Vlad Hrybok's Tech Notes

Summary

UPDATE: This sample is an open-source project now.

This article describes how to build a redistributable ASP.NET application that allows users browse remote server's file system and pick folders with MP3 files to be played by embedded Macromedia Flash-based MP3 player.

Article Sources

Download article's C# source in a form of Visual Studio 2005 Solution comprising ASP.NET application and a Setup Project. Unzip the archive to "C:\".

End Result

  

After building the project you will have an MSI-based setup package that can be installed on virtually any Windows-based PC. Installed application will be accessible from inside the LAN as an intranet application without having to install IIS.

Prerequisites

- Visual Studio 2005.
- UltiDev Cassini Web Server for ASP.NET 2.0. UltiDev Cassini is packaged together with the application into the Setup.exe so that the final application would not depend on IIS being present on target system.

Let's Begin (Getting Ducks in a Row)

A few weeks ago I stumbled upon a great piece of free software:Flash-based XSPF-compatible MP3 player. When embedded on a page, it can take playlist over HTTP and play it. Second nice thing was that XSPF play list format has XSD schema available. .NET Framework xsd.exe utility allows easy conversion of XSD schemas into C# or VB.NET classes incapsulating the structure of the data defined by the XSD, as well as implementing XML serialization to and from XML files conforming to the schema. So I had an XSPF-compatible MP3 player and a free code generating XSPF-compatible XML. That meant I could easily create XSPF-compatible playlists on a fly. Only if I had free ID3 tag (MP3 file metadata) access API...

Finding ID3v2 library for .NET was harder than I expected. However search was ultimately successful. The UltraID3Lib ended up being just what I needed. It's a nice library; may be just be a bit over the top object-oriented.

Final piece is UltiDev Cassini Web Server for ASP.NET 2.0. It's necessary because first, it can be packaged and shipped along with any ASP.NET application eliminating requirement for IIS. Second, unlike IIS UltiDev Cassini service works under "Local System" account, which enables access to any local file and folder on the server. One thing to note, while this is quite convenient to have a web server running under powerful account, it may pose a risk if the application is exposed on the web. It's best to work with the application inside protected local area network.

After you have downloaded the solution, unzip it on C:\. It will create "C:\UltiDevMusicPlayerSample" folder. If you want to put it in some other folder - you can do that too - simply adjust your project debugging settings later to point to the correct application folder (see below).

Application Flow

- Application has a single page (Default.aspx) containing the player control and file a system browser (Controls/PlayerControl.ascx and Controls/PlayerControl.ascx.cs).
- After user selected a folder with MP3 files, file system browser tree gets hidden and player control is re-rendered to point to the dynamically-generated playlist representing selected folder.
- Player control requests dynamic playlist and custom IHttpHandler (AppCode/PlaylistClass.cs and AppCode/xspf.cs) serves XSPF-encoded playlist containing songs in the selected folder. Playlist contains song information retrieved from songs' ID3v2 and ID3v1 MP3 tags.
- Player plays songs one by one: requesting each one from the custom IHttpHandler (Handlers/Song.ashx) serving songs from local file system. After song started playing player also requests song album artwork (cover art) from custom IHttpHandler (Handlers/CoverArt.ashx) which serves image extracted from song's ID3v2 tag.

Debugging

I had troubles getting Visual Studio 2005 internal web server to serve Flash component. I switched to UltiDev Cassini for debugging and that has solved the problem. Debugging with UltiDev Cassini is probably a good idea anyway since the application is eventually going to run under UltiDev Cassini.

To switch to UltiDev Cassini, bring up ASP.NET application's properties, select Start Options of the left, and check "Start External Program" radio-button. Enter "C:\Program Files\UltiDev\Cassini Web Server for ASP.NET 2.0\UltiDevCassinWebServer2.exe" as the program to be used for debugging, and specify "/run c:\UltiDevMusicPlayerSample\WebApp Default.aspx 4125" (no quotes) as command line arguments. If you have unzipped solution to a folder other than "C:\", then you will need to modify c:\UltiDevMusicPlayerSample\WebApp part of the command line arguments to point to the actual application location.

Setup Project

Unlike regular ASP.NET application, this application is using regular (non-web) setup project for installer implementation. The reason for that is the Visual Studio web setup project is actually IIS setup project. Since we are using UltiDev Cassini instead of IIS, regular setup project is required instead.

Setup project packs UltiDev Cassini into Setup.exe bootstrapper and ensures application is registered with UltiDev Cassini during installation process and gets unregistered during uninstallation.

Creating a setup project for ASP.NET application bundled with UltiDev Cassini is not complex, but if you need step-by-step guide, please refer to this walk-through.

IMPORTANT: When installing the application, don't just click the .MSI file. You will need to run Setup.exe to ensure UltiDev Cassini web server gets installed on target system. This is especially true on Vista, where clicking .MSI and running Setup.exe are not nearly as functionally close as it used to be on Windows XP.

Build & Enjoy!

Recently I've been working on the small ASP.NET 2.0 app that has a page containing Macromedia (now Adobe) Flash object. When I tried debugging it with Visual Studio 2005 and its internal web server, the Flash piece has never been loaded by Internet Explorer - I am not even sure whether it was the Flash player that failed to load or the .SWF file. I wonder if anyone else had this issue. I could not check which component was not loaded because WebDev.WebServer2.exe serves only local applications, and I could not use an http tracer to see which request gets stuck.

I worked around the issue by switching to our own UltiDev Cassini for ASP.NET 2.0 for application debugging. It served all the bits and pieces required by Flash without a hitch.

In attempt to create a less dry than your usual "Hello World" ASP.NET application to showcase UltiDev Cassini Web Server, I decided to write a simple web-based MP3 player application using Maсromedia (now Adobe) Flash. I was very surprised by how long and frustrating was my search for a free .NET-based API allowing programmatic access to ID3 tags in MP3 files from C# and VB.NET. I started working with something I found on Codeproject.com, but that piece turned out to be buggy beyond any degree of practicality. My second sweep across Internet yielded a much better (if only somewhat over-engineered) solution - the UltraID3Lib. Its UltraID3 class is the starting point of the journey. The library worked out for me very well. Thumbs up.

Here's how it works: for the last two years we at UltiDev LLC work mainly on HttpVPN - our flagship product and the main reason why our company exists. Once upon a time we've decided that making a simple redistributable web server software would be a great value-added piece completing HttpVPN offering and allowing us to probe prospective market for HttpVPN, gather contact information of people who may by interested in HttpVPN and setup our QA, build and release processes along the way. The experiment turned out to be as successful and we hoped it would be. We've got about 15,000 (and counting) installed UltiDev Cassini Web Server runtimes worldwide and we are receiving overwhelmingly positive feedback from users. All this also means that about every six months we have our Cassini task tracker full enough to suspend HttpVPN work for a few weeks and do another release or UltiDev Cassini. This time was no exception.

Although we always hope to keep our Cassini mid-version upgrade development cycle limited to three weeks, it took us usual five weeks to fix, test, fix again, test again and release the latest version of UltiDev Cassini Web Server. This release had two main points of focus: to eliminate all known installation/registration hurdles and to make UltiDev Cassini compatible with all 64-bit Windows platforms. 64 bit OSes are gaining popularity very rapidly thanks to the fact that most of the recent (and even not so recent - think Pentium D) CPUs from AMD and Intel are x64-compatible. Windows Vista comes in 32- and 64-bit versions right from the start, while existing Windows XP Pro x64 and Windows 2003 Server 64-bit were somewhat obscure because they were released before 64-bit CPUs hit the mainstream. Nowadays it's pretty much impossible to buy a CPU that does not have x64 compatibility. Hoping to please Vista 32 and 64 bit users we made sure that our latest version of Cassini runs smoothly on all the latest multicore 32 and 64 bit CPUs and supports entire (reasonable) line of Windows operating systems: from Windows 2000 to Vista.

Now, whether you own an older version of our tiny but powerful UltiDev Cassini, or you never tried it - go ahead and download the latest version. If you owned old version - most of the known issues will go away (or if you had none you will be less likely to face issues in the future). If you never saw our Cassini - it's a perfect time to spend 20 minutes on something you probably will go "wow!" about. Check it out now!

In the brave new world, where nearly all CPUs are 64 bit, and Vista x64 is poised to have a large market share, how many ASP.NET 1.1 developers will find themselves in the situation where IIS7 running on x64 OS can't create an application pool for .NET Framework 1.1, therefore making it impossible to debug ASP.NET 1.1 applications under IIS7 using Visual Studio.NET 2003? All because when looking for available ASP.NET versions, IIS7 is probably looking into 64 bit .NET Framework folder - "C:\Windows\Microsoft.NET\Framework64", which only has 2.0 and 3.0 versions in it. Not knowing this would be the case, I recently installed Vista x64 on my newly upgraded Dev box and almost fainted when I realized I can't use VS.NET 2003 to debug legacy ASP.NET 1.1 apps. It took me a while to realize that our own Cassini Web Server for ASP.NET 1.1 may work just fine, because it has its own routines for discovering location of .NET Framework 1.1 files, and it can be used for debugging of ASP.NET 1.1 application in VS.NET 2003. I tried it a few days ago, and sure enough our little Cassini saved the day - Visual Studio.NET 2003 ran an ASP.NET 1.1 app on our Cassini in Debug mode without a hitch!