Import TechBot

svn path=/trunk/; revision=13064

irc/TechBot/TechBot.IRCLibrary/IrcMessage.cs

@@ -0,0 +1,503 @@
+using System;
+
+namespace TechBot.IRCLibrary
+{
+	/*
+	<message>  ::= [':' <prefix> <SPACE> ] <command> <params> <crlf>
+	<prefix>   ::= <servername> | <nick> [ '!' <user> ] [ '@' <host> ]
+	<command>  ::= <letter> { <letter> } | <number> <number> <number>
+	<SPACE>    ::= ' ' { ' ' }
+	<params>   ::= <SPACE> [ ':' <trailing> | <middle> <params> ]
+
+	<middle>   ::= <Any *non-empty* sequence of octets not including SPACE
+				   or NUL or CR or LF, the first of which may not be ':'>
+	<trailing> ::= <Any, possibly *empty*, sequence of octets not including
+					 NUL or CR or LF>
+
+	<crlf>     ::= CR LF
+
+	NOTES:
+
+	  1)    <SPACE> is consists only of SPACE character(s) (0x20).
+			Specially notice that TABULATION, and all other control
+			characters are considered NON-WHITE-SPACE.
+
+	  2)    After extracting the parameter list, all parameters are equal,
+			whether matched by <middle> or <trailing>. <Trailing> is just
+			a syntactic trick to allow SPACE within parameter.
+
+	  3)    The fact that CR and LF cannot appear in parameter strings is
+			just artifact of the message framing. This might change later.
+
+	  4)    The NUL character is not special in message framing, and
+			basically could end up inside a parameter, but as it would
+			cause extra complexities in normal C string handling. Therefore
+			NUL is not allowed within messages.
+
+	  5)    The last parameter may be an empty string.
+
+	  6)    Use of the extended prefix (['!' <user> ] ['@' <host> ]) must
+			not be used in server to server communications and is only
+			intended for server to client messages in order to provide
+			clients with more useful information about who a message is
+			from without the need for additional queries.
+	 */
+	/*
+   NOTICE AUTH :*** Looking up your hostname
+   NOTICE AUTH :*** Checking Ident
+   NOTICE AUTH :*** Found your hostname
+   NOTICE AUTH :*** No ident response
+	 */
+
+	/// <summary>
+	/// IRC message.
+	/// </summary>
+	public class IrcMessage
+	{
+		#region Private fields
+		private string line;
+		private string prefix;
+		private string prefixServername;
+		private string prefixNickname;
+		private string prefixUser;
+		private string prefixHost;
+		private string command;
+		private string parameters;
+		#endregion
+
+		/// <summary>
+		/// Line of text that is to be parsed as an IRC message.
+		/// </summary>
+		public string Line
+		{
+			get
+			{
+				return line;
+			}
+		}
+
+		/// <summary>
+		/// Does the message have a prefix?
+		/// </summary>
+		public bool HasPrefix
+		{
+			get
+			{
+				return prefix != null;
+			}
+		}
+
+		/// <summary>
+		/// Prefix or null if none exists.
+		/// </summary>
+		public string Prefix
+		{
+			get
+			{
+				return prefix;
+			}
+		}
+
+		/// <summary>
+		/// Servername part of prefix or null if no prefix or servername exists.
+		/// </summary>
+		public string PrefixServername
+		{
+			get
+			{
+				return prefixServername;
+			}
+		}
+
+		/// <summary>
+		/// Nickname part of prefix or null if no prefix or nick exists.
+		/// </summary>
+		public string PrefixNickname
+		{
+			get
+			{
+				return prefixNickname;
+			}
+		}
+
+		/// <summary>
+		/// User part of (extended) prefix or null if no (extended) prefix exists.
+		/// </summary>
+		public string PrefixUser
+		{
+			get
+			{
+				return prefixUser;
+			}
+		}
+
+		/// <summary>
+		/// Host part of (extended) prefix or null if no (extended) prefix exists.
+		/// </summary>
+		public string PrefixHost
+		{
+			get
+			{
+				return prefixHost;
+			}
+		}
+
+		/// <summary>
+		/// Command part of message.
+		/// </summary>
+		public string Command
+		{
+			get
+			{
+				return command;
+			}
+		}
+
+		/// <summary>
+		/// Is command numeric?
+		/// </summary>
+		public bool IsCommandNumeric
+		{
+			get
+			{
+				if (command == null || command.Length != 3)
+				{
+					return false;
+				}
+				try
+				{
+					Int32.Parse(command);
+					return true;
+				}
+				catch (Exception)
+				{
+					return false;
+				}
+			}
+		}
+
+		/// <summary>
+		/// Command part of message as text.
+		/// </summary>
+		public string CommandText
+		{
+			get
+			{
+				return command;
+			}
+		}
+
+		/// <summary>
+		/// Command part of message as a number.
+		/// </summary>
+		/// <exception cref="InvalidOperationException">Thrown if IsCommandNumeric returns false.</exception>
+		public int CommandNumber
+		{
+			get
+			{
+				if (IsCommandNumeric)
+				{
+					return Int32.Parse(command);
+				}
+				else
+				{
+					throw new InvalidOperationException();
+				}
+			}
+		}
+
+		/// <summary>
+		/// Parameters part of message.
+		/// </summary>
+		public string Parameters
+		{
+			get
+			{
+				return parameters;
+			}
+		}
+
+		/// <summary>
+		/// Constructor.
+		/// </summary>
+		/// <param name="line">Line of text that is to be parsed as an IRC message.</param>
+		public IrcMessage(string line)
+		{
+			/*
+			 * <message>  ::= [':' <prefix> <SPACE> ] <command> <params> <crlf>
+			 * <prefix>   ::= <servername> | <nick> [ '!' <user> ] [ '@' <host> ]
+			 * :Oslo1.NO.EU.undernet.org 461 MYNICK USER :Not enough parameters
+			 */
+			try
+			{
+				this.line = line;
+				int i = 0;
+
+				#region Prefix
+				if (line[i].Equals(':'))
+				{
+					i++;
+					prefix = "";
+					/* This message has a prefix */
+					string s = "";
+					while (i < line.Length && line[i] != ' ' && line[i] != '!' && line[i] != '@')
+					{
+						s += line[i++];
+					}
+					if (IsValidIrcNickname(s))
+					{
+						prefixNickname = s;
+						prefix += prefixNickname;
+						if (line[i] == '!')
+						{
+							/* This message has an extended prefix */
+							i++;
+							s = "";
+							while (i < line.Length && line[i] != ' ' && line[i] != '@')
+							{
+								s += line[i];
+								i++;
+							}
+							prefixUser = s;
+							prefix += "!" + prefixUser;
+						}
+						if (line[i] == '@')
+						{
+							/* This message has a host prefix */
+							s = "";
+							do
+							{
+								s += line[++i];
+							}
+							while (i < line.Length && line[i] != ' ');
+							prefixHost = s;
+							prefix += "@" + prefixHost;
+						}
+					}
+					else /* Assume it is a servername */
+					{
+						prefixServername = s;
+						prefix += prefixServername;
+					}
+
+					/* Skip spaces */
+					while (i < line.Length && line[i] == ' ')
+					{
+						i++;
+					}
+				}
+				else
+				{
+					prefix = null;
+				}
+				#endregion
+
+				#region Command
+				if (Char.IsDigit(line[i]))
+				{
+					if (!Char.IsDigit(line, i + 1) || !Char.IsDigit(line, i + 2))
+					{
+						throw new Exception();
+					}
+					command = String.Format("{0}{1}{2}", line[i++], line[i++], line[i++]);
+				}
+				else
+				{
+					command = "";
+					while (i < line.Length && Char.IsLetter(line[i]))
+					{
+						command += line[i];
+						i++;
+					}
+				}
+				#endregion
+
+				#region Parameters
+				while (true)
+				{
+					/* Skip spaces */
+					while (i < line.Length && line[i] == ' ')
+					{
+						i++;
+					}
+					if (i < line.Length && line[i].Equals(':'))
+					{
+						i++;
+
+						/* Trailing */
+						while (i < line.Length && line[i] != ' ' && line[i] != '\r' && line[i] != '\n' && line[i] != 0)
+						{
+							if (parameters == null)
+							{
+								parameters = "";
+							}
+							parameters += line[i];
+							i++;
+						}
+					}
+					else
+					{
+						/* Middle */
+						while (i < line.Length && line[i] != '\r' && line[i] != '\n' && line[i] != 0)
+						{
+							if (parameters == null)
+							{
+								parameters = "";
+							}
+							parameters += line[i];
+							i++;
+						}
+					}
+					if (i >= line.Length)
+					{
+						break;
+					}
+				}
+				#endregion
+			}
+			catch (Exception ex)
+			{
+				throw new MalformedMessageException("The message is malformed.", ex);
+			}
+		}
+
+		/// <summary>
+		/// Constructor.
+		/// </summary>
+		/// <param name="prefixServername"></param>
+		/// <param name="prefixNickname"></param>
+		/// <param name="prefixUser"></param>
+		/// <param name="prefixHost"></param>
+		/// <param name="command"></param>
+		/// <param name="parameters"></param>
+		public IrcMessage(string prefixServername,
+			string prefixNickname,
+			string prefixUser,
+			string prefixHost,
+			string command,
+			string parameters)
+		{
+			throw new NotImplementedException();
+		}
+
+		/// <summary>
+		/// Constructor.
+		/// </summary>
+		/// <param name="command">IRC command.</param>
+		/// <param name="parameters">IRC command parameters. May be null if there are no parameters.</param>
+		public IrcMessage(string command,
+			string parameters)
+		{
+			if (command == null || !IsValidIrcCommand(command))
+			{
+				throw new ArgumentException("Command is not a valid IRC command.", "command");
+			}
+			/* An IRC message must not be longer than 512 characters (including terminating CRLF) */
+			int parametersLength = (parameters != null) ? 1 + parameters.Length : 0;
+			if (command.Length + parametersLength > 510)
+			{
+				throw new MalformedMessageException("IRC message cannot be longer than 512 characters.");
+			}
+			this.command = command;
+			this.parameters = parameters;
+			if (parameters != null)
+			{
+				this.line = String.Format("{0} {1}\r\n", command, parameters);
+			}
+			else
+			{
+				this.line = String.Format("{0}\r\n", command);
+			}
+		}
+
+		/// <summary>
+		/// Returns wether a string of text is a valid IRC command.
+		/// </summary>
+		/// <param name="command">The IRC command.</param>
+		/// <returns>True, if <c ref="command">command</c> is a valid IRC command, false if not.</returns>
+		private static bool IsValidIrcCommand(string command)
+		{
+			foreach (char c in command)
+			{
+				if (!Char.IsLetter(c))
+				{
+					return false;
+				}
+			}
+			return true;
+		}
+
+		private const string IrcSpecial = @"-[]\`^{}";
+		private const string IrcSpecialNonSpecs = @"_";
+
+		/// <summary>
+		/// Returns wether a character is an IRC special character.
+		/// </summary>
+		/// <param name="c">Character to test.</param>
+		/// <returns>True if the character is an IRC special character, false if not.</returns>
+		private static bool IsSpecial(char c)
+		{
+			foreach (char validCharacter in IrcSpecial)
+			{
+				if (c.Equals(validCharacter))
+				{
+					return true;
+				}
+			}
+			foreach (char validCharacter in IrcSpecialNonSpecs)
+			{
+				if (c.Equals(validCharacter))
+				{
+					return true;
+				}
+			}
+			return false;
+		}
+
+		/// <summary>
+		/// Returns wether a string of text is a valid IRC nickname.
+		/// </summary>
+		/// <param name="nickname">The IRC nickname.</param>
+		/// <returns>True, if <c ref="nickname">nickname</c> is a valid IRC nickname, false if not.</returns>
+		private static bool IsValidIrcNickname(string nickname)
+		{
+			/*
+			 * <nick>       ::= <letter> { <letter> | <number> | <special> }
+			 * <letter>     ::= 'a' ... 'z' | 'A' ... 'Z'
+			 * <number>     ::= '0' ... '9'
+   			 * <special>    ::= '-' | '[' | ']' | '\' | '`' | '^' | '{' | '}'
+			 */
+			/* An IRC nicknmame must be 1 - 9 characters in length. We don't care so much if it is larger */
+			if ((nickname.Length < 1) || (nickname.Length > 30))
+			{
+				return false;
+			}
+			/* First character must be a letter. */
+			if (!Char.IsLetter(nickname[0]))
+			{
+				return false;
+			}
+			/* Check the other valid characters for validity. */
+			foreach (char c in nickname)
+			{
+				if (!Char.IsLetter(c) && !Char.IsDigit(c) && !IsSpecial(c))
+				{
+					return false;
+				}
+			}
+			return true;
+		}
+
+		/// <summary>
+		/// Write contents to a string.
+		/// </summary>
+		/// <returns>Contents as a string.</returns>
+		public override string ToString()
+		{
+			return String.Format("Line({0})Prefix({1})Command({2})Parameters({3})",
+				line, prefix != null ? prefix : "(null)",
+				command != null ? command : "(null)",
+				parameters != null ? parameters : "(null)");
+		}
+	}
+}