get_meta_tags
Params with null value do not present in result string.
<?
$arr = array('test' => null, 'test2' => 1);
echo http_build_query($arr);
?>
will produce:
test2=1
http_build_query
(PHP 5)
http_build_query — Generate URL-encoded query string
Description
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_datais an array, it may be a simple one-dimensional structure, or an array of arrays (which in turn may contain other arrays).If
query_datais 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_typeisPHP_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_typeisPHP_QUERY_RFC3986, then encoding is performed according to » RFC 3986, and spaces will be percent encoded (%20).
Return Values
Returns a URL-encoded string.
Changelog
| Version | Description |
|---|---|
| 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
Example #1 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, '', '&');
?>
The above example will output:
foo=bar&baz=boom&cow=milk&php=hypertext+processor foo=bar&baz=boom&cow=milk&php=hypertext+processor
Example #2 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
Example #3 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.
Example #4 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
See Also
- parse_str() - Parses the string into variables
- parse_url() - Parse a URL and return its components
- urlencode() - URL-encodes string
- array_walk() - Apply a user function to every member of an array
add a note
User Contributed Notes
http_build_query - [10 notes]
Ilya Rudenko ¶
7 years ago
irish [-@-] ytdj [-dot-] ca ¶
3 years ago
When using the http_build_query function to create a URL query from an array for use in something like curl_setopt($ch, CURLOPT_POSTFIELDS, $post_url), be careful about the url encoding.
In my case, I simply wanted to pass on the received $_POST data to a CURL's POST data, which requires it to be in the URL format. If something like a space [ ] goes into the http_build_query, it comes out as a +. If you're then sending this off for POST again, you won't get the expected result. This is good for GET but not POST.
Instead you can make your own simple function if you simply want to pass along the data:
<?php
$post_url = '';
foreach ($_POST AS $key=>$value)
$post_url .= $key.'='.$value.'&';
$post_url = rtrim($post_url, '&');
?>
You can then use this to pass along POST data in CURL.
<?php
$ch = curl_init($some_url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_url);
curl_exec($ch);
?>
Note that at the final page that processes the POST data, you should be properly filtering/escaping it.
anonymous ¶
9 months ago
Is it worth noting that if query_data is an associative array and a value is itself an empty array, or an array of nothing but empty array (or arrays containing only empty arrays etc.), the corresponding key will not appear in the resulting query string?
E.g.
$post_data = array('name'=>'miller', 'address'=>array('address_lines'=>array()), 'age'=>23);
echo http_build_query($post_data);
will print
name=miller&age=23
Anonymous ¶
2 years ago
As noted before, with php5.3 the separator is & on some servers it seems. Normally if posting to another php5.3 machine this will not be a problem.
But if you post to a tomcat java server or something else the & might not be handled properly.
To overcome this specify:
http_build_query($array, '', '&');
and NOT
http_build_query($array); //gives & to some servers
netrox at aol dot com ¶
3 years ago
I noticed that even with the magic quotes disabled, http_build_query() automagically adds slashes to strings.
So, I had to add "stripslashes" to every string variable.
valdikss at gmail dot com ¶
5 years ago
This function is wrong for http!
arrays in http is like this:
files[]=1&files[]=2&...
but function makes like this
files[0]=1&files[1]=2&...
Here is normal function:
<?php
function cr_post($a,$b=\'\',$c=0){
if (!is_array($a)) return false;
foreach ((array)$a as $k=>$v){
if ($c) $k=$b.\"[]\"; elseif (is_int($k)) $k=$b.$k;
if (is_array($v)||is_object($v)) {$r[]=cr_post($v,$k,1);continue;}
$r[]=urlencode($k).\"=\".urlencode($v);}return implode(\"&\",$r);}
?>
v0idnull[try_to_spam_me_now] at gee-mail dot co ¶
3 years ago
on my install of PHP 5.3, http_build_query() seems to use & as the default separator. Kind of interesting when combined with stream_context_create() for a POST request, and getting $_POST['amp;fieldName'] on the receiving end.
Vitaly Dyatlov ¶
8 days ago
Correct implementation of coding the array of params without indexes (valdikks fixed code - didnt work for inner arrays):
<code>
function cr_post($a,$b='',$c=0)
{
if (!is_array($a)) return false;
foreach ((array)$a as $k=>$v)
{
if ($c)
{
if( is_numeric($k) )
$k=$b."[]";
else
$k=$b."[$k]";
}
else
{ if (is_int($k))
$k=$b.$k;
}
if (is_array($v)||is_object($v))
{
$r[]=cr_post($v,$k,1);
continue;
}
$r[]=urlencode($k)."=".urlencode($v);
}
return implode("&",$r);
}
</code>
eric dot muyser at gmail dot com ¶
1 month ago
This function makes like this
files[0]=1&files[1]=2&...
To do it like this:
files[]=1&files[]=2&...
Do this:
$query = http_build_query($query);
$query = preg_replace('/%5B[0-9]+%5D/simU', '%5B%5D', $query);
stocki dot r at gmail dot com ¶
2 months ago
If you need only key+value pairs, you can use this:
<?php
$array = array(
"type" => "welcome",
"message" => "Hello World!"
);
echo urldecode(http_build_query($array, '', ';'));
?>
Result: type=welcome;message=Hello World!