dirty code sample:
print_r(compact(array_keys(get_defined_vars())));
(PHP 4 >= 4.0.4, PHP 5, PHP 7)
get_defined_vars — Returns an array of all defined variables
This function returns a multidimensional array containing a list of all defined variables, be them environment, server or user-defined variables, within the scope that get_defined_vars() is called.
A multidimensional array with all the variables.
Example #1 get_defined_vars() Example
<?php
$b = array(1, 1, 2, 3, 5, 8);
$arr = get_defined_vars();
// print $b
print_r($arr["b"]);
/* print path to the PHP interpreter (if used as a CGI)
* e.g. /usr/local/bin/php */
echo $arr["_"];
// print the command-line parameters if any
print_r($arr["argv"]);
// print all the server vars
print_r($arr["_SERVER"]);
// print all the available keys for the arrays of variables
print_r(array_keys(get_defined_vars()));
?>
dirty code sample:
print_r(compact(array_keys(get_defined_vars())));
A little gotcha to watch out for:
If you turn off RegisterGlobals and related, then use get_defined_vars(), you may see something like the following:
<?php
Array
(
[GLOBALS] => Array
(
[GLOBALS] => Array
*RECURSION*
[_POST] => Array()
[_GET] => Array()
[_COOKIE] => Array()
[_FILES] => Array()
)
[_POST] => Array()
[_GET] => Array()
[_COOKIE] => Array()
[_FILES] => Array()
)
?>
Notice that $_SERVER isn't there. It seems that php only loads the superglobal $_SERVER if it is used somewhere. You could do this:
<?php
print '<pre>' . htmlspecialchars(print_r(get_defined_vars(), true)) . '</pre>';
print '<pre>' . htmlspecialchars(print_r($_SERVER, true)) . '</pre>';
?>
And then $_SERVER will appear in both lists. I guess it's not really a gotcha, because nothing bad will happen either way, but it's an interesting curiosity nonetheless.
Reference variables are returned by reference (tested on PHP 5.5.11):
<?php
$a = null;
$b = &$a;
get_defined_vars()['b'] = 4;
var_dump($b); // int(4)
?>
Since get_defined_vars() only gets the variables at the point you call the function, there is a simple way to get the variables defined within the current scope.
<?php
// The very top of your php script
$vars = get_defined_vars();
// Now do your stuff
$foo = 'foo';
$bar = 'bar';
// Get all the variables defined in current scope
$vars = array_diff(get_defined_vars(),$vars);
echo '<pre>';
print_r($vars);
echo '</pre>';
?>
Here is a function which generates a debug report for display or email
using get_defined_vars. Great for getting a detailed snapshot without
relying on user input.
<?php
function generateDebugReport($method,$defined_vars,$email="undefined"){
// Function to create a debug report to display or email.
// Usage: generateDebugReport(method,get_defined_vars(),email[optional]);
// Where method is "browser" or "email".
// Create an ignore list for keys returned by 'get_defined_vars'.
// For example, HTTP_POST_VARS, HTTP_GET_VARS and others are
// redundant (same as _POST, _GET)
// Also include vars you want ignored for security reasons - i.e. PHPSESSID.
$ignorelist=array("HTTP_POST_VARS","HTTP_GET_VARS",
"HTTP_COOKIE_VARS","HTTP_SERVER_VARS",
"HTTP_ENV_VARS","HTTP_SESSION_VARS",
"_ENV","PHPSESSID","SESS_DBUSER",
"SESS_DBPASS","HTTP_COOKIE");
$timestamp=date("m/d/y h:m:s");
$message="Debug report created $timestamp\n";
// Get the last SQL error for good measure, where $link is the resource identifier
// for mysql_connect. Comment out or modify for your database or abstraction setup.
global $link;
$sql_error=mysql_error($link);
if($sql_error){
$message.="\nMysql Messages:\n".mysql_error($link);
}
// End MySQL
// Could use a recursive function here. You get the idea ;-)
foreach($defined_vars as $key=>$val){
if(is_array($val) && !in_array($key,$ignorelist) && count($val) > 0){
$message.="\n$key array (key=value):\n";
foreach($val as $subkey=>$subval){
if(!in_array($subkey,$ignorelist) && !is_array($subval)){
$message.=$subkey." = ".$subval."\n";
}
elseif(!in_array($subkey,$ignorelist) && is_array($subval)){
foreach($subval as $subsubkey=>$subsubval){
if(!in_array($subsubkey,$ignorelist)){
$message.=$subsubkey." = ".$subsubval."\n";
}
}
}
}
}
elseif(!is_array($val) && !in_array($key,$ignorelist) && $val){
$message.="\nVariable ".$key." = ".$val."\n";
}
}
if($method=="browser"){
echo nl2br($message);
}
elseif($method=="email"){
if($email=="undefined"){
$email=$_SERVER["SERVER_ADMIN"];
}
$mresult=mail($email,"Debug Report for ".$_ENV["HOSTNAME"]."",$message);
if($mresult==1){
echo "Debug Report sent successfully.\n";
}
else{
echo "Failed to send Debug Report.\n";
}
}
}
?>
Simple routine to convert a get_defined_vars object to XML.
<?php
function obj2xml($v, $indent='') {
while (list($key, $val) = each($v)) {
if ($key == '__attr') continue;
// Check for __attr
if (is_object($val->__attr)) {
while (list($key2, $val2) = each($val->__attr)) {
$attr .= " $key2=\"$val2\"";
}
}
else $attr = '';
if (is_array($val) || is_object($val)) {
print("$indent<$key$attr>\n");
obj2xml($val, $indent.' ');
print("$indent</$key>\n");
}
else print("$indent<$key$attr>$val</$key>\n");
}
}
//Example object
$x->name->first = "John";
$x->name->last = "Smith";
$x->arr['Fruit'] = 'Bannana';
$x->arr['Veg'] = 'Carrot';
$y->customer = $x;
$y->customer->__attr->id='176C4';
$z = get_defined_vars();
obj2xml($z['y']);
?>
will output:
<customer id="176C4">
<name>
<first>John</first>
<last>Smith</last>
</name>
<arr>
<Fruit>Bannana</Fruit>
<Veg>Carrot</Veg>
</arr>
</customer>
As a note, get_defined_vars() does not return a set of variable references (as I hoped). For example:
<?php
// define a variable
$my_var = "foo";
// get our list of defined variables
$defined_vars = get_defined_vars();
// now try to change the value through the returned array
$defined_vars["my_var"] = "bar";
echo $my_var, "\n";
?>
will output "foo" (the original value). It'd be nice if get_defined_vars() had an optional argument to make them references, but I imagine its a rather specialized request. You can do it yourself (less conveniently) with something like:
<?php
$defined_vars = array();
$var_names = array_keys(get_defined_vars());
foreach ($var_names as $var_name)
{
$defined_vars[$var_name] =& $$var_name;
}
?>
I posted here before about "this" being in get_defined_vars.
It turns out it's not always there but in certain cases it will inexplicably appear.
php -r '
class Test {
public function a() {var_dump(array_keys(get_defined_vars()));$a = 123;}
public function b() {var_dump(array_keys(get_defined_vars()));$this;}
}
$t = new Test();
$t->a();
$t->b();
'
array()
array('this')
This does not happen in PHP 7.2 but will happen in PHP 5.6.
Some comments here point out that this function wont return references. It does however return names and names are "references".
I would not recommend the suggestions here that convert it to references.
Instead...
public function x($a, $b, $c) {
foreach(array_keys(get_defined_vars()) as $key)
if($key !== 'this')
$this->y(${$key});
}
public function y(&$input) {
$input++;
}
Instead of ${} you can also use $$.
I have done some whacky things in my time to make extremely generic code but I've never had to do anything like the above. It might not even work (but should since it's no different to $a[$key]).
You could also do $$key++ but I've never seen code like that which wasn't horrifically bad (using dynamic where dynamic isn't beneficial).
If you're doing something like that then give it additional scrutiny.
I occasionally use this as a hack to convert arguments to an array where terseness is needed (dealing with legacy code, etc).
However in an object context it'll also pull in $this.
Make sure to unset it. If you map it to properties or an array then setting the key this wont be an error.
I recommend using a wrapper function that strips this from the result.
for all those who don't know how to us this function. copy and run this code in your computer .
note: you need to know what superglobals are.....
<?php
$A = 5 ;
$B = 10 ;
$C = 15 ;
$D = 20 ;
$F = get_defined_vars($A);
var_dump($F); //don't use echo. it will show error
?>
Result : will show all superglobals status along with your defined
variables along with its values
Here's a very simple function for debugging. It's far from perfect but I find it very handy. It outputs the var value and the var name on a new line. The problem is it'll echo any vars and their name if they share the same value. No big deal when debugging and saves the hassle of writing the HTML and var name when echoing a variable. (ev=echo variable). Using get_defined_vars() inside a function renames the var name to the functions variable so isn't as useful for debugging. Of course, you'll need access to the $GLOBALS array
<?
function ev($variable){
foreach($GLOBALS as $key => $value){
if($variable===$value){
echo '<p>'.$key.' - '.$value.'</p>';
}
}
}
$a=0;
ev($a);
$b=0;
ev($b);
$c=0;
ev($c);
?>
Will output
a - 0
a - 0
b - 0
a - 0
b - 0
c - 0
Note that this only returns things you've used. See http://bugs.php.net/bug.php?id=52110 . So don't expect this to have the $this entry, unless you assign $this to return $this.
get_defined_vars() returns ALL the vars (in the current scope), what if you just want all YOUR vars, not PHP's super-globals?
<?php
var_export(array_diff(get_defined_vars(), array(array())));
?>
Example...
<?php
$TOP_LEVEL_VAR=1;
var_export(array_diff(get_defined_vars(), array(array())));
?>
The output (with register_globals off) should be...
array (
'TOP_LEVEL_VAR' => 1,
)
...it perfectly eliminated all the super-globals, without me having to specify them! (note with register_globals on, the output includes those globals, then TOP_LEVEL_VAR).
Here it is, as a function...(it's the best I could do {I can't call get_defined_vars() inside get_user_defined_vars() cuz of the scope issue}).
<?php
header('Content-type: text/plain');
$TOP_LEVEL_VAR=1;
echo 'register_globals(';
echo ini_get('register_globals');
echo ') '.phpversion()."\n";
var_export(get_user_defined_vars(get_defined_vars()));
function get_user_defined_vars($vars) {
return array_diff($vars, array(array()));
}
?>
Note that originally I had an array of the super-globals I wanted removed from get_defined_vars()'s array, then I noticed even an empty double-array, array(array()), made it give me the correct result. Weird.
This was tested on PHP 5.2.9.
Please be aware that function_get_vars only returns the variables defined at the point before you call the function_get_vars function, it does not scan the entire function for you, only the lines before you call it.