在 wordpress 主题中加入远程图片文件自动本地化代码，经常转载文章的朋友应该会用到这个功能。把外链图片自动保存到网站本地，防止外链图片失效造成图片不显示。把下面的代码添加到主题的 functions.php 文件或者是 functions.php 的引入文件中即可，以后每当在 wordpress 发布文章时如果文章中含有外链图片就会自动本地化了，无需任何设置操作非常方便。

add_filter('content_save_pre', 'auto_save_image');
function auto_save_image($content) {
$upload_path = '';
$upload_url_path = get_bloginfo('url');

//上传目录
if (($var = get_option('upload_path')) !=''){
$upload_path = $var;
} else {
$upload_path = 'wp-content/uploads';
}
if(get_option('uploads_use_yearmonth_folders')) {
$upload_path .= '/'.date("Y",time()).'/'.date("m",time());
}

//文件地址
if(($var = get_option('upload_url_path')) != '') {
$upload_url_path = $var;
} else {
$upload_url_path = bloginfo('url');
}
if(get_option('uploads_use_yearmonth_folders')) {
$upload_url_path .= '/'.date("Y",time()).'/'.date("m",time());
}

require_once ("../wp-includes/class-snoopy.php");
$snoopy_Auto_Save_Image = new Snoopy;

$img = array();

//以文章的标题作为图片的标题
if ( !empty( $_REQUEST['post_title'] ) )
$post_title = wp_specialchars( stripslashes( $_REQUEST['post_title'] ));
$text = stripslashes($content);
if (get_magic_quotes_gpc()) $text = stripslashes($text);
preg_match_all("/ src=(\"|\'){0,}(http:\/\/(.+?))(\"|\'|\s)/is",$text,$img);
$img = array_unique(dhtmlspecialchars($img[2]));
foreach ($img as $key => $value){
set_time_limit(180); //每个图片最长允许下载时间,秒
if(str_replace(get_bloginfo('url'),"",$value)==$value&&str_replace(get_bloginfo('home'),"",$value)==$value){
//判断是否是本地图片，如果不是，则保存到服务器
$fileext = substr(strrchr($value,'.'),1);
$fileext = strtolower($fileext);
if($fileext==""||strlen($fileext)>4)
$fileext = "jpg";
$savefiletype = array('jpg','gif','png','bmp');
if (in_array($fileext, $savefiletype)){
if($snoopy_Auto_Save_Image->fetch($value)){
$get_file = $snoopy_Auto_Save_Image->results;
}else{
echo "error fetching file: ".$snoopy_Auto_Save_Image->error."<br>";
echo "error url: ".$value;
die();
}
$filetime = time();
$filepath = "/".$upload_path;//图片保存的路径目录
!is_dir("..".$filepath) ? mkdirs("..".$filepath) : null;
//$filename = date("His",$filetime).random(3);
$filename = substr($value,strrpos($value,'/'),strrpos($value,'.')-strrpos($value,'/'));

//$e = '../'.$filepath.$filename.'.'.$fileext;
//if(!is_file($e)) {
// copy(htmlspecialchars_decode($value),$e);
//}
$fp = @fopen("..".$filepath.$filename.".".$fileext,"w");
@fwrite($fp,$get_file);
fclose($fp);



$wp_filetype = wp_check_filetype( $filename.".".$fileext, false );
$type = $wp_filetype['type'];
$post_id = (int)$_POST['temp_ID2'];
$title = $post_title;
$url = $upload_url_path.$filename.".".$fileext;
$file = $_SERVER['DOCUMENT_ROOT'].$filepath.$filename.".".$fileext;

//添加数据库记录
$attachment = array(
'post_type' => 'attachment',
'post_mime_type' => $type,
'guid' => $url,
'post_parent' => $post_id,
'post_title' => $title,
'post_content' => '',
);
$id = wp_insert_attachment($attachment, $file, $post_parent);
$text = str_replace($value,$url,$text); //替换文章里面的图片地址
}
}
}
$content = AddSlashes($text);
remove_filter('content_save_pre', 'auto_save_image');
return $content;
}

function mkdirs($dir)
{
if(!is_dir($dir))
{
mkdirs(dirname($dir));
mkdir($dir);
}
return ;
}
function dhtmlspecialchars($string) {
if(is_array($string)) {
foreach($string as $key => $val) {
$string[$key] = dhtmlspecialchars($val);
}
}else{
$string = str_replace('&', '&', $string);
$string = str_replace('"', '"', $string);
$string = str_replace('<', '<', $string);
$string = str_replace('>', '>', $string);
$string = preg_replace('/&(#\d;)/', '&\1', $string);
}
return $string;
}