下載/從URL流文件 - asp.net

Question

我需要流的文件，這將導致保存在瀏覽器的提示。 的問題是，該文件所在的目錄中被虛擬地映射，所以我無法使用，以使用Server.Mappath確定它的實際位置。該目錄與網站不在同一位置（或者甚至是活動框上的物理服務器）。

我想類似的追隨者，但是，讓我通過一個Web URL，而不是服務器文件的路徑。

我可能要結束了從配置基本路徑建設我的文件路徑，然後在路徑的其餘部分追加，但我希望我能做到這一點，而不是這樣。

var filePath = Server.MapPath(DOCUMENT_PATH); 

if (!File.Exists(filePath)) 
    return; 

var fileInfo = new System.IO.FileInfo(filePath); 
Response.ContentType = "application/octet-stream"; 
Response.AddHeader("Content-Disposition", String.Format("attachment;filename=\"{0}\"", filePath)); 
Response.AddHeader("Content-Length", fileInfo.Length.ToString()); 
Response.WriteFile(filePath); 
Response.End(); 

Answer 1

你可以使用的HttpWebRequest獲取文件和流它返回給客戶端。這使您可以使用url獲取文件。這是我發現的（但不記得在哪裏給予信貸）的一個例子是

//Create a stream for the file 
    Stream stream = null; 

    //This controls how many bytes to read at a time and send to the client 
    int bytesToRead = 10000; 

    // Buffer to read bytes in chunk size specified above 
    byte[] buffer = new Byte[bytesToRead]; 

    // The number of bytes read 
    try 
    { 
     //Create a WebRequest to get the file 
     HttpWebRequest fileReq = (HttpWebRequest) HttpWebRequest.Create(url); 

     //Create a response for this request 
     HttpWebResponse fileResp = (HttpWebResponse) fileReq.GetResponse(); 

     if (fileReq.ContentLength > 0) 
     fileResp.ContentLength = fileReq.ContentLength; 

     //Get the Stream returned from the response 
     stream = fileResp.GetResponseStream(); 

     // prepare the response to the client. resp is the client Response 
     var resp = HttpContext.Current.Response; 

     //Indicate the type of data being sent 
     resp.ContentType = "application/octet-stream"; 

     //Name the file 
     resp.AddHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\""); 
     resp.AddHeader("Content-Length", fileResp.ContentLength.ToString()); 

     int length; 
     do 
     { 
      // Verify that the client is connected. 
      if (resp.IsClientConnected) 
      { 
       // Read data into the buffer. 
       length = stream.Read(buffer, 0, bytesToRead); 

       // and write it out to the response's output stream 
       resp.OutputStream.Write(buffer, 0, length); 

       // Flush the data 
       resp.Flush(); 

       //Clear the buffer 
       buffer = new Byte[bytesToRead]; 
      } 
      else 
      { 
       // cancel the download if client has disconnected 
       length = -1; 
      } 
     } while (length > 0); //Repeat until no data is read 
    } 
    finally 
    { 
     if (stream != null) 
     { 
      //Close the input stream 
      stream.Close(); 
     } 
    } 

Answer 2

你可以嘗試使用的DirectoryEntry類與IIS路徑前綴：

using(DirectoryEntry de = new DirectoryEntry("IIS://Localhost/w3svc/1/root" + DOCUMENT_PATH)) 
{ 
    filePath = de.Properties["Path"].Value; 
} 

if (!File.Exists(filePath)) 
     return; 

var fileInfo = new System.IO.FileInfo(filePath); 
Response.ContentType = "application/octet-stream"; 
Response.AddHeader("Content-Disposition", String.Format("attachment;filename=\"{0}\"", filePath)); 
Response.AddHeader("Content-Length", fileInfo.Length.ToString()); 
Response.WriteFile(filePath); 
Response.End(); 

Answer 3

2年後，我用了達拉斯小牛隊的答案，但我有，因爲我是鏈接到的HttpWebRequest更改爲FileWebRequest直接文件。不知道到處都是這種情況，但我想我會添加它。此外，我除去

var resp = Http.Current.Resonse

，只是用來代替Http.Current.Response無論resp被引用。

Answer 4

我這個做了不少，我想我可以添加一個簡單的答案。我在這裏設置了一個簡單的課程，但我每天晚上都會運行這個課程來收集我所關注的公司的財務數據。

class WebPage 
{ 
    public static string Get(string uri) 
    { 
     string results = "N/A"; 

     try 
     { 
      HttpWebRequest req = (HttpWebRequest)WebRequest.Create(uri); 
      HttpWebResponse resp = (HttpWebResponse)req.GetResponse(); 

      StreamReader sr = new StreamReader(resp.GetResponseStream()); 
      results = sr.ReadToEnd(); 
      sr.Close(); 
     } 
     catch (Exception ex) 
     { 
      results = ex.Message; 
     } 
     return results; 
    } 
} 

在這種情況下，我傳遞一個url並將頁面返回爲HTML。如果你想做一些與流不同的事情，你可以輕鬆地改變它。

你使用這樣的：

string page = WebPage.Get("http://finance.yahoo.com/q?s=yhoo"); 

Answer 5

下載地址爲字節，並轉換成字節流：

using (var client = new WebClient()) 
{ 
    var content = client.DownloadData(url); 
    using (var stream = new MemoryStream(content)) 
    { 
     ... 
    } 
}