Here's a challenge. I want to change the screen saver on a mac mini, running OSX, from a browser anywhere in the world.

You may well ask why ... the screen of the mac mini is to be visible at Well House Manor where it will provide an information screen at the front door when it's not otherwise in use, and we want it to say things like "Sorry - no Vacancies" and "Welcome to the Chamber of Commerce"

Task achieved! Using PHP ... and Perl ... and Web2 technology. With a smattering of OSX!

Here's the control widget on our web page ... the page is in PHP and this particular widget is only displayed to staff members who are logged in - if you look at our Staff Resources Page you won't see it.

And the PHP that's run when you press the update button:


if ($_POST[door] == 12) { // Door Status changed
  $ds = $_POST[doorst];
  $fho = fopen("door.txt","w");
  fputs ($fho,stripslashes($ds)."\n");
  fclose ($fho); // Host and Port changed for security
  $done = file("http://zzz.wellho.net:8080/cgi-bin/dodo.pl?$ds");
  }

That piece of viewing software was called a controller on the Mac - which is running as a Web Server on a port enabled on our firewall, and redirected with NATS to the Mac Mini.

The Perl software dodo.pl looks like this:

#!/usr/bin/perl
print "content-type: text/html\n\n";
print "Changing Page";
`rm -rf /Users/lisaellis/FrontDoor`;
`cp -r /Users/lisaellis/$ENV{QUERY_STRING} /Users/lisaellis/FrontDoor`;
open (FH,"ps aux|");
while (<FH>) {
  if (/ScreenSaverEngine/) {
  @n = split;
  kill 9,$n[1];
  print "$n[1]<br>";
  }
}
sleep 1;
open (FH,'|/System/Library/Frameworks/ScreenSaver.framework/Versions'.
'/A/Resources/ScreenSaverEngine.app/Contents/MacOS/ScreenSaverEngine' );
close FH;
print "Changing Page";

And there's also a standalone version here if you want to download a copy for your own use.

You'll notice - typical use of PHP to front a web application, typical use of Perl as "glueware", and typical use of a Unix / Linux / OSX utility - in this case Mac's ScreenSaverEngine - to do the oddball job we needed.
(written 2008-05-06, updated 2008-05-07)

 A164 - Web Application Deployment - Services and Regular Jobs
  [3143] On time - (2011-01-23)
  [3011] What are .pid files? - (2010-10-23)
  [2182] What Linux run level am I in? - (2009-05-15)
  [2145] Using the internet to remotely check for power failure at home (PHP) - (2009-04-29)
  [1903] daemons - what is running on my Linux server? - (2008-11-23)
  [1765] Dialects of English and Unix - (2008-08-21)
  [1733] memcached - overview, installation, example of use in PHP - (2008-08-02)
  [1731] Apache httpd, MySQL, PHP - installation procedure - (2008-08-01)
  [1700] FTP server on Fedora Linux - (2008-07-06)
  [1553] Automatic startup and shutdown of Tomcat - (2008-02-24)
  [1288] Linux run states, shell special commands, and directory structures - (2007-08-03)
  [1028] Linux / Unix - process priority and nice - (2007-01-10)
  [907] Browser -> httpd -> Tomcat -> MySQL. Restarting. - (2006-10-28)
  [544] Repeating tasks with crontab - (2005-12-27)

H307 - PHP - Web2 and caching
  [3458] On this day ... one PHP script with three uses - (2011-09-26)
  [3186] How to add a customised twitter feed to your site - (2011-02-27)
  [3094] Setting your user_agent in PHP - telling back servers who you are - (2010-12-18)
  [3029] PHP data sources - other web servers, large data flows, and the client (browser) - (2010-11-04)
  [2545] Scraping content for your own page via PHP - (2009-12-21)
  [2321] Uploading and Downloading files - changing names (Perl and PHP) - (2009-08-04)
  [2196] New Example - cacheing results in PHP for faster loading - (2009-05-24)
  [1995] Automated server heartbeat and health check - (2009-01-16)
  [1926] Flash (client) to PHP (server) - example - (2008-12-06)
  [1814] Javascript/HTML example, dynamic server monitor - (2008-09-28)
  [1813] Ajax - going Asyncronous and what it means - (2008-09-28)
  [1812] Starting Ajax - easy example of browser calling up server data - (2008-09-27)
  [1647] Exchange Rates - PHP with your prices in your users currency - (2008-05-19)

P258 - Perl - Solaris, OSX and Linux
  [2834] Teaching examples in Perl - third and final part - (2010-06-27)
  [2022] Pre and post increment - the ++ operator - (2009-02-03)
  [1702] Running operating system commands in Perl - (2008-07-08)

Z402 - Melksham Chamber of Commerce and Industry
  [3598] Melksham Civic Awards - report and pictures - (2012-01-29)
  [3560] Melksham, Month by month through 2011 - (2011-12-23)
  [3527] Melksham - changing times, an opportunity for the future - (2011-11-23)
  [3496] Melksham - Business to Business Speed Networking - build ahead for 2012 - (2011-10-26)
  [3495] Looking forward - Chamber of Commerce has 2012 and beyond on the agenda - (2011-10-26)
  [3492] Upcoming events in and about Melksham - more dates for your diary - (2011-10-22)
  [3481] Some thoughts in answer to some Melksham Campus questions - (2011-10-14)
  [3475] Havant - Shop Frontages. - (2011-10-12)
  [3470] Currently pictured in Melksham - (2011-10-09)
  [3438] Melksham to become a part of Trowbridge? - (2011-09-13)
  [3427] What is on the Melksham Agenda? - (2011-09-09)
  [3423] 1 + 1 + 1 + 1 = 12? - (2011-09-07)
  [3420] Making best use of the new enthusiasm for Melksham - (2011-09-05)
  [3383] Are people who walk into Melksham being asked to subsidise parking? - (2011-08-09)
  [3380] Melksham Jelly - An Occasional Office for Home Workers - (2011-08-06)
  [3343] Summer Sunday Train Service Starts - Swindon Chippenham and Melksham to Weymouth - (2011-07-03)
  [3340] Summer Sunday Timetable - TransWilts Trains - (2011-06-30)
  [3334] A lesson from the sporran market? - (2011-06-25)
  [3325] The Olympic Torch, and Melksham House - (2011-06-14)
  [3307] Melksham Community Radio launches - (2011-05-28)
  [3299] Presidents Report to Melksham Chamber of Commerce, 24.5.2011 - (2011-05-24)
  [3279] Letter to The Editor - (2011-05-06)
  [3275] Melksham Chamber of Commerce - grows to appoint new Press Officer. Welcome. Sam - (2011-05-02)
  [3272] Melksham Car Parking - current charges and limits - (2011-05-01)
  [3249] Events - Spring and Early Summer 2011 in Melksham - (2011-04-17)
  [3246] Melksham - the way forward. 26th April, Well House Manor - (2011-04-13)
  [3217] Vandalism and riot from the minority - the effect - (2011-03-28)
  [3214] Melksham Campus - any last minute inputs from Melksham businesses? - (2011-03-26)
  [3193] Melksham Campus - what, why, questions, concerns and how you can input - (2011-03-04)
  [3188] What proportion of the British Workforce still works a Monday to Friday, 9 to 5, week? - (2011-03-01)
  [3173] What is the Melksham Chamber of Commerce? - (2011-02-18)
  [3172] On consultations, car parking, and Melksham town centre - (2011-02-17)
  [3162] Keep your business customer-friendly! - (2011-02-09)
  [3141] Wiltshire Rail services - a golden opportunity - (2011-01-21)
  [3117] Opportunities for Melksham - new businesses in the town - (2011-01-01)
  [3113] Trowbridge and Melksham to Chippenham - more roadworks, even slower journey over the winter - (2010-12-30)
  [3088] Melksham - two many councils? - (2010-12-16)
  [2995] A river in Melksham is not just for boaters. - (2010-10-11)
  [2982] Travel, Transport and Tourism - A vision for Melksham, 2026 - (2010-10-03)
  [2959] A Melksham news roundup - (2010-09-18)
  [2957] Welcome to Countrywides new Melksham store - (2010-09-15)
  [2932] Getting into and out of Wiltshire towns .. a.k.a. Car Parking? - (2010-08-23)
  [2891] Wiltshire Council ask how they can help businesses - (2010-07-27)
  [2883] Melksham Oak - photos of the new community school - (2010-07-22)
  [2872] Moved - Melksham Lorry Park - (2010-07-15)
  [2867] Cycling in Melksham, and looking forward - (2010-07-11)
  [2853] Transport in Wessex - today and into the future - (2010-07-04)
  [2837] Lorry Parking in Melksham - (2010-06-29)
  [2827] Melksham - a gem in Wiltshire - (2010-06-26)
  [2782] Tell the Melksham Chamber or you only have yourself to blame - (2010-05-26)
  [2779] The history and future of Melksham Chamber of Commerce - (2010-05-25)
  [2770] Melksham Chamber of Commerce - Presidents report to AGM - (2010-05-19)
  [2725] How do our tactics help us meet the strategy, for the greater good? - (2010-04-16)
  [2683] Car Parking in Melksham - (2010-03-18)
  [2666] Random thoughts on Melksham Town Planning and development - (2010-03-08)
  [2640] How is your tax pound spent? - (2010-02-18)
  [2594] Melksham Area - your community view is sought - (2010-01-23)
  [2568] Forums for your Melksham and open source discussions - (2010-01-09)
  [2546] How well do you know Melksham - a quiz for Christmas - (2009-12-21)
  [2544] Vision for Wiltshire - (2009-12-20)
  [2540] Rock and hard place .. and the relaxing right one won - (2009-12-18)
  [2531] Melksham - new Tuesday Market - (2009-12-09)
  [2521] Melksham Market - Tuesdays, 09:00 to 14:00 - (2009-12-01)
  [2514] The road show has been - where now? - (2009-11-27)
  [2508] Community Area Partnership - inaugural AGM - (2009-11-20)
  [2495] Planning the future of Wiltshire - (2009-11-07)
  [2487] Melksham Forum - (2009-11-01)
  [2465] Melksham Town - asleep or awake? - (2009-10-21)
  [2459] New Web Site for Melksham Chamber of Commerce - (2009-10-18)
  [2437] Wiltshire Unitary News - Chamber of Commerce Intelligence - (2009-10-04)
  [2328] Melksham - no trains, no southbound buses through the town - (2009-08-08)
  [2289] pre-Inaugural briefing - Melksham Community Area Partnership - (2009-07-15)
  [2288] Wiltshire Community Area Partnerships - (2009-07-15)
  [2260] Important - the future of Melksham / Chamber of Commerce - (2009-06-28)
  [2220] Melksham Traders - where do we go? - (2009-06-05)
  [2194] Melksham Business Map - Chamber of Commerce, Tourist Information and Town Council - (2009-05-21)
  [2181] You cannot please all of the people all of the time - (2009-05-14)
  [2119] Make your business a DESTINATION business - (2009-04-05)
  [2111] Business Networking for Melksham - 23rd April - (2009-04-01)
  [2095] Blue Ridge and Melksham Chambers of Commerce - (2009-03-21)
  [2043] Confidence, Customer Service and Tourism in Melksham - (2009-02-15)
  [1987] One Cheer for Local Democracy - Asda in Melksham - (2009-01-11)
  [1979] Looking forward, in Melksham, in 2009 - (2009-01-05)
  [1934] Lidl opens in Melksham - (2008-12-11)
  [1904] Ruby, Perl, Linux, MySQL - some training notes - (2008-11-23)
  [1892] Melksham Chamber of Commerce and Industry - (2008-11-17)
  [1881] Wiltshire Council says - part 1 - (2008-11-13)
  [1880] Melksham Chamber of Commerce, or the FSB - (2008-11-12)
  [1792] All the pieces fall into place - hotel and courses - (2008-09-10)
  [1748] Hotel room prices - Melksham, Wiltshire - (2008-08-11)
  [1642] Summer! - (2008-05-15)
  [1507] Comments on proposed Asda Superstore for Melksham - (2008-01-14)
  [1504] Flooding by Asda-s proposed new supermarket - (2008-01-12)
  [1476] Shopping for Christmas and looking forward - (2007-12-17)
  [1432] Wiltshire County Council - Budget Consultation - (2007-11-15)
  [1429] Remembrance day - inside a church and inside the day - (2007-11-11)
  [1250] Business speed networking - a place tonight! - (2007-06-28)
  [1223] Asda opening large new store in Melksham - (2007-06-08)
  [717] A customer service company - (2006-05-11)

Back to Lua - a powerful, up and coming scripting language

Previous and next or Horse's mouth home

Forward to Kiss and Book

Providing exceptional service - and carrying on doing so.
What to do if the Home Page is missing
Spring in Devizes
Kiss and Book
Changing a screen saver from a web page (PHP, Perl, OSX)
Lua - a powerful, up and coming scripting language
Looking back through some photos
To provide external links, or not?
A short introduction to our courses
Gant charts - drawing them with a PHP script