Physical path, virtual path, physical path and virtual path conversion, File Download Method

1. What is a physical path? What is a virtual path?
(1) Example:
Here is an example of IIS:
The Web service directory is D: \ path
When using HTTP to access the root directory of the website, the actually accessed path is D: \, where the virtual path is \ (Root), and the physical path is D: \.
 
(2) my own understanding: absolute paths generally carry disk completion paths, while virtual paths generally do not have Disks

2 conversion of virtual paths and physical paths in the program

# Region physical path and relative path Conversion
// Convert the local path to the relative URL path
Private string urlconvertor (string imagesurl1)
{
String tmprootdir = server. mappath (system. Web. httpcontext. Current. Request. applicationpath. tostring (); // obtain the program root directory
String imagesurl2 = imagesurl1.replace (tmprootdir, ""); // convert to relative path
Imagesurl2 = imagesurl2.replace (@"\",@"/");
// Imagesurl2 = imagesurl2.replace (@ "aspx_uc /",@"");
Return imagesurl2;
}
// Convert the relative path to the local physical path of the server
Private string urlconvertorlocal (string imagesurl1)
{
String tmprootdir = server. mappath (system. Web. httpcontext. Current. Request. applicationpath. tostring (); // obtain the program root directory
String imagesurl2 = tmprootdir + imagesurl1.replace (@ "/", @ "\"); // convert to absolute path
Return imagesurl2;
}
# Endregion

3. Download Method

/// <Summary>
/// Obtain the physical address
/// </Summary>
Public static string mappathfile (string filename)
{
Return httpcontext. Current. server. mappath (filename );
}
/// <Summary>
/// Normal download
/// </Summary>
/// <Param name = "FILENAME"> Virtual File Path </param>
Public static bool downloadold (string filename)
{
Bool bools = false;
String destfilename = mappathfile (filename );
If (file. exists (destfilename ))
{
Fileinfo Fi = new fileinfo (destfilename );
Httpcontext. Current. response. Clear ();
Httpcontext. Current. response. clearheaders ();
Httpcontext. Current. response. Buffer = false;
Httpcontext. current. response. appendheader ("content-disposition", "attachment; filename =" + httputility. urlencode (path. getfilename (destfilename), system. text. encoding. utf8 ));
Httpcontext. Current. response. appendheader ("Content-Length", Fi. length. tostring ());
Httpcontext. Current. response. contenttype = "application/octet-stream ";
Httpcontext. Current. response. writefile (destfilename );
Httpcontext. Current. response. Flush ();
Httpcontext. Current. response. End ();
Bools = true;
}
Return bools;
}

Public static void responsefile (string path, httpcontext context)
{
Context = httpcontext. Current;

System. Io. Stream istream = NULL;
Byte [] buffer = new byte [10000];
Int length;
Long datatoread;
String filename = system. Io. Path. getfilename (PATH );

Try
{
Istream = new system. Io. filestream (path, system. Io. filemode. Open, system. Io. fileaccess. Read, system. Io. fileshare. Read );
Datatoread = istream. length;
Context. response. contenttype = "application/octet-stream ";
Context. response. addheader ("content-disposition", "attachment; filename =" + httputility. urlencode (filename, system. Text. encoding. utf8 ));

While (datatoread> 0)
{
If (context. response. isclientconnected)
{
Length = istream. Read (buffer, 0, 10000 );
Context. response. outputstream. Write (buffer, 0, length );
Context. response. Flush ();

Buffer = new byte [10000];
Datatoread = datatoread-length;
}
Else
{
Datatoread =-1;
}
}
}
Catch (exception ex)
{
Context. response. Write (ex. Message );
}
Finally
{
If (istream! = NULL)
{
Istream. Close ();
}
}
}

Public static void responsefile (string path, string filename, httpcontext context)
{
Context = httpcontext. Current;

System. Io. Stream istream = NULL;
Byte [] buffer = new byte [10000];
Int length;
Long datatoread;

Try
{
Istream = new system. Io. filestream (path, system. Io. filemode. Open, system. Io. fileaccess. Read, system. Io. fileshare. Read );
Datatoread = istream. length;
Context. response. contenttype = "application/octet-stream ";
Context. response. addheader ("content-disposition", "attachment; filename =" + httputility. urlencode (filename, system. Text. encoding. utf8 ));

While (datatoread> 0)
{
If (context. response. isclientconnected)
{
Length = istream. Read (buffer, 0, 10000 );
Context. response. outputstream. Write (buffer, 0, length );
Context. response. Flush ();

Buffer = new byte [10000];
Datatoread = datatoread-length;
}
Else
{
Datatoread =-1;
}
}
}
Catch (exception ex)
{
Context. response. Write (ex. Message );
}
Finally
{
If (istream! = NULL)
{
Istream. Close ();
}
}
}