\input texinfo @c -*-texinfo-*-
-@c %**start of header
+
@setfilename elpher.info
-@settitle Elpher Manual v1.0.0
-@c %**end of header
+@settitle Elpher Manual v2.0.0
+
+@dircategory Emacs
+@direntry
+* Elpher: (elpher). A gopher client for Emacs.
+@end direntry
@copying
This manual documents Elpher, a gopher client for Emacs.
@insertcopying
@end ifnottex
+@macro keycmd{key,cmd}
+@item \key\ (@code{\cmd\})
+@findex \cmd\
+@end macro
+
@menu
* Introduction:: Elpher Overview: what's this all about?
* Installation:: Installing Elpher
* Navigation:: Fundamentals of Elpher navigation
* Bookmarks:: How to record and visit bookmarks
* Character encodings:: How Elpher handles different character encodings
+* Encrypted connections:: How and when TLS is enabled
+* Gemini support:: Support for the Gemini protocol
* Customization:: How to customize various aspects of Elpher
-* Index::
+* Command Index::
+
+@detailmenu
+ --- The Detailed Node Listing ---
+
+Navigation
+
+* Within-page navigation:: Moving about within a page
+* Between-page navigation:: Commands for moving between pages
+* History and Caching:: Explanation of how Elpher represents history
+
+@end detailmenu
@end menu
@node Introduction, Installation, Top, Top
Elpher provides the following bells and whistles:
@itemize
+@item
+followable web and gopher links in plain text,
+
@item
an easily navigable history, sporting caching of visited pages (both
content and cursor position),
auto-completing menu item navigation,
@item
-followable web and gopher links in plain text,
+direct visualization of image files where supported (no writing to
+disk),
@item
-direct visualization of image files where supported (no writing to
-disk), and
+a bookmark management system,
@item
-a simple bookmark management system.
+basic support for the new ``heavier than gopher, lighter than the web'' Gemini protocol.
+
@end itemize
Elpher is still under active development. Although we try very hard to
ensure that releases are bug-free, this cannot be guaranteed. However,
this also means that any usability features that you feel are missing
-can likely by incoroporated quickly, so please get in touch if you
+can likely by incorporated quickly, so please get in touch if you
have some ideas.
@node Installation, Quick Start, Introduction, Top
While not recommended, it is also possible to install Elpher directly by
downloading the file @file{elpher.el} from
-@url{https://github.com/tgvaughan/elpher}, adding it to a directory in
+@url{gopher://thelambdalab.xyz/1/projects/elpher/}, adding it to a directory in
your @code{load-path}, and then adding
@example
page, with information on each of the default keyboard bindings.
From here you can move point between links (which may be menu items or
-inline URLs in text files) by using @key{TAB} and @kbd{Shift-TAB} keys,
+inline URLs in text files) by using @key{TAB} and @kbd{S-@key{TAB}},
as in Info. You can also jump directly to a menu item using @key{m}, or
use the standard Emacs or Evil motion and search commands to find your
way around. To open a link, press @key{RET}. (Where a mouse is
@menu
* Within-page navigation:: Moving about within a page
-* Between-page navigation:: Concepts and commands for moving between pages
+* Between-page navigation:: Commands for moving between pages
+* History and Caching:: Explanation of how Elpher represents history
@end menu
links and menu items.
@table @asis
-@item @kbd{tab} (@code{elpher-next-link})
+@keycmd{@key{TAB}, elpher-next-link}
Move to the next link or menu item in the file.
-@item @kbd{<S-tab>}/@kbd{<backtab>} (@code{elpher-prev-link})
+@keycmd{@kbd{Shift-@key{TAB}}/@key{backtab}, @code{elpher-prev-link}}
Move to the previous link or menu item in the file.
-@item @kbd{m} (@code{elpher-jump})
+@keycmd{@key{m}, elpher-jump}
Jump directly to a link within a file by specifying its display string
or link text. (Unlike the previous two commands, this immediately opens
the selected link.
current page, or the address of the link at point:
@table @asis
-@item @kbd{i} (@code{elpher-info-link})
+@keycmd{@key{i}, elpher-info-link}
Display host, port and selector information for the link at point.
-@item @kbd{I} (@code{elpher-info-current})
+@keycmd{@key{I}, elpher-info-current}
Display host, port and selector information for the current page.
-@item @kbd{c} (@code{elpher-copy-link-url})
+@keycmd{@key{c}, elpher-copy-link-url}
Add URL representing address of link at point to the kill-ring and the
system clipboard (if available).
-@item @kbd{C} (@code{elpher-copy-current-url})
+@keycmd{@key{C}, elpher-copy-current-url}
Add URL representing address of the current page to the kill-ring and
the system clipboard (if available).
-@end table
+@keycmd{@key{d}, elpher-download}
+Download link at point and save the result as a file. The minibuffer
+will prompt for the name of the file to write, with the default name being
+the display string (if available) associated with the link.
-@node Between-page navigation, , Within-page navigation, Navigation
+@keycmd{@key{D}, elpher-download-current}
+This is similar to @code{elpher-download}, but instead applies to the
+current page rather than a link.
+
+@keycmd{@key{.}, elpher-view-raw}
+This displays the raw server response for the current page. While not
+useful for general browsing, it is useful for debugging incorrect rendering
+or out-of-spec server responses.
+@end table
+
+@node Between-page navigation, History and Caching, Within-page navigation, Navigation
@section Between-page navigation
Moving to a different page can be accomplished in several ways,
described by the following command:
@table @asis
-@item @kbd{RET}, @kbd{mouse-1} (@code{elpher-follow-link})
+@keycmd{@key{RET}\, @kbd{mouse-1}, elpher-follow-link}
Follow the menu item or link at point (or selected with the mouse).
Exactly what is meant by ``follow'' depends on the kind of item selected:
@itemize
@item
-For text or menu type items or links, the curent page text is replaced
+For text or menu type items or links, the current page text is replaced
by the text of this item. Unless the customization variable
@code{elpher-use-header} (@pxref{Customization}) is
@code{nil}, the display string of the link is displayed in the buffer header.
@item
Following links to binary files (and image files on unsupported systems)
causes Elpher to prompt for a filename in which to save the content.
+
+@item
+Following links of type `h' with a selector having the `URL:' prefix, or
+non-gopher URLs in text files, will result in Elpher using an external
+programme to open the URL. This will be either the default system browser
+or, if the @code{elpher-open-urls-with-eww} customization variable is non-nil,
+Emacs' own EWW browser. (See @pxref{Customization}.)
+
@end itemize
-Once a text, menu or query response page is retrieved, its contents are
+Once a text, menu or query response page has been displayed, its contents are
cached for the duration of the Emacs session.
-@item @kbd{d} (@code{elpher-download})
+@keycmd{@key{g}, elpher-go}
+Open a particular page by specifying either its full URL or just entering
+a gopher host name.
+
+If a non-gopher protocol is used in the URL the result will be the same
+as following a URL link of the same type from a gopher menu.
+
+@keycmd{@key{o}, elpher-go-current}
+Prompts for a URL similar to @code{elpher-go}, but initialized to the URL
+of the current page. This allows you to easily try other selectors for the
+same server.
-@item @kbd{g} (@code{elpher-go})
+Remember however, that the Gopher RFC 1436 provides no guarantees about the
+structure of selectors.
-@item @kbd{O} (@code{elpher-root-dir})
+@keycmd{@key{O}, elpher-root-dir}
+Open the root page (empty selector) on the current host.
-@item @kbd{u} (@code{elpher-back})
+@keycmd{@key{u}\, @kbd{mouse-3}, elpher-back}
Return to the previous page, where ``previous'' means the page where the
page which was displayed immediately before the current page.
@end table
+
+@node History and Caching, , Between-page navigation, Navigation
+@section History and Caching
+
+The history and caching strategy in Elpher is extremely simple, but
+may be confusing without a good mental model of how it works. That
+is what this section attempts to provide.
+
+Essentially, @strong{every} time you navigate to a new page, either
+by clicking or pressing @key{RET} on a link, using @key{g} to jump
+to a new page by its address, or using @key{O} to open the root selector,
+the following two things occur:
+
+@enumerate
+@item
+the cursor position and content for the original page are recorded in an
+in-memory cache, and
+
+@item
+the original page is set as the ``parent'' of the new page.
+@end enumerate
+
+The only way to return to pages in this history is by using @key{u},
+which returns to the previous of the current page.
+@footnote{The addition of the new page to the history happens even if
+the new page is one that has been seen before. This is mostly the
+desired behaviour. However, opening an explicit ``back'' link provided
+by a gopher menu will also add a new entry to the history. Unless you
+haven't yet visited that menu, it's therefore better to use @key{u} to
+go back in this case.}
+
+One aspect that may seem peculiar is that Elpher lacks a corresponding ``next'' or
+``forward'' command. However, since Elpher caches the position of point,
+this will be automatically positioned on the link that was most recently followed
+from a given page. This means that, at least for links followed from menus
+and text files, the inverse of @key{u} is actually just @key{RET}.
+
+
@node Bookmarks, Character encodings, Navigation, Top
@chapter Bookmarks
-@node Character encodings, Customization, Bookmarks, Top
+Elpher has a very simple link bookmarking system involving the
+following commands:
+
+@table @asis
+@keycmd{@key{a}, elpher-bookmark-link}
+Add a bookmark for the link at point. The minibuffer will prompt for
+a name for the bookmark, which defaults to the display string.
+
+@keycmd{@key{A}, elpher-bookmark-current}
+Add a bookmark for the current page. The minibuffer will prompt for
+a name for the bookmark, defaulting to the display string associated
+with the link that was followed to reach the current page.
+
+@keycmd{@key{x}, elpher-unbookmark-link}
+Immediately remove the bookmark (if one exists) to the link at point.
+
+@keycmd{@key{X}, elpher-unbookmark-current}
+Immediately remove the bookmark (if one exists) to the current page.
+
+@keycmd{@key{B}, elpher-bookmarks}
+Open a page displaying all current bookmarks. Note that this bookmark
+page is added to the history just as if you had opened it using a link.
+Thus to return to the previous page, use @kbd{u}. This also means
+that you can peruse the various bookmarks by visiting them in turn,
+using @kbd{u} to return to the bookmark page (where the position of point
+is cached), then moving to another bookmarked link and so on.
+@end table
+
+Bookmarks are stored as a s-exp in the file @file{elpher-bookmarks}
+in the user emacs directory (usually @file{~/.emacs.d/}).
+Any command which modifies the list of bookmarks immediately updates
+this file.
+
+@node Character encodings, Encrypted connections, Bookmarks, Top
@chapter Character encodings
-@node Customization, Index, Character encodings, Top
+Responses Elpher retrieves from servers are initially read as pure
+binary data. When the data is intended to be interpreted as textual (as
+determined by the type parameter of the gopher menu item or the gopher
+URL), this data needs to be @emph{decoded} into a sequence of
+characters. To do this properly requires knowledge of the encoding
+system used by whoever authored the document.
+
+Unfortunately gopher lacks a systematic way of acquiring this necessary
+information. Thus, the details of the coding system must be either inferred from the binary data,
+or must be specified by the user.
+
+By default, Elpher applies Emacs' built-in character encoding detection
+system to the full (undecoded) response data and uses this to attempt to
+convert it into a character string.
+(See @pxref{Recognize coding, Recognizing coding systems, ,emacs}.) While
+this approach can be okay, it is important to realize that its inference
+algorithm is extremely primitive and depends heavily on assumptions based
+on the language settings of your emacs system.
+
+The alternative is to explicitly set the coding system used for decoding
+using the following command:
+
+@table @asis
+@keycmd{@key{S},elpher-set-coding-system}
+Causes a elpher to prompt for a coding system to use for decoding
+future text. The @key{TAB} key can be used at this prompt to display a
+list of alternatives (which is extensive) and to auto-complete. An empty
+response will cause Elpher to return to its default auto-detection
+behaviour.
+@end table
+
+Note that changing the coding system only affects newly loaded text.
+Thus, if text has already been decoded using an incorrect system, you
+will need to select the correct coding and then reload the text using
+@key{R}.
+
+
+@node Encrypted connections, Gemini support, Character encodings, Top
+@chapter Encrypted connections
+
+While RFC 1436 does not broach the topic of encryption at all, several
+modern gopher servers can serve content over encrypted connections,
+and a common choice for this is TLS.
+
+Elpher can retrieve selectors using Emacs' built-in TLS support which
+uses the GnuTLS library. (It is possible to build emacs without
+GnuTLS, in which case encryption is not supported.)
+
+To retrieve documents using TLS, Elpher's TLS mode must be enabled.
+This can be directly toggled using @key{T}, but note that just as with
+the character encoding, changing this mode only affects subsequent
+connections.
+
+Alternatively, TLS mode is @emph{automatically} enabled whenever
+gopher URLs starting with @code{gophers://} are followed.
+
+The mode is sticky, so it remains active until switched off.
+It can also be automatically switched off when a TLS connection fails.
+In this case Elpher will prompt for your confirmation to ensure that
+you can't accidentally make a non-TLS connection.
+
+@node Gemini support, Customization, Encrypted connections, Top
+@chapter Gemini support
+
+@uref{gopher://zaibatsu.circumlunar.space/1/~solderpunk/gemini, Gemini}
+is a new protocol being devloped by several members of
+gopherspace. It aims to solve some of the long-standing technical
+issues associated with gopher as a protocol, while keeping the major benifits.
+For instance, it _requires_ encrypted connections, it does away with
+the selector type, and allows servers to explicitly specify the
+character coding scheme used for text documents.
+
+The latest versions of Elpher aim to provide seemless navigation between
+gemini and gopher documents. Basically you should be able to open,
+bookmark, download and otherwise interact with gemini pages in exactly
+the same way as you do with other non-gemini pages. The only major
+difference from your perspective as a user is that you should no longer
+have to worry about manually toggling TLS on or off (for gemini it's
+always on), and you should never have to manually set a character coding
+scheme.
+
+I should emphasize however that, while it is definitely functional,
+Elpher's gemini support is still experimental, and various aspects will
+change as the protocol develops further. Additionally, the use of
+client TLS certicificates is not yet supported.
+
+@node Customization, Command Index, Gemini support, Top
@chapter Customization
-@node Index, , Customization, Top
-@unnumbered Index
+Various parts of Elpher can be customized via the
+variables belonging to the elpher customization group, accessible
+using
+
+@example
+@kbd{M-x customize-group elpher @key{RET}}
+@end example
+
+@noindent This group contains a number of faces that can be modified to change
+the appearance of Elpher, including one face per menu item type.
+
+The group also contains variables for customizing the behaviour of
+Elpher. This includes how to open arbitrary (non-gopher) URLs, whether
+to display buffer headers, how to deal with ANSI escape sequences in
+text, the timeout to impose on network connections, and whether to
+prompt for confirmation when switching away from TLS.
+
+See the customization group itself for details.
+
+@node Command Index, , Customization, Top
+@unnumbered Command Index
-@printindex cp
+@printindex fn
@bye
The Lambda Lab / projects / elpher.git / blobdiff