public PolicyHtmlAttribute(FilterPolicy policy, string name, PolicyHtmlTag tag = null)
: base(policy,name)
{
Tag = tag;
}
void ValidateAction(HtmlNode node,string tagName,PolicyHtmlTag tag)
{
HtmlNode parentNode = node.ParentNode;
#region 过滤样式
if ("style".Equals(tagName))
{
try
{
node.FirstChild.InnerHtml = CssFilter.Filters(node.FirstChild.InnerHtml);
}
catch
{
parentNode.RemoveChild(node);
}
}
#endregion
#region 过滤属性
for (int currentAttributeIndex = 0; currentAttributeIndex < node.Attributes.Count; currentAttributeIndex++)
{
HtmlAttribute attribute = node.Attributes[currentAttributeIndex];
string name = attribute.Name, _value = attribute.Value;
var attr = tag.AllowedAttribute(name);
#region 如果是白名单之外的属性移除掉
if (attr == null)
{
node.Attributes.Remove(name);
currentAttributeIndex--;
continue;
}
#endregion
#region 元素内嵌样式
if ("style".Equals(name, StringComparison.OrdinalIgnoreCase))
{
try
{
attribute.Value = CssFilter.Filters(_value,true);
}
catch
{
node.Attributes.Remove(name);
currentAttributeIndex--;
}
continue;
}
#endregion
///如果未能通过验证，将执行指定的操作
if (!FilterPolicy.ValidateAttribute(attr,_value))
{
switch (attr.OnInvalid)
{
case PolicyHtmlAttributeOnInvalid.RemoveTag:
//删除当前的元素并退出函数
parentNode.RemoveChild(node);
return;
case PolicyHtmlAttributeOnInvalid.FilterTag:
///删除当前节点，但保留其有效的子节点
PromoteChildren(node);
return;
default:
//删除当前的属性，指针往回调
node.Attributes.Remove(attr.Name);
currentAttributeIndex--;
break;
}
}
}
#endregion
///过滤当前元素的子节点
FiltersTags(node.ChildNodes);
}