$_SERVER
If you need to find out whether any GET variables have been specified, you can use the empty() function.
<?php
if(empty($_GET))
echo "No GET variables";
else
print_r($_GET);
?>
empty() - http://php.net/manual/en/function.empty.php
print_r() - http://php.net/manual/en/function.print-r.php
$_GET
$HTTP_GET_VARS [obsoleto]
$_GET -- $HTTP_GET_VARS [obsoleto] — Variables HTTP GET
Descripción
Un array asociativo de variables pasado al script actual vía parámetros URL.
$HTTP_GET_VARS contiene la misma información, pero no es una superglobal. (Note que $HTTP_GET_VARS y $_GET son diferentes variables y que PHP los usa de forma diferente)
Historial de cambios
| Versión | Descripción |
|---|---|
| 4.1.0 | Se introduzco $_GET y $HTTP_GET_VARS quedó obsoleto. |
Ejemplos
Example #1 Ejemplo de $_GET
<?php
echo 'Hello ' . htmlspecialchars($_GET["name"]) . '!';
?>
Asumiendo que el usuario introduzco http://example.com/?name=Hannes
El resultado del ejemplo sería algo similar a:
Hello Hannes!
Notas
Note:
Esta es una 'superglobal' o una variable automatic global. Significa simplemente que es una variable que está disponible en cualquier parte del script. No hace falta hacer global $variable; para acceder a la misma desde funciones o métodos.
Note:
Las variables GET son pasadas vía urldecode().
add a note
User Contributed Notes
$_GET
Daniel M
14-Jan-2011 12:35
chris at bjelleklang dot org
18-Dec-2010 10:40
Please note that PHP setups with the suhosin patch installed will have a default limit of 512 characters for get parameters. Although bad practice, most browsers (including IE) supports URLs up to around 2000 characters, while Apache has a default of 8000.
To add support for long parameters with suhosin, add
suhosin.get.max_value_length = <limit> in php.ini
John Galt
15-Jun-2010 12:57
Just a note, because I didn't know for sure until I tested it.
If you have a query string that contains a parameter but no value (not even an equals sign), like so:
http://path/to/script.php?a
The following script is a good test to determine how a is valued:
<pre>
<?php
print_r($_GET);
if($_GET["a"] === "") echo "a is an empty string\n";
if($_GET["a"] === false) echo "a is false\n";
if($_GET["a"] === null) echo "a is null\n";
if(isset($_GET["a"])) echo "a is set\n";
if(!empty($_GET["a"])) echo "a is not empty";
?>
</pre>
I tested this with script.php?a, and it returned:
a is an empty string
a is set
So note that a parameter with no value associated with, even without an equals sign, is considered to be an empty string (""), isset() returns true for it, and it is considered empty, but not false or null. Seems obvious after the first test, but I just had to make sure.
Of course, if I do not include it in my browser query, the script returns
Array
(
)
a is null
Alberto Lepe dev at alepe dot com
05-Oct-2009 04:23
This Function will help you to manage your GET parameters to facilitate coding and prevent duplication. This is a basic version but it can be easily extended.
<?php
// Author: Alberto Lepe (www.alepe.com)
/* Process $_GET to preserve user custom parameters
* the arguments is a list of URL parameters that should be removed/changed from URL
* for example:
*
* URL = "index.php?s=1&fi=2&m=4&p=3
*
* if called: fixGet("s"); the result has to be: ?fi=2&m=4&p=3
* if called: fixGet("s&m"); the result has to be: ?fi=2&p=3
* if called: fixGet("s=4"); the result has to be: ?s=4&fi=2&m=4&p=3
* if called: fixGet("s=2&m"); the result has to be: ?s=2&fi=2&p=3
* if called: fixGet("s=&m=3"); the result has to be: ?s=&fi=2&m=3&p=3
* if called: fixGet("s=2&m="); the result has to be: ?s=2&fi=2&m=&p=3
* Special: when it ends with a =":" its to leave it open at the end
* (just first occurrence) to facilitate concatenation:
* if called: fixGet("s=2&m:"); the result has to be: ?s=2&fi=2&p=3&m
* if called: fixGet("s=2&m:="); the result has to be: ?s=2&fi=2&p=3&m=
*
* Usage with HTML (using the URL example above and $id = 99):
*
* <a href="index.php<?php echo fixGet('m=2&s&fi:=').$id ?>" >Link</a>
* Explanation: change "m" to 2, delete "s" and "fi" gets the $id value. ("p" is kept as it is not specified)
* will output: <a href='index.php?m=2&p=3&fi=99'>Link</a>
*/
public function fixGet($args) {
if(count($_GET) > 0) {
if(!empty($args)) {
$lastkey = "";
$pairs = explode("&",$args);
foreach($pairs as $pair) {
if(strpos($pair,":") !== false) {
list($key,$value) = explode(":",$pair);
unset($_GET[$key]);
$lastkey = "&$key$value";
} elseif(strpos($pair,"=") === false)
unset($_GET[$pair]);
else {
list($key, $value) = explode("=",$pair);
$_GET[$key] = $value;
}
}
}
return "?".((count($_GET) > 0)?http_build_query($_GET).$lastkey:"");
}
?>
To test, copy+paste the following code into testFixGet.php
<?php
/*
* Unit Test for fixGet()
*/
$cases = array (
0 => array("s" => 1, "fi" => 2, "m" => 4, "p" => 3),
1 => array("s" => "", "fi" => "", "m" => 4, "p" => 3),
);
$test[0] = array(
"s" => "fi=2&m=4&p=3",
"s&m" => "fi=2&p=3",
"s=4" => "s=4&fi=2&m=4&p=3",
"s=2&m" => "s=2&fi=2&p=3",
"s=&m=3" => "s=&fi=2&m=3&p=3",
"s=2&m=" => "s=2&fi=2&m=&p=3",
"s=2&m:=" => "s=2&fi=2&p=3&m=",
"z=9" => "s=1&fi=2&m=4&p=3&z=9",
"z:" => "s=1&fi=2&m=4&p=3&z",
"s:&m=3" => "fi=2&m=3&p=3&s",
"s&m=3" => "fi=2&m=3&p=3",
);
$test[1] = array(
"s" => "fi=&m=4&p=3",
"s&m" => "fi=&p=3",
"s=4" => "s=4&fi=&m=4&p=3",
"s=2&m" => "s=2&fi=&p=3",
"s=&m=3" => "s=&fi=&m=3&p=3",
"s=2&m=" => "s=2&fi=&m=&p=3",
"s=2&m:=" => "s=2&fi=&p=3&m=",
"z=9" => "s=&fi=&m=4&p=3&z=9",
"z:" => "s=&fi=&m=4&p=3&z",
);
foreach($cases as $x => $value) {
echo "<hr> CASE: $x <hr>\n";
foreach($test[$x] as $arg => $expected) {
$_GET = $cases[$x];
$res = myForm::fixGet($arg);
echo (($res === "?".$expected)?"OK":"NG ($res)")." [$arg]<br>\n";
}
}
?>
robotreply at gmail dot com
24-Jul-2009 07:17
Parsing of GET/POST drops duplicate variables unless those variables have "[]" (PHP bugs #10502, #15498 and #16195). Adding "[]" makes a mess of your javascript code, so here is a small workaround to it.
This function basically scans your raw POST and GET input and tries to fix the same. This function must be called near the top of your script. Optimizations are welcome.
<?php
function php_fix_raw_query() {
$post = '';
// Try globals array
if (!$post && isset($_GLOBALS) && isset($_GLOBALS["HTTP_RAW_POST_DATA"]))
$post = $_GLOBALS["HTTP_RAW_POST_DATA"];
// Try globals variable
if (!$post && isset($HTTP_RAW_POST_DATA))
$post = $HTTP_RAW_POST_DATA;
// Try stream
if (!$post) {
if (!function_exists('file_get_contents')) {
$fp = fopen("php://input", "r");
if ($fp) {
$post = '';
while (!feof($fp))
$post = fread($fp, 1024);
fclose($fp);
}
} else {
$post = "" . file_get_contents("php://input");
}
}
$raw = !empty($_SERVER['QUERY_STRING']) ? sprintf('%s&%s', $_SERVER['QUERY_STRING'], $post) : $post;
$arr = array();
$pairs = explode('&', $raw);
foreach ($pairs as $i) {
if (!empty($i)) {
list($name, $value) = explode('=', $i, 2);
if (isset($arr[$name]) ) {
if (is_array($arr[$name]) ) {
$arr[$name][] = $value;
} else {
$arr[$name] = array($arr[$name], $value);
}
} else {
$arr[$name] = $value;
}
}
}
foreach ( $_POST as $key => $value ) {
if (is_array($arr[$key]) ) {
$_POST[$key] = $arr[$name];
$_REQUEST[$key] = $arr[$name];
}
}
foreach ( $_GET as $key => $value ) {
if (is_array($arr[$key]) ) {
$_GET[$key] = $arr[$name];
$_REQUEST[$key] = $arr[$name];
}
}
# optionally return result array
return $arr;
}
?>
slavik0329
19-Mar-2009 03:01
the addget function below actually has more use when you dont use the recursive merge as such:
<?php
function AddGet($ArrayOrString){
if(is_array($ArrayOrString))
return http_build_query(array_merge($GLOBALS['_GET'], $ArrayOrString));
parse_str($ArrayOrString, $output);
return http_build_query(array_merge($GLOBALS['_GET'], $output));
}
?>
In this case, if the key is added again with a different value it will be replaced with the new value.
addget("change=true"); // ?change=true
addget("change=false"); // ?change=false
admin at bordeux dot net
29-Jan-2009 08:03
<?php
function AddGet($ArrayOrString){
if(is_array($ArrayOrString))
return http_build_query(array_merge_recursive($GLOBALS['_GET'], $ArrayOrString));
parse_str($ArrayOrString, $output);
return http_build_query(array_merge_recursive($GLOBALS['_GET'], $output));
}
?>
<a href="index.php?<?php echo AddGet(array("change"=>true,"jump"=>"42m"));?>">URL</a>
<a href="index.php?<?php echo AddGet("change=true&jump=42m");?>">URL</a>
Assuming the user entered http://example.com/?name=Hannes
The above example will output something similar to:
<a href="index.php?name=Hannes&change=1&jump=42m">URL</a>
<a href="index.php?name=Hannes&change=true&jump=42m">URL</a>
hmaloney at contactpoint dot com dot au
18-Sep-2008 11:38
This code is really useful for reproducing the values in the $_GET variable, and attaching that to a $_SERVER['PHP_SELF'] value when building the action value of a form tag, so that you don't lose any other values that could have been passed:
foreach ($_GET as $key => $value) {
if ($key != "C") { // ignore this particular $_GET value
$querystring .= $key."=".$value;
}
}
RJ Regalado
17-Jun-2008 02:57
Use this code if you want to retrieve your queries no matter what method is used. Hope it helps.
<?php
// By: RJ Regalado
// http://rjfiles.uni.cc/~php_examples/?id=1
$name = trim ((!empty($_POST['name'])) ? $_POST['name'] : $_GET['name'] );
if ( strlen ($name) < 1)
{
echo "Please enter your name";
} else {
printf ("Hello <b>%s</b><br>", $name);
printf ("Bonjour <b>%s</b><br>", $name);
printf ("Hallo <b>%s</b><br>", $name);
printf ("Ciao <b>%s</b><br>", $name);
printf ("Hola <b>%s</b><br>", $name);
}
?><hr>
<form method="POST">
Name: <input type="text" name="name">
<input type="submit" value="POST">
</form><hr>
<form method="GET">
Name: <input type="text" name="name">
<input type="submit" value="GET">
</form>
timberspine _AT_ gmail _DOT_ com
14-May-2008 11:38
Note that named anchors are not part of the query string and are never submitted by the browser to the server.
Eg.
http://www.xyz-abc.kz/index.php?title=apocalypse.php#doom
echo $_GET['title'];
// returns "apocalypse.php" and NOT "apocalypse.php#doom"
you would be better off treating the named anchor as another query string variable like so:
http://www.xyz-abc.kz/index.php?title=apocalypse.php&na=doom
...and then retrieve it using something like this:
$url = $_GET['title']."#".$_GET['na'];
Hope this helps someone...
niwil at djes dot dk
14-May-2008 01:00
Note:
If nothing is set in the address bar, the value of $_GET['n'] will be NULL, not ""(empty string) or false.