irc: URL scheme

Вторник, 29 Май 2007
Internet-Draft Mandar Mirashi draft-mirashi-url-irc-01.txt [email protected] Expires: February 28, 1997 August 29, 1996 "irc: URL scheme" Status of This Memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as ``work in progress.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet- Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Abstract A new URL scheme "irc:" is defined. The IRC URL scheme is used to refer to either IRC (Internet Relay Chat) servers or individual entities (channels or people) on IRC servers. Description With the advent of "plugins", and realtime support via CGI and Java, web developers have come up with different means to integrate IRC support into their products. This document attempts to define a URL scheme ("irc:") which would make this process easier. An IRC URL takes the form: irc:[ //[ [:] ]/[] [,needpass] ] where, The IRC server host to connect to. See RFC 1034 [Sec 3.5] and RFC 1123 [Sec 2.1] for details on allowed Internet hostname formats. If omitted, the client must connect to a prespecified default IRC server. irc: URL scheme implementors are recommended Expires February 28th, 1997 [Page 1] Internet Draft irc: URL scheme August 29, 1996 to provide a preconfigured list of IRC servers/networks to choose from, and must have the ability to let the user designate a default IRC server host. The port number to connect to. If : is omitted, the default IANA assigned IRC port 194 is used. Clients may use port 6667 as an alternate port in case connection to the default port fails. Clients should also maintain a default port number, as well as associations of port numbers with specific hosts. If a target is referred to, it takes the form: ::= | ::= | ::= ',needkey' The target can be either an IRC channel or a person on IRC (identified by his/her nickname and other associated information) RFC 1459 (sec 2.3) defines an IRC channel as: ::= ('#' | '&' | '+') ::= In the irc: URL scheme, "unsafe" characters (RFC 1738, Sec 2.2) in or must be encoded by a character triplet consisting of the character "%" followed by the two hexadecimal digits (from "0123456789ABCDEF") which form the hexadecimal value of the octet. (The characters "abcdef" may also be used in hexadecimal encodings.) Since most IRC channels begin with the '#' character which is unsafe in a URL, it must be encoded. To avoid the cumbersome % encoding for most references, this draft omits the specific mention of a channel prefix in a of type . irc: URL scheme implementors must maintain a prefix variable (by default, '#', with '&' and '+' as other allowable values) to form channel names in accordance with RFC 1459. Further, the characters '!', ',', ':' and '@' are reserved in the irc: URL scheme and must also be encoded. [,needkey] IRC channels can require a keyword (RFC 1459, Sec 4.2.1) before entrance to the channel is granted. This parameter indicates to the irc: URL scheme implementor that the user should be prompted for the channel key, before an attempt to dereference the URL is made. This parameter should be ignored for modeless + channels. Expires February 28th, 1997 [Page 2] Internet Draft irc: URL scheme August 29, 1996 is described by (also see RFC1459, Sec 2.3): ::= ',isnick' ::= | | ::= '!' '@' ::= '@' ::= { | | } ::= { } ::= 'a' ... 'z' | 'A' ... 'Z' ::= '0' ... '9' ::= '-' | '[' | ']' | '\' | '`' | '^' | '{' | '}' ::= ::= ::= Characters deemed unsafe (RFC 1738, Sec. 2.2) in (and thus in ) must be encoded as usual. The irc: URL scheme implementor may choose to initiate a DCC (direct client to client) chat connection to the user when is specified. Many IRC clients currently support DCC functionality and a rough draft appears at ftp://ftp.undernet.org/irc/docs/technical/DCC.doc. Alternatively, they may choose to stick to exchanging messages via IRC, or offer the user a choice between the two. [,needpass] IRC servers can require a password (RFC 1459, Sec 7) before a connection to the server is granted. This parameter indicates to the irc: URL scheme implementor that the user should be prompted for the server password, before an attempt to dereference the URL is made. Client issues irc: URL scheme implementors must have the following user configurable fields or variables in their clients (also see RFC 1459): * Default IRC server host to connect to (alternate servers if the connection to the default server fails, may also be listed). A list of IRC servers/networks to choose from is also suggested for inclusion. * Default port to connect on (alternate ports if the connection to the default port fails may also be listed) * Default channelname prefix (usually '#', but can also take the values '&' and '+') Expires February 28th, 1997 [Page 3] Internet Draft irc: URL scheme August 29, 1996 * Default nickname to connect under (alternate nicknames should be specified since the specified nickname may already be in use) * Real name (also known as the IRCNAME variable) of the person. The USER command passed to an IRC server requires a parameter. Since it is easy for a client to lie about its username by relying solely on the USER message, the availability of this as a user configurable field should be avoided. This field may be automatically obtained on Unix systems via the getpwuid () (or a similar) system call. On other systems, the identity section of mail programs on the system frequently contains a "reply-to" or an "e-mail" field, often in a [email protected] format. The user portion of this may be used for the parameter. Only if these methods fail, should the user be prompted for a . As discussed earlier, the client must be able to prompt the user for a channel key or server password, based on the irc: URL specified. It may also offer the user a choice of a DCC chat connection when a nickname is dereferenced. Examples The URL's: irc: irc:// irc:/// reference the default/local IRC server. The URL: irc:///,needpass references the default IRC server and prompts the user for a password, before connecting to it. The URL irc:///help references IRC channel help (this could be #help, &help or +help, depending on the channel prefix set) on the default IRC server. The URL irc:///[email protected]*uoknor.edu,isnick references a person with nickname Mmmm, and [email protected] matching [email protected]*uoknor.edu on the default IRC server. The URL, Expires February 28th, 1997 [Page 4] Internet Draft irc: URL scheme August 29, 1996 irc://foobar.org/Mmmm,isnick,needpass references a person with nickname Mmmm on server foobar.org. The connection to foobar.org takes place over the default port, and the user is prompted for a server password. The URL irc://foobar.org:6665/secret,needkey references the IRC channel secret on server foobar.org. The connection takes place over port 6665, and the user is prompted for a channel key in order to reference the channel. Current Implementations Despite the lack of a common URL scheme, many integration efforts between IRC and the world wide web have been successful. These can be roughly categorised into: IRC plugins: These are IRC clients distributed separately and designed to work in close conjunction with the browser. Current plugins include: http://home.netscape.com/comprod/chat.html (Netscape Chat - Netscape Corp) http://www.globalchat.com (Global Chat - Quarterdeck Corp) http://www.ichat.com/client.htm (iChat - iChat Inc) They often include proprietary protocol implementations, in addition to IRC support. Java gateways: These take the form of a Java capable Web browser that interacts with an IRC server and updates "live content" web pages. The foll. URL's which illustrate these, were functional at the time of writing: http://polaris.ibm.com/~gong/irc_room.html http://www.blackdown.org/~kbs/irctst/demo.html http://irc.webmaster.com http://virtual.itribe.net/jirc/ http://www.dimensionx.com/products/cafe/index.html http://www.hdmdigital.com/~cknight/dotcom/zirc/ These gateways take up resources on the machine hosting the web server, and are also slower than IRC clients which open a direct connection to the IRC server. A variation of the Java gateway is a CGI gateway, which is based on CGI scripts instead of Java, but quickly fading from existence due to CGI's limited realtime functionality. Expires February 28th, 1997 [Page 5] Internet Draft irc: URL scheme August 29, 1996 IRC client - Web browser communication: Recent IRC clients often communicate with the Web browser via mechanisms such as API calls or DDE, and pass back a URL to be opened via the browser. Some of these can also be set up as "plugins" or "helper applications". Clients that implement this include: http://apollo3.com/~acable/virc.html (Visual IRC) http://www.mirc.co.uk/ (mIRC) http://www.bcpl.lib.md.us/~frappa/pirch.html (Pirch) http://www.vapor.com/support/amirc/ (AmIRC) http://catless.ncl.ac.uk/Programs/Zircon/ (Zircon) http://xirc.bitgate.com/ (XIRC) It is anticipated that the irc: URL scheme would allow Web browsers to open a local dynamic "live content" page as demonstrated by the gateways (thus eliminating the need to go via a gateway). They may also choose to open a plugin IRC client. The choice is left to the individual irc: URL scheme implementor. History IRC as a protocol first appeared in 1988 and thus predates the world wide web by several years. A formal specification of the protocol was drawn up in 1993 (RFC 1459). Today, there are thousands of simultaneous users on various IRC networks. Integration efforts with the World Wide Web continue (as outlined above). The irc: URL scheme first appeared in the Rating Services and Rating Systems document published by the PICS (Platform for Internet Content Selection) technical subcommitee of the World Wide Web Consortium: http://www.w3.org/pub/WWW/PICS/ser vices.html However, the original definition lacked RFC 1459 conformance. This draft attempts to add RFC 1459 conformance to the scheme, besides other features previously lacking. Security Considerations Security issues are tackled in RFC 1738 and RFC 1459. Character encoding rules must be followed for unsafe and reserved characters. Clients should take care that attempts to connect to ports other than 194 in the well known port range 1-1024, are disregarded. IRC servers often use the non-registered port 6667 (or ports in the range 6000-7000) for clients to connect to. Since the URL dereference would always result in client to server messages prefixed by NICK, or USER, or JOIN or MSG, chances of a dangerous URL resolution are minimized. Nicknames on IRC are not constant - different people may use the Expires February 28th, 1997 [Page 6] Internet Draft irc: URL scheme August 29, 1996 same nickname at different times (although not simultaneously on the same IRC server or network). This feature/anomaly is inherent to the definition of the current IRC protocol (RFC 1459). It is highly recommended that irc: URL scheme implementors warn the user when dereferencing a instead of . A WHOIS IRC lookup is also suggested. Scheme summary The irc: URL scheme is unique in its own way. It does borrow concepts from other URL schemes (RFC 1738) however. Like the nntp: URL scheme, it allows the specification of a for a unique resource location. However, many IRC servers often limit connections from outside domains. Thus, like the news: and mailto: URL schemes, it allows for the resolution of this information at the client level, and like the file: URL scheme, allows to be an empty string. Like the telnet: URL scheme, it does not designate a data object, but rather an interactive service. The draft defines the irc: URL scheme and "must be configured" fields. This scheme is extremely useful given the shortcomings of current implementations. There's only one operation defined on this UR*, and it is not very GET like (the IRC protocol is outlined in RFC 1459). It can be proxied into HTTP/HTML, but this does have severe limitations as mentioned earlier. Security considerations have been outlined. It does not follow the relative URL (RFC 1808) model. References [RFC1738] RFC 1738. Uniform Resource Locators (URL). T. Berners-Lee, L. Masinter & M. McCahill. December 1994. [RFC 1459] RFC 1459. Internet Relay Chat (IRC) Protocol J. Oikarinen, D. Reed. May 1993. Acknowledgements A sincere thanks to various IRC server and client coders, HTML/WWW developers, the PICS technical subcommittee, W3 members, and former URI working group members, who offered help, advice and suggestions at all stages of the draft. People who offered help/advice/reviews/ new suggestions (in no particular order): Dan Connolly, Harald T. Alvestran, Larry Masinter, Darren Reed, Matthew Green, Bjorn Borud, Carl von Loesch, Dennis Holmes, Niels Bakker, James Egelhof, Arthur Liu, Robert Ullman, Klaus Wissmann. Expires February 28th, 1997 [Page 7] Internet Draft irc: URL scheme August 29, 1996 Those of you whom I inadvertently missed, you know who you are. Author's contact information: Name: Mandar Mirashi Address: 35B, Hudson Harbour Drive, Poughkeepsie, NY 12601. Phone#: 914-485-6264 Email: [email protected], [email protected] IRC Nick: Mmmm