I previously gave a glimpse of how to zip into an HttpResponse's OutputStream, but it wasn't explaining all aspects of zipping from ASP.NET. So I'll get in more details here.

First, I have used my fantastic talent in UI designs to create this web page:

Yup, three checkboxes and a button is enough gadgets for me!

The first piece of code involves Application_Start. Since I know I won't be zipping gazillions of bytes, I want my web page to use memory as a temporary location for compressed data. How you do this with Xceed Zip for .NET is simple: You create a RAM drive! Oh the good old days of RAM drives...

    protected void Application_Start(Object sender, EventArgs e)
    {
      Xceed.Zip.Licenser.LicenseKey = "ZIN23-#####-#####-####";
      ZipArchive.DefaultTempFolder = new MemoryFolder();
    }

This new MemoryFolder is acting exactly like a per-process RAM drive. It's an AbstractFolder like any other AbstractFolder. The TempFolder of all new ZipArchive instances will be initialized to that value. Application_Start is also a great place where to set your license key, before anything else.

We're now ready for the button's click event. Again, I want to avoid write access on the hard drive, and wish to zip directly in the response stream. But the idea behind the Xceed FileSystem is to copy source files and folders to destination files and folders. How can I zip into a Stream? The StreamFile class comes to the rescue. It lets you expose a Stream as if it were an AbstractFile. Then, you can pass this StreamFile to the ZipArchive's constructor, to tell that new instance to write into that Stream. The rest is glue code for my wonderful ASP.NET application to zip the correct files.

    private void Button1_Click(object sender, System.EventArgs e)
    {
      if( !CheckBox1.Checked && !CheckBox2.Checked && !CheckBox3.Checked )
      {
        // Redirect to error page...
        return;
      }

      // The "MACHINE\ASP_NET" user must have read access to that folder.
      DiskFolder source = new DiskFolder( @"d:\" );

      // We want the client-side to recognize the upcoming file as a zip file.
      this.Response.ContentType = "application/zip";
      this.Response.AddHeader( "Content-Disposition", "attachment; filename=YourFiles.zip" );

      // We will zip directly in the response stream. The temporary compressed
      // data will be written to the ZipArchive's TempFolder, thus the MemoryFolder 
      // we set in Application_Start.
      ZipArchive destination = new ZipArchive( new StreamFile( this.Response.OutputStream ) );

      // And finally we zip in a single operation. If we had to zip more than
      // one source, we could have used ZipArchive.BeginUpdate/EndUpdate.
      ArrayList nameFilters = new ArrayList();

      if( CheckBox1.Checked )
        nameFilters.Add( new NameFilter( "*.txt" ) );

      if( CheckBox2.Checked )
        nameFilters.Add( new NameFilter( "*.jpg" ) );

      if( CheckBox3.Checked )
        nameFilters.Add( new NameFilter( "*.exe|*.dll" ) );

      // Passing more than one filter to CopyFilesTo does an "AndFilter"
      // by default.
      Filter mainFilter = ( nameFilters.Count == 1 )
        ? nameFilters[ 0 ] as Filter
        : new OrFilter( nameFilters.ToArray( typeof( NameFilter ) ) );

      source.CopyFilesTo( destination, false, true, mainFilter );

      this.Response.End();
    }

We now have an ASP.NET application which only requires read access to the source files and folders to zip. Everything else is done in memory, without drifting away from the logic of the Xceed FileSystem; manipulating files and folders.

Just in case my previous post on the subject did not ring a bell, the release of version 2.1 of Xceed FTP for .NET means you can directly unzip from a zip file located on an FTP server, without downloading the file first! Look at the following code:

  using( FtpConnection connection = new FtpConnection( "ftp.xceed.com" ) )
  {
    FtpFile source = new FtpFile( connection, @"/images/Flowers/Backup/Flowers.zip" );
    DiskFolder dest = new DiskFolder( @"d:\temp\flowers" );

    ZipArchive zip = new ZipArchive( source );
    zip.CopyFilesTo( dest, true, true );
  }

The secret behind this code is the kind of stream "FtpFile.OpenRead" returns. Though we are dealing with a network connection, this stream is fully seekable! The FtpFile takes advantage of the "REST" FTP command, which tells the FTP server we wish to start the transfer at a specific offset. Thus, when the ZipArchive needs to seek at the end of the file to locate the ending header, a proper "REST" command is issued to avoid having to read all the zip file first. And the same happens when reading the central directory, or unzipping specific files.

I have put forward my incredible talent with ASCII art (sic) and updated my wonderful "FileSystem.txt" file, which describes classes available with the Xceed FileSystem for .NET.

                             ==============
                             FileSystemItem
                             ==============
                                    |
                     +--------------+------------------+
                     |                                 |
              ==============                     ============
              AbstractFolder                     AbstractFile
              ==============                     ============
                     |                                 |
         +---+---+---+---+---+---+     +---+---+---+---+---+---+---+
         |   |   |   |   |   |   |     |   |   |   |   |   |   |   |
 ==========  |   |   |   |   |   |     |   |   |   |   |   |   |  ========
 DiskFolder  |   |   |   |   |   |     |   |   |   |   |   |   |  DiskFile
 --============  |   |   |   |   |     |   |   |   |   |   |  ==========--
   MemoryFolder  |   |   |   |   |     |   |   |   |   |   |  MemoryFile
   --==============  |   |   |   |     |   |   |   |   |  ============--
     IsolatedFolder  |   |   |   |     |   |   |   |   |  IsolatedFile
     ------============  |   |   |     |   |   |   |  ============----
           ZippedFolder  |   |   |     |   |   |   |  ZippedFile
           -------=========  |   |     |   |   |  =======-------
                  FtpFolder  |   |     |   |   |  FtpFile
                  -============  |     |   |  ==========-
                   TarredFolder  |     |   |  TarredFile
                   ---=============    |  ===========---
                      GZippedFolder    |  GZippedFile
                      -------------   ==========-----
                                      StreamFile
                                      ----------

Can you guess what I'm working on?

Have you ever thought of changing career? How about hockey? Here's your chance! Become one of the lucky graduates of the NHL Academy.

(Thanks Jeff, you made my day.)

I'm glad to announce that Xceed FTP for .NET 2.1 is now available for download. I've been working on this release for the past few months, and I'm very excited to finally see the FTP FileSystem come to life.

For those not familiar with the Xceed FileSystem, which comes with Xceed Zip for .NET, here is some code that sheds some light on what you can do with it. Consider these variables of the same base type:

// A file on disk

AbstractFile first = new DiskFile( @"d:\FileSystem.txt" );

// Another file on disk

AbstractFile second = new DiskFile( @"c:\temp\AnotherFileSystem.txt" );

// A file compressed in a zip file on disk

AbstractFile third = new ZippedFile( 

  new DiskFile( @"c:\temp\data.zip" ), "FileSystemInAZip.txt" );;

// A file in the isolated storage

AbstractFile fourth = new IsolatedFile( "Isolated.txt" );

// A file in memory (random name)

AbstractFile fifth = new MemoryFile();

// A file compressed in a zip file in memory

AbstractFile sixth = new ZippedFile( 

  new MemoryFile(), "VolatileFileSystem.txt" );

You can copy files around very easily:

// Copying the first file anywhere else is always the same!

first.CopyTo( second, true );

first.CopyTo( third, true );

first.CopyTo( fourth, true );

first.CopyTo( fifth, true );

first.CopyTo( sixth, true );

And accessing the contents of any file is always the same:

private void DisplayTextFile( AbstractFile file )

{

  Console.WriteLine( "Displaying the contents of {0}, which is a {1}.", 

    file.FullName,

    file.GetType().Name );

  using( StreamReader reader = new StreamReader( file.OpenRead() ) )

  {

    string line;

    while( ( line = reader.ReadLine() ) != null )

    {

      Console.WriteLine( line );

    }

  }

  Console.WriteLine();

}

// Displaying the contents of those files is always the same!

DisplayTextFile( first );

DisplayTextFile( second );

DisplayTextFile( third );

DisplayTextFile( fourth );

DisplayTextFile( fifth );

DisplayTextFile( sixth );

And why not finish this demonstration by deleting the files we just created.

// And finally, deleting files is the same!

second.Delete();

third.Delete();

fourth.Delete();

fifth.Delete();

sixth.Delete();

Any kind of file is an AbstractFile. Any kind of folder is an AbstractFolder. This way, a DiskFile, an IsolatedFile, a ZippedFile and a MemoryFile share a common set of properties and methods for accessing their metadata and reading/writing their actual data. And a DiskFolder, an IsolatedFolder, a ZippedFolder and a MemoryFolder share a common set of methods for discovering child items.

How does the FTP FileSystem come into play? Simply by offering the same abstraction over files and folders stored on an FTP server. We could simply add this code to the above sample, and everything works just as expected!

AbstractFile seventh = new FtpFile( 

  new FtpConnection( "localhost" ), @"\RemoteFileSystem.txt" );

first.CopyTo( seventh, true );

DisplayTextFile( seventh );

seventh.Delete();

Let's dive a little bit into this implementation of an AbstractFile and AbstractFolder. Each constructor requires an FtpConnection instance, which contains information on how to connect to the target FTP server. Though it looks like a simple information storage class, it does much more. Each time an FtpFile or an FtpFolder requires information, or an incoming or outgoing stream on a file's data, it asks the FtpConnection for an active command channel connection to the server. This way, a unique command channel is generally required for accessing many files on the server.

using( FtpConnection connection = new FtpConnection( "ftp.xceed.com" ) )

{

  connection.TraceWriter = Console.Out;

  FtpFolder root = new FtpFolder( connection );

  foreach( AbstractFile file in root.GetFiles( false, "*.txt" ) )

  {

    DisplayTextFile( file );

  }

}

If we comment out the "Console.WriteLine( line );" line in "DisplayTextFile", we can see the FTP conversation that occurred for the above code:

Connected to 66.46.177.250:21 on 9/27/2005 @ 2:24:54 PM
< 220 Serv-U FTP Server v6.0 for WinSock ready...
> USER anonymous
< 331 User name okay, please send complete E-mail address as password.
> PASS *****
< 230 User logged in, proceed.
> PWD
< 257 "/" is current directory.
> CWD /
< 250 Directory changed to /
> CWD /
< 250 Directory changed to /
> CWD /
< 250 Directory changed to /
> TYPE A
< 200 Type set to A.
> PASV
< 227 Entering Passive Mode (66,46,177,250,6,238)
> LIST
Data connection established with 66.46.177.250:1774 on 9/27/2005 @ 2:24:56 PM
< 150 Opening ASCII mode data connection for /bin/ls.
< 226-Maximum disk quota limited to Unlimited kBytes
<     Used disk quota 0 kBytes, available Unlimited kBytes
< 226 Transfer complete.
Displaying the contents of \FileSystem.txt, which is a FtpFile.
> CWD /
< 250 Directory changed to /
> TYPE I
< 200 Type set to I.
> PASV
< 227 Entering Passive Mode (66,46,177,250,6,240)
> RETR FileSystem.txt
Data connection established with 66.46.177.250:1776 on 9/27/2005 @ 2:24:57 PM
< 150 Opening BINARY mode data connection for FileSystem.txt (1198 Bytes).
< 226-Maximum disk quota limited to Unlimited kBytes
<     Used disk quota 0 kBytes, available Unlimited kBytes
< 226 Transfer complete.

Displaying the contents of \appnote.txt, which is a FtpFile.
> CWD /
< 250 Directory changed to /
> TYPE I
< 200 Type set to I.
> PASV
< 227 Entering Passive Mode (66,46,177,250,6,246)
> RETR appnote.txt
Data connection established with 66.46.177.250:1782 on 9/27/2005 @ 2:24:58 PM
< 150 Opening BINARY mode data connection for appnote.txt (109785 Bytes).
< 226-Maximum disk quota limited to Unlimited kBytes
<     Used disk quota 0 kBytes, available Unlimited kBytes
< 226 Transfer complete.

> QUIT
Disconnected from 66.46.177.250:21 on 9/27/2005 @ 2:25:04 PM

Each FtpFolder and FtpFile instance shared the same FtpConnection, and since no two operations were done at the same time, a single connection was required, as the log indicates. The FtpConnection object implements the IDisposable interface, since it keeps any active connection available until disposed (or finalized).

Now what happens if I try to open two files at the same time, like this?

using( FtpConnection connection = new FtpConnection( "ftp.xceed.com" ) )

{

  connection.TraceWriter = Console.Out;

  AbstractFile first = new FtpFile( connection, @"\FileSystem.txt" );

  AbstractFile second = new FtpFile( connection, @"\appnote.txt" );

  using( Stream firstStream = first.OpenRead() )

  {

    using( Stream secondStream = second.OpenRead() )

    {

      // In an FTP conversation with an FTP server, only one command

      // at a time can be pending. Here, we clearly have two files

      // open at the same time on the same FTP server. How? Each file

      // has its own connection to the FTP server!

    }

  }

}

The FtpConnection object will create extra command channel connections as required. The output shows two command channel connections were made:

Connected to 66.46.177.250:21 on 9/27/2005 @ 2:38:06 PM
< 220 Serv-U FTP Server v6.0 for WinSock ready...
> USER anonymous
< 331 User name okay, please send complete E-mail address as password.
> PASS *****
< 230 User logged in, proceed.
> CWD /
< 250 Directory changed to /
> TYPE A
< 200 Type set to A.
> PASV
< 227 Entering Passive Mode (66,46,177,250,10,53)
> LIST
Data connection established with 66.46.177.250:2613 on 9/27/2005 @ 2:38:07 PM
< 150 Opening ASCII mode data connection for /bin/ls.
< 226-Maximum disk quota limited to Unlimited kBytes
<     Used disk quota 0 kBytes, available Unlimited kBytes
< 226 Transfer complete.
> CWD /
< 250 Directory changed to /
> TYPE I
< 200 Type set to I.
> PASV
< 227 Entering Passive Mode (66,46,177,250,10,54)
> RETR FileSystem.txt
Data connection established with 66.46.177.250:2614 on 9/27/2005 @ 2:38:08 PM
< 150 Opening BINARY mode data connection for FileSystem.txt (1198 Bytes).
Connected to 66.46.177.250:21 on 9/27/2005 @ 2:38:08 PM
< 220 Serv-U FTP Server v6.0 for WinSock ready...
> USER anonymous
< 226-Maximum disk quota limited to Unlimited kBytes
<     Used disk quota 0 kBytes, available Unlimited kBytes
< 226 Transfer complete.
< 331 User name okay, please send complete E-mail address as password.
> PASS *****
< 230 User logged in, proceed.
> CWD /
< 250 Directory changed to /
> TYPE I
< 200 Type set to I.
> PASV
< 227 Entering Passive Mode (66,46,177,250,10,55)
> RETR appnote.txt
Data connection established with 66.46.177.250:2615 on 9/27/2005 @ 2:38:09 PM
< 150 Opening BINARY mode data connection for appnote.txt (109785 Bytes).
< 426-Maximum disk quota limited to Unlimited kBytes
<     Used disk quota 0 kBytes, available Unlimited kBytes
< 426 Data connection closed, file transfer appnote.txt aborted.
> QUIT
Disconnected from 66.46.177.250:21 on 9/27/2005 @ 2:38:13 PM
> QUIT
Disconnected from 66.46.177.250:21 on 9/27/2005 @ 2:38:13 PM

And the great part about all this is that you don't have to worry about this while coding. You're just manipulating yet another kind of AbstractFile or AbstractFolder.

If we get back to the Zip implementation of the Xceed FileSystem, you can see that a ZippedFile or ZippedFolder (or ZipArchive, the root ZippedFolder) constructor needs to know which AbstractFile is holding the actual zip file that should contain this file or folder. "AbstractFile" truly means "any file", as long as there is an AbstractFile-derived class somewhere to expose this file. It means that zipping directly onto an FTP server is no more difficult than zipping in a regular file on disk.

AbstractFolder source = new DiskFolder( @"d:\Data" );

AbstractFolder localDest = new ZipArchive( 

  new DiskFile( @"d:\temp\local.zip" ) );

AbstractFolder remoteDest = new ZipArchive(

  new FtpFile( new FtpConnection( "localhost" ), @"remote.zip" ) );

// Copying is the same, no matter what is the destination

// file or folder.

source.CopyTo( localDest, true );

source.CopyTo( remoteDest, true );

Code for zipping in "D:\temp\local.zip" is no different than code for zipping in "ftp://localhost/remote.zip". And obviously, reading or unzipping from any zip file is the same.

AbstractFolder localSource = new ZipArchive( 

  new DiskFile( @"d:\temp\local.zip" ) );

AbstractFolder remoteSource = new ZipArchive(

  new FtpFile( new FtpConnection( "localhost" ), @"remote.zip" ) );

AbstractFolder dest = new DiskFolder( @"d:\restored" );

// Unzipping text files from any source is the same!

localSource.CopyFilesTo( dest, true, true, "*.txt" );

remoteSource.CopyFilesTo( dest, true, true, "*.txt" );

I really hope this new addition to the Xceed FileSystem will generate the same enthusiasm we had inventing and developping it. I'm very interested in hearing your opinions!

I just discovered this amasing little gem through Scott. It's called PureText, and what it does is convert the clipboard's formatted text to unformatted text before pasting it to the current window.

By default, it binds to the Win-V key sequence. For example, you select some text on a web page, then press Win-V in a new email, and it will paste the unformatted text, without the web page's formatting. I already can see great use when pasting code from VS.NET! It will save me extra steps.

Yesterday's sessions I attented were rather disapointing. I went to many WinFS sessions, and I realize that except for ADO.NET integration, the product didn't change much. It's still the same data store, with data types, schemes, relations, and a searching APIs, or browsing APIs should I say, as I learned it wasn't mere searching… yeah, right.

I guess this year's PDC is less about listening to Microsoft, and more about installing the bits as soon as possible and play with them. Even though the bits are related to the same products as two years ago, they are more stable, and the interface has less chances to change until release.

I'm already shopping for a new machine to install Vista on. I was thinking about a laptop, as I don't have one. What do you think? Should I stick to a desktop machine?

Tags: PDC05

Yesterday, I went to the Mono meeting. Miguel and his crew were not prepared at all. The room was too small (that's a good sign though), the projector didn't work with two of the laptops, and Miguel ended up doing Q&A for two hours, only showing glimpses of the applications he wanted to demonstrate. I left before the end. I wanted to talk with Miguel, but I guess I'll use the email channel.

I've always been curious about Mono, because I would feel great proud seeing the software I conceived and developed being run on more and more computers. It's not because I'm a Linux advocate. I'm a "liberty-of-choice" advocate. I used to be a Windows developer (WIN32, COM). I'm now a .NET developer, whatever the platform. Why would I complain on seeing Xceed Zip for .NET work on Linux?

Tags: PDC05