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19.14. Program: Site Search

You can use site-search.php, shown in Example 19-5, as a search engine for a small-to-medium size, file-based site.

The program looks for a search term (in $_REQUEST['term']) in all files within a specified set of directories under the document root. Those directories are set in $search_dirs. It also recurses into subdirectories and follows symbolic links but keeps track of which files and directories it has seen so that it doesn't get caught in an endless loop.

If any pages are found that contain the search term, it prints list of links to those pages, alphabetically ordered by each page's title. If a page doesn't have a title (between the <title> and </title> tags), the page's relative URI from the document root is used.

The program looks for the search term between the <body> and </body> tags in each file. If you have a lot of text in your pages inside <body> tags that you want to exclude from the search, surround the text that should be searched with specific HTML comments and then modify $body_regex to look for those tags instead. Say, for example, if your page looks like this:


// Some HTML for menus, headers, etc.

<!-- search-start -->

<h1>Aliens Invade Earth</h1>

<h3>by H.G. Wells</h3>

<p>Aliens invaded earth today. Uh Oh.</p>

// More of the story

<!-- search-end -->

// Some HTML for footers, etc.


To match the search term against just the title, author, and story inside the HTML comments, change $body_regex to:

$body_regex = '#<!-- search-start -->(.*' . preg_quote($_REQUEST['term'],'#'). 
              '.*)<!-- search-end -->#Sis';

If you don't want the search term to match text that's inside HTML or PHP tags in your pages, add a call to strip_tags( ) to the code that loads the contents of the file for searching:

// load the contents of the file into $file
$file = strip_tags(join('',file($path)));

Example 19-5. site-search.php

function pc_search_dir($dir) { 
    global $body_regex,$title_regex,$seen;

    // array to hold pages that match
    $pages = array();

    // array to hold directories to recurse into
    $dirs = array();

    // mark this directory as seen so we don't look in it again
    $seen[realpath($dir)] = true;
    // if we can get a directory handle for this directory
    if (is_readable($dir) && ($d = dir($dir))) {
        // get each file name in the directory
        while (false !== ($f = $d->read())) {
            // build the full path of the file
            $path = $d->path.'/'.$f;
            // if it's a regular file and we can read it
            if (is_file($path) && is_readable($path)) {
                $realpath = realpath($path);
                // if we've seen this file already,
                if ($seen[$realpath]) {
                    // then skip it
                } else {
                    // otherwise, mark it as seen so we skip it
                    // if we come to it again
                    $seen[$realpath] = true;

                // load the contents of the file into $file
                $file = join('',file($path));

                // if the search term is inside the body delimiters
                if (preg_match($body_regex,$file)) {

                    // construct the relative URI of the file by removing
                    // the document root from the full path
                    $uri = substr_replace($path,'',0,strlen($_SERVER['DOCUMENT_ROOT']));

                    // If the page has a title, find it
                    if (preg_match('#<title>(.*?)</title>#Sis',$file,$match)) {
                        // and add the title and URI to $pages
                    } else {
                        // otherwise use the URI as the title
            } else {
                // if the directory entry is a valid subdirectory
                if (is_dir($path) && ('.' != $f) && ('..' != $f)) {
                    // add it to the list of directories to recurse into

    /* look through each file in each subdirectory of this one, and add
       the matching pages in those directories to $pages. only look in
       a subdirectory if we haven't seen it yet.
    foreach ($dirs as $subdir) {
        $realdir = realpath($subdir);
        if (! $seen[$realdir]) {
            $seen[$realdir] = true;
            $pages = array_merge($pages,pc_search_dir($subdir));

    return $pages;

// helper function to sort matched pages alphabetically by title
function pc_page_sort($a,$b) {
    if ($a[1] == $b[1]) {
        return strcmp($a[0],$b[0]);
    } else {
        return ($a[1] > $b[1]);

// array to hold the pages that match the search term
$matching_pages = array();
// array to hold pages seen while scanning for the search term
$seen = array();
// directories underneath the document root to search
$search_dirs = array('sports','movies','food');
// regular expression to use in searching files. The "S" pattern
// modifier tells the PCRE engine to "study" the regex for greater
// efficiency.
$body_regex = '#<body>(.*' . preg_quote($_REQUEST['term'],'#'). 

// add the files that match in each directory to $matching pages
foreach ($search_dirs as $dir) {
    $matching_pages = array_merge($matching_pages,

if (count($matching_pages)) {
    // sort the matching pages by title
    print '<ul>';
    // print out each title with a link to the page
    foreach ($matching_pages as $k => $v) {
        print sprintf('<li> <a href="%s">%s</a>',$v[0],$v[1]);
    print '</ul>';
} else {
    print 'No pages found.';

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