP.NET Core 3.1 读取请求正文空字符串答案

【问题标题】：ASP.NET Core 3.1 reading Request body empty stringASP.NET Core 3.1 读取请求正文空字符串
【发布时间】：2021-07-09 18:23:25
【问题描述】：

所以我有这个：

app.Use(async (context, next) =>
            {
                context.Request.EnableBuffering();
                await next();
            });

还有这个：

private async Task<JObject> GetRequestBodyAsync(HttpRequest request)
{
        JObject objRequestBody = new JObject();

        try
        {
            // IMPORTANT: Leave the body open so the next middleware can read it.
            using (StreamReader reader = new StreamReader(
                request.Body,
                Encoding.UTF8,
                detectEncodingFromByteOrderMarks: false,
                leaveOpen: true))
            {
                string strRequestBody = await reader.ReadToEndAsync();
                objRequestBody = JsonConvert.DeserializeObject<JObject>(strRequestBody);
            }
        }
        finally
        {
            // IMPORTANT: Reset the request body stream position so the next middleware can read it
            request.Body.Position = 0;
        }

        return objRequestBody;
}

但是虽然request.Body.Length > 0（如预期的那样），这行：

string strRequestBody = await reader.ReadToEndAsync();

总是返回一个空字符串。有什么想法吗？

接下来的操作检索[FromBody] OK。

【问题讨论】：

标签： asp.net-core-3.1

【解决方案1】：

从 .NET Core 2.2 升级到 3.1 后，我在应用程序中遇到了同样的问题并找到了解决方案。

在 startup.cs 中，您的代码必须位于管道的开头：`

public void Configure(IApplicationBuilder app)
{
    app.Use((context, next) =>
    {
        context.Request.EnableBuffering();
        return next();
    });


    // ...More configurations go here
}

之后，您可以在代码中使用它：

    private async Task<JObject> GetRequestBodyAsync(HttpRequest request)
    {
        JObject objRequestBody = new JObject();

        try
        {
            // set the pointer to the beninig of the stream in case it already been readed
            request.Body.Position = 0; 
            using (StreamReader reader = new StreamReader(request.Body)
            {
                string strRequestBody = await reader.ReadToEndAsync();
                objRequestBody = JsonConvert.DeserializeObject<JObject>(strRequestBody);
            }
        }
        finally
        {
            request.Body.Position = 0;
        }

        return objRequestBody;
}

【讨论】：