How to download an object as an attachment

1 // Output hard disk files, which support large files, resumable transfers, speed limits, and low resource usage
2 // Input parameter _ Request: page. Request object, _ response: page. Response object, _ filename: Download file name, _ fullpath: Download path with file name, _ speed the number of bytes allowed to be downloaded per second
3 // Success or not
4 Public   Static   Bool Responsefile (httprequest _ Request, httpresponse _ response, String _ Filename, String _ Fullpath, Long _ Speed)
5 {
6 Try
7 {
8 Filestream myfile =   New Filestream (_ fullpath, filemode. Open, fileaccess. Read, fileshare. readwrite );
9 Binaryreader br =   New Binaryreader (myfile );
10 Try
11 {
12 _ Response. addheader ( " Accept-ranges " , " Bytes " );
13 _ Response. Buffer =   False ;
14 Long Filelength = Myfile. length;
15 Long Startbytes =   0 ;
16
17 Int Pack =   102400 ; // 10 K bytes
18 // Integer sleep = 200; // 5 times per second, that is, 5*10 K bytes per second
19 Int Sleep = ( Int ) Math. Floor ( 1000   * Pack / _ Speed) +   1 ;
20 If (_ Request. headers [ " Range " ] ! =   Null )
21 {
22 _ Response. statuscode =   206 ;
23 String [] Range = _ Request. headers [ " Range " ]. Split ( New   Char [] {'=','-'} );
24 Startbytes = Convert. toint64 (range [ 1 ]);
25 }
26 _ Response. addheader ( " Content-Length " , (Filelength - Startbytes). tostring ());
27 If (Startbytes ! =   0 )
28 {
29 _ Response. addheader ( " Content-Range " , String . Format ( " Bytes {0}-{1}/{2} " , Startbytes, filelength - 1 , Filelength ));
30 }
31 _ Response. addheader ( " Connection " , " Keep-alive " );
32 _ Response. contenttype =   " Application/octet-stream " ;
33 _ Response. addheader ( " Content-Disposition " , " Attachment; filename = "   + Httputility. urlencode (_ filename, system. Text. encoding. utf8 ));
34  
35 BR. basestream. Seek (startbytes, seekorigin. Begin );
36 Int Maxcount = ( Int ) Math. Floor (filelength - Startbytes) / Pack) +   1 ;
37
38 For ( Int I =   0 ; I < Maxcount; I ++ )
39 {
40 If (_ Response. isclientconnected)
41 {
42_ Response. binarywrite (Br. readbytes (pack ));
43Thread. Sleep (sleep );
44}
45 Else
46 {
47I=Maxcount;
48}
49 }
50 }
51 Catch
52 {
53Return False;
54}
55 Finally
56 {
57BR. Close ();
58Myfile. Close ();
59}
60 }
61 Catch
62 {
63Return False;
64}
65 Return   True ;
66 }