http_build_query

(PHP 5, PHP 7)

Generate URL-encoded query string

string http_build_query ( mixed $query_data [, string $numeric_prefix [, string $arg_separator [, int $enc_type = PHP_QUERY_RFC1738 ]]] )

Generates a URL-encoded query string from the associative (or indexed) array provided.

Parameters:

query_data

May be an array or object containing properties.

If query_data is an array, it may be a simple one-dimensional structure, or an array of arrays (which in turn may contain other arrays).

If query_data is an object, then only public properties will be incorporated into the result.

numeric_prefix

If numeric indices are used in the base array and this parameter is provided, it will be prepended to the numeric index for elements in the base array only.

This is meant to allow for legal variable names when the data is decoded by PHP or another CGI application later on.

arg_separator

arg_separator.output is used to separate arguments, unless this parameter is specified, and is then used.

enc_type

By default, PHP_QUERY_RFC1738.

If enc_type is PHP_QUERY_RFC1738, then encoding is performed per » RFC 1738 and the application/x-www-form-urlencoded media type, which implies that spaces are encoded as plus (+) signs.

If enc_type is PHP_QUERY_RFC3986, then encoding is performed according to » RFC 3986, and spaces will be percent encoded (%20).

Returns:

Returns a URL-encoded string.

Changelog:

5.4.0

The enc_type parameter was added.

5.1.3

Square brackets are escaped.

5.1.2

The arg_separator parameter was added.

Examples:

Simple usage of http_build_query()

<?php
$data = array('foo'=>'bar',
              'baz'=>'boom',
              'cow'=>'milk',
              'php'=>'hypertext processor');

echo http_build_query($data) . "\n";
echo http_build_query($data, '', '&amp;');

?>

The above example will output:

foo=bar&baz=boom&cow=milk&php=hypertext+processor
foo=bar&amp;baz=boom&amp;cow=milk&amp;php=hypertext+processor

http_build_query() with numerically index elements.

<?php
$data = array('foo', 'bar', 'baz', 'boom', 'cow' => 'milk', 'php' =>'hypertext processor');

echo http_build_query($data) . "\n";
echo http_build_query($data, 'myvar_');
?>

The above example will output:

0=foo&1=bar&2=baz&3=boom&cow=milk&php=hypertext+processor
myvar_0=foo&myvar_1=bar&myvar_2=baz&myvar_3=boom&cow=milk&php=hypertext+processor

http_build_query() with complex arrays

<?php
$data = array('user'=>array('name'=>'Bob Smith',
                            'age'=>47,
                            'sex'=>'M',
                            'dob'=>'5/12/1956'),
              'pastimes'=>array('golf', 'opera', 'poker', 'rap'),
              'children'=>array('bobby'=>array('age'=>12,
                                               'sex'=>'M'),
                                'sally'=>array('age'=>8,
                                               'sex'=>'F')),
              'CEO');

echo http_build_query($data, 'flags_');
?>

this will output : (word wrapped for readability)

user%5Bname%5D=Bob+Smith&user%5Bage%5D=47&user%5Bsex%5D=M&
user%5Bdob%5D=5%2F12%2F1956&pastimes%5B0%5D=golf&pastimes%5B1%5D=opera&
pastimes%5B2%5D=poker&pastimes%5B3%5D=rap&children%5Bbobby%5D%5Bage%5D=12&
children%5Bbobby%5D%5Bsex%5D=M&children%5Bsally%5D%5Bage%5D=8&
children%5Bsally%5D%5Bsex%5D=F&flags_0=CEO

Note:

Only the numerically indexed element in the base array "CEO" received a prefix. The other numeric indices, found under pastimes, do not require a string prefix to be legal variable names.

Using http_build_query() with an object

<?php
class parentClass {
    public    $pub      = 'publicParent';
    protected $prot     = 'protectedParent';
    private   $priv     = 'privateParent';
    public    $pub_bar  = Null;
    protected $prot_bar = Null;
    private   $priv_bar = Null;

    public function __construct(){
        $this->pub_bar  = new childClass();
        $this->prot_bar = new childClass();
        $this->priv_bar = new childClass();
    }
}

class childClass {
    public    $pub  = 'publicChild';
    protected $prot = 'protectedChild';
    private   $priv = 'privateChild';
}

$parent = new parentClass();

echo http_build_query($parent);
?>

The above example will output:

pub=publicParent&pub_bar%5Bpub%5D=publicChild