Relative to absolute paths in HTML (asp.net)

Question

Hello all,

I need to create a newsletters by URL. I to do next:

1. Create a WebClient;
2. Use WebClient's method DownloadData to get a source of page in byte array;
3. Get string from source-html byte array and set it to the newsletter content.

But I have some troubles with paths. All elements' sources were relative (/img/welcome.png) but I need absolute (http://www.mysite.com/img/welcome.png).

How can I do this?

Best regards, Alex.

Answer 1

if the request comes in from your site (same domain links) then you can use this:

new Uri(Request.Uri, "/img/welcome.png").ToString();

If you're in a non-web app, or you want to hardcode the domain name:

new Uri("http://www.mysite.com", "/img/welcome.png").ToString();

Answer 2

One of the possible ways to resolve this task is the use the HtmlAgilityPack library.

Some example (fix links):

WebClient client = new WebClient();
byte[] requestHTML = client.DownloadData(sourceUrl);
string sourceHTML = new UTF8Encoding().GetString(requestHTML);

HtmlDocument htmlDoc = new HtmlDocument();
htmlDoc.LoadHtml(sourceHTML);

foreach (HtmlNode link in htmlDoc.DocumentNode.SelectNodes("//a[@href]"))
{
    if (!string.IsNullOrEmpty(link.Attributes["href"].Value))
    {
        HtmlAttribute att = link.Attributes["href"];
        att.Value = this.AbsoluteUrlByRelative(att.Value);
    }
}