php xml节点 修改,增加,编辑,删除代码

<?php
function loadfile($file) {
    $newfile = new domdocument();
    $newfile->validateonparse = true;
    $newfile->load($file);
    return $newfile;
}
function add($file, $parentname, $children) { //增加xml节点
    $xml = loadfile($file);
    $id = uniqid('m' . rand(1, 5) , true);
    $parentnode = $xml->createelement($parentname);
    $parentnode->setattribute('mid', $id);
    foreach ($children as $child => $value) {
        $childnode = $xml->createelement($child, $value);
        $parentnode->appendchild($childnode);
    }
    $xml->documentelement->appendchild($parentnode);
    $xml->save($file);
    return $id;
}
function delete($file, $id) { //删除xml 节点
    $xml = loadfile($file);
    $ids = explode(",", $id);
    foreach ($ids as $oldnodeid) {
        $oldnode = $xml->getelementbyid($oldnodeid);
        $parentnode = $oldnode->parentnode;
        $parentnode->removechild($oldnode);
    }
    $xml->save($file);
}
function edit($file, $id, $child, $value) { //编辑xml 节点
    $xml = loadfile($file);
    $parentnode = $xml->getelementbyid($id);
    $childnode = $parentnode->childnodes->item($child);
    $textnode = $childnode->childnodes->item(0);
    $textnode->nodevalue = $value;
    $xml->save($file);
}
function move($file, $moveid, $refid = null) { //移动xml节点
    $xml = loadfile($file);
    $movenode = $xml->getelementbyid($moveid);
    $parentnode = $movenode->parentnode;
    if ($refid != null) {
        $refnode = $xml->getelementbyid($refid);
        if (!$parentnode->issamenode($refnode->parentnode)) return false;
    } else $refnode = null;
    $movenode = $parentnode->removechild($movenode);
    $parentnode->insertbefore($movenode, $refnode);
    $xml->save($file);
}