I do have configured a auto_prepend_file in my .htaccess. It works fine!
Now I wanted to know how to make a string globally without using GLOBALS.
I do have something like this:
define('WWW_URL', 'http://www.xyz.de');
define('STATIC_URL', 'http://static.xyz.de');
How do I get the WWW_URL or STATIC_URL in my index.php which is loaded right after the prepend and before append file?
Thanks in advance,
Daniel
Like superglobals, the scope of a constant is global. You can access constants anywhere in your script without regard to scope.
From php manual
So you can access the constants inside your index.php using WWW_URL / STATIC_URL.
Beware constants are read-only: you won't be able to change their value after you "define()" them, unlike GLOBALS variables.
Related
Is there anyway in php, by which we can define our own magic constants, which value could vary throughout the program and how to define variables with the SUPER GLOBAL SCOPE.
Just add the variable as an Apache environment variable:
SetEnv foo bar
You could set that in httpd.conf, apache2.conf, or .htaccess.PHP should then be able to access it via one or more of the following methods:
$_SERVER['foo']
$_ENV['foo']
getenv('foo')
While you can declare global variables, superglobals are limited to those found in PHP. You might want to keep your data as $_SESSION['mysuperglobal'], althou I suggest more elaborated patterns like a config-singleton, a registry or dependency injection.
You cannot define magic constant w/o building own flavour of PHP. But you can mimic this by putting all your "magic" define()s in separate file and including it in each of your script you can use auto_prepend_file config directive. Still, if you think you need something like this, the I'd try to rethink that approach. Whenever "magic" or "global" things comes to play, it's rather indication of need of refactoring.
I need to edit a variable (array) that is defined outside of the function, so I can use it in another function further in. The easiest way I can think of is to define it as global inside the function, but I have many required files involved as well.
The documentation of global variables says that it can be used "anywhere in the program." Does that imply throughout all files (is it global in a sense of across all files) or is it just the file it's in (locally global, if that makes sense).
I did find a question about globals on this site that suggests passing it by reference, but I have this function implemented extensively in other files and requiring them to have an additional variable in their calls would be obnoxious to say the least.
If you define your variable global within the function, you will be referring to the globally scoped variable, and changes to that variable made within your function will be visible to other functions that use that global variable, whatever files they're in, so long as the inclusion / execution order is correct.
If the file you declare the global in is in memory, then that variable is available for you to use. But, if you don't include or require the file the global is declared in on a certain page, it will not be available to you.
Order is also important. If you try to call the global variable before the include or require of the file you set it in, it will be unavailable.
Globals are shared among all files. By the way, instead of declaring them with global $variable;, you should use $GLOBALS['variable'] to make explicit that you're accessing a global variable.
If a lot of functions grouped in a file require access to some common state, chances are you need to turn them into a class. That's pretty much the definition of a class.
Or you could turn the array into a class and have functions call methods on it.
Perhaps a singleton or a registry (2) could help.
Note that most OOP implementations pass a reference to the object as a method's first parameter, hidden (C++, PHP) or not (C, Python).
In one PHP file, I have this code:
require_once $_SERVER['DOCUMENT_ROOT'] . '/custom/functions.php';
global $testVar;
var_dump($testVar);
In the functions.php file, I have this at the beginning, followed by a few other functions:
function pr($s) {
echo '<pre>', htmlspecialchars(print_r($s,true)), '</pre>';
}
$testVar = 'hello world';
When running the first file, the variable comes back as NULL. I added the global bit but it shouldn't be necessary. This is part of a Joomla module but I've never had problems including files before, it should just work like regular PHP. Why might this be happening?
First, try to use Joomla's path constants such as JPATH_BASE instead of $_SERVER['DOCUMENT_ROOT']. Joomla has a lot of useful constants, check it's documentation.
I've read your answer, and reading php documentation I tried to find a reason to why you need to use global keyword twice.
First, Variable scope.
The scope of a variable is the context within which it is defined. For the most
part all PHP variables only have a single scope.
(...)
However, within user-defined functions a local function scope is introduced.
Any variable used inside a function is by default limited to the local
function scope.
The variable isn't in a function scope, so that's why we thought the NULL was a strange behavior.
But then I read include and found something interesting:
(...)
Any variables available at that line in the calling file will be available
within the called file, from that point forward. However, all **functions**
and **classes** defined in the included file have the global scope.
I can't see any mention about the variables being global in this paragraph. So,it seens that, being cumbersome or not, your solution is the right thing to do when you want to use global variables like that.
In your situation, if doing this is cumbersome, I would create a simple class. If you have just helper functions in your file, create a class Util{} with a lot of methods and $testVar as an attribute.
I have found a solution that seems to work: using the global keyword both when setting the variable initially, and just before I need to use it.
(However this is quite cumbersome, and I'm still not sure why it happens, so if anyone has a better solution, feel free to post.)
I have a seperate PHP file I include that has a several important functions on it. I also have a file called variables.php which I include into each function so I can call some important variables too. Is there a way to just call variables.php at the top of the page, instead of inside each function manually? I just thought it would be easier if there was a way to do like a 'global' include or something.
You can set auto_prepend_file in the INI or .htaccess file to automatically include a file.
Well, if they are constant variables (AKA they don't change) you can define a constant instead
define("CONSTANT_NAME", "constant_value");
Or as of PHP5.3
const COSTANT_NAME="constant_value";
Then you can access them in every function
function test(){
echo CONSTANT_NAME;
}
Can someone explain the difference between using
define('SOMETHING', true);
and
$SOMETHING = true;
And maybe the benefits between one or the other?
I use variables everywhere and even in a config type file that is included to everypage I still use variables as I don't see why to use the define method.
DEFINE makes a constant, and constants are global and can be used anywhere. They also cannot be redefined, which variables can be.
I normally use DEFINE for Configs because no one can mess with it after the fact, and I can check it anywhere without global-ling, making for easier checks.
Once defined, a 'constant' cannot be changed at runtime, whereas an ordinary variable assignment can.
Constants are better for things like configuration directives which should not be changed during execution. Furthermore, code is easier to read (and maintain & handover) if values which are meant to be constant are explicitly made so.
There is also a difference in scope.
In the example given by the orignal poster, $SOMETHING will not be accessible within a function whereas define('SOMETHING', true) will be.
define() makes a read-only variable, compared to a standard variable that supports read and write operations.
A constant is very useful when you want access data from inside a function, check this
<?php
function data(){
define("app","hey you can see me from outside the function",false);
$tech = "xampp";
}
data();
echo $tech;
echo app;
?>
If you use a variable you are never going to get the inside value here is what i get
Notice: Undefined variable: tech in D:\xampp\htdocs\data\index.php on line 8
hey you can see me from outside the function