PHP Manual
libxml 函数
Changes the default external entity loader

libxml_set_external_entity_loader

(PHP 5 >= 5.4.0, PHP 7)

libxml_set_external_entity_loader — Changes the default external entity loader

说明

libxml_set_external_entity_loader ( callable $resolver_function ) : bool

Changes the default external entity loader.

参数

resolver_function: A callable that takes three arguments. Two strings, a public id and system id, and a context (an array with four keys) as the third argument. This callback should return a resource, a string from which a resource can be opened, or NULL.

返回值

成功时返回 TRUE，或者在失败时返回 FALSE。

范例

Example #1 libxml_set_external_entity_loader() example

 <?php
$xml = <<<XML
<!DOCTYPE foo PUBLIC "-//FOO/BAR" "http://example.com/foobar">
<foo>bar</foo>
XML;

$dtd = <<<DTD
<!ELEMENT foo (#PCDATA)>
DTD;

libxml_set_external_entity_loader(
    function ($public, $system, $context) use($dtd) {
        var_dump($public);
        var_dump($system);
        var_dump($context);
        $f = fopen("php://temp", "r+");
        fwrite($f, $dtd);
        rewind($f);
        return $f;
    }
);

$dd = new DOMDocument;
$r  = $dd->loadXML($xml);

var_dump($dd->validate());
?>

以上例程会输出：

string(10) "-//FOO/BAR"
string(25) "http://example.com/foobar"
array(4) {
    ["directory"]    => NULL
    ["intSubName"]   => NULL
    ["extSubURI"]    => NULL
    ["extSubSystem"] => NULL
}
bool(true)

参见

libxml_disable_entity_loader() - Disable the ability to load external entities