Chris Taylor

Parsing CSV files into DataTable with RegEx

Just sitting blindly surfing, I came across a routine that appears to do a good job of using RegEx to parse CSV files and build a DataTable. It needs some enhancing to switch between generated columns and using the first row as column headers, also requires some changes to be able to handle very large files, but it seems to be a good starting point. Here is the RegEx used

 ((?<field>[^\",\\r\\n]+)|\"(?<field>([^\"]|\"\")+)\")(,|(?<rowbreak>\\r\\n|\\n|$))

It needs some post processing for the double quoted identifiers, but for the details take a look at the original link

http://www.hotblue.com/article0000.aspx?a=0006

HttpWebRequest and persistent cookies

Today a poster wanted to know how to associate a persistent cookie with its URL when performing a HttpWebRequest to the URL. Fortunately I recently wrote an automated login application in C++ and knew of the WININET function InternetGetCookie, which returns the contents of a cookie related to a URL. I could not find a corresponding .NET method so I put toghether the following piece of code. It lacks decent error handling, but gets the cookies and builds a CookieContainer that can then be assigned to the CookieContainer of a HttpWebRequest.

[DllImport("wininet.dll", SetLastError=true)]
public static extern bool InternetGetCookie(
  string url, string cookieName,
  StringBuilder cookieData, ref int size);

private static CookieContainer GetUriCookieContainer(Uri uri)
{
  CookieContainer cookies = null;
 
  // Determine the size of the cookie
  int datasize = 256;
  StringBuilder cookieData = new StringBuilder(datasize);

  if (!InternetGetCookie(uri.ToString(), null, cookieData,
    ref datasize))
  {
    if (datasize < 0) 
      return null;

    // Allocate stringbuilder large enough to hold the cookie
    cookieData = new StringBuilder(datasize);
    if ( !InternetGetCookie(uri.ToString(), null, cookieData,
      ref datasize) )
      return null;
  }

  if (cookieData.Length > 0)
  {
    cookies = new CookieContainer();
    cookies.SetCookies(uri, cookieData.ToString().Replace(';', ','));
  }
  return cookies;
}