轉換html中的相對路徑成絕對路徑

Convert Relative Paths to Absolute Using Regular Expressions

I ran into a situation where I needed to screen scrape some content from a site and display it on my own site. This works really well except for dependent files like javascripts, SWFs and images that had src attributes with relative paths. So I figured it wouldn't be that hard to create a helper method to find and replace them using Regular Expressions. So here it is:

public static String ConvertRelativePathsToAbsolute(String text, String absoluteUrl)
{
String value = Regex.Replace(text,
"<(.*?)(src|href)=\"(?!http)(.*?)\"(.*?)>",
"<$1$2=\"" + absoluteUrl + "$3\"$4>",
RegexOptions.IgnoreCase | RegexOptions.Multiline);
// Now just make sure that there isn't a // because if
// the original relative path started with a / then the
// replacement above would create a //.
return value.Replace(absoluteUrl + "/", absoluteUrl);
}

Sample Usage:

String html = "<p><img src=\"images/dot.gif\" alt=\"test\" /></p>";
String baseUrl = "http//hovertree.com/";
String replacedHtml = ConvertRelativePathsToAbsolute(html, baseUrl);
// replacedHtml => <p><img src="http://hovertree.com/images/dot.gif" alt=\"test\" /></p> 

本文原文：http://hovertree.com/