Is there a way to build a query automatically with http_build_query using parameters with the same name?
If I do something like
array('foo' => 'x', 'foo' => 'y');
They are obviously overwritten within the array, but even if I do:
array('foo' => array('x', 'y'));
The function creates something like foo[0]=x&foo[1], which isn't what I want, since I need the parameters in this format foo=x&foo=y.
You can solve this by doing substitution on the result of http_build_query() where the [0], [1], …, suffixes are URL-encoded.
$vars = array('foo' => array('x', 'y'));
$query = http_build_query($vars);
# $query is now foo%5B0%5D=x&foo%5B1%5D=y (URL-encoded foo[0]=x&foo[1]=y)
$query = preg_replace('/%5B\d+%5D(?==)/', '', $query);
# $query is now foo=x&foo=y
The look-ahead ((?= … )) ensures it only replaces values at the end of a name because they are always followed by an =.
PHP won't produce indices with leading zeroes, so \d+ (1 or more digits) is sufficient to detect them.
Some systems require the square brackets without indices inside them. In that case you can use this:
$query = preg_replace('/%5B\K\d+(?=%5D=)/', '', $query);
# $query is now foo%5B%5D=x&foo%5B%5D=y (URL-encoded foo[]=x&foo[]=y)
Here is a function I created to build the query and preserve names. I created this to work with a third-party API that requires multiple query string parameters with the same name.
function custom_build_query(
array|object $query_data,
string $numeric_prefix = "",
?string $arg_separator = null,
int $encoding_type = PHP_QUERY_RFC1738
): string {
// Cast to array if object is supplied.
$query_data = is_object($query_data) ? get_object_vars($query_data) : $query_data;
// Use supplied arg_separator value, defaulting to the `arg_separator.output` php configuration.
$arg_separator = $arg_separator ?? ini_get("arg_separator.output");
// If PHP_QUERY_RFC3986 is specified, use rawurlencode to encode parameters.
$encoding_function = $encoding_type === PHP_QUERY_RFC3986 ? "rawurlencode" : "urlencode";
$query = [];
foreach ($query_data as $name => $value) {
$value = (array) $value;
$name = is_int($name) ? $numeric_prefix . $name : $name;
array_walk_recursive($value, function ($value) use (&$query, $name, $encoding_function) {
$query[] = $encoding_function($name) . "=" . $encoding_function($value);
});
}
return implode($arg_separator, $query);
}
Usage:
echo custom_build_query(['a' => 1, 'b' => 2, 'c' => [3, 4]]);
Output:
a=1&b=2&c=3&c=4
Note: The function's signature is fully compatible with http_build_query. The only difference is, of course, the function will not use brackets for sub-array parameters.
