HTML index and RSS feed from a folder of photos

index.php

<?php
//CONFIGURATION:

//feed name & details
$title = 'My Fabulous Photos';
$subtitle = 'A fabulous collection of photos.';
$author = 'Richard Avedon';
$limit = 20; //only 20 photos
date_default_timezone_set ( 'America/New_York' );

/**
* Place this file in a folder full of images to publish an RSS feed of the photos.
* 
*  -  Files are sorted latest-first by modification date.
* 
*  -  If present, IPTC comments will be used for the captions. If not, 
*     file names are used, (underscore is replaced with a space, extension
*     is removed).
*
*  -  JPEG, GIF, and PNG images are supported
*
*  -  Requires PHP5
*
* LICENSE (BSD License)
* 
* Copyright (c) 2012, Walter Lee Davis <waltd@wdstudio.com>
* All rights reserved.
* 
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 
*  - Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
*
*  - Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in
*    the documentation and/or other materials provided with the
*    distribution. 
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
* TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
* THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/

//FUNCTIONS
/**
* recursive variable replacement
*
* @param string $strText Input text including {{variable}} placeholders
* @return string with all templates replaced with existing global vars
* @author Walter Lee Davis
*/
function replace_vars($strText){
  $out = preg_replace_callback('/\{\{(.+?)\}\}/im','replace_vars_callback',$strText);
  if(strpos($out,'{{') !== false) {
    return replace_vars($out);
  }
  return $out;
}

function replace_vars_callback($arrMatches){
  $match = $arrMatches[1];
  if(isset($GLOBALS[$match])) return $GLOBALS[$match];
  //the spaces between the brackets here are Unicode Word Joiner characters (U+2060) 
  //not actual spaces. This keeps away the infinite loop.
  return '{⁠{' . $match . '}⁠}'; 
}

/**
 * test for variable present and not empty
 *
 * @param string $var Variable name
 * @return void
 * @author Walter Lee Davis
 */
function present($var){
  return (isset($var) && !empty($var));
}

/**
 * IPTC caption reader
 *
 * @param string $path path to file
 * @return string
 * @author Tim Plumb
 */
function readCaption($path){
  $IPTC_Caption = ""; 
  $size = getimagesize( $path, $info ); 
  if (isset($info["APP13"])) { 
    if($iptc = iptcparse( $info["APP13"] ) ) { 
      $IPTC_Caption = present($iptc["2#005"][0]) ? $iptc["2#005"][0] : $iptc["2#120"][0]; 
    } 
  }
  return( $IPTC_Caption );
}

/**
 * file extension from filename
 *
 * @param string $path 
 * @return string
 * @author Walter Lee Davis
 */
function extension($path){
  return strtolower(array_pop(explode('.',$path)));
}

/**
 * read the current request and return the full external URL
 *
 * @return string
 * @author Walter Lee Davis
 */
function absolute_url() {
  $out = 'http' . (($_SERVER['HTTPS'] == 'on') ? 's' : '') . '://';
  $out .= $_SERVER['SERVER_NAME'] . (($_SERVER['SERVER_PORT'] != '80') ? $_SERVER['SERVER_PORT'] : '');
  return $out . $_SERVER['PHP_SELF'];
}

function h($key){
  return htmlentities($key,ENT_COMPAT,'UTF-8');
}


//CONSTANTS

$url = dirname(absolute_url()) . '/';
$mimes = array('jpeg' => 'photo/jpeg', 'jpg' => 'photo/jpeg', 'png' => 'photo/png', 'gif' => 'photo/gif');
$dir = dirname(__FILE__);
$me = basename(__FILE__);
$files = $photos = $times = $entries = $figures = array();
$latest = $i = 0;

//MAIN LOOP
//read the directory
foreach(scandir($dir) as $file){
  if(preg_match('/^[^\.].+?\.(jpe?g|png|gif)$/i', $file)){
    $timestamp = filemtime($dir . '/' . $file);
    $latest = ($timestamp > $latest) ? $timestamp : $latest;
    $files[] = $file;
    $times[] = $timestamp;
  }
}
$page_updated = date('F j, Y, g:i a', $latest);
$pubdate = date('Y-m-d H:i\Z', $latest);
$latest = gmdate('Y-m-d\TH:i:s\Z',$latest);

//sort by date descending
arsort($times);
foreach($times as $k => $v){
  $photos[] = array($files[$k], $times[$k]);
}

//templates
$feed = '<?xml version="1.0" encoding="UTF-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
  <title>
    {{title}}
  </title>
  <updated>
    {{latest}}
  </updated>
  <author>
    <name>
      {{author}}
    </name>
  </author>
  <id>
    {{url}}
  </id>
  <subtitle>
    {{subtitle}}
  </subtitle>
  <link rel="self" href="{{url}}feed.php"/>
{{entries}}
</feed>
';
$page = '<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8" />
  <title>{{title}}</title>
  <!--[if IE]>
    <script src="http://html5shiv.googlecode.com/svn/trunk/html5.js"></script>
  <![endif]-->
  <link rel="alternate" type="application/rss+xml" title="RSS" href="{{url}}{{me}}?mode=rss" />
  <style type="text/css">
    body {
      background-color: #ccc;
      padding: 40px 0;
      margin: 0;
      font-family: "Lucida Grande", "Lucida Sans Unicode", Lucida, sans-serif;
      font-size: 90%;
      color: #333;
    }
    header, section {
      width: 75%;
      margin: auto;
    }
    figure {
      padding: 2em;
      margin: 2em 0;
      border: 1px solid #999;
      background-color: #fff;
      box-shadow: 0 8px 20px #666;
    }
    figure img {
      width: 100%;
      border: 1px solid #ccc;
      margin: 0 0 .5em
    }
    figcaption {
      font-style: italic;
      text-align: center;
    }
    .right {
      float: right;
    }
    h1 {
      overflow: hidden;
      border-bottom: 1px solid #999;
      padding-bottom: .2em
    }
    /* RSS feed icon in CSS3! */
    span.rss{float:right;width:36px;height:36px;margin:0;font:0.475em/1 Arial,sans-serif;}
    .rss a{width:32px;height:32px;display:inline-block;overflow:hidden;border:1px solid transparent;
    line-height:32px;text-decoration:none;text-shadow:0 -1px 0 rgba(0,0,0,0.5);-moz-border-radius:6px;
    -webkit-border-radius:6px;border-radius:6px;position:relative;padding:0 0 0 2px;border-color:#ea6635;
    text-transform:lowercase;text-indent:-900px;font-size:22px;font-weight:bold;color:#fff;background:#e36443;
    -moz-box-shadow:0 0 4px rgba(0,0,0,0.4);-webkit-box-shadow:0 0 4px rgba(0,0,0,0.4);
    box-shadow:0 0 4px rgba(0,0,0,0.4);background:-webkit-gradient(linear,left top,left bottom,from(#f19242),to(#e36443));
    background:-moz-linear-gradient(top,#f19242,#e36443);background:linear-gradient(top,#f19242,#e36443);}
    .rss a:before{width:6px;height:6px;background:#fff;-moz-border-radius:6px;-webkit-border-radius:6px;
    border-radius:6px;}.rss a:before,.rss a:after{content:"";position:absolute;bottom:5px;left:5px;}
    .rss a:hover,.rss a:focus,.rss a:active{opacity:0.8;border-color:#000;}.rss a:after{width:11px;height:11px;
    border-style:double;border-width:12px 12px 0 0;border-color:#fff;-moz-border-radius:0 25px 0 0;
    -webkit-border-radius:0 25px 0 0;border-radius:0 25px 0 0;}
  </style>
</head>
<body>
  <header>

    <h1><span class="rss"><a rel="alternate" type="application/rss+xml" title="Subscribe to our RSS feed" href="{{url}}{{me}}?mode=rss">RSS</a></span>{{title}}</h1>
    <p id="subtitle">{{subtitle}}</p>
    <p id="author">{{author}}</p>
    <p id="pubdate">Last update: <time pubdate="{{pubdate}}">{{page_updated}}</time></p>
  </header>
  <section id="pictures">
{{figures}}
  </section>
</body>
</html>
';
$entry = '  <entry>
    <title type="html">
      {{item_title}}
    </title>
    <id>
      {{id}}
    </id>
    <link rel="enclosure" type="{{mime_type}}" href="{{url}}{{photo}}" />
    <link rel="alternate" href="{{url}}{{photo}}" />
    <summary type="html">
      {{image_tag}}
    </summary>
    <published>
      {{published}}
    </published>
    <updated>
      {{published}}
    </updated>
  </entry>
';
$figure = '  <figure>
     {{image}}
    <figcaption>
      {{figure_title}} — Posted <time datetime="{{datetime}}">{{posted}}</time>
    </figure>
   </figure>
';


//build the current set of entries as an array of strings
foreach($photos as $photo){
  if($i < $limit){
    $published = gmdate('Y-m-d\TH:i:s\Z',$photo[1]);
    $datetime = date('Y-m-d H:i\Z', $photo[1]);
    $posted = date('F j, Y, g:i a', $photo[1]);
    $id = $url . $photo[0];
    $item_title = readCaption($dir . '/' . $photo[0]);
    $mime_type = $mimes[extension($photo[0])];
    if ($item_title === ""){
      $item_title = preg_replace('/_/', ' ', preg_replace('/\.[a-zA-Z]{3,4}$/','',$photo[0]));
    }
    $figure_title = $item_title;
    $item_title = h($figure_title);
    $image = '<img src="' . $id . '" alt="' . $item_title . '" />';
    $image_tag = h($image . '<br /><br />');
    $entries[] = replace_vars($entry);
    $figures[] = replace_vars($figure);
    $i++;
  }else{
    break;
  }
}
//concatenate into a single string
$entries = implode("\n",$entries);
$figures = implode("\n",$figures);
//build the outer shell
$feed = replace_vars($feed);
$page = replace_vars($page);
//send the result
if(present($_GET['mode']) && $_GET['mode'] == 'rss'){
  header('Content-type: application/xml; charset=utf-8');
  print $feed;
}else{
  header('Content-type: text/html; charset=utf-8');
  print $page;
}
?>