X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?p=elpher.git;a=blobdiff_plain;f=elpher.texi;h=0de237cabfd1b9fe4eb0dbdca4a307f939d2b2a0;hp=a81f7ef71e4c9439bdfc848ecfaf4dbef349067d;hb=c9175aedfaf3daeca6b2414f74ef703f2f6cbc1f;hpb=ba4c61bb10efe2e751419010e4eb4d6c5e7fa1ee diff --git a/elpher.texi b/elpher.texi index a81f7ef..0de237c 100644 --- a/elpher.texi +++ b/elpher.texi @@ -1,8 +1,12 @@ \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. @@ -40,16 +44,36 @@ the file COPYING in the same directory as this file for more details. @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 +* Quick Start:: Get up and running quickly * 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 -* Hacking:: Contributing changes to 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, Navigation, Top, Top +@node Introduction, Installation, Top, Top @chapter Introduction Elpher aims to be a capable and practical gopher client for Emacs. Its @@ -60,61 +84,437 @@ Elpher provides the following bells and whistles: @itemize @item -an easily navigable history, sporting caching of visited sites (both +followable web and gopher links in plain text, + +@item +an easily navigable history, sporting caching of visited pages (both content and cursor position), @item 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. -@end itemize +basic support for the new ``heavier than gopher, lighter than the web'' Gemini protocol. -Throughout this manual, the +@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 Navigation, Bookmarks, Introduction, Top +@node Installation, Quick Start, Introduction, Top +@chapter Installation + +Elpher is available from the MELPA package repository. If you have +never installed packages from this repository before, you'll need +to follow the instructions at @url{https://melpa.org/#/getting-started}. + +@noindent To install Elpher, enter the following: + +@example +@kbd{M-x package-install @key{RET} elpher @key{RET}} +@end example + +@noindent To uninstall, use + +@example +@kbd{M-x package-delete @key{RET} elpher @key{RET}}. +@end example + +While not recommended, it is also possible to install Elpher directly by +downloading the file @file{elpher.el} from +@url{gopher://thelambdalab.xyz/1/projects/elpher/}, adding it to a directory in +your @code{load-path}, and then adding + +@example +(require 'elpher) +@end example + +@noindent to your Emacs initialization file. + +@node Quick Start, Navigation, Installation, Top +@chapter Quick Start + +Before diving into the minutiae of the different commands available, +we will quickly describe how to get up and running with Elpher. + +Once installed, you can launch Elpher using + +@example +@kbd{M-x elpher @key{RET}} +@end example + +@noindent This will switch to the *Elpher* buffer and display a start +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{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 +available, Clicking on a link with the mouse cursor has the same +effect.) + +To return to the page you just followed the link from, press @key{u}. + +Elpher caches (for the duration of an Emacs session) both page contents +and the position of point on each of the pages (gopher menus, query +results, or text pages) you visit, restoring these when you next visit +the same page. Thus, pressing @key{u} displays the previous page in +exactly the same state as when you left, meaning that you can quickly +and visually explore the different documents in a menu without having to +wait for anything to reload. + +Of course, sometimes you'll @emph{want} to reload the current page +rather than stick with the cached version. To do this use @key{R}. +(This is particularly useful for search query results, where this +allows you to perform a different search.) + +That's more-or-less it. Elpher supports a number of other features, such +as bookmarking, support for different coding schemes and TLS encryption, +and a variety of customization options, all of which are explained in +the rest of this document. However the emphasis is on keeping the basic +navigation experience as intuitive and responsive as possible. + +@node Navigation, Bookmarks, Quick Start, Top @chapter Navigation +by +Throughout this manual, we use the word ``page'' to refer to any +visualization of a response from a gopher server, be it a +menu/directory, query result, text file or image. We use -Elpher's navigation interface heavily inspired by the Emacs Info mode. +Elpher's navigation interface is inspired by the Emacs Info mode. +Movement within a page is essentially the same as moving +around any other text file in Emacs, but with special keys +for quickly jumping between menu items and URLs in text files. +Movement between pages is facilitated by a simple linear history +coupled with caching of pages and cursor position. @menu -* Within-page navigation:: -* Between-page 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 menu + @node Within-page navigation, Between-page navigation, Navigation, Navigation @section Within-page navigation -Within a single page +To move about within a page, you should be able use the same keys you usually +use to browse files in Emacs. This is even true when Evil mode is +enabled. Paragraph hopping, searching etc should work as usual. + +In addition, the following commands are provided for quickly moving between +links and menu items. + +@table @asis +@keycmd{@key{TAB}, elpher-next-link} +Move to the next link or menu item in the file. + +@keycmd{@kbd{Shift-@key{TAB}}/@key{backtab}, @code{elpher-prev-link}} +Move to the previous link or menu item in the file. + +@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. +@end table + +The following commands can be used to retrieve information about the +current page, or the address of the link at point: + +@table @asis +@keycmd{@key{i}, elpher-info-link} +Display host, port and selector information for the link at point. -@node Between-page navigation, , Within-page navigation, Navigation +@keycmd{@key{I}, elpher-info-current} +Display host, port and selector information for the current page. + +@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). + +@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). + +@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. + +@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 -@node Bookmarks, Customization, Navigation, Top +Moving to a different page can be accomplished in several ways, +described by the following command: + +@table @asis +@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 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. +Links to images behave similarly on Emacs systems supporting the display of +bitmap graphics, however their content is not cached in memory by default. + +@item +When followed, links to search/query items (type 7) prompt for input in +the minibuffer then display the results in the same way as for text and menu +items. + +@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 has been displayed, its contents are +cached for the duration of the Emacs session. + +@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. + +Remember however, that the Gopher RFC 1436 provides no guarantees about the +structure of selectors. + +@keycmd{@key{O}, elpher-root-dir} +Open the root page (empty selector) on the current host. + +@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 Customization, Hacking, 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 + +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 Hacking, Index, Customization, Top -@chapter Hacking +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 Index, , Hacking, Top -@unnumbered Index +@node Command Index, , Customization, Top +@unnumbered Command Index -@printindex cp +@printindex fn @bye