URI Parser: A set of 20 CLR functions for URI parsing

• bret.lowery

  Old Hand

  Points: 302

  More actions

  July 21, 2011 at 12:04 am

  #240195

  Comments posted to this topic are about the item URI Parser: A set of 20 CLR functions for URI parsing

• richardd

  Hall of Fame

  Points: 3972

  More actions

  July 21, 2011 at 10:39 am

  #1356598

  Some suggestions:

  [font="Courier New"]if (URI.IsNull == true)[/font]

  The IsNull property is a boolean, so this should be: "if (URI.IsNull)".

  [font="Courier New"]URI.ToString().TrimStart().TrimEnd().Length < 1[/font]

  Or, as it's known in .NET, ".ToString().Trim().Length == 0". You've just saved one string allocation per call, and you'll never be able to produce a .NET string with a negative length.

  [font="Courier New"]throw new Exception(...)[/font]

  Don't do this. Ever. Throw a more specific exception - ArgumentNullException or ArgumentException would be appropriate here.

  [font="Courier New"]catch (Exception ex)[/font]

  Can your code handle every possible error condition? Thread abort? Out of memory? Stack overflow?

  No, I didn't think so.

  The Uri constructor will only throw two types of exception: ArgumentNullException if the parameter is null, or UriFormatException if the parameter is not a valid URI. You've already tested for a null parameter, so you only need to catch a UriFormatException.

  [font="Courier New"]throw ex;[/font]

  You've just destroyed the stack trace for that exception. Thanks a lot!

  If you need to re-throw an exception, use "throw;", not "throw ex;". Your users will thank you for it.

  [font="Courier New"]try { ... new Uri(value) ... } catch ...[/font]

  If you're going to re-throw the exception, you don't need the "try ... catch" block. If you're not going to re-throw the exception, it would be significantly more efficient to use the static TryCreate method instead.

  Here's a cleaned-up version of the ParseURI function to get you going:

  public static SqlString ParseURI(

  SqlString URI,

  UriComponents Component,

  short EscapeMode,

  SqlBoolean ReturnNullOnParseError,

  SqlBoolean ReturnNullIfURINull,

  SqlBoolean ReturnNullIfURIEmpty

  )

  {

  if (URI.IsNull)

  {

  if (ReturnNullIfURINull.IsTrue) return SqlString.Null;

  throw new ArgumentNullException("URI");

  }

  string uriString = URI.ToString().Trim();

  if (uriString.Length == 0)

  {

  if (ReturnNullIfURIEmpty.IsTrue) return SqlString.Null;

  throw new ArgumentException("URI must not be empty.", "URI");

  }

  Uri uri;

  if (ReturnNullOnParseError.IsTrue)

  {

  if (!Uri.TryCreate(uriString, UriKind.Absolute, out uri))

  {

  return SqlString.Null;

  }

  }

  else

  {

  uri = new Uri(uriString);

  }

  UriFormat format;

  switch (EscapeMode)

  {

  case 1:

  format = UriFormat.Unescaped;

  break;

  case 2:

  format = UriFormat.UriEscaped;

  break;

  default:

  format = UriFormat.SafeUnescaped;

  break;

  }

  return (SqlString)uri.GetComponents(Component, format);

  }