i have alias to include() in my functions.php file:
function render_template($template)
{
include($template);
}
and simple template.html :
Hello, <?php echo $name ?>
But unfortunately, alias function gave me this output:
require 'functions.php';
$name = "world";
include('template.html'); // Hello, world
render_template('template.html'); // PHP Notice:Undefined variable: name
why is that? and how i can fix this?
thanks.
You have two more options to make it work around the scope issue. (Using global would require localising a long list of vars. Also it's not actually clear if your $name resides in the global scope anyway and always.)
First you could just turn your render_template() function into a name-resolver:
function template($t) {
return $t; // maybe add a directory later on
}
Using it like this:
$name = "world";
include(template('template.html'));
Which is nicer to read and has obvious syntactical meaning.
The more quirky alternative is capturing the local variables for render_template:
$name = "world";
render_template('template.html', get_defined_vars());
Where render_template would require this addition:
function render_template($template, $vars)
{
extract($vars); // in lieu of global $var1,$var2,$var3,...
include($template);
}
So that's more cumbersome than using a name-resolver.
The variable $name is not visible at the point where include is called (inside function render_template). One way to fix it would be:
function render_template($template)
{
global $name;
include($template);
}
Its a Scope Problem, you can set the variable to global, or encapsulate the whole thing a little bit more, for example like that:
class view{
private $_data;
public function __construct(){
$this->_data = new stdClass();
}
public function __get($name){
return $this->_data->{$name};
}
public function __set($name,$value){
$this->_data->{$name} = $value;
}
public function render($template){
$data = $this->_data;
include($template);
}
}
$view = new view;
$view->name = "world";
$view->render('template.html');
template.html :
Hello <?php print $data->name; ?>
If $name is in the global scope then you can get around it by declaring the variable global with the function. But a better solution would be to re-architect the code to require passing the relevant variable value into the function.
This is expected.
Look here.
You would be interested in the following quote, "If the include occurs inside a function within the calling file, then all of the code contained in the called file will behave as though it had been defined inside that function. So, it will follow the variable scope of that function. An exception to this rule are magic constants which are evaluated by the parser before the include occurs".
Related
I'm writing now an app, which is supposed to be as simple as possible. My controllers implement the render($Layout) method which just does the following:
public function render($Layout) {
$this->Layout = $Layout;
include( ... .php)
}
I don't really understand the following problem: in my controller, I define a variable:
public function somethingAction() {
$someVariable = "something";
$this->render('someLayout');
}
in the php view file (same I have included in the render function) I try to echo the variable, but there is nothing. However, if I declare my action method like this:
public function somethingAction() {
global $someVariable;
$someVariable = "something";
$this->render('someLayout');
}
and in my view like this:
global $someVariable;
echo $someVariable;
it does work. Still it is annoying to write the word global each time.
How can I do this? I'd rather not use the $_GLOBAL arrays. In Cake PHP, for example, there is a method like $this->set('varName', $value). Then I can just access the variable in the view as $varName. How is it done?
From the PHP Manual on include:
When a file is included, the code it contains inherits the variable scope of the line on which the include occurs. 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.
When you do
public function somethingAction() {
$someVariable = "something";
$this->render('someLayout');
}
the $someVariable variable is limited to the somethingAction() scope. Calling your render() method will not magically make the variable available in render(), because the render() method has it's own variable scope. A possible solution would be to do
public function somethingAction() {
$this->render(
'someLayout',
array(
'someVariable' => 'something'
)
);
}
and then change render() to
public function render($Layout, array $viewData) {
$this->Layout = $Layout;
include( ... .php)
}
You will then have access to $viewData in the included file, given that you are not trying to use it in some other function or method, e.g. if your included file looks like this:
<h1><?php echo $viewData['someVariable']; ?></h1>
it will work, but if it is looks like this:
function foo() {
return $viewData['someVariable'];
}
echo foo();
it will not work, because foo() has it's own variable scope.
However, a controller's sole responsibility is to handle input. Rendering is the responsibility of the View. Thus, your controller should not have a render() method at all. Consider moving the method to your View class and then do
public function somethingAction() {
$view = new View('someLayout');
$view->setData('someVariable', 'something');
$view->render();
}
The render() method of your View object could then be implemented like this:
class View
…
$private $viewData = array();
public function setData($key, $value)
{
$this->viewData[$key] = $data;
}
public function render()
{
extract($this->viewData, EXTR_SKIP);
include sprintf('/path/to/layouts/%s.php', $this->layout);
}
The extract function will import the values of an array in the current scope using their keys as the name. This will allow you to use data in the viewData as $someVariable instead of $this->viewData['someVariable']. Make sure you understand the security implications of extract before using it though.
Note that this is just one possible alternative to your current way of doing things. You could also move out the View completely from the controller.
Using global you're implicitly using the $_GLOBALS array.
A not recommended example, because globals are never a good thing:
function something() {
global $var;
$var = 'data';
}
// now these lines are the same result:
echo $_GLOBALS['var'];
global $var; echo $var;
Why don't you use simply the $this->set function?
public function render($Layout) {
$this->Layout = $Layout;
include( ... .php)
}
public function somethingAction() {
$this->set('someVariable', "something");
$this->render('someLayout');
}
// in a framework's managed view:
echo $someVariable;
I'm sorry not to know your framework in detail, but that makes perfectly sense.
Actually how it's done: There is a native extract function, that loads an associative array into the current symbol table:
array( 'var0' => 'val0', 'var1' => 'val1')
becomes
echo $var0; // val0
echo $var1; // val1
That's most likely 'what happens'.
I am trying to build a php class that will let me include other php "template" files to display. I want all of the variables that are in the scope that it is called from to be available in the included file. Here's the catch, I want to pass off the actual including to a helper method to keep the code DRY. Here is what I have so far:
/* TemplateLoader.php */
class TemplateLoader {
public function foo() {
$var = "FOO!";
//Works
include 'template.php';
}
public function bar() {
$var = "BAR!";
//Doesn't work
$this->render("template");
}
private function render( $name ) {
include $name . '.php';
}
}
/* template.php */
<?php echo $var; ?>
My question is: How can I accomplish the behaviour of including the template directly in the original method while still using helper method to actually do the "heavy lifting"? I would really appreciate any help you can give!
This is what first came to my mind - I'm not sure I like it too much, but I'm not sure of a generic alternative. This captures all of the current variables with get_defined_vars(), and passes them to render(), where they are they extract()ed, and thus accessible by the included file.
You could probably filter the return from get_defined_vars() before you pass it to render(), but I should work.
public function bar() {
$var = "BAR!";
$this->render("template", get_defined_vars());
}
private function render( $name, &$vars) {
extract( $vars);
include $name . '.php';
}
You could probably filter the return from get_defined_vars() before you pass it to render(), but it should work.
I have a template class which goes like this:
class Template{
public $pageTitle = "";
public function __construct($pageTitle){
$this->pageTitle = $pageTitle;
}
public function display(){
include "/includes/head.php";
include "/includes/body.php";
}
}
Now, I'm used to Java's workings but I don't understand why I'm getting an undefined variable ($pageTitle) error. The included files need to be able to access that variable. I know it's going to be very simple but I actually haven't found out why.
What do I need to do to allow includes to see this variable?
The includes will also have to use $this->pageTitle. Effectively, the include makes them part of the method body.
The included file lives in the same scope as your object. So you need to call:
$this->pageTitle
If you don't want to do the whole $this->, you can do something like the following... The extract function will extract the array $this->data into variables with names respective to the key/index of each item. So now you will be able to do echo $pageTitle;
class Template{
public $data = Array();
public function __construct($pageTitle){
$this->data['pageTitle'] = $pageTitle;
}
public function display(){
extract($this->data);
include "/includes/head.php";
include "/includes/body.php";
}
}
Scope is a little different in PHP than in java.
For your specific case you need
$this->pageTitle
To access a variable declared outside the class, you'll need to make it global
global $myVar;
In PHP, how do you use an external $var for use within a function in a class? For example, say $some_external_var sets to true and you have something like
class myclass {
bla ....
bla ....
function myfunction() {
if (isset($some_external_var)) do something ...
}
}
$some_external_var =true;
$obj = new myclass();
$obj->myfunction();
Thanks
You'll need to use the global keyword inside your function, to make your external variable visible to that function.
For instance :
$my_var_2 = 'glop';
function test_2()
{
global $my_var_2;
var_dump($my_var_2); // string 'glop' (length=4)
}
test_2();
You could also use the $GLOBALS array, which is always visible, even inside functions.
But it is generally not considered a good practice to use global variables: your classes should not depend on some kind of external stuff that might or might not be there !
A better way would be to pass the variables you need as parameters, either to the methods themselves, or to the constructor of the class...
Global $some_external_var;
function myfunction() {
Global $some_external_var;
if (!empty($some_external_var)) do something ...
}
}
But because Global automatically sets it, check if it isn't empty.
that's bad software design. In order for a class to function, it needs to be provided with data. So, pass that external var into your class, otherwise you're creating unnecessary dependencies.
Why don't you just pass this variable during __construct() and make what the object does during construction conditional on the truth value of that variable?
Use Setters and Getters or maybe a centralized config like:
function config()
{
static $data;
if(!isset($data))
{
$data = new stdClass();
}
return $data;
}
class myClass
{
public function myFunction()
{
echo "config()->myConfigVar: " . config()->myConfigVar;
}
}
and the use it:
config()->myConfigVar = "Hello world";
$myClass = new myClass();
$myClass->myFunction();
http://www.evanbot.com/article/universally-accessible-data-php/24
is there a way to create my own custom superglobal variables like $_POST and $_GET?
Static class variables can be referenced globally, e.g.:
class myGlobals {
static $myVariable;
}
function a() {
print myGlobals::$myVariable;
}
Yes, it is possible, but not with the so-called "core" PHP functionalities. You have to install an extension called runkit7:
Installation
After that, you can set your custom superglobals in php.ini as documented here:
ini.runkit.superglobal
I think you already have it - every variable you create in global space can be accessed using the $GLOBALS superglobal like this:
// in global space
$myVar = "hello";
// inside a function
function foo() {
echo $GLOBALS['myVar'];
}
Class Registry {
private $vars = array();
public function __set($index, $value){$this->vars[$index] = $value;}
public function __get($index){return $this->vars[$index];}
}
$registry = new Registry;
function _REGISTRY(){
global $registry;
return $registry;
}
_REGISTRY()->sampleArray=array(1,2,'red','white');
//_REGISTRY()->someOtherClassName = new className;
//_REGISTRY()->someOtherClassName->dosomething();
class sampleClass {
public function sampleMethod(){
print_r(_REGISTRY()->sampleArray); echo '<br/>';
_REGISTRY()->sampleVar='value';
echo _REGISTRY()->sampleVar.'<br/>';
}
}
$whatever = new sampleClass;
$whatever->sampleMethod();
One other way to get around this issue is to use a static class method or variable.
For example:
class myGlobals {
public static $myVariable;
}
Then, in your functions you can simply refer to your global variable like this:
function Test()
{
echo myGlobals::$myVariable;
}
Not as clean as some other languages, but at least you don't have to keep declaring it global all the time.
No
There are only built-in superglobals listed in this manual
Not really. though you can just abuse the ones that are there if you don't mind the ugliness of it.
You can also use the Environment variables of the server, and access these in PHP
This is a good way to maybe store global database access if you own and exclusively use the server.
possible workaround with $GLOBALS:
file.php:
$GLOBALS['xyz'] = "hello";
any_included_file.php:
echo $GLOBALS['xyz'];
One solution is to create your superglobal variable in a separate php file and then auto load that file with every php call using the auto_prepend_file directive.
something like this should work after restarting your php server (your ini file location might be different):
/usr/local/etc/php/conf.d/load-my-custom-superglobals.ini
auto_prepend_file=/var/www/html/superglobals.php
/var/www/html/superglobals.php
<?php
$_GLOBALS['_MY_SUPER_GLOBAL'] = 'example';
/var/www/html/index.php
<?php
echo $_MY_SUPER_GLOBAL;
Actually, there is no direct way to define your own superglobal variables; But it's a trick that I always do to access simpler to my useful variables!
class _ {
public static $VAR1;
public static $VAR2;
public static $VAR3;
}
Then I want to use:
function Test() {
echo \_::$VAR2;
}
Notice: Don't forget to use \ before, If you want to use it everywhere you have a namespace too...
Enjoy...