PHP Script for hCalendar to iCalendar Conversion

<div class="vevent" id="llt2009-call-for-proposals-hcalendar"><a href="http://www.oln.org/conferences/LLT2009/pdf/LLT09precons.pdf">Pre-conference workshop descriptions</a> [PDF] and the <a href="http://www.oln.org/conferences/LLT2009/pdf/LLT09draftprogram.pdf">preliminary program</a> [PDF] as well as the <a href="https://secure.oln.org/LLT2009/LLT2009registration.php">registration form </a>for the <span class="summary"><a href="http://www.oln.org/conferences/LLT2009/" class="url">Learning, Libraries and Technology Conference</a></span> have been posted to the conference website.  <span class="description">Learning, Libraries &amp; Technology 2009 is a learning and networking opportunity from the <a href="http://www.uso.edu/">University System of Ohio</a> with content of interest to everyone involved in Ohio education, including those from colleges and universities of all sizes, independent colleges, workforce development centers and high schools.</span>  Held at the <span class="location"><a href="http://www.eastontowncenter.com/">Easton Town Center</a> in Columbus, Ohio</span>, the pre-conference Workshops will be on <abbr class="dtstart" title="2009-03-01" style="border:none;text-decoration: none;">March 1, 2009</abbr> followed by the main conference on <abbr class="dtend" title="2009-03-04" style="border:none;text-decoration: none;">March 2-3, 2009</abbr>.</div>

# Copyright 2008 by Peter Murray.   Licensed under the
# Educational Community License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may
# obtain a copy of the License at
#
#  http://www.osedu.org/licenses/ECL-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an "AS IS"
# BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
# or implied. See the License for the specific language governing
# permissions and limitations under the License.

## For more information about this program, see:
##   http://dltj.org/article/xhtml2vcal

# Array of tokens representing site prefixes.  To see how these
# are used, look at the $pathInfo explode() below.
$siteTokens = array(
    "dltj" => "http://dltj.org/article/%pageToken%/",
);

# $pathInfo[0] is blank; it represents the empty space before the leading slash
# $pathInfo[1] is the site token; see site tokens above
# $pathInfo[2] is the page token; it is appended to the end of the URI
$pathInfo = explode("/",$_SERVER['PATH_INFO']);

# Check to see if the token is one that we know about
if (array_key_exists($pathInfo[1], $siteTokens)) {
  # Substitute the page token into the site uri template
  $uri = preg_replace('/%pageToken%/', $pathInfo[2], $siteTokens[$pathInfo[1]]);
} else {
  header('HTTP/1.0 400 Invalid site token '.$pathInfo[1]);
  header('Content-Type: text/plain');
  echo 'Invalid site token: '.$pathInfo[1];
}

# See if we have 'curl'  
if ( !function_exists( 'curl_init' ) ) {
  header('HTTP/1.0 500 curl_init() function not found');
  exit;
}

# Prepare and execute a 'curl' request
$handle = curl_init();
curl_setopt($handle, CURLOPT_URL, $uri);
curl_setopt($handle, CURLOPT_RETURNTRANSFER, 1);
$buffer = curl_exec($handle);

# Check to see if we got a resource back
$httpCode = curl_getinfo($handle, CURLINFO_HTTP_CODE);
if ($httpCode != '200') {
  header('HTTP/1.0 404 Remote document not found');
  header('Content-Type: text/plain');
  echo "Remote resource returned HTTP code '$httpCode' for URI $uri";
  exit;
} else {
  curl_close($handle);
}

# Load the XML source from that URI
$xml = new DOMDocument;
$xml->loadHTML($buffer);

# Load the XSLT document
$xsl = new DOMDocument;
if (! $xsl->load('x2v/hcalendar/xhtml2vcal.xsl')) {
  header('HTTP/1.0 500 XSLT style sheet not found');
  header('Content-Type: text/plain');
  echo "XSLT stylesheet not found";
  exit;  
}

# Configure the transformer
$proc = new XSLTProcessor;
$proc->importStyleSheet($xsl); // attach the xsl rules
$proc->setParameter('', 'Source', $uri);

# Tell the browser we're sending an iCalendar file
$fileName=$pathInfo[2].".ics";
header("Content-Type: text/calendar; charset=utf-8; name=$fileName");
header("Content-Disposition: attachment; filename=$fileName");

# Do the transformation
echo $proc->transformToXML($xml);

# Add a Control-M to the end of the file and flush the output
echo "15n";
flush();