Question

I am using the regex below to match the following statements:

@import url(normalize.css); @import url(style.css); @import
url(helpers.css);

   /// <summary>
   /// The regular expression to search files for.
   /// </summary>
   private static readonly Regex ImportsRegex = new Regex(@"@import\surl\(([^.]+\.css)\);", RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace);

This is matching my statements but when I am trying to get the groups out of my match I am getting the full result rather than the value I am expecting.

e.g expected result normalize.css
actual result @import url(normalize.css);

The code to do this is below. Can anyone tell me what I am doing wrong?

    /// <summary>
    /// Parses the string for css imports and adds them to the file dependency list.
    /// </summary>
    /// <param name="css">
    /// The css to parse.
    /// </param>
    private void ParseImportsToCache(string css)
    {
        GroupCollection groups = ImportsRegex.Match(css).Groups;

        // Check and add the @import params to the cache dependancy list.
        foreach (string groupName in ImportsRegex.GetGroupNames())
        {
            // I'm getting the full match here??
            string file = groups[groupName].Value;

            List<string> files = new List<string>();
            Array.ForEach(
                CSSPaths,
                cssPath => Array.ForEach(
                    Directory.GetFiles(
                        HttpContext.Current.Server.MapPath(cssPath),
                        file,
                        SearchOption.AllDirectories),
                    files.Add));

            this.cacheDependencies.Add(new CacheDependency(files.FirstOrDefault()));
        }
    }

Answer 1

You should always denote your Regex to what you are looking for. (?:exp) is for non-capturing groups, while () is for capturing groups. You can also give them names, like (?<name>exp)

Change your Regex to (?:@import\surl\()(?<filename>[^.]+\.css)(?:\);) and capture it like

pRegexMatch.Groups["filename"].Captures[0].Value.Trim();

Hope this helps.

Regards