'How to find a unique string within html and wrap it with a tag, but exclude links and urls

I'm looking for a way to look for a specific string within a page in the visible text and then wrap that string in <em> tags. I have tried used HTML Agility Pack and had some success with a Regex.Replace but if the string is included within a url it also gets replaced which I do not want, if it's within an image name, it gets replaced and this obviously breaks the link or image url.

An example attempt:

var markup = Encoding.UTF8.GetString(buffer);
var replaced = Regex.Replace(markup, "product-xs", " <em>product</em>-xs", RegexOptions.IgnoreCase);
        
var output = Encoding.UTF8.GetBytes(replaced);
    
    _stream.Write(output, 0, output.Length);

This does not work as it would replace a <a href="product/product-xs"> with <a href="product/<em>product</em>-xs"> - which I don't want.

The string is coming from a text string value within a CMS so the user can't wrap the words there and ideally, I want to catch all instances of the word that are already published.

Ideally I would want to exclude <title> tags, <img> tags and <a> tags, everything else should get the wrapped tag.

Before I used the HTML Agility Pack, a fellow front end dev tried it with JavaScript but that had an unexpected impact on dropdown menus.

If you need any more info, just ask.

javascriptc++sharphtmlhtml-agility-pack


Solution 1:[1]

You can use HTML Agility Pack to select only the text nodes (i.e. the text that exists between any two tags) with a bit of XPath and modify them like this.

Looking only in body will exclude <title>, <meta> etc. The not excludes script tags, you can exclude others in the same way (or check the parent node in the loop).

foreach (HtmlNode node in htmlDoc.DocumentNode.SelectNodes("//body//*[not(self::script)]/text()"))
{
    var newNode = htmlDoc.CreateTextNode(node.InnerText.Replace("product-xs", "<em>product</em>-xs"));
    node.ParentNode.ReplaceChild(newNode, node);
}

I've used a simple replace, regex will work fine too, prob best to check the performance of each approach and choose which works best for your use case.

Sources

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Source: Stack Overflow

Solution Source
Solution 1

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