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Training, Open Source Programming Languages This is page http://www.wellho.net/mouth/2682_Add ... backs.html Our email: info@wellho.net • Phone: 01144 1225 708225 |
| For 2023 (and 2024 ...) - we are now fully retired from IT training. We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk. Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active! I am also active in many other area and still look after a lot of web sites - you can find an index ((here)) |
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Adding extensions to PHP Open Source applications - callbacks
Over the last two days, I've installed and configured MediaWiki, WordPress, Status.net and Drupal on one of our training systems, and looked (in each case) at how to configure them and install extra plugins / modules - both standardly available ones, and also how to start writing your own. In two days we've only been able to scratch the surface of these huge topic, but the question arose "How do the standard packages see / register call the add ons". Details vary, but much of it is done through the use of callbacks. So - how do callbacks work? The base code of each of these open source applications includes arrays which contain the names of all the functions that might be called - as strings. And other strings can be dynamically added to the list too. When the code if run, these extra routines will be called at predetermined places in the source, thus running that extra code; a check with function_exists ensures that the application doesn't fall over by trying to run code that's not available. There's a demonstration [here] which shows you the mechanism. I was very impressed by the extensive documentation in MediaWiki for its extension hooks - see [here] - perhaps this is the open source application that I'm most familiar with tailoring, although we also use the SMF forum in many guises ;-) (written 2010-03-17, updated 2010-03-25) Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles H401 - Some extra PHP modules[732] Where is a web site visitor browsing from - (2006-05-24) [2343] World Flags in your PHP pages - (2009-08-10) [3453] Reading and using emails including enclosures on your web server. - (2011-09-23) [3454] Your PHP website - how to factor and refactor to reduce growing pains - (2011-09-24) H400 - Open Source Applications in PHP H105 - PHP - Functions [96] Variable Scope - (2004-10-22) [223] There is a function in PHP to do that - (2005-02-21) [308] Call by name v call by value - (2005-05-11) [339] Passing information into and out of PHP functions - (2005-06-07) [340] Code and code maintainance efficiency - (2005-06-08) [409] Functions and commands with dangerous names - (2005-08-11) [421] Don't repeat code - use loops or functions - (2005-08-21) [775] Do not duplicate your code - (2006-06-23) [866] A lazy programmer is a good programmer - (2006-09-15) [936] Global, Superglobal, Session variables - scope and persistance in PHP - (2006-11-21) [1021] PHP - static declaration - (2007-01-04) [1163] A better alternative to cutting and pasting code - (2007-04-26) [1202] Returning multiple values from a function (Perl, PHP, Python) - (2007-05-24) [1267] is there a lookup function in php? - (2007-07-15) [1357] Clean my plate, but keep my wine bottle. (PHP; Static) - (2007-09-18) [1380] Static variables in PHP - (2007-10-05) [1784] Global - Tcl, PHP, Python - (2008-09-03) [2488] A variable number of arguments in a PHP function - (2009-11-02) [2630] Static variables and ampersands in PHP - (2010-02-10) [2737] Improving your function calls (APIs) - General and PHP - (2010-04-24) [2929] Passing a variable number of parameters in to a function / method - (2010-08-20) [3026] Coding efficiency - do not repeat yourself! - (2010-11-02)
Some other Articles
Freedom of Information - consideration for web site designersStairs Exception handling in PHP Car Parking in Melksham Adding extensions to PHP Open Source applications - callbacks Tcl - a great engineering language Static class members in PHP - a documented example How to build a test harness into your PHP Reaching out to the community - a good case for support Blowing out the winter cobwebs |
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Link to page ... 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96 at 50 posts per pageThis is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.
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