/// <summary>
/// 从表示节点的字符串解析出节点
/// </summary>
/// <param name="text"></param>
/// <returns></returns>
public static HtmlNode ParseNode(string text)
{
int type = GetNodeStringType(text);
if (type == 3)
{
return(HtmlNode.CreateTextNode(text)); //文本节点
}
string tagName = HtmlNode.GetNodeName(text);
if (type == 0)
{
HtmlNode node = new HtmlNode(tagName);
node.Attributes = ParseAttribute(text);
return(node);
}
else if (type == 2)
{
HtmlNode node = HtmlNode.CreateClosedNode(tagName);
node.Attributes = ParseAttribute(text);
return(node);
}
else
{
return(null);
}
}
private static NodeString ParseNodeStringByName(string text, ref int index, string nodeName)
{
if (text == "")
{
return(null);
}
NodeString nodeStr = new NodeString();
while (index < text.Length)
{
int start = text.IndexOf('<', index);
if (start == -1)
{
return(null);
}
int end = text.IndexOf('>', start);
if (end == -1)
{
return(null);
}
int length = end - start + 1;
if (length < 3)
{
continue;
}
else
{
string tagBlock = text.Substring(start, length);
string tagName = HtmlNode.GetNodeName(tagBlock);
index = end + 1; //索引前进
if (HtmlNode.IsValidHtmlNode(tagName) && tagName.ToLower() == nodeName.ToLower()) //检验标签名是否合法
{
nodeStr.Type = HtmlNode.GetNodeStringType(tagBlock);
nodeStr.NodeBlock = tagBlock;
return(nodeStr);
}
}
}
return(null);
}
public static List <HtmlNode> ParseNodeByName(string text, string nodeName)
{
if (text == "")
{
return(null);
}
List <HtmlNode> nodeList = new List <HtmlNode>();
int nodeIndex = 0;
while (nodeIndex < text.Length - 1)
{
NodeString nodeStr = ParseNodeStringByName(text, ref nodeIndex, nodeName);
if (nodeStr == null)
{
break;
}
else if (nodeStr.Type == 2)
{
nodeList.Add(HtmlNode.ParseNode(nodeStr.NodeBlock));
}
else if (nodeStr.Type == 0)
{
int tmpIndex = nodeIndex;
string tagName = HtmlNode.GetNodeName(nodeStr.NodeBlock);
NodeString tmpNode = null;
Stack <int> cntStack = new Stack <int>();
cntStack.Push(0);
while (cntStack.Count != 0)
{
if (tmpIndex >= text.Length)
{
break; //到文本结尾仍未找到结束标签,则跳出
}
tmpNode = ParseNodeString(text, ref tmpIndex);
string tmpTagName = HtmlNode.GetNodeName(tmpNode.NodeBlock);
if (tmpTagName.ToLower() == nodeName.ToLower())
{
if (tmpNode.Type == 0)
{
cntStack.Push(0);
}
else if (tmpNode.Type == 1)
{
cntStack.Pop();
}
}
}
if (cntStack.Count == 0)//找到结束标签
{
HtmlNode node = HtmlNode.ParseNode(nodeStr.NodeBlock);
string innerNode = text.Substring(nodeIndex, tmpIndex - nodeIndex - tmpNode.NodeBlock.Length);
if (innerNode != "")//递归解析子节点
{
node.Childs = ParseNode(innerNode);
}
nodeList.Add(node);
nodeIndex = tmpIndex;
}
else
{
break;
}
}
}//循环结束
return(nodeList);
}
/// <summary>
/// 解析第一个节点（包括文本节点）
/// </summary>
/// <param name="text"></param>
/// <param name="index"></param>
/// <returns></returns>
private static NodeString ParseNodeString(string text, ref int index)
{
if (text == "")
{
return(null);
}
NodeString nodeStr = new NodeString();
int start = text.IndexOf('<', index);
if (start == -1)//文本节点
{
nodeStr.Type = 3;
nodeStr.NodeBlock = text.Substring(index);
index = text.Length - 1;
return(nodeStr);
}
else if (start > index)//前面有文本节点
{
nodeStr.Type = 3;
nodeStr.NodeBlock = text.Substring(index, start - index);//保存文本节点
index = start;
int tmpIndex = index;
NodeString tmp = ParseNodeString(text, ref tmpIndex);
if (tmp.Type == 3)
{
nodeStr.NodeBlock = nodeStr.NodeBlock + tmp.NodeBlock;
index = tmpIndex;
}
//如果不是文本节点，则还原index到上一次位置
return(nodeStr);
}
int end = text.IndexOf('>', start); //若Tag内出现>会出错
if (end == -1) //无>标记表示为文本节点
{
index = text.Length - 1;
nodeStr.Type = 3;
nodeStr.NodeBlock = text.Substring(index);
return(nodeStr);
}
int length = end - start + 1;
if (length < 3)//一个标签长度最少为3
{
nodeStr.Type = 3;
nodeStr.NodeBlock = text.Substring(index, length);
index = end + 1;
int tmpIndex = index;
NodeString tmp = ParseNodeString(text, ref tmpIndex);
if (tmp.Type == 3)
{
nodeStr.NodeBlock = nodeStr.NodeBlock + tmp.NodeBlock;
index = tmpIndex;
}
return(nodeStr); //若文本里出现<>继续搜索
}
else//解析到类常规标签,可能是<123>等不合法标签
{
string tagBlock = text.Substring(start, length);
string tagName = HtmlNode.GetNodeName(tagBlock);
if (HtmlNode.IsValidHtmlNode(tagName)) //检验标签名是否合法
{
index = end + 1; //索引前进
nodeStr.Type = HtmlNode.GetNodeStringType(tagBlock);
nodeStr.NodeBlock = tagBlock;
return(nodeStr);
}
else//标签不合法则视为文本
{
nodeStr.Type = 3;
nodeStr.NodeBlock = text.Substring(index, length);
index = end + 1;
int tmpIndex = index;
NodeString tmp = ParseNodeString(text, ref tmpIndex);
if (tmp.Type == 3)
{
nodeStr.NodeBlock = nodeStr.NodeBlock + tmp.NodeBlock;
index = tmpIndex;
}
return(nodeStr); //若文本里出现<>继续搜索
}
}
}
/// <summary>
/// 解析传入的字符串，并返回最上层节点列表
/// </summary>
/// <param name="context"></param>
/// <returns></returns>
public static List <HtmlNode> ParseNode(string text)
{
if (text == "")
{
return(null);
}
List <HtmlNode> nodeList = new List <HtmlNode>();
int nodeIndex = 0;
while (nodeIndex < text.Length - 1)
{
NodeString nodeStr = ParseNodeString(text, ref nodeIndex);
if (nodeStr.Type == 3 || nodeStr.Type == 2)//文本节点和闭合标签
{
nodeList.Add(HtmlNode.ParseNode(nodeStr.NodeBlock));
}
else if (nodeStr.Type == 0)//处理开放节点,寻找结束标记
{
int tmpIndex = nodeIndex;
string tagName = HtmlNode.GetNodeName(nodeStr.NodeBlock);
NodeString tmpNode = null;
Stack <int> cntStack = new Stack <int>();
cntStack.Push(0);
while (cntStack.Count != 0)
{
if (tmpIndex >= text.Length)
{
break; //到文本结尾仍未找到结束标签,则跳出
}
tmpNode = ParseNodeString(text, ref tmpIndex);
string tmpTagName = HtmlNode.GetNodeName(tmpNode.NodeBlock);
if (tmpTagName.ToLower() == tagName.ToLower())
{
if (tmpNode.Type == 0)
{
cntStack.Push(0);
}
else if (tmpNode.Type == 1)
{
cntStack.Pop();
}
}
}
if (cntStack.Count == 0)//找到结束标签
{
HtmlNode node = HtmlNode.ParseNode(nodeStr.NodeBlock);
string innerNode = text.Substring(nodeIndex, tmpIndex - nodeIndex - tmpNode.NodeBlock.Length);
if (innerNode != "")//递归解析子节点
{
node.Childs = ParseNode(innerNode);
}
nodeList.Add(node);
nodeIndex = tmpIndex;
}
else
{
HtmlDocParseExeption err = new HtmlDocParseExeption("Bad Document,Miss enclosed tag for " + nodeStr.NodeBlock);
throw err;
}
}
}//循环结束
return(nodeList);
}
