fish-shell/share/functions/help.fish
Ilya Grigoriev 1a03c23b58 Improve error when help fails to find a browser
Previously, this message told the user to "set $BROWSER and try again". However,
when I first saw this error, I didn't know how I can set `BROWSER` in fish. Moreover,
I often see this error in situations when no browser will work. For instance, I might be
using fish over ssh, and I might either not know whether that system has a text-mode
browser installed or not want to use it.

A further improvement would be to report this message if a browser fails to start.
2021-03-11 18:32:24 +01:00

222 lines
9.1 KiB
Fish

function help --description 'Show help for the fish shell'
set -l options h/help
argparse -n help $options -- $argv
or return
if set -q _flag_help
__fish_print_help help
return 0
end
set -l fish_help_item $argv[1]
if test (count $argv) -gt 1
if string match -q string $argv[1]
set fish_help_item (string join '-' $argv[1] $argv[2])
else
echo "help: Expected at most 1 args, got 2"
return 1
end
end
# Find a suitable browser for viewing the help pages.
# The first thing we try is $fish_help_browser.
set -l fish_browser $fish_help_browser
# A list of graphical browsers we know about.
set -l graphical_browsers htmlview x-www-browser firefox galeon mozilla
set -a graphical_browsers konqueror epiphany opera netscape rekonq google-chrome chromium-browser
# On mac we may have to write a temporary file that redirects to the desired
# help page, since `open` will drop fragments from file URIs (issue #4480).
set -l need_trampoline
if not set -q fish_browser[1]
if set -q BROWSER
# User has manually set a preferred browser, so we respect that
echo $BROWSER | read -at fish_browser
else
# No browser set up, inferring.
# We check a bunch and use the last we find.
# Check for a text-based browser.
for i in htmlview www-browser links elinks lynx w3m
if type -q -f $i
set fish_browser $i
break
end
end
# If we are in a graphical environment, check if there is a graphical
# browser to use instead.
if test -n "$DISPLAY" -a \( "$XAUTHORITY" = "$HOME/.Xauthority" -o "$XAUTHORITY" = "" \)
for i in $graphical_browsers
if type -q -f $i
set fish_browser $i
break
end
end
end
# If we have an open _command_ we use it - otherwise it's our function,
# which might not have a backend to use.
# Note that we prefer xdg-open, because this open might also be a symlink to "openvt"
# like it is on Debian.
if command -sq open
set fish_browser open
# The open command needs a trampoline because the macOS version can't handle #-fragments.
set need_trampoline 1
end
# If the OS appears to be Windows (graphical), try to use cygstart
if type -q cygstart
set fish_browser cygstart
# If xdg-open is available, just use that
else if type -q xdg-open
set fish_browser xdg-open
end
# Try to find cmd.exe via $PATH or one of the paths that it's often at.
#
# We use this instead of xdg-open because that's useless without a backend
# like wsl-open which we'll check in a minute.
if test -f /proc/version
and string match -riq 'Microsoft|WSL|MSYS|MINGW' </proc/version
and set -l cmd (command -s cmd.exe /mnt/c/Windows/System32/cmd.exe)
# Use the first of these.
set fish_browser $cmd[1]
end
if type -q wsl-open
set fish_browser wsl-open
end
end
end
if not set -q fish_browser[1]
printf (_ '%s: Could not find a web browser.\n') help
printf (_ 'Please try `BROWSER=some_browser help`, `man fish-doc`, or `man fish-tutorial`.\n\n')
return 1
end
# In Cygwin, start the user-specified browser using cygstart,
# only if a Windows browser is to be used.
if type -q cygstart
if test $fish_browser != cygstart
and not command -sq $fish_browser[1]
# Escaped quotes are necessary to work with spaces in the path
# when the command is finally eval'd.
set fish_browser cygstart $fish_browser
else
set need_trampoline 1
end
end
set -l fish_help_page
switch "$fish_help_item"
case "."
set fish_help_page "cmds/source.html"
case globbing
set fish_help_page "index.html#expand"
case (builtin -n) (__fish_print_commands)
# If the docs aren't installed, __fish_print_commands won't print anything
# Since we document all our builtins, check those at least.
# The alternative is to create this list at build time.
set fish_help_page "cmds/$fish_help_item.html"
case 'completion-*'
set fish_help_page "completions.html#$fish_help_item"
case 'tut-*'
set fish_help_page "tutorial.html#"(string sub -s 5 -- $fish_help_item | string replace -a -- _ -)
case tutorial
set fish_help_page "tutorial.html"
case releasenotes
set fish_help_page relnotes.html
case completions
set fish_help_page completions.html
case faq
set fish_help_page faq.html
case fish-for-bash-users
set fish_help_page fish_for_bash_users.html
case ''
set fish_help_page "index.html"
case "*"
set fish_help_page "index.html#$fish_help_item"
end
# In Crostini Chrome OS Linux, the default browser opens URLs in Chrome running outside the
# linux VM. This browser does not have access to the Linux filesystem. This uses Garcon, see e.g.
# https://chromium.googlesource.com/chromiumos/platform2/+/master/vm_tools/garcon/#opening-urls
# https://source.chromium.org/search?q=garcon-url-handler
string match -q '*garcon-url-handler*' $fish_browser[1]
and set -l chromeos_linux_garcon
set -l page_url
if test -f $__fish_help_dir/index.html; and not set -lq chromeos_linux_garcon
# Help is installed, use it
set page_url file://$__fish_help_dir/$fish_help_page
# For Windows (Cygwin, msys2 and WSL), we need to convert the base
# help dir to a Windows path before converting it to a file URL
# but only if a Windows browser is being used
if type -q cygpath
and string match -qr '(cygstart|\.exe)(\s+|$)' $fish_browser[1]
set page_url file://(cygpath -m $__fish_help_dir)/$fish_help_page
else if type -q wslpath
and string match -qr '\.exe(\s+|$)' $fish_browser[1]
set page_url file://(wslpath -w $__fish_help_dir)/$fish_help_page
end
else
# Go to the web. Only include one dot in the version string
set -l version_string (string split . -f 1,2 -- $version | string join .)
set page_url https://fishshell.com/docs/$version_string/$fish_help_page
# We don't need a trampoline for a remote URL.
set need_trampoline
end
if set -q need_trampoline[1]
# If string replace doesn't replace anything, we don't actually need a
# trampoline (they're only needed if there's a fragment in the path)
if set -l clean_url (string match -re '#' $page_url)
# Write a temporary file that will redirect where we want.
set -q TMPDIR
or set -l TMPDIR /tmp
set -l tmpdir (mktemp -d $TMPDIR/help.XXXXXX)
or return 1
set -l tmpname $tmpdir/help.html
echo '<meta http-equiv="refresh" content="0;URL=\''$clean_url'\'" />' >$tmpname
set page_url file://$tmpname
# For Windows (Cygwin, msys2 and WSL), we need to convert the base help dir to a Windows path before converting it to a file URL
# but only if a Windows browser is being used
if type -q cygpath
and string match -qr '(cygstart|\.exe)(\s+|$)' $fish_browser[1]
set page_url file://(cygpath -m $tmpname)
else if type -q wslpath
and string match -qr '\.exe(\s+|$)' $fish_browser[1]
set page_url file://(wslpath -w $tmpname)
end
end
end
# cmd.exe needs more coaxing.
if string match -qr 'cmd\.exe$' -- $fish_browser[1]
# The space before the /c is to prevent msys2 from expanding it to a path
$fish_browser " /c" start $page_url
# If browser is known to be graphical, put into background
else if contains -- $fish_browser[1] $graphical_browsers
switch $fish_browser[1]
case htmlview x-www-browser
printf (_ 'help: Help is being displayed in your default browser.\n')
case '*'
printf (_ 'help: Help is being displayed in %s.\n') $fish_browser[1]
end
$fish_browser $page_url &
disown $last_pid >/dev/null 2>&1
else
# Work around lynx bug where <div class="contents"> always has the same formatting as links (unreadable)
# by using a custom style sheet. See https://github.com/fish-shell/fish-shell/issues/4170
if string match -qr '^lynx' -- $fish_browser
set fish_browser $fish_browser -lss={$__fish_data_dir}/lynx.lss
end
$fish_browser $page_url
end
end