HomeMenu
Jesus · Bible · HTML · CSS · JS · PHP · SVG · Applications

libxml_set_external_entity_loader

Description

The libxml_set_external_entity_loader of libxml for PHP changes the default external entity loader.

Syntax

libxml_set_external_entity_loader(
    ?callable $resolver_function
): bool

Parameters

resolver_function

A callable with the following signature:

resolver(
    ?string $public_id,
    string $system_id,
    array $context
): resource|string|null
public_id

The public ID.

system_id

The system ID.

context

An array with the four elements "directory", "intSubName", "extSubURI" and "extSubSystem".

This callable should return a resource, a string from which a resource can be opened. If null is returned, the entity reference resolution will fail.

Return

Returns true on success or false on failure.

Examples

1 · resolver_function

<?

function resolver($public_id, $system_id, $context)
{
    return "mystring";
}

$resolver_function = "resolver";

$return = libxml_set_external_entity_loader($resolver_function);

var_export($return);

true

2 · DOMDocument

<?

function resolver($public_id, $system_id, $context)
{
    var_dump($public_id, $system_id, $context);

    return "mystring";
}

$resolver_function = "resolver";

libxml_set_external_entity_loader($resolver_function);

$source =
<<<XML
<!DOCTYPE mytopelement PUBLIC "myregistration//myorganization//mytype mylabel mydefinition//mylanguage" "https://mydomain.com/mypath">
<my-element></my-element>
XML;

$dom = new DOMDocument;
$dom->loadXML($source);
$dom->validate();

string(71) "myregistration//myorganization//mytype mylabel mydefinition//mylanguage"
string(27) "https://mydomain.com/mypath"
array(4) {
  ["directory"]=>
  NULL
  ["intSubName"]=>
  NULL
  ["extSubURI"]=>
  NULL
  ["extSubSystem"]=>
  NULL
}