Michael的雲端筆記本: 2014/7/1

2014年7月17日

[Azure][WebSites] 在WebSite上使用HttpModule取得Response Length

其實絕大多數一般的網站都可以直接搬上Azure Website，不過最近剛好有客戶需要，因此還是寫起來。

首先我們需要一個HttpModule以及一個Custom Response Filter
建立一個HttpModule，在Init()中加入以下程式碼
```
context.PostRequestHandlerExecute += delegate(object sender, EventArgs e)
{
   HttpContext httpContext = ((HttpApplication)sender).Context;
   HttpResponse response = httpContext.Response;
   response.Filter = new IWantMyResponseLengthStream(response.Filter);
}
```

接著我們需要撰寫一個IWantMyResponseLengthStream類別，繼承自MemoryStream

    public class IWantMyResponseLengthStream: MemoryStream
    {
        private readonly Stream responseStream;
        private long responseLen = 0;
        public override long Length
        {
            get
            {
                return responseLen ;
            }
        }
        public IWantMyResponseLengthStream(Stream responseStream)
        {
            this.responseStream = responseStream;
        }

        public override void Write(byte[] buffer, int offset, int count)
        {
            this.responseLen += count;
            this.responseStream.Write(buffer, offset, count);
        }

        public override void Flush()
        {
            //this.Length就是回應的訊息大小了
            //var requestURL = HttpContext.Current.Request.Url.ToString();
            //var remoteIP = HttpContext.Current.Request.UserHostAddress;
            base.Flush();
        }
    }