Can u tell me the regular expression for finding the image url in <img> tag in HTML using VB .Net code

Question

Hi

I want to extract the image url from any website. I am reading the source info through webRequest. I want a regular expression which will fetch the Image url from this content i.e the Src value in the tag.

Thanks

Answer 1

/(?:\"|')[^\\x22*<>|\\\\]+?\.(?:jpg|bmp|gif|png)(?:\"|')/i

is a decent one I have used before. This gets any reference to an image file within an html document. I didn't strip " or ' around the match, so you will need to do that.

Answer 2

Try this*:

<img .*?src=["']?([^'">]+)["']?.*?>

Tested here with:

<img class="test" src="/content/img/so/logo.png" alt="logo homepage">

Gives

$1 = /content/img/so/logo.png

The $1 (you have to mouseover the match to see it) corresponds to the part of the regex between (). How you access that value will depend on what implementation of regex you are using.

*If you want to know how this works, leave a comment

EDIT As nearly always with regexp, there are edge cases:

<img title="src=hack" src="/content/img/so/logo.png" alt="logo homepage">

This would be matched as 'hack'.

Answer 3

I'd recommend using an HTML parser to read the html and pull the image tags out of it, as regexes don't mesh well with data structures like xml and html.

In C#: (from this SO question)

    var web = new HtmlWeb();
    var doc = web.Load("http://www.stackoverflow.com");

    var nodes = doc.DocumentNode.SelectNodes("//img[@src]");

    foreach (var node in nodes)
    {
            Console.WriteLine(node.src);
    }