Extract all image urls from html except for those commented out

Question

I am using this regex to get all image urls in an html file:

(?<=img\s*\S*src\=[\x27\x22])(?<Url>[^\x27\x22]*)(?=[\x27\x22])

Is there any way to modify this regex to exclude any img tags that are commented out with html comment ""?

Answer 1

If your regex already works for extracting images (which would be a miracle in itself), consider a regex to strip HTML comments, like so:

<!--.*?-->

Replace that with an empty string, and any images inside the comment will no longer show up in your other regex.

Alternatively, if you're using PHP (you didn't tag a programming language), you can use the strip_tags function with "<img>" as the "allowable tags" parameter. This will strip out HTML comments, as well as other tags that may interfere with your regex.

Answer 2

It's actually also very simple when using the HTML agility pack, there's a bunch of settings in there that helps fixing bad HTML if needed. Like:

HtmlAgilityPack.HtmlDocument doc = new HtmlAgilityPack.HtmlDocument();
doc.OptionAutoCloseOnEnd = true;
doc.OptionCheckSyntax = false;
doc.OptionFixNestedTags = true;
// etc, just set them before calling Load or LoadHtml

http://htmlagilitypack.codeplex.com/

string textToExtractSrcFrom = "... your text here ...";

doc.LoadHtml(textToExtractSrcFrom);

var nodes = doc.DocumentNode.SelectNodes("//img[@src]") ?? new HtmlNodeCollection();
foreach (var node in nodes)
{
    string src = node.Attributes["src"].Value;
}

//or 
var links = nodes.Select(node => node.Attributes["src"].Value);