Andrew Beaton :: FAQ » Programming

Read MP3 ID3 Tags in Perl

Andrew — Thu, 03 Dec 2009 20:59:12 +0000

The package I use for simple tag reading is MP3::Tag, available on CPAN with more information here.

The following example shows how easy it is to retrieve tags from an MP3 file.

use MP3::Tag;
 
my $file = MP3::Tag->new($filename);
 
my ($title, $track, $artist, $album, $comment, $year, $genre) = $file->autoinfo();
 
print "Title: [$title]\n";
print "Artist: [$artist]\n";
print "Album: [$album]\n";
print "Track: [$track]\n";
print "Year: [$year]\n";
print "Genre: [$genre]\n";
print "Comment: [$comment]\n\n";

Add a space in XSL

Andrew — Fri, 13 Nov 2009 23:35:52 +0000

The following shows you how to add a space or in XSL:

 disable-output-escaping="yes"> >

Specifically target each browser in CSS

Andrew — Fri, 13 Nov 2009 23:31:33 +0000

The following CSS ‘hack’ can be used to target all browsers IE 7, IE 6 and IE < 6 ...

All browsers:

margin-top: 44px;

IE7 and below:

*margin-top: 26px;

IE6 and below:

_margin-top: 44px;

IE6 only:

_mar\gin-top: 44px;

All firefox:

#selector[id=selector] { color: red; }

All firefox:

@-moz-document url-prefix() { .selector { color: red; } }

All Gecko:

*>.selector { color: red; }

Firefox 1.5 and newer:

.selector, x:-moz-any-link, x:only-child { color: red; }

Firefox 2 and older:

body:empty .selector { color: red; }

Firefox 2 and older:

#selector[id=SELECTOR] { color: red; }

Firefox 2 and older:

html>/**/body .selector, x:-moz-any-link { color: red; }

Firefox 3:

html>/**/body .selector, x:-moz-any-link, x:default { color: red; }

Use a button as an A Href link

Andrew — Fri, 13 Nov 2009 23:06:42 +0000

To create an A Href link that can be used as a button, we can use one of the two following methods:

function SubmitFrom(){
    document.myform.target.value="somescript.php3"
    document.myfrom.submit()
}
function ResetFrom(){
    document.myfrom.reset()
}
 
<a href="javascript:SubmitForm()"><img src=....>a>

<FORM name=remove ACTION='removeItem.php3' METHOD='POST' ENCTYPE='application/x-
www-form-urlencoded'> 
    <a href="javascript:document.remove.submit()">remove from cart</a>
</form>

Run only one instance of a program in C#

Andrew — Fri, 13 Nov 2009 22:45:22 +0000

This example shows you how to ensure that only one instance of an application is running.

// Ensure only one instance of this application is running.
bool alone = false;
Mutex m = new Mutex(true, "", out alone);
 
if (!alone)
{
    Console.WriteLine("Another instance is already running.");
    Console.ReadKey();
    return;
}
 
Console.WriteLine("Running...\n");
Console.ReadKey();
 
// Needed to ensure only one instance is running.
GC.KeepAlive(m);

Restart a Windows service using C#

Andrew — Fri, 13 Nov 2009 22:38:05 +0000

This example shows how to start, stop and restart a windows service programmatically in C#.

Start service

The following method tries to start a service specified by a service name. Then it waits until the service is running or a timeout occurs.

public static void StartService(string serviceName, int timeoutMilliseconds)
{
    ServiceController service = new ServiceController(serviceName);
    try
    {
        TimeSpan timeout = TimeSpan.FromMilliseconds(timeoutMilliseconds);
 
        service.Start();
        service.WaitForStatus(ServiceControllerStatus.Running, timeout);
    }
    catch
    {
        // ...
    }
}

Stop service

The following method tries to stop the specified service and it waits until the service is stopped or a timeout occurs.

public static void StopService(string serviceName, int timeoutMilliseconds)
{
    ServiceController service = new ServiceController(serviceName);
    try
    {
        TimeSpan timeout = TimeSpan.FromMilliseconds(timeoutMilliseconds);
 
        service.Stop();
        service.WaitForStatus(ServiceControllerStatus.Stopped, timeout);
    }
    catch
    {
        // ...
    }
}

Restart service

This method combinates both previous methods. It tries to stop the service (and waits until it’s stopped) then it begins to start the service (and waits until the service is running). The specified timeout is used for both operations together.

public static void RestartService(string serviceName, int timeoutMilliseconds)
{
    ServiceController service = new ServiceController(serviceName);
    try
    {
        int millisec1 = Environment.TickCount;
        TimeSpan timeout = TimeSpan.FromMilliseconds(timeoutMilliseconds);
 
        service.Stop();
        service.WaitForStatus(ServiceControllerStatus.Stopped, timeout);
 
        // count the rest of the timeout
        int millisec2 = Environment.TickCount;
        timeout = TimeSpan.FromMilliseconds(timeoutMilliseconds - (millisec2-millisec1));
 
        service.Start();
        service.WaitForStatus(ServiceControllerStatus.Running, timeout);
   }
   catch
   {
       // ...
   }
}

Read source of a web page in C#

Andrew — Fri, 13 Nov 2009 22:31:03 +0000

This example shows how to read the source of a web page in C#.

// used to build entire input
StringBuilder sb = new StringBuilder();
 
// used on each read operation
byte[] buf = new byte[8192];
 
// prepare the web page we will be asking for
WebRequest request  = WebRequest.Create("http://andrewbeaton.com");
 
// execute the request
WebResponse response = request.GetResponse();
 
// we will read data via the response stream
Stream resStream = response.GetResponseStream();
 
string tempString = null;
int count = 0;
 
do
{
    // fill the buffer with data
    count = resStream.Read(buf, 0, buf.Length);
 
    // make sure we read some data
    if (count != 0) 
    {
        // translate from bytes to ASCII text
        tempString = Encoding.ASCII.GetString(buf, 0, count);
 
        // continue building the string
       sb.Append(tempString);
    }
}
while (count &gt; 0);