I'm using HtmlAgilityPack to sanitize user entered rich text and strip any harmful/unwanted text. Problem occurs though when a simple text is also treated as html node
If I enter
a<b, c>d
and try to sanitize it, the output generated is
a<b, c="">d</b,>
The code I used was
HtmlDocument doc = new HthmlDocument();
doc.LoadHtml(value);
// Sanitizing Logic
var result = doc.DocumentNode.WriteTo();
I tried to set different parameters on HtmlDocument ('OptionCheckSyntax', 'OptionAutoCloseOnEnd', 'OptionWriteEmptyNodes') to not have the text be treated as a node but nothing worked. Is this is a known issue or any workaround possible?
IMO, there's no way you can tell HAP to not treat every '<' as start of new html node. But you can check if your html is a validate html or not by using
string html = "your-html";
HtmlDocument doc = new HtmlDocument();
doc.LoadHtml(html);
if (doc.ParseErrors.Count() > 0)
{
//here you can ignore or do whatever you want
}
Related
I am trying to get the text value of this a tag:
67 comments
so i'm trying to get '67' from this. however there are no defining classes or id's.
i've managed to get this far:
IEnumerable<HtmlNode> commentsNode = htmlDoc.DocumentNode.Descendants(0).Where(n => n.HasClass("subtext"));
var storyComments = commentsNode.Select(n =>
n.SelectSingleNode("//a[3]")).ToList();
this only give me "comments" annoyingly enough.
I can't use the href id as there are many of these items, so i cant hardcord the href
how can i extract the number aswell?
Just use the #href attribute and a dedicated string function :
substring-before(//a[#href="item?id=22513425"],"comments")
returns 67.
EDIT : Since you can't hardcode all the content of #href, maybe you can use starts-with. XPath 1.0 solution.
Shortest form (+ text has to contain "comments") :
substring-before(//a[starts-with(#href,"item?") and text()[contains(.,"comments")]],"c")
More restrictive (+ text has to finish with "comments") :
substring-before(//a[starts-with(#href,"item?")][substring(//a, string-length(//a) - string-length('comments')+1) = 'comments'],"c")
I am using ScrapySharp nuget which adds in my sample below, (It's possible HtmlAgilityPack offers the same functionality built it, I am just used to ScrapySharp from years ago)
var doc = new HtmlDocument();
doc.Load(#"C:\desktop\anchor.html"); //I created an html file with your <a> element as the body
var anchor = doc.DocumentNode.CssSelect("a").FirstOrDefault();
if (anchor == null) return;
var digits = anchor.InnerText.ToCharArray().Where(c => Char.IsDigit(c));
Console.WriteLine($"anchor text: {anchor.InnerText} - digits only: {new string(digits.ToArray())}");
Output:
I am working on the WebBrowser control in WP7 This is the sample HTML I wrote and asked the webBrowser to navigate To String than its working fine but when i stored this html in to variable and asked to navigate To String than out put is html format.My HTML string was came from web service so i am not able to pass direct string.
my C# code is:
JObject cityblog1 = (JObject)cityblog[0];
string cityimg = (string)cityblog1["CityImage"];
string citydetail = (string)cityblog1["CityDetail"];
City_Blog cb = new City_Blog();
cb.CityImage = cityimg;
cb.CityDetail = citydetail;
lstcityblogdetail.Add(cb);
setimg();
//"\u003cbody style=\"text-align:justify\"\u003e\u003cp\u003e\r\n\tname\u003c/p\u003e\r\n\u003cp\u003e\r\n\t\u003ca href=\"36\" style=\"color: red\"\u003emovieplex\u003c/a\u003e\u003c/p\u003e\r\n\u003cp\u003e\r\n\t\u003ca href=\"47\" style=\"color: red\"\u003etest\u003c/a\u003e\u003c/p\u003e\r\n\u003c/body\u003e"
webBrowser1.NavigateToString(citydetail);
see this string is came from web service when i pass this String than its give right output but when i strored this string in to citydetail variable and pass than it give output on html formate.
How can i solve this problem give some instruction.
To remove nbsp; use this citydetail.Replace("nbsp;","");. You can also learn about using Regex Expressions according to your application.
Given an HTML document, I want to identify all the numbers in the document and add custom tags around the numbers.
Right now, i use the following:
HtmlNodeCollection bodyNode = htmlDoc.DocumentNode.SelectNodes("//body");
MatchCollection numbersColl = Regex.Matches(htmlNode.InnerText, <some regex>);
Once I get the numbersColl, I can traverse through each Match and get the index.
However, I can't change the InnerText since it is read-only.
What I need is that if match.Value = 100 and match.Index=25, I want to replace that 25 with
<span isIdentified='true'> 25 </span>
Any help on this will be greatly appreciated. Currently, since I am not able to modify the inner text, I have to modify the InnerHtml but some element might have 25 in it's innerHtml. That should not be touched. But how do I identify whether the number is within
an html tag i.e. < table border='1' > has 1 in the tag.
Here's what I did to work around the read-only property limitation of the InnerText property of a Text node, just select the Parent node of the Text node and note the index of the Text node in the child node collections of the Parent node. Then just do a ReplaceChild(...).
private void WriteText(HtmlNode node, string text)
{
if (node.ChildNodes.Count > 0)
{
node.ReplaceChild(htmlDocument.CreateTextNode(text), node.ChildNodes.First());
}
else
{
node.AppendChild(htmlDocument.CreateTextNode(text));
}
}
In your case I believe you need to create a new Element node that wraps the text into an HtmlElement and then just use it as a replacement of the Text node.
Or even better, see if you can do something like the answer posted here:
Replacing a HTML div InnerText tag using HTML Agility Pack
creating a textnode does not what it should do in this case:
myParentNode.AppendChild(D.CreateTextNode("<script>alert('a');</script>"));
Console.Write(myParentNode.InnerHtml);
The result should be something like
<script....
but it is a working script task even if i add it as "TEXT" not as html. This causes kind of a security issue for me because the text would be a input from a anonymous user.
I'm trying to get a list of tags from a particular tag group in Umbraco (v4.0.2.1) using the following code:
var tags = umbraco.editorControls.tags.library.getAllTagsInGroup("document downloads");
What I want to do is just output a list of those tags. However, if I output the variable 'tags' it just outputs a list of all tags in a string. I want to split each tag onto a new line.
When I check the datatype of the 'tags' variable:
string tagType = tags.GetType().ToString();
...it outputs MS.Internal.Xml.XPath.XPathSelectionIterator.
So question is, how do I get the individual tags out of the 'tags' variable? How do I work with a variable of this data type? I can find examples of how to do it by loading an actual XML file, but I don't have an actual XML file - just the 'tags' variable to work with.
Thanks very much for any help!
EDIT1: I guess what I'm asking is, how do I loop through the nodes returned by an XPathSelectionIterator data type?
EDIT2: I've found this code, which almost does what I need:
XPathDocument document = new XPathDocument("file.xml");
XPathNavigator navigator = document.CreateNavigator();
XPathNodeIterator nodes = navigator.Select("/tags/tag");
nodes.MoveNext();
XPathNavigator nodesNavigator = nodes.Current;
XPathNodeIterator nodesText = nodesNavigator.SelectDescendants(XPathNodeType.Text, false);
while (nodesText.MoveNext())
debugString += nodesText.Current.Value.ToString();
...but it expects the URL of an actual XML file to load into the first line. My XML file is essentially the 'tags' variable, not an actual XML file. So when I replace:
XPathDocument document = new XPathDocument("file.xml");
...with:
XPathDocument document = new XPathDocument(tags);
...it just errors.
Since it is an Iterator, I would suggest you iterate it. ;-)
var tags = umbraco.editorControls.tags.library.getAllTagsInGroup("document downloads");
foreach (XPathNavigator tag in tags) {
// handle current tag
}
I think this does the trick a little better.
The problem is that getAllTagsInGroup returns the container for all tags, you need to get its children.
foreach( var tag in umbraco.editorControls.tags.library.getAllTagsInGroup("category").Current.Select("/tags/tag") )
{
/// Your Code
}
Using the HTMLAgilityPack to write out a new image node, it seems to remove the closing tag of an image, e.g. should be but when you check outer html, has .
string strIMG = "<img src='" + imgPath + "' height='" + pubImg.Height + "px' width='" + pubImg.Width + "px' />";
HtmlNode newNode = HtmlNode.Create(strIMG);
This breaks xhtml.
Telling it to output XML as Micky suggests works, but if you have other reasons not to want XML, try this:
doc.OptionWriteEmptyNodes = true;
Edit 1:Here is how to fix an HTML Agilty Pack document to correctly display image (img) tags:
if (HtmlNode.ElementsFlags.ContainsKey("img"))
{ HtmlNode.ElementsFlags["img"] = HtmlElementFlag.Closed;}
else
{ HtmlNode.ElementsFlags.Add("img", HtmlElementFlag.Closed);}
replace "img" for any other tag to fix them as well (input, select, and option come up frequently). Repeat as needed. Keep in mind that this will produce rather than , because of the HAP bug preventing the "closed" and "empty" flags from being set simultaneously.
Source: Mike Bridge
Original answer:
Having just labored over solutions to this issue, and not finding any sufficient answers (doctype set properly, using Output as XML, Check Syntax, AutoCloseOnEnd, and Write Empty Node options), I was able to solve this with a dirty hack.
This will certainly not solve the issue outright for everyone, but for anyone returning their generated html/xml as a string (EG via a web service), the simple solution is to use fake tags that the agility pack doesn't know to break.
Once you have finished doing everything you need to do on your document, call the following method once for each tag giving you a headache (notable examples being option, input, and img). Immediately after, render your final string and do a simple replace for each tag prefixed with some string (in this case "Fix_", and return your string.
This is only marginally better in my opinion than the regex solution proposed in another question I cannot locate at the moment (something along the lines of )
private void fixHAPUnclosedTags(ref HtmlDocument doc, string tagName, bool hasInnerText = false)
{
HtmlNode tagReplacement = null;
foreach(var tag in doc.DocumentNode.SelectNodes("//"+tagName))
{
tagReplacement = HtmlTextNode.CreateNode("<fix_"+tagName+"></fix_"+tagName+">");
foreach(var attr in tag.Attributes)
{
tagReplacement.SetAttributeValue(attr.Name, attr.Value);
}
if(hasInnerText)//for option tags and other non-empty nodes, the next (text) node will be its inner HTML
{
tagReplacement.InnerHtml = tag.InnerHtml + tag.NextSibling.InnerHtml;
tag.NextSibling.Remove();
}
tag.ParentNode.ReplaceChild(tagReplacement, tag);
}
}
As a note, if I were a betting man I would guess that MikeBridge's answer above inadvertently identifies the source of this bug in the pack - something is causing the closed and empty flags to be mutually exclusive
Additionally, after a bit more digging, I don't appear to be the only one who has taken this approach:
HtmlAgilityPack Drops Option End Tags
Furthermore, in cases where you ONLY need non-empty elements, there is a very simple fix listed in that same question, as well as the HAP codeplex discussion here: This essentially sets the empty flag option listed in Mike Bridge's answer above permanently everywhere.
There is an option to turn on XML output that makes this issue go away.
var htmlDoc = new HtmlDocument();
htmlDoc.OptionOutputAsXml = true;
htmlDoc.LoadHtml(rawHtml);
This seems to be a bug with HtmlAgilityPack. There are many ways to reproduce this, for example:
Debug.WriteLine(HtmlNode.CreateNode("<img id=\"bla\"></img>").OuterHtml);
Outputs malformed HTML. Using the suggested fixes in the other answers does nothing.
HtmlDocument doc = new HtmlDocument();
doc.OptionOutputAsXml = true;
HtmlNode node = doc.CreateElement("x");
node.InnerHtml = "<img id=\"bla\"></img>";
doc.DocumentNode.AppendChild(node);
Debug.WriteLine(doc.DocumentNode.OuterHtml);
Produces malformed XML / XHTML like <x><img id="bla"></x>
I have created a issue in CodePlex for this.