远程下载图片

function get_url_image($url)
{
    $ext = explode(".", $url);
    $ext = strtolower(end($ext));
    if($ext != "gif" && $ext != "jpg" && $ext != "png" && $ext != "bmp" && $ext != "jpeg")
    {
        return $url;
    }

    $name = date("Ymd");
    for ($i = 0; $i < 6; $i++)
    {
        $name .= chr(mt_rand(97, 122));
    }
    $name .= "." . $ext;
    $target = ROOT_PATH . DATA_DIR . "/afficheimg/" . $name;

    $tmp_file = DATA_DIR . "/afficheimg/" . $name;
    $filename = ROOT_PATH . $tmp_file;

    $img = file_get_contents($url);

    $fp = @fopen($filename, "a");
    fwrite($fp, $img);
    fclose($fp);

    return $tmp_file;
}

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// 主图上传
if ($_FILES["topic_img"]["name"] && $_FILES["topic_img"]["size"] > 0)
{
    /* 检查文件合法性 */
    if(!get_file_suffix($_FILES["topic_img"]["name"], $allow_suffix))
    {
        sys_msg($_LANG["invalid_type"]);
    }

    /* 处理 */
    $name = date("Ymd");
    for ($i = 0; $i < 6; $i++)
    {
        $name .= chr(mt_rand(97, 122));
    }
    $name .= "." . end(explode(".", $_FILES["topic_img"]["name"]));
    $target = ROOT_PATH . DATA_DIR . "/afficheimg/" . $name;

    if (move_upload_file($_FILES["topic_img"]["tmp_name"], $target))
    {
        $topic_img = DATA_DIR . "/afficheimg/" . $name;
    }
}
else if (!empty($_REQUEST["url"]))
{
    /* 来自互联网图片 不可以是服务器地址 */
    if(strstr($_REQUEST["url"], "http") && !strstr($_REQUEST["url"], $_SERVER["SERVER_NAME"]))
    {
        /* 取互联网图片至本地 */
        $topic_img = get_url_image($_REQUEST["url"]);
    }
    else{
        sys_msg($_LANG["web_url_no"]);
    }
}