<?php
// "Expiry Checker"
// A script to automatically remind FaCES web page owners...
// ...when their web pages are older than their expiry dates.
// author = Martin Bush, South Bank University
// date = 7th August 2002
// filename = expirychecker.php3
// version = first prototype
// history = -
// Comments in quotations are inherited from the pseudocode
// "read Expiry Checker information (url&expiry&owner&message)"
// "parse the information using the parse_str function"
parse_str($QUERY_STRING); // defines $url, $expiry, $owner, $message
// "if (expiry_date <= today's date) then"
$today = date ("d/m/y")
if ( $today <= $expiry ) {
// "lock file reminders_sent_today.txt" -- abbreviate to "reminders"
$reminders_file = "reminders_sent_today.txt"; //file is assumed to exist
// need to open reminders file first -- "r+" means for reading and writing
$reminders_file_pointer = fopen($reminders_file, "r+");
// now lock reminders file to ensure mutually exclusive access
$lock = flock($reminders_file_pointer, 2); // "2" for exclusive writing lock
// continue when lock is obtained
if ($lock) {
// "read date_of_file from file" -- assumed to be present and valid
$date_of_file = fgets($reminders_file_pointer, 8); // reads up to 8 chars
// "if (date_of_file < today's date) then"
if ( $date_of_file < $today ) {
// "rewind file"
rewind($reminders_file_pointer);
// "write today's date to file"
fwrite($reminders_file_pointer, "$today\n");
} // "endif"
// "search file for url of web page" -- stored in alphabetical order
$found = 0;
// get next entry if there is one
if (!feof($reminders_file_pointer)) {
$next_entry = fgets($reminders_file_pointer, 256);
// "url" in web page corresponds to "filed_url" in reminders file...
// ...and likewise for "expiry", "owner" and "message"
parse_str($next_entry); // defines $filed_url, filed_expiry, etc.
// while loop stops if it goes past the point where $url should be
while (!feof($reminders_file_pointer) & (($filed_url <= $url)
& ($found == 0))) {
if ($filed_url == $url) {
$found = 1;
} else {
// accumulate entries read so far, and get next entry
$file_contents_so_far = $file_contents_so_far.$next_entry;
$next_entry = fgets($reminders_file_pointer, 256);
}
}
}
// "if (URL not found in file) then"
if ($found == 0) {
// "write URL to file"
// must carry on reading contents first
$file_contents_remainder = fread($reminders_file_pointer,
filesize($reminders_file));
// now rewind the file
rewind($reminders_file_pointer);
// write accumulate entries up to point of insertion
fwrite($reminders_file_pointer, "$file_contents_so_far\n");
// prepare new reminder entry
$new_reminder = "filed-url=".$url."&filed-expiry=".$expiry.
"&filed-owner=".$owner."&filed-message=".$message;
// insert new reminder entry
fwrite($reminders_file_pointer, "$new_reminder\n");
// write remainder
fwrite($reminders_file_pointer, "$file_contents_remainder");
// "email URL and message to owner"
$mail_message = "This message has been sent automatically,
\nto remind you that the contents of this FaCES web page...
\n @url
\nnow needs your attention.
\n\nHere is the message that accompanied your email address...
\n @message";
mail($owner, "Expiry Checker: FaCES web page needs your attention.",
$mail_message)
} // "endif"
} // endif ($lock)
// "unlock file reminders_sent_today.txt"
$lock = flock($respondees_file_pointer, 3); // "3" means unlock
// need to close respondees file
fclose($respondees_file_pointer);
} // "endif" ( $today <= $expiry )
?>
|