Get repository to current brcon2022 state. - gopher-protocol - Gopher Protocol Extension Project
HTML git clone git://bitreich.org/gopher-protocol git://enlrupgkhuxnvlhsf6lc3fziv5h2hhfrinws65d7roiv6bfj7d652fid.onion/gopher-protocol
DIR Log
DIR Files
DIR Refs
DIR Tags
DIR README
DIR LICENSE
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DIR commit f7bb7959972ce0d459cb2a7b478250f908b3728d
HTML Author: Christoph Lohmann <20h@r-36.net>
Date: Sat, 6 Aug 2022 14:06:48 +0200
Get repository to current brcon2022 state.
Diffstat:
A LICENSE | 12 ++++++++++++
A README.md | 29 +++++++++++++++++++++++++++++
A TODO.md | 7 +++++++
A references/gopherplus.txt | 1267 ++++++++++++++++++++++++++++++
A references/rfc1436.txt | 906 +++++++++++++++++++++++++++++++
A references/rfc4266.txt | 339 +++++++++++++++++++++++++++++++
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DIR diff --git a/LICENSE b/LICENSE
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+/*
+ * ----------------------------------------------------------------------------
+ * "THE FRIKANDEL-WARE LICENSE":
+ * The authors of this repository wrote this file. As long as you retain this
+ * notice you can do whatever you want with this stuff. If we meet some day,
+ * and you think this stuff is worth it, you can buy me a frikandel in return.
+ * ----------------------------------------------------------------------------
+ *
+ * Authors:
+ * Hiltjo Posthuma <hiltjo@codemadness.org>
+ * Christoph Lohmann <20h@r-36.net>
+ */
DIR diff --git a/README.md b/README.md
@@ -0,0 +1,29 @@
+# Gopher Protocol
+
+## Introduction
+
+Gopher is a really old protocol. It has much history to preserve. Over
+time and development the usage changed from the original RFC 1436 (see
+rfc1436.txt) to usage now (2018). We now use UTF-8, we have other media
+format, file type detection is more advanced, the web has grown and
+brought use URIs and gopher+ has failed.
+
+The goal of this repository is to gather and document recommendations
+for how to use gopher today so errors of the past are not redone.
+
+We do not plan to write a new RFC, since the recommendations are rather
+small and do not require a big redefinition of the basic gopher
+protocol.
+
+## Recommendations
+
+See the gopher-extension.md for the current state.
+
+## License
+
+See LICENSE file.
+
+## Have Fun
+
+We all should have fun!
+
DIR diff --git a/TODO.md b/TODO.md
@@ -0,0 +1,7 @@
+## TODO
+
+* define more types such as 'd', 's', 'a'?
+ * TODO: add all historical item types found
+* define robots.txt? (probably out of scope for this document)?
+ * search for mailing list post about robots.txt of 20h
+
DIR diff --git a/references/gopherplus.txt b/references/gopherplus.txt
@@ -0,0 +1,1267 @@
+
+Gopher+
+
+
+upward compatible enhancements to
+the Internet Gopher protocol
+
+
+
+Farhad Anklesaria, Paul Lindner, Mark P. McCahill,
+Daniel Torrey, David Johnson, Bob Alberti
+
+Microcomputer and Workstation Networks Center /
+Computer and Information Systems
+University of Minnesota
+
+July 30, 1993
+
+
+
+gopher+ n. 1. Hardier strains of mammals of the
+family Geomyidae. 2. (Amer. colloq.) Native or
+inhabitant of Minnesota, the Gopher state, in full
+winter regalia (see PARKA). 3. (Amer. colloq.)
+Executive secretary. 4. (computer tech.) Software
+following a simple protocol for burrowing through a
+TCP/IP internet, made more powerful by simple
+enhancements (see CREEPING FEATURISM).
+
+
+Abstract
+
+The internet Gopher protocol was designed for
+distributed document search and retrieval. The
+documents "The internet Gopher protocol: a
+distributed document search and retrieval protocol"
+and internet RFC 1436 describe the basic protocol and
+has an overview of how to implement new client and
+server applications. This document describes a set of
+enhancements to the syntax, semantics and
+functionality of the original Gopher protocol.
+
+
+Distribution of this document is unlimited. Please
+send comments to the Gopher development team:
+<gopher@boombox.micro.umn.edu>. Implementation of
+the mechanisms described here is encouraged.
+
+
+
+1. Introduction
+
+The Internet Gopher protocol was designed primarily to
+act as a distributed document delivery system. It
+has enjoyed increasing popularity, and is being used
+for purposes that were not visualized when the
+protocol was first outlined. The rest of this
+document describes the Gopher+ enhancements in a non-
+rigorous but easily read and understood way. There
+is a short BNF-like section at the end for exact
+syntax descriptions. Throughout the document, "F"
+stands for the ASCII TAB character. There is an
+implicit carriage return and linefeed at the ends of
+lines; these will only be explicitly mentioned where
+necessary to avoid confusion. To understand this
+document, you really must be familiar with the basic
+Gopher protocol.
+
+
+Servers and clients understanding the Gopher+
+extensions will transmit extra information at the ends
+of list and request lines. Old, basic gopher clients
+ignore such information. New Gopher+ aware servers
+continue to work at their old level with unenhanced
+clients. The extra information that can be
+communicated by Gopher+ clients may be used to summon
+new capabilities to bridge the most keenly felt
+shortcomings of the venerable old Gopher.
+
+
+
+
+2. How does Gopher+ work?
+
+Gopher+ enhancements rely on transmitting an "extra"
+tab delimited fields beyond what regular (old) Gopher
+servers and clients now use. If most existing (old)
+clients were to encounter extra stuff beyond the
+"port" field in a list (directory), most would ignore
+it. Gopher+ servers will return item descriptions in
+this form:
+
+
+1Display stringFselector stringFhostFportFextra
+stuff<CRLF>
+
+
+If an existing (old) client has problems with
+additional information beyond the port, it should not
+take much more than a simple tweak to have it discard
+unneeded stuff.
+
+
+
+
+2.1 Advisory issued to client maintainers.
+
+If it does not do this already, your existing client
+should be modified as soon as possible to ignore
+extra fields beyond what it expects to find. This
+will ensure thatyour clients does not break when it
+encounters Gopher+ servers in gopherspace.
+
+
+All the regular Gopher protocol info remains intact
+except for:
+
+
+(1) Instead of just a CRLF after the port field in
+any item of a list (directory) there may be an
+optional TAB followed by extra stuff as noted above
+(explanation to follow).
+
+
+
+(2) In the original Gopher protocol, there was
+provision for a date-time descriptor (sec 3.6) to be
+sent after the selector (for use by autoindexer
+beasts). As far as we know, while the descriptor is
+implemented in the Mac server, it is not in any other
+server and no clients or daemons use it. This is a
+good time to withdraw this feature. The basic gopher
+protocol has been revised for the final time and will
+be frozen.
+
+
+
+
+
+
+2.2 Gopher+ item lists.
+
+Gopher servers that can utilize the Gopher+
+enhancements will send some additional stuff
+(frequently the character "+") after the port field
+describing any list item. eg:
+
+
+1Some old directoryFfoo selectorFhost1Fport1
+
+1Some new directoryFbar selectorFhost1Fport1F+
+
+0Some file or otherFmoo selectorFhost2Fport2F+
+
+
+The first line is the regular old gopher item
+description. The second line is new Gopher+ item
+description. The third line is a Gopher+ description
+of a document. Old gopher clients can request the
+latter two items using old format gopher selector
+strings and retrieve the items. New, Gopher+ savvy
+clients will notice the trailing + and know that they
+can do extra things with these kinds of items.
+
+
+
+
+
+2.3 Gopher+ data transfer.
+
+If a client sends out a Gopher+ type request to a
+server (by tagging on a tab and a "+" to the
+request):
+
+
+ bar selectorF+
+
+
+The server may return the response in one of three
+ways; examples below:
+
+
+ +5340<CRLF><data>
+
+
+
+ +-1<CRLF><data><CRLF>.<CRLF>
+
+
+
+ +-2<CRLF><data>
+
+
+The first response means: I am going to send exactly
+5340 bytes at you and they will begin right after this
+line. The second response means: I have no idea how
+many bytes I have to send (or I am lazy), but I will
+send a period on a line by itself when I am done.
+The third means: I really have no idea how many
+bytes I have to send, and what's more, they COULD
+contain the <CRLF>.<CRLF> pattern, so just read until
+I close the connection.
+
+
+The first character of a response to a Gopher+ query
+denotes success (+) or failure (-). Following that is
+a token to be interpreted as a decimal number. If the
+number is >= 0, it describes the length of the
+dataBlock. If = -1, it means the data is period
+terminated. If = -2, it means the data ends when the
+connection closes.
+
+
+The server may return an error also, as in:
+
+
+--1<CRLF><data><CRLF>.<CRLF>
+
+
+The (short!) error message will be in ASCII text in
+the data part. The first token on the first line of
+the error text (data) contains an error-code (an
+integer). It is recommended that the first line also
+contain the e-mail address of the administrator of
+the server (in angle brackets). Both the error-code
+and the email address may easily be extracted by the
+client. Subsequent lines contain a short error
+message that may be displayed to the user. Basic error
+codes are:
+
+
+ 1 Item is not available.
+
+ 2 Try again later ("eg. My load is too high
+right now.")
+
+ 3 Item has moved. Following the error-code is
+the gopher descriptor
+
+ of where it now lives.
+
+
+More error codes may be defined as the need arises.
+
+
+
+This should be obvious: if the client sends out an
+"old" Gopher kind of request:
+
+
+
+ bar selector
+
+
+
+the server will know that it is talking to an old
+client and will respond in the old way. This means
+that old gopher clients can still access information
+on Gopher+ servers.
+
+
+
+
+2.4 Gopher+ client requests.
+
+
+Clients can send requests to retrieve the contents of
+an item in this form:
+
+
+
+selectorstringF+[representation][FdataFlag]<CRLF>[dat
+ablock]
+
+
+If dataFlag is '0', or nonexistent, then the client
+will not send any data besides the selector string.
+If the dataFlag is '1' then a block of data will
+follow in the same format as Section 2.3. The client
+can send a large amount of data to the server in the
+dataBlock. Representations or alternative views of an
+item's contents may be discovered by interrogating the
+server about the item's attribute information; this is
+explained below.
+
+
+Note that in the original Gopher protocol, a query
+submitted to an index server might have a selector
+string followed by a TAB and the words for which the
+index server was being asked to search. In Gopher+,
+the extra TAB and Gopher+ information follow the words
+for which the server is being asked to search. Gopher+
+client have to be smart enough to know that in the
+case of a type 7 item (an index server) they append
+the Gopher+ information after the words being searched
+for.
+
+
+
+2.5 Gopher+ Item Attribute Information.
+
+
+The most basic enhancement of Gopher+ items is the
+ability to associate information about an item such
+as size, alternative views, the administrator, an
+abstract, etc. with the item. To get Attribute
+Information, a client can send out a request to the
+gopher server that looks like this:
+
+
+ selector stringF!<CRLF>
+
+
+(think of "!" as an upside-down i for "information").
+To the server this means "Instead of returning the
+contents of the item, return the item's Attribute
+Information". The Attribute Information is returned as
+an ASCII text stream containing blocks of
+information.For example, a server might return:
+
+
+ +INFO: 0Some file or otherFmoo
+selectorFhost2Fport2F+
+
+ +ADMIN:
+
+ Admin: Frodo Gophermeister <fng@bogus.edu>
+
+ Mod-Date: Wed Jul 28 17:02:01 1993
+<19930728170201>
+
+ +VIEWS:
+
+ Text/plain: <10k>
+
+ application/postscript: <100k>
+
+ Text/plain De_DE: <15k>
+
+ application/MacWriteII: <45K>
+
+ +ABSTRACT:
+
+ This is a short (but multi-line) abstract about
+the
+
+ item. Two or three lines ought to be enough
+
+
+The beginning of a block of information is denoted by
+a "+" in column 1 of a line. Another way to think of
+it is: the name of each block begins with a + and the
+rest of the name cannot contain a +. Each line of
+information within a block begins with a space so
+that it is easy to locate the beginning of a block.
+
+
+There can be multiple blocks of information about an
+item, but the first block must be the one-line +INFO
+block containing the keyword +INFO followed by the
+gopher item description. This is done to make it easy
+to associate informational attributes with the gopher
+items to which they refer (see section 2.7 for some
+good reasons for doing this). The very first line of
+Attribute Information for an item contains a one-line
++INFO block containing the gopher descriptor for the
+item. All Gopher+ servers must return an "+INFO"
+block for all items listed by the server. Also
+present may be an +ADMIN block that can be many lines
+long. The server must also send an +ADMIN block when
+asked to send all the item's attributes (as in the
+example above). The +ADMIN block must contain at
+least an Admin attribute and Mod-Date attributes,
+though there may be many other administrative items
+also present in the +ADMIN block. The Admin (the
+administrator of the item) and Date (the date of the
+item's last modification) attributes are required to
+be returned by the server, and other optional
+attributes may be returned as well. In this example,
+there are two pieces of information within the +ADMIN
+block (Admin and Mod-Date). The Admin attribute must
+contain the e-mail address of an administrator inside
+angle brackets. The Admin line might also contain the
+administrator's name and phone number. The Date line
+must contain the modification date in angle brackets.
+The format of the date is <YYYYMMDDhhmmss> where YYYY
+is year, MM is month, DD is day, hh is hours, mm is
+minutes, and ss is seconds.
+
+
+The third block in the example is the +VIEWS block.
+This block lists different formats in which the
+document can be retrieved. The first format listed is
+what the server believes to be the preferred format.
+A gopher client might display the list of possible
+view labels of the item to the user and let the user
+select the view they prefer. Alternatively, a smart
+client might look at the content of the labels and
+preferentially retrieve Postscript views of items.
+Note that the view labels are structured. View labels
+specify a Content-Type (application/Postscript,
+Text/plain, etc.), an optional language (En_US, De_DE,
+etc.) and an optional size. Note that the View labels
+for content type use the MIME content types to specify
+names of the variious views. The optional language
+descriptors use the ISO-639 codes for representing
+languages to name the language. Smart clients might
+want to translate these rather cryptic codes into
+something mere mortals can read and understand.
+
+
+The client software can pick off the size of each
+view IF there are any angle brackets on the line.
+There might not be a size that the server cares to
+tell you about. Also this might NOT be the exact size
+that the server will wind up delivering to you if you
+ask for it... but it should be reasonably close. This
+information makes it possible for clever clients to
+select views based on size, data representation, or
+language. See section 2.6 for how alternate
+representations (views) are retrieved.
+
+
+The next block in the example is an (optional)
++ABSTRACT. Here the block consists of lines of text
+that might be displayed to the user.
+
+
+Other blocks of information can defined and added as
+the need arises. For instance, a Neuromancer-esque 3-D
+cyberspace attribute might be accommodated by
+including a 3D-ICON block (with an image to display
+in 3-space) and a 3D-COORDINATE block (with y,x, and
+z coordinates). More immediate needs can also
+addressed by defining other information blocks. For
+instance, a SCRIPT block would be a natural place to
+put information for scripting telnet sessions.
+Information blocks give us an extensible way of
+adding attributes (or what Macintosh programmers call
+resources) to gopher items.
+
+
+Some of the really cool ideas we have for information
+attributes may require sending large amounts of data,
+some of which may not be easily represented as ASCII
+text, but the idea of the attributes information is
+that it is a relatively compact list of attributes.
+These somewhat conflicting desires can be reconciled
+by allowing references to gopher items in an
+attribute. For example, an +ABSTRACT block might be
+returned this way:
+
+
+ +ABSTRACT: 0long abstractFselectorFhost2Fport2F+
+
+
+In this example, the abstract is a document that
+resides on a gopher server. By allowing references to
+to gopher items, we can also accommodate data that
+must be sent in an 8-bit clear stream by using the
+Gopher+ methods for retrieving binary data.
+
+
+If both a reference to an attribute and an explicit
+value for the attribute are present in an attribute
+list, the preferred version is the explicit value. In
+the example below, the preferred version is "the
+short abstract goes here".
+
+
+ +ABSTRACT: 0long abstractFselectorFhost2Fport2F+
+
+ the short abstract goes here
+
+
+Note that if you want to have several views of (for
+example) an +ABSTRACT this is possible by using a
+reference to a item residing on a gopher server
+because the item can have its own attributes.
+
+
+Attributes names are case sensitive (easier to match
+and more of them). There is no need to "preregister"
+all possible attributes since we cannot anticipate
+all possible future needs. However it would be
+reasonable to maintain a registry for implementors
+and administrators so duplication can be avoided.
+Server implementors or administrators can request that
+new attributes be included in the attribute registry.
+
+
+Dream on: What gets us excited are alternate
+representations for directory lists. Sure, the
+standard representation for a gopher directory list
+is known to us all. But isn't hypertext (in a WWW
+sense) an alternate kind of directory list? We also
+envisioned a "geographical view" (GView?) mapping
+servers onto a map of the world (throw up a gif
+picture and then overlay dots based on latitude and
+longitude or xy coordinates). OK. Dream off.
+
+
+ Note that interested parties outside gopherspace have
+long and complex wish-lists for "attributes" that all
+well-dressed Internet citizens should have. We don't
+want to comment on the use or value of these laundry-
+lists. Suffice it to say that nothing precludes
+server administrators from including whatever
+attributes they see fit to include. Certainly IAFA
+blocks are desirable, bearing UDIs, URL's or whatever
+else is desired. The gopher community will probably
+arrive at a list of "recommended" attributes that
+server administrators should try to support. Because
+not every server administrator sees advantage to
+cluttering Attribute Info files with information
+their primary users will never need, it does not seem
+fair to "force" folks to include them; most will
+just ignore the harsh protocol guideline and the
+value of the protocol will be diminished. We want to
+mandate as little as we possibly can.
+
+
+
+
+
+2.6 Using Attribute Info: Alternate
+representations (+VIEWS).
+
+
+The user may locate a document and wonder if there are
+representations of it besides, say, the standard Text.
+Using the appropriate client incantation (Option
+Double-Click? or whatever) the user indicates a wish
+to see what's available. The client retrieves the
+Attribute Information, displays the list of views to
+the user in some kind of scrolling list dialog. User
+selects a line and client now requests the document
+in say, Postscript representation:
+
+
+ the selectorF+application/Postscript
+
+
+
+Smart clients are not precluded from doing things like
+"Always get Postscript if you can" or "Always get
+Postscript if that is less than 700K in size." etc.
+And the "smarter" you make it, the hairier your
+client will become - unless you are a user interface
+wizard of awesome proportions. While the example
+above is of fetching a document's postscript view,
+there is nothing precluding having different views
+for directories. In the dream sequence earlier, we
+imagined a geographic view of a directory. For a
+client to fetch that view, it would say this:
+
+
+ the selectorF+GView
+
+
+
+2.7 Getting attributes for all items in a
+directory in one transaction.
+
+
+Heavyweight/clever/special-purpose clients may want to
+know all the attributes of items in a given directory
+in one transaction. The "$" command is used to
+request all the attributes of a directory at once.
+For instance, a client might sent the request:
+
+
+ selector stringF$
+
+
+ and the server might return this:
+
+
+ +INFO: 0Salmon dogsFsome selectorFhost2Fport2F+
+
+ +ADMIN:
+
+ Admin: Frodo Gophermeister <fng@bogus.edu>
+
+ Mod-Date: August 15, 1992 <19920815185503>
+
+ +VIEWS:
+
+ Text/plain: <10k>
+
+ application/Postscript De_DE: <100k>
+
+ +ABSTRACT:
+
+ A great recipe for making salmon
+
+ +INFO: 0Hot pupsFother selectorFhost3Fport3F+
+
+ +ADMIN:
+
+ Admin: Bilbo Gophernovice <bng@bogus.edu>
+
+ Date: <19910101080003>
+
+
+In this example, the server returned the attribute
+lists for two items because there were only two items
+in the directory.. The client software can easily
+separate the attributes for the items since each
+attribute list starts with "+INFO". It is also easy
+for the client to use the "$" command to get
+directory listings since the gopher item descriptor is
+on the +INFO line for each item.
+
+
+Note that the $ command is the only way to find the
+administrator of a remote link. To get the full
+attribute information for a link on another machine
+may require asking the master machine for the item
+information. It is possible to append which
+attributes you are interested in retrieving after the
+$, eg:
+
+
+ some directory selectorF$+VIEWS
+
+or
+
+ other directory selectorF$+VIEWS+ABSTRACT
+
+
+
+The $ command makes it possible for a client that does
+not mind burning bandwidth to get attribute
+information for all items as the user navigates
+gopherspace. Clients using 2400 bps SLIP links will
+probably not use this method... but clients on
+Ethernet may not mind. This command may also be useful
+for building smart indexes of items in gopherspace.
+Note that the specific requested attributes are only
+suggestions to the server that the client would like
+less than a full set of attributes. The server may
+choose to ignore the request (if it is not capable of
+extracting the required attributes) and return the
+client the full set anyway. Other caveats: even if
+the attributes requested are not available, the
+server WILL NOT return an error, but will send
+whatever IS available. It is the client's
+responsibility inspect the returned attributes.
+
+
+Analogous to use of the $ command, the ! command can
+also be used to request certain attribute blocks.
+
+
+
+
+2.8 Gopher+ Interactive Query items.
+
+
+The principle here is based on Roland Schemer's "Q/q"
+type ideas. We're calling it the Interactive Query
+enhancements...
+
+
+The server may list items that have a "?" following
+the port field:
+
+
+ 0A fileFfile selectorFhostFportF?
+
+ 1A directoryFdir selectorFhostFportF?
+
+
+Now the fact that there's something after the port
+field means that these are Gopher+ items. Old clients
+will still be able to show such items in lists, but
+if they simply send the old style plain selector
+string to retrieve them, the server will respond with
+an old style error telling them to get an updated
+client. New clients will know that before getting one
+of these items, it will be necessary to retrieve
+questions from the server, have the user answer them,
+and then feed the answers back to the server along
+with the selector. The questions to be asked of the
+user are retrieved from the server by looking at the
++ASK attribute in the item's attribute information.
+
+
+
+
+When the user selects a query item, the client quickly
+connects to the server and requests the Attribute
+Information for the item. Then the client extracts
+the information in the +ASK attribute block. Here's
+an example:
+
+
+ +INFO: 0inquisitiveFmoo moo
+selectorFhost2Fport2F+
+
+ +ADMIN
+
+ Admin: Frank Gophermeister <fng@bogus.edu>
+
+ Mod-Date: August 15, 1992 <19920815185503>
+
+ +ASK:
+
+ Ask: How many volts?
+
+ Choose: Deliver electric shock to administrator
+now?FYesFNot!
+
+
+
+
+
+The client will use all lines in the order they appear
+in the +ASK attribute block. The content will be
+presented to the user as questions or prompts or
+dialogs or something like that.
+
+
+The "Ask" presents the user with a question, supplies
+a default text answer if it exists and allows the
+user to enter a one-line responce.
+
+
+The "AskP" presents the user with a question, and
+bullets out the responce typed in by the user so that
+someone watching over the user's sholder cannot read
+the responce.
+
+
+The "AskL" presents the user with a question, and
+ideally should allo the user to enter several lines of
+responce.
+
+
+The "AskF" requests the user for a new local filename,
+presumably for stashing the response returned by the
+server. It may supply a default filename.
+
+
+The "Select" presents the user with a set of options
+from which the use can select one or many. This is
+equivalent to Macintosh check boxes.
+
+
+The "Choose" presents the user with a few short
+choices only one of which may be selected at a time.
+This is equivalent to Macintosh radio buttons.
+
+
+The "ChooseF" requests that the user select an
+existing local file, presumably for sending to the
+server. On some systems, the client writer or
+administrator might want to restrict the selection of
+such files to the current directory (ie. not allow
+paths in the filename to prevent sending things like
+password files).
+
+
+The n responses harvested from the user are sent on to
+the server as the first n lines in the dataBlock.
+There can only be one file sent, and it will be the
+remainder of the dataBlock if any. If there is an
+AskL the responce is returned with a count of the
+number of lines entered by the user on a line by
+itself, followed by the lines entered by the user.
+
+
+Gopher was originally designed as an essentially
+anonymous document retrieval protocol to facilitate
+easy access to information rather than limited
+access. Various kinds of restrictive mechanisms have
+been implemented at the server end (for example,
+access restriction by source IP address); however if
+you have sensitive information, we emphasize that
+putting it under a Gopher's nose is not a good idea.
+
+
+
+
+The folks with a hirsute tendency will have noticed
+that all these interactions are static rather than
+truly dynamic and interactive. In other words, the
+server cannot ask different questions in response to
+different answers. +ASK does not constitute a
+scripting language by any means.
+
+
+To do "true" scripting, we have to do one of two
+things
+
+
+1. Write a full language parser/interpreter into
+clients. The server loads a whole script into the
+client's brain, and the client "runs" it. This
+rather grossly violates the spirit of simplicity in
+cross-platform gopher implementation. However, when
+and if a standard scripting language is adopted,
+there will be room for it in a SCRIPT attribute block.
+
+
+2. Client enters a complex back-and-forth transaction
+with the server. This requires the server, client, or
+both to save rather a lot of state. NOPE! Server
+saving state means holding open a connection or
+(worse) the server retaining tokens between
+connections. Client saving state means the server
+has an even worse job to do.
+
+
+As Opus the Penguin would say: a Hairball.
+
+
+
+2.9 Gopher+ Pictures, Sounds, Movies.
+
+
+A lot of folks need ability to retrieve and display
+pictures, but there is no real consensus on ONE format
+for these pictures. We don't want to define a type
+character for every oddball picture type. Gopher+
+handles Pictures, Movies, and Sounds by defining
+three item types: ":" for bitmap images, ";" for
+movies, and "<" for sounds (originally I, M, and S
+were suggested, but they were informally in use in
+other ways; the only thing magic about ":", ";", and
+"<", is that they are the first characters after '9')
+
+
+Note that there is NO default format for Pictures,
+Movies and Sounds; the specific format of the image,
+movie, or sound must be gleaned from the +VIEWS
+information for the item (eg. Gif, PICT, TIFF, etc.).
+
+
+
+
+Appendix I
+
+
+Required attributes and suggested attributes.
+
+
+
+A1.0 The +INFO attribute block
+
+
+The +INFO atttribute block is sent whenever an item's
+attributes are requested. It is required that the
+Attribute Information list for an item must contain a
+one-line +INFO attribute, and the +INFO attribute
+must contain the gopher+ descriptor for the item.
+
+
+ +INFO: 1Nice stuffF/selectorFhostFportF+
+
+
+
+A2.0 The +ADMIN attribute
+
+
+ A Gopher+ server is required to have an +ADMIN block
+for every item and the +ADMIN block must contain
+Admin and a Mod-Date lines:
+
+
+ +ADMIN:
+
+ Admin: [comments] <administrator e-mail address>
+
+ Mod-Date: [comments] <YYYYMMDDhhmmss>
+
+
+In addition to the required lines, we recommend that
+the +ADMIN attribute of items returned by a full-text
+search engine contain a SCORE attribute. The SCORE
+attribute should contain the relevance ranking (an
+integer) of the item.
+
+
+ Score: relevance-ranking
+
+
+We recommend that the +ADMIN attribute of a full-text
+search engine contain a Score-Range attribute. This
+attribute is used to specify the range of values
+taken on by the relevance ranking scores of items
+returned by the search engine. The Score-Range makes
+it possible to normalize scores from different search
+engine technologies. The first number is the lower
+bound, the second number is the upper bound.
+
+
+ Score-range: lower-bound upper-bound
+
+
+We also recommend that the +ADMIN attribute for the
+root of the server (i.e. what you get back when you
+ask for the attributes of the item with the empty
+selector string) also contain these fields:
+
+
+ Site: the name of the site
+
+ Org: organization or group owning the site
+
+ Loc: city, state, country
+
+ Geog: latitude longitude
+
+ TZ: timezone as gmt-offset
+
+
+Other useful attributes might include:
+
+
+ Provider: who provided this item
+
+ Author: who wrote this item
+
+ Creation-Date: when it was born <YYYYMMDDhhmmss>
+
+ Expiration-Date: when it expires <YYYYMMDDhhmmss>
+
+
+
+A3.0 The +VIEWS attribute
+
+
+The +VIEWS attribute is used to specify alternative
+representations of an item. The form of the +VIEWS
+attribute is:
+
+
+ +VIEWS: [gopher descriptor]
+
+ Content-Type[ viewLanguage]: [<56K>]
+
+ Content-Type[ viewLanguage]: [<93K>]
+
+ Content-Type[ viewLanguage]: [<77K>]
+
+
+Some values for Content-Type are
+
+
+ Text/plain, application/Postscript, image/Gif,
+image/jpeg,
+
+
+Content Types are defined by the Internet Assigned
+Numbers Authority (IANA). To register a new content
+type send e-mail to IANA@isi.edu. For a
+comprehensive list, consult the most up-to-date MIME
+Request for Comments (RFC). A list of currently
+defined views may be retrieved by anonymous ftp from
+isi.edu in the directory
+
+
+/pub/in-notes/MIME/mime-types
+
+
+All gopher servers must support the Text/plain view
+for readable documents and the application/gopher-
+menu view (the basic Gopher+ directory list) for
+directories. These are the views that must be
+returned by default. If all a server supports is the
+default views, then it may omit the +VIEWS attribute
+block (although we suggest that it not do so).
+
+
+The viewLanguage is defined as a concatanation of two
+ISO standard values, the ISO 639 language code and
+the ISO-3166 country code.
+
+
+Some values for viewLanguage are:
+
+
+ En_US, De_DE, Es_ES, Se_SE
+
+
+
+A4.0 The +ABSTRACT attribute
+
+
+The +ABSTRACT attribute is used to specify a short
+abstract for the item. The form of the +ABSTRACT
+attribute is:
+
+
+ +ABSTRACT: [gopher reference]
+
+ A line of text<CRLF>
+
+ another line of text<CRLF>
+
+ still another line of text.<CRLF>
+
+
+We recommend that a description of the sorts of
+information at the site, a postal address, a phone
+number, and the administrator name for the site be
+included in the +ABSTRACT attribute for the server
+root (i.e. what you get when you ask for the
+attribute list of the server with no selector
+string).
+
+
+
+
+
+Appendix II
+
+
+Paul's NQBNF (Not Quite BNF) for the Gopher+
+Enhancements.
+
+
+
+Note: This is modified BNF (as used by the Pascal
+people) with a few English modifiers thrown in.
+Stuff enclosed in '{}' can be repeated zero or more
+times. Stuff in '[]' denotes a set of items. The '-
+' operator denotes set subtraction.
+
+
+This section is not quite solid yet. Please send us
+information on any errors you might notice.
+
+
+Directory Entity
+
+
+CR-LF ::= Carriage Return Character followed by
+Line Feed character.
+
+Tab ::= ASCII Tab character
+
+NUL ::= ASCII NUL character
+
+PLUS ::= ASCII '+' character
+
+LEFT ::= ASCII '<' character
+
+RIGHT ::= ASCII '>' character
+
+OCTET ::= $00 -> $ff
+
+UNASCII ::= OCTET - [Tab CR-LF NUL]
+
+UNASCIINOPLUS ::= UNASCII - [PLUS]
+
+UNASCIINOANGLE ::= UNASCII - [LEFT, RIGHT]
+
+Lastline ::= '.'CR-LF
+
+TextBlock ::= Block of ASCII text not containing
+Lastline pattern.
+
+Type ::= UNASCII
+
+DisplayString ::= {UNASCII}
+
+Selector ::= {UNASCII}
+
+Otherflds ::= {UNASCII + TAB}
+
+Host ::= {{UNASCII - ['.']} '.'} {UNASCII -
+['.']}
+
+
+
+Note: This is a Fully Qualified Domain Name as defined
+in RFC 830. (e.g. gopher.micro.umn.edu) Hosts that
+have a CR-LF TAB or NUL in their name get what they
+deserve.
+
+
+Digit ::= '0' | '1' | '2' | '3' | '4' | '5' | '6'
+| '7' | '8' | '9'
+
+DigitSeq ::= digit {digit}.
+
+Port ::= DigitSeq.
+
+
+Note: Port corresponds the the TCP Port Number, its
+value should be in the range [0..65535]; port 70 is
+officially assigned to gopher.
+
+
+
+Bool ::= '0' | '1'
+
+G+Field ::= '+' | '?'
+
+
+Success ::= '+' | '-'.
+
+Transfer ::= DigitSeq | '-1' | '-2'
+
+DataHead ::= Success Transfer CR-LF
+
+DataBlock ::= DataHead {OCTET}
+
+
+
+G1DirEntity ::= Type DisplayString Tab Selector Tab
+Host Tab Port Tab Otherflds CR-LF
+
+G+DirEntity ::= Type DisplayString Tab Selector Tab
+Host Tab Port Tab G+Field
+
+ CR-LF
+
+
+
+Notes:
+
+ It is *highly* recommended that the DisplayString
+field contain only printable characters, since many
+different clients will be using it. However if eight
+bit characters are used, the characters should
+conform with the ISO-Latin1 Character Set. The length
+of the User displayable line should be less than 70
+Characters; longer lines may not fit across some
+screens. Warning! The Selector string can be longer
+than 255 characters.
+
+
+Menu Entity
+
+Menu ::= DataHead {G+DirEntity}.
+
+
+Continues ::= Bool
+
+Representation ::= 'Text' | 'List' | 'Postscript' |
+'MacWriteII' | 'RTF' |{UNASCII}
+
+
+
+Retrieving a document/menu/etc.:
+
+
+C: Opens Connection
+
+S: Accepts Connection
+
+C: Sends Selector String Tab '+' Representation [Tab
+DataFlag]
+
+C: [Optional] Client sends a DataBlock depending on
+value of DataFlag.
+
+S: Sends DataBlock
+
+Connection is closed by either client or server
+(typically server).
+
+
+Spaceline ::= ' ' {UNASCII} CR-LF
+
+Blockname ::= '+' {UNASCIINOPLUS}
+
+Attrblock ::= Blockname ' ' [G+Direntry] CR-LF
+{Spaceline}
+
+Attrval ::= SPACE {UNASCII} CR-LF
+
+E-Mail ::= {UNASCII} s.t. it conforms to RFC 822
+
+Adminval ::= ' Admin:' {UNASCII} '<' E-Mailaddr
+'>' CR-LF
+
+Dateval ::= ' Mod-Date:' {UNASCII} '<'
+YYYYMMDDhhmmss '>' CR-LF
+
+AdminReq ::= AdminVal Dateval
+
+Infoblock ::= '+INFO: ' G+Direntry CR-LF
+
+AdminBlock ::= '+ADMIN: ' {G+Direntry} CR-LF
+AdminReq {Attrval}
+
+Language ::= 'English' | 'French' | 'German' |
+{UNASCII}
+
+ViewVal ::= ' ' Representation [' ' Language] ":"
+ASCIINOANGLE '<'
+
+ Size 'k>' CR-LF
+
+ViewBlock ::= '+VIEWS: ' {G+Direntry} CR-LF
+{ViewVal}
+
+AttrBlocks ::= InfoBlock ViewBlock {AttrBlock}
+
+
+
+Retrieving item Information.
+
+
+
+For non-index server (non-type 7 items)
+
+
+C: Opens Connection
+
+S: Accepts Connection
+
+C: Sends Selector String Tab '!' {BlockName}CR-LF
+
+S: Sends DataBlock with data in AttrrBlocks format.
+
+Connection is closed by either client or server
+(typically server).
+
+
+
+For index server (type 7 items) the client asks the
+search engine to so a search for nothing
+
+(i.e. the client does not provide any words to search
+for) and appends a TAB and a "!" after the null-
+search:
+
+
+C: Opens Connection
+
+S: Accepts Connection
+
+C: Sends Selector String Tab Tab '!' {BlockName}CR-LF
+
+S: Sends DataBlock with data in AttrrBlocks format.
+
+Connection is closed by either client or server
+(typically server).
+
+
+Attributes ::= {AttrBlocks}
+
+
+
+Retrieving all Item Information entries for a
+directory.
+
+
+C: Opens Connection
+
+S: Accepts Connection
+
+C: Sends Selector String Tab '$'{BlockName} CR-LF
+
+S: Sends DataBlock with data in Attributes format.
+
+Connection is closed by either client or server
+(typically server).
+
+
+.
DIR diff --git a/references/rfc1436.txt b/references/rfc1436.txt
@@ -0,0 +1,906 @@
+
+
+
+
+
+
+Network Working Group F. Anklesaria
+Request for Comments: 1436 M. McCahill
+ P. Lindner
+ D. Johnson
+ D. Torrey
+ B. Alberti
+ University of Minnesota
+ March 1993
+
+
+ The Internet Gopher Protocol
+ (a distributed document search and retrieval protocol)
+
+Status of this Memo
+
+ This memo provides information for the Internet community. It does
+ not specify an Internet standard. Distribution of this memo is
+ unlimited.
+
+Abstract
+
+ The Internet Gopher protocol is designed for distributed document
+ search and retrieval. This document describes the protocol, lists
+ some of the implementations currently available, and has an overview
+ of how to implement new client and server applications. This
+ document is adapted from the basic Internet Gopher protocol document
+ first issued by the Microcomputer Center at the University of
+ Minnesota in 1991.
+
+Introduction
+
+ gopher n. 1. Any of various short tailed, burrowing mammals of the
+ family Geomyidae, of North America. 2. (Amer. colloq.) Native or
+ inhabitant of Minnesota: the Gopher State. 3. (Amer. colloq.) One
+ who runs errands, does odd-jobs, fetches or delivers documents for
+ office staff. 4. (computer tech.) software following a simple
+ protocol for burrowing through a TCP/IP internet.
+
+ The Internet Gopher protocol and software follow a client-server
+ model. This protocol assumes a reliable data stream; TCP is assumed.
+ Gopher servers should listen on port 70 (port 70 is assigned to
+ Internet Gopher by IANA). Documents reside on many autonomous
+ servers on the Internet. Users run client software on their desktop
+ systems, connecting to a server and sending the server a selector (a
+ line of text, which may be empty) via a TCP connection at a well-
+ known port. The server responds with a block of text terminated by a
+ period on a line by itself and closes the connection. No state is
+ retained by the server.
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 1]
+
+RFC 1436 Gopher March 1993
+
+
+ While documents (and services) reside on many servers, Gopher client
+ software presents users with a hierarchy of items and directories
+ much like a file system. The Gopher interface is designed to
+ resemble a file system since a file system is a good model for
+ organizing documents and services; the user sees what amounts to one
+ big networked information system containing primarily document items,
+ directory items, and search items (the latter allowing searches for
+ documents across subsets of the information base).
+
+ Servers return either directory lists or documents. Each item in a
+ directory is identified by a type (the kind of object the item is),
+ user-visible name (used to browse and select from listings), an
+ opaque selector string (typically containing a pathname used by the
+ destination host to locate the desired object), a host name (which
+ host to contact to obtain this item), and an IP port number (the port
+ at which the server process listens for connections). The user only
+ sees the user-visible name. The client software can locate and
+ retrieve any item by the trio of selector, hostname, and port.
+
+ To use a search item, the client submits a query to a special kind of
+ Gopher server: a search server. In this case, the client sends the
+ selector string (if any) and the list of words to be matched. The
+ response yields "virtual directory listings" that contain items
+ matching the search criteria.
+
+ Gopher servers and clients exist for all popular platforms. Because
+ the protocol is so sparse and simple, writing servers or clients is
+ quick and straightforward.
+
+1. Introduction
+
+ The Internet Gopher protocol is designed primarily to act as a
+ distributed document delivery system. While documents (and services)
+ reside on many servers, Gopher client software presents users with a
+ hierarchy of items and directories much like a file system. In fact,
+ the Gopher interface is designed to resemble a file system since a
+ file system is a good model for locating documents and services. Why
+ model a campus-wide information system after a file system? Several
+ reasons:
+
+ (a) A hierarchical arrangement of information is familiar to many
+ users. Hierarchical directories containing items (such as
+ documents, servers, and subdirectories) are widely used in
+ electronic bulletin boards and other campus-wide information
+ systems. People who access a campus-wide information server will
+ expect some sort of hierarchical organization to the information
+ presented.
+
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 2]
+
+RFC 1436 Gopher March 1993
+
+
+ (b) A file-system style hierarchy can be expressed in a simple
+ syntax. The syntax used for the internet Gopher protocol is
+ easily understandable, and was designed to make debugging servers
+ and clients easy. You can use Telnet to simulate an internet
+ Gopher client's requests and observe the responses from a server.
+ Special purpose software tools are not required. By keeping the
+ syntax of the pseudo-file system client/server protocol simple, we
+ can also achieve better performance for a very common user
+ activity: browsing through the directory hierarchy.
+
+ (c) Since Gopher originated in a University setting, one of the
+ goals was for departments to have the option of publishing
+ information from their inexpensive desktop machines, and since
+ much of the information can be presented as simple text files
+ arranged in directories, a protocol modeled after a file system
+ has immediate utility. Because there can be a direct mapping from
+ the file system on the user's desktop machine to the directory
+ structure published via the Gopher protocol, the problem of
+ writing server software for slow desktop systems is minimized.
+
+ (d) A file system metaphor is extensible. By giving a "type"
+ attribute to items in the pseudo-file system, it is possible to
+ accommodate documents other than simple text documents. Complex
+ database services can be handled as a separate type of item. A
+ file-system metaphor does not rule out search or database-style
+ queries for access to documents. A search-server type is also
+ defined in this pseudo-file system. Such servers return "virtual
+ directories" or list of documents matching user specified
+ criteria.
+
+2. The internet Gopher Model
+
+ A detailed BNF rendering of the internet Gopher syntax is available
+ in the appendix...but a close reading of the appendix may not be
+ necessary to understand the internet Gopher protocol.
+
+ In essence, the Gopher protocol consists of a client connecting to a
+ server and sending the server a selector (a line of text, which may
+ be empty) via a TCP connection. The server responds with a block of
+ text terminated with a period on a line by itself, and closes the
+ connection. No state is retained by the server between transactions
+ with a client. The simple nature of the protocol stems from the need
+ to implement servers and clients for the slow, smaller desktop
+ computers (1 MB Macs and DOS machines), quickly, and efficiently.
+
+ Below is a simple example of a client/server interaction; more
+ complex interactions are dealt with later. Assume that a "well-
+ known" Gopher server (this may be duplicated, details are discussed
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 3]
+
+RFC 1436 Gopher March 1993
+
+
+ later) listens at a well known port for the campus (much like a
+ domain-name server). The only configuration information the client
+ software retains is this server's name and port number (in this
+ example that machine is rawBits.micro.umn.edu and the port 70). In
+ the example below the F character denotes the TAB character.
+
+ Client: {Opens connection to rawBits.micro.umn.edu at port 70}
+
+ Server: {Accepts connection but says nothing}
+
+ Client: <CR><LF> {Sends an empty line: Meaning "list what you have"}
+
+ Server: {Sends a series of lines, each ending with CR LF}
+ 0About internet GopherFStuff:About usFrawBits.micro.umn.eduF70
+ 1Around University of MinnesotaFZ,5692,AUMFunderdog.micro.umn.eduF70
+ 1Microcomputer News & PricesFPrices/Fpserver.bookstore.umn.eduF70
+ 1Courses, Schedules, CalendarsFFevents.ais.umn.eduF9120
+ 1Student-Staff DirectoriesFFuinfo.ais.umn.eduF70
+ 1Departmental PublicationsFStuff:DP:FrawBits.micro.umn.eduF70
+ {.....etc.....}
+ . {Period on a line by itself}
+ {Server closes connection}
+
+
+ The first character on each line tells whether the line describes a
+ document, directory, or search service (characters '0', '1', '7';
+ there are a handful more of these characters described later). The
+ succeeding characters up to the tab form a user display string to be
+ shown to the user for use in selecting this document (or directory)
+ for retrieval. The first character of the line is really defining
+ the type of item described on this line. In nearly every case, the
+ Gopher client software will give the users some sort of idea about
+ what type of item this is (by displaying an icon, a short text tag,
+ or the like).
+
+ The characters following the tab, up to the next tab form a selector
+ string that the client software must send to the server to retrieve
+ the document (or directory listing). The selector string should mean
+ nothing to the client software; it should never be modified by the
+ client. In practice, the selector string is often a pathname or
+ other file selector used by the server to locate the item desired.
+ The next two tab delimited fields denote the domain-name of the host
+ that has this document (or directory), and the port at which to
+ connect. If there are yet other tab delimited fields, the basic
+ Gopher client should ignore them. A CR LF denotes the end of the
+ item.
+
+
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 4]
+
+RFC 1436 Gopher March 1993
+
+
+ In the example, line 1 describes a document the user will see as
+ "About internet Gopher". To retrieve this document, the client
+ software must send the retrieval string: "Stuff:About us" to
+ rawBits.micro.umn.edu at port 70. If the client does this, the
+ server will respond with the contents of the document, terminated by
+ a period on a line by itself. A client might present the user with a
+ view of the world something like the following list of items:
+
+
+ About Internet Gopher
+ Around the University of Minnesota...
+ Microcomputer News & Prices...
+ Courses, Schedules, Calendars...
+ Student-Staff Directories...
+ Departmental Publications...
+
+
+
+ In this case, directories are displayed with an ellipsis and files
+ are displayed without any. However, depending on the platform the
+ client is written for and the author's taste, item types could be
+ denoted by other text tags or by icons. For example, the UNIX
+ curses-based client displays directories with a slash (/) following
+ the name; Macintosh clients display directories alongside an icon of
+ a folder.
+
+ The user does not know or care that the items up for selection may
+ reside on many different machines anywhere on the Internet.
+
+ Suppose the user selects the line "Microcomputer News & Prices...".
+ This appears to be a directory, and so the user expects to see
+ contents of the directory upon request that it be fetched. The
+ following lines illustrate the ensuing client-server interaction:
+
+
+ Client: (Connects to pserver.bookstore.umn.edu at port 70)
+ Server: (Accepts connection but says nothing)
+ Client: Prices/ (Sends the magic string terminated by CRLF)
+ Server: (Sends a series of lines, each ending with CR LF)
+ 0About PricesFPrices/AboutusFpserver.bookstore.umn.eduF70
+ 0Macintosh PricesFPrices/MacFpserver.bookstore.umn.eduF70
+ 0IBM PricesFPrices/IckFpserver.bookstore.umn.eduF70
+ 0Printer & Peripheral PricesFPrices/PPPFpserver.bookstore.umn.eduF70
+ (.....etc.....)
+ . (Period on a line by itself)
+ (Server closes connection)
+
+
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 5]
+
+RFC 1436 Gopher March 1993
+
+
+3. More details
+
+3.1 Locating services
+
+ Documents (or other services that may be viewed ultimately as
+ documents, such as a student-staff phonebook) are linked to the
+ machine they are on by the trio of selector string, machine domain-
+ name, and IP port. It is assumed that there will be one well-known
+ top-level or root server for an institution or campus. The
+ information on this server may be duplicated by one or more other
+ servers to avoid a single point of failure and to spread the load
+ over several servers. Departments that wish to put up their own
+ departmental servers need to register the machine name and port with
+ the administrators of the top-level Gopher server, much the same way
+ as they register a machine name with the campus domain-name server.
+ An entry which points to the departmental server will then be made at
+ the top level server. This ensures that users will be able to
+ navigate their way down what amounts to a virtual hierarchical file
+ system with a well known root to any campus server if they desire.
+
+ Note that there is no requirement that a department register
+ secondary servers with the central top-level server; they may just
+ place a link to the secondary servers in their own primary servers.
+ They may indeed place links to any servers they desire in their own
+ server, thus creating a customized view of thethe Gopher information
+ universe; links can of course point back at the top-level server.
+ The virtual (networked) file system is therefore an arbitrary graph
+ structure and not necessarily a rooted tree. The top-level node is
+ merely one convenient, well-known point of entry. A set of Gopher
+ servers linked in this manner may function as a campus-wide
+ information system.
+
+ Servers may of course point links at other than secondary servers.
+ Indeed servers may point at other servers offering useful services
+ anywhere on the internet. Viewed in this manner, Gopher can be seen
+ as an Internet-wide information system.
+
+3.2 Server portability and naming
+
+ It is recommended that all registered servers have alias names
+ (domain name system CNAME) that are used by Gopher clients to locate
+ them. Links to these servers should use these alias names rather
+ than the primary names. If information needs to be moved from one
+ machine to another, a simple change of domain name system alias
+ (CNAME) allows this to occur without any reconfiguration of clients
+ in the field. In short, the domain name system may be used to re-map
+ a server to a new address. There is nothing to prevent secondary
+ servers or services from running on otherwise named servers or ports
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 6]
+
+RFC 1436 Gopher March 1993
+
+
+ other than 70, however these should be reachable via a primary
+ server.
+
+3.3 Contacting server administrators
+
+ It is recommended that every server administrator have a document
+ called something like: "About Bogus University's Gopher server" as
+ the first item in their server's top level directory. In this
+ document should be a short description of what the server holds, as
+ well as name, address, phone, and an e-mail address of the person who
+ administers the server. This provides a way for users to get word to
+ the administrator of a server that has inaccurate information or is
+ not running correctly. It is also recommended that administrators
+ place the date of last update in files for which such information
+ matters to the users.
+
+3.4 Modular addition of services
+
+ The first character of each line in a server-supplied directory
+ listing indicates whether the item is a file (character '0'), a
+ directory (character '1'), or a search (character '7'). This is the
+ base set of item types in the Gopher protocol. It is desirable for
+ clients to be able to use different services and speak different
+ protocols (simple ones such as finger; others such as CSO phonebook
+ service, or Telnet, or X.500 directory service) as needs dictate.
+ CSO phonebook service is a client/server phonebook system typically
+ used at Universities to publish names, e-mail addresses, and so on.
+ The CSO phonebook software was developed at the University of
+ Illinois and is also sometimes refered to as ph or qi. For example,
+ if a server-supplied directory listing marks a certain item with type
+ character '2', then it means that to use this item, the client must
+ speak the CSO protocol. This removes the need to be able to
+ anticipate all future needs and hard-wire them in the basic Internet
+ Gopher protocol; it keeps the basic protocol extremely simple. In
+ spite of this simplicity, the scheme has the capability to expand and
+ change with the times by adding an agreed upon type-character for a
+ new service. This also allows the client implementations to evolve
+ in a modular fashion, simply by dropping in a module (or launching a
+ new process) for some new service. The servers for the new service
+ of course have to know nothing about Internet Gopher; they can just
+ be off-the shelf CSO, X.500, or other servers. We do not however,
+ encourage arbitrary or machine-specific proliferation of service
+ types in the basic Gopher protocol.
+
+ On the other hand, subsets of other document retrieval schemes may be
+ mapped onto the Gopher protocol by means of "gateway-servers".
+ Examples of such servers include Gopher-to-FTP gateways, Gopher-to-
+ archie gateways, Gopher-to-WAIS gateways, etc. There are a number of
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 7]
+
+RFC 1436 Gopher March 1993
+
+
+ advantages of such mechanisms. First, a relatively powerful server
+ machine inherits both the intelligence and work, rather than the more
+ modest, inexpensive desktop system that typically runs client
+ software or basic server software. Equally important, clients do not
+ have to be modified to take advantage of a new resource.
+
+3.5 Building clients
+
+ A client simply sends the retrieval string to a server if it wants to
+ retrieve a document or view the contents of a directory. Of course,
+ each host may have pointers to other hosts, resulting in a "graph"
+ (not necessarily a rooted tree) of hosts. The client software may
+ save (or rather "stack") the locations that it has visited in search
+ of a document. The user could therefore back out of the current
+ location by unwinding the stack. Alternatively, a client with
+ multiple-window capability might just be able to display more than
+ one directory or document at the same time.
+
+ A smart client could cache the contents of visited directories
+ (rather than just the directory's item descriptor), thus avoiding
+ network transactions if the information has been previously
+ retrieved.
+
+ If a client does not understand what a say, type 'B' item (not a core
+ item) is, then it may simply ignore the item in the directory
+ listing; the user never even has to see it. Alternatively, the item
+ could be displayed as an unknown type.
+
+ Top-level or primary servers for a campus are likely to get more
+ traffic than secondary servers, and it would be less tolerable for
+ such primary servers to be down for any long time. So it makes sense
+ to "clone" such important servers and construct clients that can
+ randomly choose between two such equivalent primary servers when they
+ first connect (to balance server load), moving to one if the other
+ seems to be down. In fact, smart client implementations do this
+ clone server and load balancing. Alternatively, it may make sense to
+ have the domain name system return one of a set of redundant of
+ server's IP address to load balance betwen redundant sets of
+ important servers.
+
+3.6 Building ordinary internet Gopher servers
+
+ The retrieval string sent to the server might be a path to a file or
+ directory. It might be the name of a script, an application or even
+ a query that generates the document or directory returned. The basic
+ server uses the string it gets up to but not including a CR-LF or a
+ TAB, whichever comes first.
+
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 8]
+
+RFC 1436 Gopher March 1993
+
+
+ All intelligence is carried by the server implementation rather than
+ the protocol. What you build into more exotic servers is up to you.
+ Server implementations may grow as needs dictate and time allows.
+
+3.7 Special purpose servers
+
+ There are two special server types (beyond the normal Gopher server)
+ also discussed below:
+
+ 1. A server directory listing can point at a CSO nameserver (the
+ server returns a type character of '2') to allow a campus
+ student-staff phonebook lookup service. This may show up on the
+ user's list of choices, perhaps preceded by the icon of a phone-
+ book. If this item is selected, the client software must resort
+ to a pure CSO nameserver protocol when it connects to the
+ appropriate host.
+
+ 2. A server can also point at a "search server" (returns a first
+ character of '7'). Such servers may implement campus network (or
+ subnet) wide searching capability. The most common search servers
+ maintain full-text indexes on the contents of text documents held
+ by some subset of Gopher servers. Such a "full-text search
+ server" responds to client requests with a list of all documents
+ that contain one or more words (the search criteria). The client
+ sends the server the selector string, a tab, and the search string
+ (words to search for). If the selector string is empty, the client
+ merely sends the search string. The server returns the equivalent
+ of a directory listing for documents matching the search criteria.
+ Spaces between words are usually implied Boolean ANDs (although in
+ different implementations or search types, this may not
+ necessarily be true).
+
+ The CSO addition exists for historical reasons: at time of design,
+ the campus phone-book servers at the University of Minnesota used the
+ CSO protocol and it seemed simplest to just engulf them. The index-
+ server is however very much a Gopher in spirit, albeit with a slight
+ twist in the meaning of the selector-string. Index servers are a
+ natural place to incorperate gateways to WAIS and WHOIS services.
+
+3.7.1 Building CSO-servers
+
+ A CSO Nameserver implementation for UNIX and associated documentation
+ is available by anonymous ftp from uxa.cso.uiuc.edu. We do not
+ anticipate implementing it on other machines.
+
+
+
+
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 9]
+
+RFC 1436 Gopher March 1993
+
+
+3.7.2 Building full-text search servers
+
+ A full-text search server is a special-purpose server that knows
+ about the Gopher scheme for retrieving documents. These servers
+ maintain a full-text index of the contents of plain text documents on
+ Gopher servers in some specified domain. A Gopher full-text search
+ server was implemented using several NeXTstations because it was easy
+ to take advantage of the full-text index/search engine built into the
+ NeXT system software. A search server for generic UNIX systems based
+ on the public domain WAIS search engine, is also available and
+ currently an optional part of the UNIX gopher server. In addition,
+ at least one implementation of the gopher server incorperates a
+ gateway to WAIS servers by presenting the WAIS servers to gopherspace
+ as full-text search servers. The gopher<->WAIS gateway servers does
+ the work of translating from gopher protocol to WAIS so unmodified
+ gopher clients can access WAIS servers via the gateway server.
+
+ By using several index servers (rather than a monolithic index
+ server) indexes may be searched in parallel (although the client
+ software is not aware of this). While maintaining full-text indexes
+ of documents distributed over many machines may seem a daunting task,
+ the task can be broken into smaller pieces (update only a portion of
+ the indexes, search several partial indexes in parallel) so that it
+ is manageable. By spreading this task over several small, cheap (and
+ fast) workstations it is possible to take advantage of fine-grain
+ parallelism. Again, the client software is not aware of this. Client
+ software only needs to know that it can send a search string to an
+ index server and will receive a list of documents that contain the
+ words in the search string.
+
+3.8 Item type characters
+
+ The client software decides what items are available by looking at
+ the first character of each line in a directory listing. Augmenting
+ this list can extend the protocol. A list of defined item-type
+ characters follows:
+
+ 0 Item is a file
+ 1 Item is a directory
+ 2 Item is a CSO phone-book server
+ 3 Error
+ 4 Item is a BinHexed Macintosh file.
+ 5 Item is DOS binary archive of some sort.
+ Client must read until the TCP connection closes. Beware.
+ 6 Item is a UNIX uuencoded file.
+ 7 Item is an Index-Search server.
+ 8 Item points to a text-based telnet session.
+ 9 Item is a binary file!
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 10]
+
+RFC 1436 Gopher March 1993
+
+
+ Client must read until the TCP connection closes. Beware.
+ + Item is a redundant server
+ T Item points to a text-based tn3270 session.
+ g Item is a GIF format graphics file.
+ I Item is some kind of image file. Client decides how to display.
+
+ Characters '0' through 'Z' are reserved. Local experiments should
+ use other characters. Machine-specific extensions are not
+ encouraged. Note that for type 5 or type 9 the client must be
+ prepared to read until the connection closes. There will be no
+ period at the end of the file; the contents of these files are binary
+ and the client must decide what to do with them based perhaps on the
+ .xxx extension.
+
+3.9 User display strings and server selector strings
+
+ User display strings are intended to be displayed on a line on a
+ typical screen for a user's viewing pleasure. While many screens can
+ accommodate 80 character lines, some space is needed to display a tag
+ of some sort to tell the user what sort of item this is. Because of
+ this, the user display string should be kept under 70 characters in
+ length. Clients may truncate to a length convenient to them.
+
+4. Simplicity is intentional
+
+ As far as possible we desire any new features to be carried as new
+ protocols that will be hidden behind new document-types. The
+ internet Gopher philosophy is:
+
+ (a) Intelligence is held by the server. Clients have the option
+ of being able to access new document types (different, other types
+ of servers) by simply recognizing the document-type character.
+ Further intelligence to be borne by the protocol should be
+ minimized.
+
+ (b) The well-tempered server ought to send "text" (unless a file
+ must be transferred as raw binary). Should this text include
+ tabs, formfeeds, frufru? Probably not, but rude servers will
+ probably send them anyway. Publishers of documents should be
+ given simple tools (filters) that will alert them if there are any
+ funny characters in the documents they wish to publish, and give
+ them the opportunity to strip the questionable characters out; the
+ publisher may well refuse.
+
+ (c) The well-tempered client should do something reasonable with
+ funny characters received in text; filter them out, leave them in,
+ whatever.
+
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 11]
+
+RFC 1436 Gopher March 1993
+
+
+Appendix
+
+ Paul's NQBNF (Not Quite BNF) for the Gopher Protocol.
+
+ Note: This is modified BNF (as used by the Pascal people) with a few
+ English modifiers thrown in. Stuff enclosed in '{}' can be
+ repeated zero or more times. Stuff in '[]' denotes a set of
+ items. The '-' operator denotes set subtraction.
+
+
+Directory Entity
+
+CR-LF ::= ASCII Carriage Return Character followed by Line Feed
+ character.
+
+Tab ::= ASCII Tab character.
+
+NUL ::= ASCII NUL character.
+
+UNASCII ::= ASCII - [Tab CR-LF NUL].
+
+Lastline ::= '.'CR-LF.
+
+TextBlock ::= Block of ASCII text not containing Lastline pattern.
+
+Type ::= UNASCII.
+
+RedType ::= '+'.
+
+User_Name ::= {UNASCII}.
+
+Selector ::= {UNASCII}.
+
+Host ::= {{UNASCII - ['.']} '.'} {UNASCII - ['.']}.
+
+Note: This is a Fully Qualified Domain Name as defined in RFC 1034.
+ (e.g., gopher.micro.umn.edu) Hosts that have a CR-LF
+ TAB or NUL in their name get what they deserve.
+
+Digit ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' .
+
+DigitSeq ::= digit {digit}.
+
+Port ::= DigitSeq.
+
+Note: Port corresponds the the TCP Port Number, its value should
+ be in the range [0..65535]; port 70 is officially assigned
+ to gopher.
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 12]
+
+RFC 1436 Gopher March 1993
+
+
+DirEntity ::= Type User_Name Tab Selector Tab Host Tab Port CR-LF
+ {RedType User_Name Tab Selector Tab Host Tab Port CR-LF}
+
+
+
+Notes:
+
+ It is *highly* recommended that the User_Name field contain only
+ printable characters, since many different clients will be using
+ it. However if eight bit characters are used, the characters
+ should conform with the ISO Latin1 Character Set. The length of
+ the User displayable line should be less than 70 Characters; longer
+ lines may not fit across some screens.
+
+ The Selector string should be no longer than 255 characters.
+
+
+Menu Entity
+
+Menu ::= {DirEntity} Lastline.
+
+
+Menu Transaction (Type 1 item)
+
+C: Opens Connection
+S: Accepts Connection
+C: Sends Selector String
+S: Sends Menu Entity
+
+ Connection is closed by either client or server (typically server).
+
+
+Textfile Entity
+
+TextFile ::= {TextBlock} Lastline
+
+Note: Lines beginning with periods must be prepended with an extra
+ period to ensure that the transmission is not terminated early.
+ The client should strip extra periods at the beginning of the line.
+
+
+TextFile Transaction (Type 0 item)
+
+C: Opens Connection.
+S: Accepts connection
+C: Sends Selector String.
+S: Sends TextFile Entity.
+
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 13]
+
+RFC 1436 Gopher March 1993
+
+
+ Connection is closed by either client or server (typically server).
+
+Note: The client should be prepared for the server closing the
+ connection without sending the Lastline. This allows the
+ client to use fingerd servers.
+
+
+Full-Text Search Transaction (Type 7 item)
+
+Word ::= {UNASCII - ' '}
+BoolOp ::= 'and' | 'or' | 'not' | SPACE
+SearchStr ::= Word {{SPACE BoolOp} SPACE Word}
+
+C: Opens Connection.
+C: Sends Selector String, Tab, Search String.
+S: Sends Menu Entity.
+
+Note: In absence of 'and', 'or', or 'not' operators, a SPACE is
+ regarded as an implied 'and' operator. Expression is evaluated
+ left to right. Further, not all search engines or search
+ gateways currently implemented have the boolean operators
+ implemented.
+
+Binary file Transaction (Type 9 or 5 item)
+
+C: Opens Connection.
+S: Accepts connection
+C: Sends Selector String.
+S: Sends a binary file and closes connection when done.
+
+
+Syntactic Meaning for Directory Entities
+
+
+The client should interpret the type field as follows:
+
+0 The item is a TextFile Entity.
+ Client should use a TextFile Transaction.
+
+1 The item is a Menu Entity.
+ Client should use a Menu Transaction.
+
+2 The information applies to a CSO phone book entity.
+ Client should talk CSO protocol.
+
+3 Signals an error condition.
+
+4 Item is a Macintosh file encoded in BINHEX format
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 14]
+
+RFC 1436 Gopher March 1993
+
+
+5 Item is PC-DOS binary file of some sort. Client gets to decide.
+
+6 Item is a uuencoded file.
+
+7 The information applies to a Index Server.
+ Client should use a FullText Search transaction.
+
+8 The information applies to a Telnet session.
+ Connect to given host at given port. The name to login as at this
+ host is in the selector string.
+
+9 Item is a binary file. Client must decide what to do with it.
+
++ The information applies to a duplicated server. The information
+ contained within is a duplicate of the primary server. The primary
+ server is defined as the last DirEntity that is has a non-plus
+ "Type" field. The client should use the transaction as defined by
+ the primary server Type field.
+
+g Item is a GIF graphic file.
+
+I Item is some kind of image file. Client gets to decide.
+
+T The information applies to a tn3270 based telnet session.
+ Connect to given host at given port. The name to login as at this
+ host is in the selector string.
+
+Security Considerations
+
+ Security issues are not discussed in this memo.
+
+Authors' Addresses
+
+ Farhad Anklesaria
+ Computer and Information Services, University of Minnesota
+ Room 152 Shepherd Labs
+ 100 Union Street SE
+ Minneapolis, MN 55455
+
+ Phone: (612) 625 1300
+ EMail: fxa@boombox.micro.umn.edu
+
+
+
+
+
+
+
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 15]
+
+RFC 1436 Gopher March 1993
+
+
+ Mark McCahill
+ Computer and Information Services, University of Minnesota
+ Room 152 Shepherd Labs
+ 100 Union Street SE
+ Minneapolis, MN 55455
+
+ Phone: (612) 625 1300
+ EMail: mpm@boombox.micro.umn.edu
+
+
+ Paul Lindner
+ Computer and Information Services, University of Minnesota
+ Room 152 Shepherd Labs
+ 100 Union Street SE
+ Minneapolis, MN 55455
+
+ Phone: (612) 625 1300
+ EMail: lindner@boombox.micro.umn.edu
+
+
+ David Johnson
+ Computer and Information Services, University of Minnesota
+ Room 152 Shepherd Labs
+ 100 Union Street SE
+ Minneapolis, MN 55455
+
+ Phone: (612) 625 1300
+ EMail: dmj@boombox.micro.umn.edu
+
+
+ Daniel Torrey
+ Computer and Information Services, University of Minnesota
+ Room 152 Shepherd Labs
+ 100 Union Street SE
+ Minneapolis, MN 55455
+
+ Phone: (612) 625 1300
+ EMail: daniel@boombox.micro.umn.edu
+
+
+ Bob Alberti
+ Computer and Information Services, University of Minnesota
+ Room 152 Shepherd Labs
+ 100 Union Street SE
+ Minneapolis, MN 55455
+
+ Phone: (612) 625 1300
+ EMail: alberti@boombox.micro.umn.edu
+
+
+
+Anklesari, McCahill, Lindner, Johnson, Torrey & Alberti [Page 16]
+
+
+
+
+
+
+
+
DIR diff --git a/references/rfc4266.txt b/references/rfc4266.txt
@@ -0,0 +1,339 @@
+
+
+
+
+
+
+Network Working Group P. Hoffman
+Request for Comments: 4266 VPN Consortium
+Obsoletes: 1738 November 2005
+Category: Standards Track
+
+
+ The gopher URI Scheme
+
+Status of This Memo
+
+ This document specifies an Internet standards track protocol for the
+ Internet community, and requests discussion and suggestions for
+ improvements. Please refer to the current edition of the "Internet
+ Official Protocol Standards" (STD 1) for the standardization state
+ and status of this protocol. Distribution of this memo is unlimited.
+
+Copyright Notice
+
+ Copyright (C) The Internet Society (2005).
+
+Abstract
+
+ This document specifies the gopher Uniform Resource Identifier (URI)
+ scheme that was originally specified in RFC 1738. The purpose of
+ this document is to allow RFC 1738 to be made obsolete while keeping
+ the information about the scheme on standards track.
+
+1. Introduction
+
+ URIs were previously defined in RFC 2396 [RFC2396], which was updated
+ by RFC 3986 [RFC3986]. Those documents also specify how to define
+ schemes for URIs.
+
+ The first definition for many URI schemes appeared in RFC 1738
+ [RFC1738]. Because that document has been made obsolete, this
+ document copies the gopher URI scheme from it to allow that material
+ to remain on standards track.
+
+2. Scheme Definition
+
+ The gopher URL scheme is used to designate Internet resources
+ accessible using the Gopher protocol.
+
+ The base Gopher protocol is described in RFC 1436 [RFC1436] and
+ supports items and collections of items (directories). The Gopher+
+ protocol is a set of upward-compatible extensions to the base Gopher
+ protocol and is described in [Gopher+]. Gopher+ supports associating
+
+
+
+
+Hoffman Standards Track [Page 1]
+
+RFC 4266 The gopher URI Scheme November 2005
+
+
+ arbitrary sets of attributes and alternate data representations with
+ Gopher items. Gopher URLs accommodate both Gopher and Gopher+ items
+ and item attributes.
+
+ Historical note: The Gopher protocol was widely implemented in the
+ early 1990s, but few Gopher servers are in use today.
+
+2.1. Gopher URL Syntax
+
+ A Gopher URL takes the form:
+
+ gopher://<host>:<port>/<gopher-path>
+
+ where <gopher-path> is one of:
+
+ <gophertype><selector>
+ <gophertype><selector>%09<search>
+ <gophertype><selector>%09<search>%09<gopher+_string>
+
+ If :<port> is omitted, the port defaults to 70. <gophertype> is a
+ single-character field to denote the Gopher type of the resource to
+ which the URL refers. The entire <gopher-path> may also be empty, in
+ which case the delimiting "/" is also optional and the <gophertype>
+ defaults to "1".
+
+ <selector> is the Gopher selector string. In the Gopher protocol,
+ Gopher selector strings are a sequence of octets that may contain any
+ octets except 09 hexadecimal (US-ASCII HT or tab), 0A hexadecimal
+ (US-ASCII character LF), and 0D (US-ASCII character CR).
+
+ Gopher clients specify which item to retrieve by sending the Gopher
+ selector string to a Gopher server.
+
+ Within the <gopher-path>, no characters are reserved.
+
+ Note that some Gopher <selector> strings begin with a copy of the
+ <gophertype> character, in which case that character will occur twice
+ consecutively. The Gopher selector string may be an empty string;
+ this is how Gopher clients refer to the top-level directory on a
+ Gopher server.
+
+2.2. Specifying URLs for Gopher Search Engines
+
+ If the URL refers to a search to be submitted to a Gopher search
+ engine, the selector is followed by an encoded tab (%09) and the
+ search string. To submit a search to a Gopher search engine, the
+ Gopher client sends the <selector> string (after decoding), a tab,
+ and the search string to the Gopher server.
+
+
+
+Hoffman Standards Track [Page 2]
+
+RFC 4266 The gopher URI Scheme November 2005
+
+
+2.3. URL Syntax for Gopher+ Items
+
+ Historical note: Gopher+ was uncommon even when Gopher was popular.
+
+ URLs for Gopher+ items have a second encoded tab (%09) and a Gopher+
+ string. Note that in this case, the %09<search> string must be
+ supplied, although the <search> element may be the empty string.
+
+ The <gopher+_string> is used to represent information required for
+ retrieval of the Gopher+ item. Gopher+ items may have alternate
+ views and arbitrary sets of attributes, and they may have electronic
+ forms associated with them.
+
+ To retrieve the data associated with a Gopher+ URL, a client will
+ connect to the server and send the Gopher selector, followed by a tab
+ and the search string (which may be empty), followed by a tab and the
+ Gopher+ commands.
+
+2.4. Default Gopher+ Data Representation
+
+ When a Gopher server returns a directory listing to a client, the
+ Gopher+ items are tagged with either a "+" (denoting Gopher+ items)
+ or a "?" (denoting Gopher+ items that have a +ASK form associated
+ with them). A Gopher URL with a Gopher+ string consisting of only a
+ "+" refers to the default view (data representation) of the item, and
+ a Gopher+ string containing only a "?" refers to an item with a
+ Gopher electronic form associated with it.
+
+2.5. Gopher+ Items with Electronic Forms
+
+ Gopher+ items that have a +ASK associated with them (i.e., Gopher+
+ items tagged with a "?") require the client to fetch the item's +ASK
+ attribute to get the form definition, and then ask the user to fill
+ out the form and return the user's responses along with the selector
+ string to retrieve the item. Gopher+ clients know how to do this but
+ depend on the "?" tag in the Gopher+ item description to know when to
+ handle this case. The "?" is used in the Gopher+ string to be
+ consistent with Gopher+ protocol's use of this symbol.
+
+2.6. Gopher+ Item Attribute Collections
+
+ To refer to the Gopher+ attributes of an item, the Gopher URL's
+ Gopher+ string consists of "!" or "$". "!" refers to all of a Gopher+
+ item's attributes. "$" refers to all the item attributes for all
+ items in a Gopher directory.
+
+
+
+
+
+
+Hoffman Standards Track [Page 3]
+
+RFC 4266 The gopher URI Scheme November 2005
+
+
+2.7. Referring to Specific Gopher+ Attributes
+
+ To refer to specific attributes, the URL's gopher+_string is
+ "!<attribute_name>" or "$<attribute_name>". For example, to refer to
+ the attribute containing the abstract of an item, the gopher+_string
+ would be "!+ABSTRACT".
+
+ To refer to several attributes, the gopher+_string consists of the
+ attribute names separated by coded spaces. For example,
+ "!+ABSTRACT% 20+SMELL" refers to the +ABSTRACT and +SMELL attributes
+ of an item.
+
+2.8. URL Syntax for Gopher+ Alternate Views
+
+ Gopher+ allows for optional alternate data representations (alternate
+ views) of items. To retrieve a Gopher+ alternate view, a Gopher+
+ client sends the appropriate view and language identifier (found in
+ the item's +VIEW attribute). To refer to a specific Gopher+
+ alternate view, the URL's Gopher+ string would be in the form:
+
+ +<view_name>%20<language_name>
+
+ For example, a Gopher+ string of "+application/postscript%20Es_ES"
+ refers to the Spanish language postscript alternate view of a Gopher+
+ item.
+
+2.9. URL Syntax for Gopher+ Electronic Forms
+
+ The gopher+_string for a URL that refers to an item referenced by a
+ Gopher+ electronic form (an ASK block) filled out with specific
+ values is a coded version of what the client sends to the server.
+ The gopher+_string is of the form:
+
+ +%091%0D%0A+-1%0D%0A<ask_item1_value>%0D%0A
+ <ask_item2_value>%0D%0A.%0D%0A
+
+ To retrieve this item, the Gopher client sends the following text to
+ the Gopher server.
+
+ <a_gopher_selector><tab>+<tab>1<cr><lf>
+ +-1<cr><lf>
+ <ask_item1_value><cr><lf>
+ <ask_item2_value><cr><lf>
+ .<cr><lf>
+
+
+
+
+
+
+
+Hoffman Standards Track [Page 4]
+
+RFC 4266 The gopher URI Scheme November 2005
+
+
+3. Security Considerations
+
+ There are many security considerations for URI schemes discussed in
+ [RFC3986]. The Gopher protocol uses passwords in the clear for
+ authentication, and offers no privacy, both of which are considered
+ extremely unsafe in current practice.
+
+4. Informative References
+
+ [Gopher+] Anklesaria, F., et al., "Gopher+: Upward compatible
+ enhancements to the Internet Gopher protocol", University
+ of Minnesota, July 1993, <ftp://boombox.micro.umn.edu/pub/
+ gopher/gopher_protocol/Gopher+/Gopher+.txt>
+
+ [RFC1738] Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform
+ Resource Locators (URL)", RFC 1738, December 1994.
+
+ [RFC2396] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
+ Resource Identifiers (URI): Generic Syntax", RFC 2396,
+ August 1998.
+
+ [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
+ Resource Identifier (URI): Generic Syntax", STD 66,
+ RFC 3986, January 2005.
+
+ [RFC1436] Anklesaria, F., McCahill, M., Lindner, P., Johnson, D.,
+ Torrey, D., and B. Albert, "The Internet Gopher Protocol
+ (a distributed document search and retrieval protocol)",
+ RFC 1436, March 1993.
+
+Author's Address
+
+ Paul Hoffman
+ VPN Consortium
+ 127 Segre Place
+ Santa Cruz, CA 95060
+ US
+
+ EMail: paul.hoffman@vpnc.org
+
+
+
+
+
+
+
+
+
+
+
+
+Hoffman Standards Track [Page 5]
+
+RFC 4266 The gopher URI Scheme November 2005
+
+
+Full Copyright Statement
+
+ Copyright (C) The Internet Society (2005).
+
+ This document is subject to the rights, licenses and restrictions
+ contained in BCP 78, and except as set forth therein, the authors
+ retain all their rights.
+
+ This document and the information contained herein are provided on an
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+
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+
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+
+Acknowledgement
+
+ Funding for the RFC Editor function is currently provided by the
+ Internet Society.
+
+
+
+
+
+
+
+Hoffman Standards Track [Page 6]
+