On my pages i usually do a big if/else/switch to decide which function to call PHP: if ($_GET['action'] == 'whatever') doThis(); else if ($_GET['action'] == 'bob') doThis2(); Is it possible to do sumthing like this: $action['whatever'] = doThis(); $action['bob'] = doThis2(); Then how would I call the appropiate function to be called depending on the value of $_GET['action']? Is it possible? Is there another way to do what I want with less/tidy/efficient code? Thx
Ok i found a way, however if $_GET['action'] isnt set or is set to a value that is not in the array then i recieve an error. How could I get around this? Again this may not be the best way to do it so if anyone has another method, please share. PHP: function login() { } function logout() { } function registrationForm() { } $_action['login'] = 'login'; $_action['logout'] = 'logout'; $_action['register'] = 'registrationForm'; call_user_func($_action[$_GET['action']]); Thx
1st method. Only thing that changes is the last if statement. PHP: if(isset($_GET['action'])){ $action = $_GET['action']; } if($action == "whatever"){ DoThisFunction(); } elseif($action == "me"){ ExecuteMe(); } 2nd method PHP: if($action){ DoThisFunction($action); }
If you've got a large block of if/else statements with fixed values to compare to, always go with a switch statement for efficiency. Its faster since PHP doesn't need to evaluate evaluate every conditional once a statement returns true. For further efficiency, put the most commonly executed cases at the top so it has fewer lines of code to run through in most executions. Code: <?php switch ($_GET['action']) { case 'login': login(); break; case 'logout': logout(); break; default: echo 'Hello new user'; } ?> default is the fallback block used when no case matches. /edit - Also, when using isset() as Beansprout mentioned, opt for a ternary operator for more concise code: Code: $action = isset($_GET['action']) ? $_GET['action'] : null; Neater than an if/else. Though I'd use an !empty() instead of isset() as you only really want to act on valid values for $_GET['action'].
Augmented's example is much preferred, however this is a sneaky chance to introduce function_exists Code: <?php if ((isset($_GET['action'])) && (function_exists($_GET['action']))) { call_user_func($_GET['action']); } else { DefaultFunction(); } ?> EDIT: On the note of concise.. you can use variable functions and void the need to use call_user_func() at all: http://us2.php.net/manual/en/functions.variable-functions.php Code: <?php @$_GET['action'](); ?> but that is just .. meh, as far as good practice goes
But then what happens if I request /foo.php?action=bulkEmail() or similar? Though good app design would prevent that, I'd filter it through an array of predefined actions with in_array() or a switch. Augmented - hehheh depends if he'll ever use 0 though, so I reckoned isset() was better to show him generally (the notes on the PHP page are great)
It was a quick example to introduce function_exists(), that is all. I'm lazy and cba to type out a filter when I've already said Augmented's switch() example is better.
I guess I'm just anti-lazy this morning Probably something to do with waking up 2hrs before I was supposed to. Grr.
Ill have a look at the in_array() and isset() stuff. Id know i could do it with if/else/switches but I find the code quite ugly and hard to organise etc, which is why I thought the array idea would be good. --- The following method seems to work, can anyone spot a time where it will fail? PHP: $_action = array ( '' => 'login', 'login' => 'login', 'logout' => 'logout', 'register' => 'registerForm' ); if (array_key_exists($_GET['action'], $_action)) call_user_func($_action[$_GET['action']]); else header("Location: index.php"); Thx
Should work. However, there is a specific design pattern laid out for what you want to do, namely the Front Controller - which is a part of the big daddy of design patterns the Model View Controller. Have a read for more ideas on how to implement it (the code you have there is fine, but there are always other ways): http://www.phpwact.org/pattern/front_controller http://www.phppatterns.com/docs/design/the_front_controller_and_php
Good reading there. The second link in turn links to this post which I think gives a very good explanation
