合并流：Web应用程序

Question

此问题主要涉及.net中的Web应用程序中的流。在我的web应用，我将显示如下：

1. bottle.doc
2. sheet.xls
3. presentation.ppt

4. stackof.jpg

   按钮

我将保留每个人的复选框以供选择。假设用户选择了四个文件并单击了我保存的按钮。然后，我为每种类型的文件实例化分类器，将其转换为pdf，我已经写入并将它们转换为pdf并返回它们。我的问题是clases能够读取数据表单URL并将它们转换为pdf。但我不知道如何返回流并合并它们。

string url = @"url"; 

//Prepare the web page we will be asking for 
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url); 
request.Method = "GET"; 
request.ContentType = "application/mspowerpoint"; 
request.UserAgent = "Mozilla/4.0+(compatible;+MSIE+5.01;+Windows+NT+5.0"; 

//Execute the request 
HttpWebResponse response = (HttpWebResponse)request.GetResponse(); 

//We will read data via the response stream 
Stream resStream = response.GetResponseStream(); 

//Write content into the MemoryStream 
BinaryReader resReader = new BinaryReader(resStream); 

MemoryStream PresentaionStream = new MemoryStream(resReader.ReadBytes((int)response.ContentLength)); 
//convert the presention stream into pdf and save it to local disk. 

但我想再次返回流。我怎样才能实现这个任何想法是受欢迎的。

Answer 1

我假设这是一个asp.net页面，并且您从服务中获取pdf。在将其返回给用户之前，您不需要将其保存在本地。您只需以块的形式写入输出流即可。

//Execute the request 
HttpWebResponse response = null; 
try 
{ 
    response = (HttpWebResponse)request.GetResponse(); 
} 
catch (WebException we) { // handle web excetpions } 
catch (Exception e) { // handle other exceptions } 

this.Response.ContentType = "application/pdf"; 

const int BUFFER_SIZE = 1024; 
byte[] buffer = new byte[BUFFER_SIZE]; 
int bytes = 0; 
while ((bytes = resStream.Read(buffer, 0, BUFFER_SIZE)) > 0) 
{ 
    //Write the stream directly to the client 
    this.Response.OutputStream.Write(buff, 0, bytes); 
} 

Answer 2

如果我正确理解你的问题，你可以立即发送响应，这样用户将得到一个下载请求。

System.Web.HttpResponse response = System.Web.HttpContext.Current.Response; 
response.Clear(); 
response.AddHeader("Content-Type", "binary/octet-stream"); 
response.AddHeader("Content-Disposition", "attachment; filename=nameofthefile.pdf; size=" + downloadBytes.Length.ToString()); 
response.Flush(); 
response.BinaryWrite(downloadBytes); 
response.Flush(); 
response.End(); 

其中downloadBytes是byte[]并包含pdf。