bollux/bollux

1732 lines
53 KiB
Bash
Executable File

#!/usr/bin/env bash
################################################################################
# BOLLUX: a bash gemini client
# Author: Case Duckworth
# License: MIT
# Version: 0.4.1
#
# Commentary:
#
# The impetus for this program came from a Mastodon conversation I had where
# someone mentioned the "simplest possible Gemini client" was this:
#
# openssl s_client -ign_eof -quiet -connect $server:1965 <<< "$url"
#
# That's still at the heart of this program (see `gemini_request'): `bollux' is
# basically a half-functioning convenience wrapper around that openssl call.
# The first versions of `bollux' used `gawk' and a lot of other tools on top of
# bash, but after reading Dylan Araps' Pure Bash Bible[1] and other works, I
# decided to make as much of it in Bash as possible. Thus, currently `bollux'
# requires `bash' v. 4+, `less' (a recent, non-busybox version), `dd' for
# downloads, `openssl' for requests, and `iconv' to convert pages to UTF-8.
# Future versions will hopefully have a pager fully implemented in bash, so that
# I won't have to worry about less's weird incompatibilities and keybinding
# things. That's a major project though, and I'm scared.
#
# The following works were referenced when writing this, and I've tried to
# credit them in comments below. Further in the commentary on this script, I'll
# include the following link numbers to refer to these documents, in order to
# keep the line length as short as possible.
#
# [1]: Pure Bash Bible
# https://github.com/dylanaraps/pure-bash-bible
# [2]: URL Specification
# https://tools.ietf.org/html/rfc3986
# [3]: Gemini Specification
# https://gemini.circumlunar.space/docs/specification.html
# [4]: Gemini Best Practices
# https://gemini.circumlunar.space/docs/best-practices.gmi
# [5]: Gemini FAQ
# https://gemini.circumlunar.space/docs/faq.gmi
# [6]: Gopher Specification
# https://tools.ietf.org/html/rfc1436
# [7]: Gopher URLs
# https://tools.ietf.org/html/rfc4266
# [8]: Gophermap to Gemini script (by tomasino)
# https://github.com/jamestomasino/dotfiles-minimal/blob/master/bin/gophermap2gemini.awk
# [9]: OpenSSL `s_client' online manual
# https://www.openssl.org/docs/manmaster/man1/openssl-s_client.html
#
################################################################################
# Code:
# Program information
PRGN="${0##*/}" # Easiest way to get the script name
VRSN=0.4.1 # I /try/ to follow semver? IDK.
# Print a useful help message (`bollux -h').
bollux_usage() {
cat <<END
$PRGN (v. $VRSN): a bash gemini client
usage:
$PRGN [-h]
$PRGN [-q] [-v] [URL]
flags:
-h show this help and exit
-q be quiet: log no messages
-v be verbose: log more messages
parameters:
URL the URL to start in
If not provided, the user will be prompted.
END
}
# Main entry point into `bollux'.
#
# See the `if' block at the bottom of this script.
bollux() {
run bollux_config # TODO: figure out better config method
run bollux_args "$@" # and argument parsing
run bollux_init
# If the user hasn't configured a home page, $BOLLUX_URL will be blank.
# So, prompt the user where to go.
if [[ ! "${BOLLUX_URL:+x}" ]]; then
run prompt GO BOLLUX_URL
fi
log d "BOLLUX_URL='$BOLLUX_URL'"
run blastoff -u "$BOLLUX_URL" # Visit the specified URL.
}
# Process command-line arguments.
bollux_args() {
while getopts :hvq OPT; do
case "$OPT" in
h)
bollux_usage
exit
;;
v) BOLLUX_LOGLEVEL=DEBUG ;;
q) BOLLUX_LOGLEVEL=QUIET ;;
:) die 1 "Option -$OPTARG requires an argument" ;;
*) die 1 "Unknown option: -$OPTARG" ;;
esac
done
shift $((OPTIND - 1))
# If there's a leftover argument, it's the URL to visit.
if (($# == 1)); then
BOLLUX_URL="$1"
fi
}
# Source the configuration file and set remaining variables.
#
# Since `bollux_config' is loaded before `bollux_args', there's no way to
# specify a configuration file from the command line. I run `bollux_args'
# second so that command-line options (mostly $BOLLUX_URL) can supersede
# config-file options, and I'm not sure how to rectify the situation.
#
# Anyway, the config file `bollux.conf' is just a bash file that's sourced in
# this function. After that, I use a little bash trick to set all the remaining
# variables to default values with `: "${VAR:=value}"'.
bollux_config() {
: "${BOLLUX_CONF_DIR:=${XDG_CONFIG_HOME:-$HOME/.config}/bollux}"
: "${BOLLUX_CONFIG:=$BOLLUX_CONF_DIR/bollux.conf}"
if [ -f "$BOLLUX_CONFIG" ]; then
log debug "Loading config file '$BOLLUX_CONFIG'"
# Shellcheck gets mad when we try to source a file behind a
# variable -- it doesn't know where it is. This line ignores
# that warning, since the user can put $BOLLUX_CONFIG wherever.
# shellcheck disable=1090
. "$BOLLUX_CONFIG"
else
# It's an error if bollux can't find the config file, but I
# don't want to kill the program over it.
log error "Can't load config file '$BOLLUX_CONFIG'."
fi
## behavior
: "${BOLLUX_TIMEOUT:=30}" # connection timeout
: "${BOLLUX_MAXREDIR:=5}" # max redirects
: "${BOLLUX_PROTO:=gemini}" # default protocol
: "${BOLLUX_GEMINI_PORT:=1965}" # default port for gemini
: "${BOLLUX_GOPHER_PORT:=70}" # default port for gopher
: "${BOLLUX_URL:=}" # start url
: "${BOLLUX_BYEMSG:=See You Space Cowboy ...}" # bye message
## lesskeys
: "${KEY_OPEN:=o}" # prompt for a link to open
: "${KEY_GOTO:=g}" # prompt for a page to 'goto'
: "${KEY_GOTO_FROM:=G}" # goto a page with current prefilled
: "${KEY_BACK:=[}" # go back in the history
: "${KEY_FORWARD:=]}" # go forward in the history
: "${KEY_REFRESH:=r}" # refresh the page
: "${KEY_CYCLE_PRE:=p}" # cycle T_PRE_DISPLAY
: "${BOLLUX_CUSTOM_LESSKEY:=$BOLLUX_CONF_DIR/bollux.lesskey}"
## files
: "${BOLLUX_DATADIR:=${XDG_DATA_HOME:-$HOME/.local/share}/bollux}"
: "${BOLLUX_DOWNDIR:=.}" # where to save downloads
: "${BOLLUX_LESSKEY:=$BOLLUX_DATADIR/lesskey}" # where to store binds
: "${BOLLUX_PAGESRC:=$BOLLUX_DATADIR/pagesrc}" # where to save source
BOLLUX_HISTFILE="$BOLLUX_DATADIR/history" # where to save history
## typesetting
: "${T_MARGIN:=4}" # left and right margin
: "${T_WIDTH:=0}" # width of the view port
# 0 = get term width
: "${T_PRE_DISPLAY:=both,pre,alt}" # how to view PRE blocks
# colors -- these will be wrapped in \e[ __ m
C_RESET='\e[0m' # reset
: "${C_SIGIL:=35}" # sigil (=>, #, ##, ###, *, ```)
: "${C_LINK_NUMBER:=1}" # link number
: "${C_LINK_TITLE:=4}" # link title
: "${C_LINK_URL:=36}" # link URL
: "${C_HEADER1:=1;4}" # header 1 formatting
: "${C_HEADER2:=1}" # header 2 formatting
: "${C_HEADER3:=3}" # header 3 formatting
: "${C_LIST:=0}" # list formatting
: "${C_QUOTE:=3}" # quote formatting
: "${C_PRE:=0}" # preformatted text formatting
## state
UC_BLANK=':?:' # internal use only, should be non-URL chars
}
# Initialize bollux state
bollux_init() {
# Trap `bollux_cleanup' on quit and exit
trap bollux_cleanup INT QUIT EXIT
# Trap `bollux_quit' on interrupt (C-c)
trap bollux_quit SIGINT
# Disable pathname expansion.
#
# It's very unlikely the user will want to navigate to a file when
# answering the GO prompt.
set -f
# Initialize state
#
# Other than $REDIRECTS, bollux's mutable state includes
# $BOLLUX_URL, but that's initialized elsewhere (possibly even by
# the user)
REDIRECTS=0
# History
#
# See also `history_append', `history_back', `history_forward'
declare -a HISTORY # history is kept in an array
HN=0 # position of history in the array
run mkdir -p "${BOLLUX_HISTFILE%/*}"
# Remove $BOLLUX_LESSKEY and re-generate keybindings (to catch rebinds)
run rm -f "$BOLLUX_LESSKEY"
}
# Cleanup on exit
bollux_cleanup() {
# Stubbed in case of need in future
:
}
# Exit with success, printing a fun message.
#
# The default message is from the wonderful show "Cowboy Bebop."
bollux_quit() {
printf '\e[1m%s\e[0m:\t\e[3m%s\e[0m\n' "$PRGN" "$BOLLUX_BYEMSG"
exit
}
# UTILITY FUNCTIONS ############################################################
# Run a command, but log it first.
#
# See `log' for the available levels.
run() { # run COMMAND...
# I have to add a `trap' here for SIGINT to work properly.
trap bollux_quit SIGINT
LOG_FUNC=2 log debug "> $*"
"$@"
}
# Log a message to stderr (&2).
#
# `log' in this script can take 3 different parameters: `d', `e', and `x', where
# `x' is any other string (though I usually use `x'), followed by the message to
# log. Most messages are either `d' (debug) level or `x' (diagnostic) level,
# meaning I want to show them all the time or only when bollux is called with
# `-v' (verbose). The levels are somewhat arbitrary, like I suspect all logging
# levels are, but you can read the rest of bollux to see what I've chosen to
# classify as what.
log() { # log LEVEL MESSAGE...
# 'QUIET' means don't log anything.
[[ "$BOLLUX_LOGLEVEL" == QUIET ]] && return
local fmt # ANSI escape code
case "$1" in
[dD]*) # Debug level -- only print if bollux -v.
[[ "$BOLLUX_LOGLEVEL" == DEBUG ]] || return
fmt=34 # Blue
;;
[eE]*) # Error level -- always print.
fmt=31 # Red
;;
*) # Diagnostic level -- print unless QUIET.
fmt=1 # Bold
;;
esac
shift
printf >&2 '\e[%sm%s:%-16s:\e[0m %s\n' \
"$fmt" "$PRGN" "${FUNCNAME[${LOG_FUNC:-1}]}" "$*"
}
# Exit with an error and a message describing it.
die() { # die EXIT_CODE MESSAGE
local exit_code="$1"
shift
log error "$*"
exit "$exit_code"
}
# Trim leading and trailing whitespace from a string.
#
# [1]: #trim-leading-and-trailing-white-space-from-string
trim_string() { # trim_string STRING
: "${1#"${1%%[![:space:]]*}"}"
: "${_%"${_##*[![:space:]]}"}"
printf '%s\n' "$_"
}
# Cycle a variable in a list given a delimiter.
#
# e.g. 'list_cycle one,two,three ,' => 'two,three,one'
list_cycle() { # list_cycle LIST<string> DELIM
# I could've set up `list_cycle' to use an array instead of a delimited
# string, but the one variable this function is used for is
# T_PRE_DISPLAY, which is user-configurable. I wanted it to be as easy
# to configure for users who might not immediately know the bash array
# syntax, but can figure out 'variable=value' without much thought.
local list="${!1}" # Pass the list by name, not value
local delim="$2" # The delimiter of the string
local first="${list%%${delim}*}" # The first element
local rest="${list#*${delim}}" # The rest of the elements
# -v prints to the variable specified.
printf -v "$1" '%s%s%s' "${rest}" "${delim}" "${first}"
}
# Set the terminal title.
set_title() { # set_title TITLE...
printf '\e]2;%s\007' "$*"
}
# Prompt the user for input.
#
# This is a thin wrapper around `read', a bash built-in. Because of the
# way bollux messes around with stdin and stdout, I need to read directly from
# the TTY with this function.
prompt() { # prompt [-u] PROMPT [READ_ARGS...]
# `-e' gets the line "interactively", so it can see history and stuff
# `-r' reads a "raw" string, i.e., without backslash escaping
local read_cmd=(read -e -r)
if [[ "$1" == "-u" ]]; then
# `-i TEXT' uses TEXT as the initial text for `read'
read_cmd+=(-i "$BOLLUX_URL")
shift
fi
local prompt="$1" # How to prompt the user
shift
read_cmd+=(-p "$prompt> ")
"${read_cmd[@]}" </dev/tty "$@"
}
# Bash built-in replacement for `cat'
#
# One of the more pedantic bits of bollux (is 'pedantic' the right word?) --
# `cat' is more than likely installed on any system with bash, so this function
# is really just here so I can say that bollux is written as purely in bash as
# possible.
passthru() {
while IFS= read -r; do
printf '%s\n' "$REPLY"
done
}
# Bash built-in replacement for `sleep'
#
# The commentary for `passthru' applies here as well, though I didn't write this
# function -- Dylan Araps did.
#
# [1]: #use-read-as-an-alternative-to-the-sleep-command
sleep() { # sleep SECONDS
read -rt "$1" <> <(:) || :
}
# Normalize files.
normalize() {
shopt -s extglob # for the printf call below
while IFS= read -r; do
# Normalize line endings to Unix-style (LF)
printf '%s\n' "${REPLY//$'\r'?($'\n')/}"
done
shopt -u extglob # reset 'extglob'
}
# URLS #########################################################################
# https://tools.ietf.org/html/rfc3986 [2]
#
# Most of these functions are Bash implementations of functionality laid out in
# the linked RFC specification. I'll refer to the section numbers above each
# function.
#
# In addition, most of these functions take arrays or array elements passed /by
# name/, instead of /value/ -- i.e., instead of calling `usplit $url', call
# `usplit url'. Passing values by name is necessary because of Bash's weird
# array handling.
#
################################################################################
# Make sure a URL is "well-formed:" add a default protocol if it's missing and
# trim whitespace.
#
# Useful for URLs that were probably input by humans.
uwellform() { # uwellform URL
local url="$1"
if [[ "$url" != *://* ]]; then
url="$BOLLUX_PROTO://$url"
fi
url="$(trim_string "$url")"
printf '%s\n' "$url"
}
# Split a URL into its constituent parts, placing them all in the given array.
#
# The regular expression given at the top of the function ($re) is taken
# directly from [2] Appendix B -- and if the URL provided doesn't match it, the
# function bails.
#
# `usplit' takes advantage of bash's regex abilities: when the regex comparison
# operator `=~' is used, bash populates the array $BASH_REMATCH with the groups
# matched, and ${BASH_REMATCH[0]} is the entirety of the match. So `usplit'
# takes the matched URL, splits it using the regex, then assigns each part to an
# element of the url array NAME by using `printf -v', which prints to a
# variable.
usplit() { # usplit URL_ARRAY<name> URL
# Note: URL_ARRAY isn't assigned in `usplit', because it should
# already exist. Pass /only/ the name of URL_ARRAY to this
# function, not its contents.
local re='^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))?'
local u="$2"
[[ "$u" =~ $re ]] || {
exit_code=$?
log error "usplit: '$2' doesn't match '$re'"
return $?
}
# ShellCheck doesn't see that I'm using these variables in the `for'
# loop below, because I'm not technically using them /as/ variables, but
# as names to the variables. The ${!c} formation in the `printf' call
# below performs a reverse lookup on the name to get the actual data.
# shellcheck disable=2034
local entire_url="${BASH_REMATCH[0]}" \
scheme="${BASH_REMATCH[2]}" \
authority="${BASH_REMATCH[4]}" \
path="${BASH_REMATCH[5]}" \
query="${BASH_REMATCH[7]}" \
fragment="${BASH_REMATCH[9]}"
# Iterate through the 5 components of a URL and assign them to elements
# of URL_ARRAY, as follows:
# 0=url 1=scheme 2=authority 3=path 4=query 5=fragment
run printf -v "$1[0]" '%s' "$entire_url"
# This loop tests whether the component exists first -- if it
# doesn't, the special variable $UC_BLANK is used in the spot
# instead. Bash doesn't have a useful way of differentiating an
# /unset/ element of an array, versus an /empty/ element.
# The only exception is that 'path' component, which always exists
# in a URL (I think the simplest URL possible is '/', the empty
# path).
local i=1 # begin at 1 -- the full URL is [0].
for c in scheme authority path query fragment; do
if [[ "${!c}" || "$c" == path ]]; then
run printf -v "$1[$i]" '%s' "${!c}"
else
run printf -v "$1[$i]" '%s' "$UC_BLANK"
fi
((i += 1))
done
}
# Join a URL array, split with `usplit', back into a string, assigning
# it to the 0th element of the array.
ujoin() { # ujoin URL_ARRAY<name>
# Here's the documentation for local's '-n' flag:
#
# Give each name the nameref attribute, making it a name reference
# to another variable. That other variable is defined by the value of
# name. All references, assignments, and attribute modifications to
# name, except for those using or changing the -n attribute itself,
# are performed on the variable referenced by name's value. The
# nameref attribute cannot be applied to array variables.
#
# Pretty handy for passing-by-name! Except that last part -- "The
# nameref attribute cannot be applied to array variables." However,
# I've found a clever hack -- you can use 'printf -v' to print the
# value to the array element.
local -n URL_ARRAY="$1"
# For each possible URL component, check if it exists with `ucdef'.
# If it does, append it (with the correct component delimiter) to
# URL_ARRAY[0].
if ucdef URL_ARRAY[1]; then
printf -v URL_ARRAY[0] "%s:" "${URL_ARRAY[1]}"
fi
# Need special casing for file: protocol:
# https://datatracker.ietf.org/doc/html/rfc1738#section-3.10
if ucdef URL_ARRAY[2] || [[ "${URL_ARRAY[1]}" == file ]]; then
printf -v URL_ARRAY[0] "${URL_ARRAY[0]}//%s" "${URL_ARRAY[2]}"
fi
# The path component is required.
printf -v URL_ARRAY[0] "${URL_ARRAY[0]}%s" "${URL_ARRAY[3]}"
if ucdef URL_ARRAY[4]; then
printf -v URL_ARRAY[0] "${URL_ARRAY[0]}?%s" "${URL_ARRAY[4]}"
fi
if ucdef URL_ARRAY[5]; then
printf -v URL_ARRAY[0] "${URL_ARRAY[0]}#%s" "${URL_ARRAY[5]}"
fi
log d "${URL_ARRAY[0]}"
}
# `ucdef' checks whether a URL component is blank or not -- if a component
# doesn't exist, `usplit' writes $UC_BLANK there instead (which is :?: by
# default, though it really doesn't matter much *what* it is, as long as it's
# not going to really be in a URL). I tried really hard to differentiate an
# unset array element from a simply empty one, but like, as far as I could tell,
# you can't do that in Bash.
ucdef() { # ucdef COMPONENT<name>
local component="$1"
[[ "${!component}" != "$UC_BLANK" ]]
}
# `ucblank' determines whether a URL component is blank (""), as opposed to
# undefined.
ucblank() { # ucblank COMPONENT<name>
local component="$1"
[[ -z "${!component}" ]]
}
# `ucset' sets one component of a URL array and setting the 0th element to the
# new full URL. Use it instead of directly setting the array element with U[x],
# because U[0] will fall out of sync with the rest of the contents.
ucset() { # ucset URL_ARRAY_INDEX<name> NEW_VALUE
local url_array_component="$1" # Of form 'URL_ARRAY[INDEX]'
local value="$2"
# Assign $value to $url_array_component.
#
# Wrapped in an 'eval' for the extra layer of indirection.
run eval "${url_array_component}='$value'"
# Rejoin the URL_ARRAY with the changed value.
#
# The substitution here strips the array index subscript (i.e.,
# URL[4] => URL), passing the name of the full array to `ujoin'.
run ujoin "${url_array_component/\[*\]/}"
}
# [1]: Encode a URL using percent-encoding.
uencode() { # uencode URL
local LC_ALL=C
for ((i = 0; i < ${#1}; i++)); do
: "${1:i:1}"
case "$_" in
[a-zA-Z0-9.~_-]) printf '%s' "$_" ;;
*) printf '%%%02X' "'$_" ;;
esac
done
printf '\n'
}
# [1]: Decode a percent-encoded URL.
udecode() { # udecode URL
: "${1//+/ }"
printf '%b\n' "${_//%/\\x}"
}
# Implement [2]: 5.2.4, "Remove Dot Segments".
pundot() { # pundot PATH
local input="$1"
local output
while [[ "$input" ]]; do
if [[ "$input" =~ ^\.\.?/ ]]; then
input="${input#${BASH_REMATCH[0]}}"
elif [[ "$input" =~ ^/\.(/|$) ]]; then
input="/${input#${BASH_REMATCH[0]}}"
elif [[ "$input" =~ ^/\.\.(/|$) ]]; then
input="/${input#${BASH_REMATCH[0]}}"
[[ "$output" =~ /?[^/]+$ ]]
output="${output%${BASH_REMATCH[0]}}"
elif [[ "$input" == . || "$input" == .. ]]; then
input=
else
[[ $input =~ ^(/?[^/]*)(/?.*)$ ]] || return 1
output="$output${BASH_REMATCH[1]}"
input="${BASH_REMATCH[2]}"
fi
done
printf '%s\n' "${output//\/\//\//}"
}
# Implement [2] Section 5.2.3, "Merge Paths".
pmerge() { # pmerge BASE_PATH<name> REFERENCE_PATH<name>
local -n base_path="$1"
local -n reference_path="$2"
if ucblank reference_path[3]; then
printf '%s\n' "${base_path[3]//\/\//\//}"
return
fi
if ucdef base_path[2] && ucblank base_path[3]; then
printf '/%s\n' "${reference_path[3]//\/\//\//}"
else
local bp=""
if [[ "${base_path[3]}" == */* ]]; then
bp="${base_path[3]%/*}"
fi
printf '%s/%s\n' "${bp%/}" "${reference_path[3]#/}"
fi
}
# `utransform' implements [2]6 Section 5.2.2, "Transform Resources."
#
# That section conveniently lays out a pseudocode algorithm describing how URL
# resources should be transformed from one to another. This function just
# implements that pseudocode in Bash, using the helper functions defined above.
utransform() { # utransform TARGET:ARRAY BASE:STRING REFERENCE:STRING
local -a B R # base, reference
local -n T="$1" # target
usplit B "$2"
usplit R "$3"
# initialize T
for ((i = 1; i <= 5; i++)); do
T[$i]="$UC_BLANK"
done
# 0=url 1=scheme 2=authority 3=path 4=query 5=fragment
if ucdef R[1]; then
T[1]="${R[1]}"
if ucdef R[2]; then
T[2]="${R[2]}"
fi
if ucdef R[3]; then
T[3]="$(pundot "${R[3]}")"
fi
if ucdef R[4]; then
T[4]="${R[4]}"
fi
else
if ucdef R[2]; then
T[2]="${R[2]}"
if ucdef R[2]; then
T[3]="$(pundot "${R[3]}")"
fi
if ucdef R[4]; then
T[4]="${R[4]}"
fi
else
if ucblank R[3]; then
T[3]="${B[3]}"
if ucdef R[4]; then
T[4]="${R[4]}"
else
T[4]="${B[4]}"
fi
else
if [[ "${R[3]}" == /* ]]; then
T[3]="$(pundot "${R[3]}")"
else
T[3]="$(pmerge B R)"
T[3]="$(pundot "${T[3]}")"
fi
if ucdef R[4]; then
T[4]="${R[4]}"
fi
fi
T[2]="${B[2]}"
fi
T[1]="${B[1]}"
fi
if ucdef R[5]; then
T[5]="${R[5]}"
fi
ujoin T
}
# GEMINI #######################################################################
# https://gemini.circumlunar.space/docs/specification.html [3]
#
# The reason we're all here, folks. Gemini is a new protocol that aims to be a
# middle ground between Gopher and HTTP, blah blah. You know the spiel. I know
# the spiel. It's great stuff!
#
################################################################################
# Request a resource from a gemini server - see [3] Sections 2, 4.
gemini_request() { # gemini_request URL
local -a url
run usplit url "$1"
log debug "${url[@]}"
# Remove user info from the URL.
#
# URLs can technically be of the form <proto>://<user>:<pass>@<domain>
# (see [2] Section 3.2, "Authority"). I don't know of any Gemini servers
# that use the <user> or <pass> parts, so `gemini_request' just strips
# them from the requested URL. This will need to be changed if servers
# decide to use this method of authentication.
log debug "Removing user info from the URL"
run ucset url[2] "${url[2]#*@}"
# Determine the port to request.
#
# The default port for Gemini is 1965 (the year of the first Gemini
# space mission), but some servers use a different port. In a URL, a
# port can be specified after the domain, separated with a colon. The
# user can also request a different default port, for whatever reason,
# by setting the variable $BOLLUX_GEMINI_PORT.
log debug "Determining the port to request"
local port
if [[ "${url[2]}" == *:* ]]; then
port="${url[2]#*:}"
ucset url[2] "${url[2]%:*}"
else
port="$BOLLUX_GEMINI_PORT"
fi
# Build the SSL command to request the resource.
#
# This is the beating heart of bollux, the command that does all the
# important work of actually fetching the gemini content the user wants
# to read. I've broken it out into an array for ease of editing (and
# now, commenting!).
local ssl_cmd=(
# `s_client' is OpenSSL's reference client implementation In the
# manual [9] it says not to use it, but who reads the manual,
# anyway?
openssl s_client
-crlf # Automatically add CR+LF to line
-quiet # Don't print all the cert stuff
# -ign_eof # `-quiet' implies `-ign_eof'
-connect "${url[2]}:$port" # The server and port to connect
-servername "${url[2]}" # SNI: Server Name Identification
-no_ssl3 -no_tls1 -no_tls1_1 # disable old TLS/SSL versions
)
# Actually request the resource.
#
# I could probably use 'printf '%s\r\n' "$url" | run "${ssl_cmd[@]}",
# and maybe I should. I wrote this little line a while ago.
run "${ssl_cmd[@]}" <<<"$url"
}
# Handle the gemini response - see [3] Section 3.
gemini_response() { # gemini_response URL
local code meta # received on the first line of the response
local title # determined by a clunky heuristic, see read loop: (2*)
local url="$1" # the currently-visited URL.
# Read the first line.
#
# The first line of a Gemini response is the "header line," which is of
# the format "STATUS METADATA\r\n". I use a `while' loop using `read'
# with a timeout to handle non-responsive servers. Technically,
# METADATA shouldn't exceed 1024 bytes, but I can't think of a good way
# to break at that point -- so bollux is not quite spec-compliant in
# this regard.
#
# Additionally, there are sometimes bugs with caching and
# byte-shifting(?) when trying to download a binary file (see
# `download', below), but I'm not sure how to remedy that issue either.
# It requires more research.
while read -t "$BOLLUX_TIMEOUT" -r code meta ||
{ (($? > 128)) && die 99 "Timeout."; }; do
break
done
log d "[$code] $meta"
# Branch depending on the status code. See [3] Appendix 1.
#
# Notes:
# - All codes other than 3* (Redirects) reset the REDIRECTS counter.
# - I branch on the first digit of the status code, instead of both, to
# minimize the amount of duplicated code I need to write.
case "$code" in
1*) # INPUT
# Gemini allows GET-style requests, and the INPUT family of
# response codes facilitate them. `10' is for standard input,
# and `11' is for sensitive information, like passwords.
REDIRECTS=0
BOLLUX_URL="$url"
case "$code" in
10) run prompt "$meta" ;;
11) run prompt "$meta" -s ;; # sensitive input
esac
run history_append "$url" "${title:-}"
run blastoff "?$(uencode "$REPLY")"
;;
2*) # OK
# The `20' family of requests is like HTTP's `200' family: it
# means that the request worked and the server is sending the
# requested content.
REDIRECTS=0
BOLLUX_URL="$url"
# Janky heuristic to guess the title of a page.
#
# This while loop reads through the file looking for a line
# starting with `#', which is a level-one heading in text/gemini
# (see [3] Section 5). It assumes that the first such heading is the
# title of the page, and uses that title for the terminal title
# and for the history.
local pretitle
while read -r; do
# Since looping through the file consumes it (that is,
# the file pointer (I think?) moves away from the
# beginning of the file), the content we've read so far
# must be saved in a `pretitle' variable, so it can be
# printed later with the rest of the page.
pretitle="$pretitle$REPLY"$'\n'
if [[ "$REPLY" =~ ^#[[:space:]]*(.*) ]]; then
title="${BASH_REMATCH[1]}"
break
fi
done
run history_append "$url" "${title:-}"
# Print the pretitle and the rest of the document (`passthru' is
# a pure-bash rewrite of `cat'), and pipe it through `display'
# for typesetting.
{
printf '%s' "$pretitle"
passthru
} | run display "$meta" "${title:-}"
;;
3*) # REDIRECT
# Redirects are a fundamental part of any hypertext framework,
# and if I remember correctly, one of the main reasons
# solderpunk and others began thinking about gemini (the others
# being TLS and URLs, I believe).
#
# Note that although [3] specifies both a temporary (30) and
# permanent (31) redirect, bollux isn't smart enough to make a
# distinction. I'm not sure what the difference would be in
# practice, anyway.
#
# Per [4] bollux limits the number of redirects a page is
# allowed to make (by default, five). Change `$BOLLUX_MAXREDIR'
# to customize that limit.
((REDIRECTS += 1))
if ((REDIRECTS > BOLLUX_MAXREDIR)); then
die $((100 + code)) "Too many redirects!"
fi
BOLLUX_URL="$url"
# Another discussion on [4] pertains to the value of alerting
# the user to (A) a cross-domain redirect, or even (B) all
# redirects. I have yet to implement that particular
# functionality, and even when I do implement it I don't think
# (B) will be the default. Perhaps (A) though. No notification
# will also be an option, however.
run blastoff "$meta" # TODO: confirm redirect
;;
4*) # TEMPORARY ERROR
# Since the 4* codes ([3] Appendix 1) are all server issues,
# bollux can treat them all basically the same. This is an area
# that could use some expansion.
local desc="Temporary error"
case "$code" in
41) desc+=" (server unavailable)" ;;
42) desc+=" (CGI error)" ;;
43) desc+=" (proxy error)" ;;
44) desc+=" (slow down)" ;; # could be particularly improved
esac
REDIRECTS=0
die "$((100 + code))" "$desc [$code]: $meta"
;;
5*) # PERMANENT ERROR
# The situation with the 5* codes is basically similar to the 4*
# codes. It could maybe use more thought as to what behavior to
# implement. Maybe adding the (bad) requests to history,
# subject to configuration?
local desc="Permanent failure"
case "$code" in
51) desc+=" (not found)" ;;
52) desc+=" (gone)" ;;
53) desc+=" (proxy request refused)" ;;
# For some reason, codes 54--58 inclusive aren't used.
59) desc+=" (bad request)" ;;
esac
REDIRECTS=0
die "$((100 + code))" "$desc [$code]: $meta"
;;
6*) # CERTIFICATE ERROR (TODO)
# Dealing with certificates is honestly the most important
# feature missing from bollux to get it to 1.0. Right now,
# bollux deals with 6* status codes identically to 4* and 5*
# codes. This is not ideal, in the slightest.
local desc="Client certificate required"
case "$code" in
61) desc+=" (certificate not authorized)" ;;
62) desc+=" (certificate not valid)" ;;
esac
REDIRECTS=0
log d "Not implemented: Client certificates"
die "$((100 + code))" "[$code] $meta"
;;
*) # UNKNOWN
# Just in case we get a weird, un-spec-compliant status code.
[[ -z "${code-}" ]] && die 100 "Empty response code."
die "$((100 + code))" "Unknown response code: $code."
;;
esac
}
# GOPHER #######################################################################
# https://tools.ietf.org/html/rfc1436 protocol
# https://tools.ietf.org/html/rfc4266 url
#
# Gopher is the grand-daddy of gemini (or maybe just weird uncle? hm..),
# invented in 1991 as a fancier FTP. There's been a sort of resurgence in it as
# a consequence of the shittifying of the WWW, but it's shown its age (which is
# why Gemini was born). But why am I telling you this? You're reading the
# source code of a Gemini browser! You're a meganerd just like me. Welcome to
# the club, kid.
#
# Since gopher is so old, it actually has two RFCs: RFC 1436 [6] for the
# protocol itself, and RFC 4266 [7] for the URL format (gopher predates the
# URL!). However, requesting and handling responses is still fundamentally the
# same to gemini, so it was pretty easy to implement this. I don't think bollux
# handles all the possible item types, but it should get the main ones.
#
################################################################################
# Request a resource.
gopher_request() { # gopher_request URL
local url="$1"
# [7] Section 2.1
[[ "$url" =~ gopher://([^/?#:]*)(:([0-9]+))?(/((.))?(/?.*))?$ ]]
local server="${BASH_REMATCH[1]}" \
port="${BASH_REMATCH[3]:-$BOLLUX_GOPHER_PORT}" \
type="${BASH_REMATCH[6]:-1}" \
path="${BASH_REMATCH[7]}"
log d "URL='$url' SERVER='$server' TYPE='$type' PATH='$path'"
# Bash has this really neat feature where it can open a TCP socket
# directly. bollux uses that feature here to ask the server for the
# resource and then `passthru' it to the next thing.
exec 9<>"/dev/tcp/$server/$port"
printf '%s\r\n' "$path" >&9
passthru <&9
}
# Handle a server response.
gopher_response() { # gopher_response URL
local url="$1" pre=false
# [7] Section 2.1
#
# Note that this duplicates the code in `gopher_request'. There might
# be a good way to thread this data through so that it's not computed
# twice.
[[ "$url" =~ gopher://([^/?#:]*)(:([0-9]+))?(/((.))?(/?.*))?$ ]]
local cur_server="${BASH_REMATCH[1]}"
local type="${BASH_REMATCH[6]:-1}"
run history_append "$url" "" # gopher doesn't really have titles, huh
# Gopher has a concept of 'line types', or maybe 'item types' --
# basically, each line in a gophermap starts with a character, its type,
# and then is followed by a series of tab-separated fields describing
# where that type is and how to display it. The full list of original
# line types can be found in [6] Section 3.8, though the types have also been
# extended over the years. Since bollux can only display types that are
# text-ish, it only concerns itself with those in this case statement.
# All the others are simply downloaded.
case "$type" in
0) # Item is a file
# Since gopher doesn't send MIME-type information in-band, we
# just assume it's text/plain, and try to convert it later to
# UTF-8 with `iconv'.
run display text/plain
;;
1) # Item is a directory [gophermap]
# Since I've already written all the code to typeset gemini
# well, it's easy to convert a gophermap to text/gemini and
# display it than to write a whole new gophermap typesetter.
run gopher_convert | run display text/gemini
;;
3) # Error
# I don't know all the gopher error cases, and the spec is
# pretty quiet on them. So bollux just signals failure and
# bails.
die 203 "GOPHER: failed"
;;
7) # Item is an Index-Search server
# Gopher search queries are separated from their resources by a
# TAB. It's wild.
if [[ "$url" =~ $'\t' ]]; then
run gopher_convert | run display text/gemini
else
run prompt 'SEARCH'
run blastoff "$url $REPLY"
fi
;;
*) # Anything else
# The list at [6] Section 3.8 includes the following (noted where it
# might be good to differently handle them in the future):
#
# 2. Item is a CSO phone-book server *****
# 4. Item is a BinHexed Macintosh file
# 5. Item is DOS binary archive of some sort
# 6. Item is a UNIX uuencoded file
# 8. Item points to a text-based telnet session *****
# 9. Item is a binary file! [exclamation point sic. -- ed.]
# +. Item is a redundant server *****
# T. Item points to a text-based tn3270 session
# g. Item is a GIF format graphics file
# I. Item is some kind of image file
#
# As mentioned, there are other line types floating around as
# well. Since I don't browse gopher much, there's not much
# personal motivation to extend `gopher_response'; however pull
# requests are always welcome.
run download "$url"
;;
esac
}
# Convert a gophermap naively to a gemini page.
#
# Based strongly on [8] but bash-ified. Due to the properties of link lines in
# gemini, many of the item types in `gemini_reponse' can be linked to the proper
# protocol handlers here -- so if a user is trying to reach a TCP link through
# gopher, bollux won't have to handle it, for example.*
#
# * Ideally -- right now, bollux simply errors out on all unknown protocols.
# More research needs to be done into how to farm out to `xdg-open' or a
# similar generic opener.
gopher_convert() {
local type label path server port regex
while IFS= read -r; do
printf -v regex '(.)([^\t]*)(\t([^\t]*)\t([^\t]*)\t([^\t]*))?'
if [[ "$REPLY" =~ $regex ]]; then
type="${BASH_REMATCH[1]}"
label="${BASH_REMATCH[2]}"
path="${BASH_REMATCH[4]:-/}"
server="${BASH_REMATCH[5]:-$cur_server}"
port="${BASH_REMATCH[6]}"
else
log e "CAN'T PARSE LINE"
printf '%s\n' "$REPLY"
continue
fi
case "$type" in
.) # end of file
printf '.\n'
break
;;
i) # label
case "$label" in
'#'* | '*'[[:space:]]*)
if $pre; then
printf '%s\n' '```'
pre=false
fi
;;
*)
if ! $pre; then
printf '%s\n' '```'
pre=true
fi
;;
esac
printf '%s\n' "$label"
;;
h) # html link
if $pre; then
printf '%s\n' '```'
pre=false
fi
printf '=> %s %s\n' "${path:4}" "$label"
;;
T) # telnet link
if $pre; then
printf '%s\n' '```'
pre=false
fi
printf '=> telnet://%s:%s/%s%s %s\n' \
"$server" "$port" "$type" "$path" "$label"
;;
*) # other type
if $pre; then
printf '%s\n' '```'
pre=false
fi
printf '=> gopher://%s:%s/%s%s %s\n' \
"$server" "$port" "$type" "$path" "$label"
;;
esac
done
if $pre; then
printf '%s\n' '```'
fi
# close the connection
exec 9<&-
exec 9>&-
}
# HANDLING CONTENT #############################################################
#
# After fetching the resource requested by the user, bollux needs to display or
# otherwise 'give' the resource to the user for consumption.
#
################################################################################
# display the fetched content
display() { # display METADATA [TITLE]
local -a less_cmd
local mime charset
# split header line
local -a hdr
IFS=';' read -ra hdr <<<"$1"
# title is optional but nice looking
local title
if (($# == 2)); then
title="$2"
fi
mime="$(trim_string "${hdr[0],,}")"
for ((i = 1; i <= "${#hdr[@]}"; i++)); do
h="${hdr[$i]}"
case "$h" in
*charset=*) charset="${h#*=}" ;;
esac
done
[[ -z "$mime" ]] && mime="text/gemini"
[[ -z "$charset" ]] && charset="utf-8"
log debug "mime='$mime'; charset='$charset'"
case "$mime" in
text/*)
set_title "$title${title:+ - }bollux"
# Build the `less' command
less_cmd=(less)
# Render ANSI color escapes ONLY (as opposed to `-r', which
# renders all escapes)
less_cmd+=(-R)
# Don't wrap text. `fold_line' takes care of wrapping normal
# text, and pre-formatted text shouldn't wrap.
less_cmd+=(-S)
# Load the keybindings (see `lesskey').
mklesskey && less_cmd+=(-k "$BOLLUX_LESSKEY")
local helpline="${KEY_OPEN}:open, "
helpline+="${KEY_GOTO}/"
helpline+="${KEY_GOTO_FROM}:goto, "
helpline+="${KEY_BACK}:back, "
helpline+="${KEY_FORWARD}:forward, "
helpline+="${KEY_REFRESH}:refresh"
less_cmd+=(
# 'status'line
-Pm"$(less_prompt_escape "$BOLLUX_URL") - bollux$"
# helpline
-P="$(less_prompt_escape "$helpline")$"
# start with statusline
-m
# float content to the top
+k
)
local typeset
local submime="${mime#*/}"
if declare -Fp "typeset_$submime" &>/dev/null; then
typeset="typeset_$submime"
else
typeset="passthru"
fi
{
run iconv -f "${charset^^}" -t "UTF-8" |
run tee "$BOLLUX_PAGESRC" |
run "$typeset" | #cat
run "${less_cmd[@]}" && bollux_quit
} || run handle_keypress "$?"
;;
*) run download "$BOLLUX_URL" ;;
esac
}
# escape strings for the less prompt
less_prompt_escape() { # less_prompt_escape STRING
local i
for ((i = 0; i < ${#1}; i++)); do
: "${1:i:1}"
case "$_" in
[\?:\.%\\]) printf '\%s' "$_" ;;
*) printf '%s' "$_" ;;
esac
done
printf '\n'
}
## Generate a lesskey(1) file for custom keybinds
# After less 582, less itself can read lesskey configuration files, rendering
# the lesskey *program* deprecated. The exact message is, apparently, this:
#
# NOTE: lesskey is deprecated.
# It is no longer necessary to run lesskey,
# when using less version 582 and later.
#
# Now I don't have less 582 available on my machine (Debian of course!), so I'm
# relying on a report from 'bencollver' on tildegit. (Thanks for the report,
# ben!)
#
# That being said, this may not work. *Please test!* --- acdw 2022-08-09
#
# PS. Here's a link to less's homepage in case something else comes up:
# https://www.greenwoodsoftware.com/less/
mklesskey() { # mklesskey
if [[ -f "$BOLLUX_CUSTOM_LESSKEY" ]]; then
log d "Using custom lesskey: '$BOLLUX_CUSTOM_LESSKEY'"
BOLLUX_LESSKEY="${BOLLUX_CUSTOM_LESSKEY}"
return
fi
less_version="$(less --version | awk '{print $2;exit;}')"
lesskey_ft="$(file -i "$BOLUX_LESSKEY")"
lesskey_make=false
if [[ "$lesskey_ft" =~ .*application.* && less_version -lt 582 ]] ||
[[ "$lesskey_ft" =~ .*text.* && less_version -ge 582 ]]; then
mv "$BOLLUX_LESSKEY" "${BOLLUX_LESSKEY}.bak"
log e "Moved incompatible lesskey '$BOLLUX_LESSKEY' to '${BOLLUX_LESSKEY}.bak'."
lesskey_make=true
fi
if [[ ! -f "$BOLLUX_LESSKEY" ]]; then
lesskey_make=true
fi
if "$lesskey_make"; then
log d "Generating lesskey..."
cat >/tmp/bollux_lesskey <<-EOF
#command
${KEY_OPEN} quit 0 # 48 open a link
${KEY_GOTO} quit 1 # 49 goto a url
${KEY_BACK} quit 2 # 50 back
${KEY_FORWARD} quit 3 # 51 forward
${KEY_REFRESH} quit 4 # 52 re-request / download
${KEY_GOTO_FROM} quit 5 # 53 goto a url (pre-filled)
${KEY_CYCLE_PRE} quit 6 # 54 cycle T_PRE_DISPLAY and refresh
# other keybinds
\\40 forw-screen-force
h left-scroll
l right-scroll
? status # 'status' will show a little help thing.
= noaction
EOF
if ((less_version >= 582)); then
mv /tmp/bollux_lesskey "$BOLLUX_LESSKEY"
else
lesskey -o "$BOLLUX_LESSKEY" /tmp/bollux_lesskey
fi
else
log d "Lesskey found: $BOLLUX_LESSKEY"
fi
}
# typeset a text/gemini document
typeset_gemini() {
local pre=false
local ln=0 # link number
if ((T_WIDTH == 0)); then
shopt -s checkwinsize
(
:
:
) # dumb formatting brought to you by shfmt
log d "LINES=$LINES; COLUMNS=$COLUMNS"
T_WIDTH=$COLUMNS
fi
WIDTH=$((T_WIDTH - T_MARGIN))
((WIDTH < 0)) && WIDTH=80 # default if dumb
S_MARGIN=$((T_MARGIN - 1)) # spacing
log d "T_WIDTH=$T_WIDTH"
log d "WIDTH=$WIDTH"
log d "$T_PRE_DISPLAY"
while IFS= read -r; do
case "$REPLY" in
'```'*)
PRE_LINE_FORCE=false
if $pre; then
pre=false
else
pre=true
fi
case "${T_PRE_DISPLAY%%,*}" in
pre)
:
;;
alt | both)
$pre && PRE_LINE_FORCE=true \
gemini_pre "${REPLY#\`\`\`}"
;;
esac
continue
;;
'=>'*)
: $((ln += 1))
gemini_link "$REPLY" $pre "$ln"
;;
'#'*) gemini_header "$REPLY" $pre ;;
'*'[[:space:]]*)
gemini_list "$REPLY" $pre
;;
'>'*)
gemini_quote "$REPLY" $pre
;;
*) gemini_text "$REPLY" $pre ;;
esac
done
}
gemini_link() {
local re="^(=>)[[:blank:]]*([^[:blank:]]+)[[:blank:]]*(.*)"
local s t a # sigil, text, annotation(url)
local ln="$3"
if ! ${2-false} && [[ "$1" =~ $re ]]; then
s="${BASH_REMATCH[1]}"
a="${BASH_REMATCH[2]}"
t="${BASH_REMATCH[3]}"
if [[ -z "$t" ]]; then
t="$a"
a=
fi
printf "\e[${C_SIGIL}m%${S_MARGIN}s ${C_RESET}" "$s"
printf "\e[${C_LINK_NUMBER}m[%d]${C_RESET} " "$ln"
fold_line -n -B "\e[${C_LINK_TITLE}m" -A "${C_RESET}" \
-l "$((${#ln} + 3))" -m "${T_MARGIN}" \
"$WIDTH" "$(trim_string "$t")"
fold_line -B " \e[${C_LINK_URL}m" \
-A "${C_RESET}" \
-l "$((${#ln} + 3 + ${#t}))" \
-m "$((T_MARGIN + ${#ln} + 2))" \
"$WIDTH" "$a"
else
gemini_pre "$1"
fi
}
gemini_header() {
local re="^(#+)[[:blank:]]*(.*)"
local s t a # sigil, text, annotation(lvl)
if ! ${2-false} && [[ "$1" =~ $re ]]; then
s="${BASH_REMATCH[1]}"
a="${#BASH_REMATCH[1]}"
t="${BASH_REMATCH[2]}"
local hdrfmt
hdrfmt="$(eval echo "\$C_HEADER$a")"
printf "\e[${C_SIGIL}m%${S_MARGIN}s ${C_RESET}" "$s"
fold_line -B "\e[${hdrfmt}m" -A "${C_RESET}" -m "${T_MARGIN}" \
"$WIDTH" "$t"
else
gemini_pre "$1"
fi
}
gemini_list() {
local re="^(\*)[[:blank:]]*(.*)"
local s t # sigil, text
if ! ${2-false} && [[ "$1" =~ $re ]]; then
s="${BASH_REMATCH[1]}"
t="${BASH_REMATCH[2]}"
printf "\e[${C_SIGIL}m%${S_MARGIN}s ${C_RESET}" "$s"
fold_line -B "\e[${C_LIST}m" -A "${C_RESET}" -m "$T_MARGIN" \
"$WIDTH" "$t"
else
gemini_pre "$1"
fi
}
gemini_quote() {
local re="^(>)[[:blank:]]*(.*)"
local s t # sigil, text
if ! ${2-false} && [[ "$1" =~ $re ]]; then
s="${BASH_REMATCH[1]}"
t="${BASH_REMATCH[2]}"
printf "\e[${C_SIGIL}m%${S_MARGIN}s ${C_RESET}" "$s"
fold_line -B "\e[${C_QUOTE}m" -A "${C_RESET}" -m "$T_MARGIN" \
"$WIDTH" "$t"
else
gemini_pre "$1"
fi
}
gemini_text() {
if ! ${2-false}; then
printf "%${S_MARGIN}s " ' '
fold_line -m "$T_MARGIN" \
"$WIDTH" "$1"
else
gemini_pre "$1"
fi
}
gemini_pre() {
# Print preformatted text, dependent on $T_PRE_DISPLAY and
# $PRE_LINE_FORCE
if [[ alt != "${T_PRE_DISPLAY%%,*}" ]] || $PRE_LINE_FORCE; then
printf "\e[${C_SIGIL}m%${S_MARGIN}s " '```'
printf "\e[${C_PRE}m%s${C_RESET}\n" "$1"
fi
}
# wrap lines on words to WIDTH
fold_line() { # fold_line [OPTIONS...] WIDTH TEXT
# see getopts, below, for options
local newline=true
local -i margin_all=0 margin_first=0 width ll=0 wl=0 wn=0
local before="" after=""
OPTIND=0
while getopts nm:f:l:B:A: OPT; do
case "$OPT" in
n) # -n = no trailing newline
newline=false
;;
m) # -m MARGIN = margin for all lines
margin_all="$OPTARG"
;;
f) # -f MARGIN = margin for first line
margin_first="$OPTARG"
;;
l) # -l LENGTH = length of line before starting fold
ll="$OPTARG"
;;
B) # -B BEFORE = text to insert before each line
before="$OPTARG"
;;
A) # -A AFTER = text to insert after each line
after="$OPTARG"
;;
*) return 1 ;;
esac
done
shift "$((OPTIND - 1))"
width="$1"
ll=$((ll % width))
#shellcheck disable=2086
set -- $2
local plain=""
if ((margin_first > 0 && ll == 0)); then
printf "%${margin_first}s" " "
fi
if [[ -n "$before" ]]; then
printf '%b' "$before"
fi
for word; do
((wn += 1))
shopt -s extglob
plain="${word//$'\x1b'\[*([0-9;])m/}"
shopt -u extglob
wl=$((${#plain} + 1))
if (((ll + wl) >= width)); then
printf "${after:-}\n%${margin_all}s${before:-}" ' '
ll=$wl
else
((ll += wl))
fi
printf '%s' "$word"
((wn != $#)) && printf ' '
done
[[ -n "$after" ]] && printf '%b' "$after"
$newline && printf '\n'
}
# use the exit code from less (see mklesskey) to do things
handle_keypress() { # handle_keypress CODE
case "$1" in
48) # o - open a link -- show a menu of links on the page
run select_url "$BOLLUX_PAGESRC"
;;
49) # g - goto a url -- input a new url
prompt GO
run blastoff -u "$REPLY"
;;
50) # [ - back in the history
run history_back || {
sleep 0.5
run blastoff "$BOLLUX_URL"
}
;;
51) # ] - forward in the history
run history_forward || {
sleep 0.5
run blastoff "$BOLLUX_URL"
}
;;
52) # r - re-request the current resource
run blastoff "$BOLLUX_URL"
;;
53) # G - goto a url (pre-filled with current)
run prompt -u GO
run blastoff -u "$REPLY"
;;
54) # ` - change alt-text visibility and refresh
run list_cycle T_PRE_DISPLAY ,
run blastoff "$BOLLUX_URL"
;;
55) # 55-57 -- still available for binding
die "$?" "less(1) error"
;;
esac
}
# select a URL from a text/gemini file
select_url() { # select_url FILE
run mapfile -t < <(extract_links <"$1")
if ((${#MAPFILE[@]} == 0)); then
log e "No links on this page!"
sleep 0.5
run blastoff "$BOLLUX_URL"
fi
PS3="OPEN> "
select u in "${MAPFILE[@]}"; do
case "$REPLY" in
q) bollux_quit ;;
[^0-9]*) run blastoff -u "$REPLY" && break ;;
esac
run blastoff "${u%%[[:space:]]*}" && break
done </dev/tty
}
# extract the links from a text/gemini file
extract_links() {
local url alt
local re="^=>[[:space:]]*([^[:space:]]+)([[:space:]]+(.*))?$"
while read -r; do
log d "$re"
if [[ $REPLY =~ $re ]]; then
url="${BASH_REMATCH[1]}"
alt="${BASH_REMATCH[3]}"
if [[ "$alt" ]]; then
printf '%s \e[34m(%s)\e[0m\n' "$url" "$alt"
else
printf '%s\n' "$url"
fi
fi
done
}
# Download a file.
#
# Any non-otherwise-handled MIME type will be downloaded using this function.
# It uses 'dd' to download the resource to a temporary file, then attempts to
# move it to $BOLLUX_DOWNDIR (by default, $PWD). If that's not possible (either
# because the target file already exists or the 'mv' invocation fails for some
# reason), `download' logs the error and alerts the user where the temporary
# file is saved.
#
# `download' works by reading the end of the pipe from `display', which means
# that sometimes, due to something with the way bash or while or ... something
# ... chunks the data, sometimes binary data gets corrupted. This is an area
# that requires more research. UPDATE 2022-06-08: White_Rabbit has figured out
# solution! From their email:
#
# > by the time we're ready to save a non-text/* resource, it's already
# > corrupted beyond repair. One possibile solution, attached, is to request it
# > again, presume the reply is 20 and save the data to the filesystem. What do
# > you think?
#
# I think this is great, thanks!!!
download() {
# The binary file has been corrupted by normalize, which strips 0x0d
# bytes. Something also drops NULL bytes. So, we'll discard this data
cat >/dev/null
# Now it's time to re-download the binary file
temp_data="$(mktemp)"
log x "Downloading: '$BOLLUX_URL' => '$temp_data'..."
gemini_request "$BOLLUX_URL" | dd status=progress >"$temp_data"
# Now $temp_data holds both the header and the data
HEADER=$(head -1 "$temp_data")
# To get the header length we use ${#HEADER} syntax, but this gives
# a bad value because it doesn't count the last byte 0x0A.
# We sum 2 because tail wants the first useful byte.
let FIRST_BYTE=$((${#HEADER} + 2))
temp_name="$(mktemp)"
if tail --bytes=+$FIRST_BYTE "$temp_data" >"$temp_name"; then
rm "$temp_data"
else
log error "Error removing the header from '$temp_data'."
fi
final_name="$BOLLUX_DOWNDIR/${BOLLUX_URL##*/}"
if [[ -f "$final_name" ]]; then
log x "Saved '$temp_name'."
elif mv "$temp_name" "$final_name"; then
log x "Saved '$final_name'."
else
log error "Error saving '$final_name': downloaded to '$temp_name'."
fi
}
# HISTORY #####################################################################
#
# While bollux saves history to a file ($BOLLUX_HISTFILE), it doesn't /do/
# anything with the history that's been saved. When I do implement the history
# functionality, it'll probably be on top of a file:// protocol, which will make
# it very simple to also implement bookmarks and the previewing of pages. In
# fact, I should be able to implement this change by the weekend (2021-03-07).
#
###############################################################################
# Append a URL to history.
history_append() { # history_append URL TITLE
local url="$1"
local title="$2"
# Print the URL and its title (if given) to $BOLLUX_HISTFILE.
local fmt=''
fmt+='%(%FT%T)T\t' # %(_)T calls directly to 'strftime'.
if (($# == 2)); then
fmt+='%s\t' # $url
fmt+='%s\n' # $title
else
fmt+='%s%s\n' # printf needs a field for every argument.
fi
run printf -- "$fmt" -1 "$url" "$title" >>"$BOLLUX_HISTFILE"
# Add the URL to the HISTORY array and increment the pointer.
HISTORY[$HN]="$url"
((HN += 1))
# Update $BOLLUX_URL.
BOLLUX_URL="$url"
}
# Move back in session history.
history_back() {
log d "HN=$HN"
# We need to subtract 2 from HN because it automatically increases by
# one with each call to `history_append'. If we subtract 1, we'll just
# be at the end of the array again, reloading the page.
((HN -= 2))
if ((HN < 0)); then
HN=0
log e "Beginning of history."
return 1
fi
run blastoff "${HISTORY[$HN]}"
}
# Move forward in session history.
history_forward() {
log d "HN=$HN"
if ((HN >= ${#HISTORY[@]})); then
HN="${#HISTORY[@]}"
log e "End of history."
return 1
fi
run blastoff "${HISTORY[$HN]}"
}
# Load a URL.
#
# I was feeling fancy when I named this function -- a more descriptive name
# would be 'bollux_goto' or something.
blastoff() { # blastoff [-u] URL
local u
# `blastoff' assumes a "well-formed" URL by default -- i.e., a URL with
# a protocol string and no extraneous whitespace. Since bollux can't
# trust the user to input a proper URL at a prompt, nor capsule authors
# to fully-form their URLs, so the -u flag is necessary for those
# use-cases. Otherwise, bollux knows the URL is well-formed -- or
# should be, due to the Gemini specification.
if [[ "$1" == "-u" ]]; then
u="$(run uwellform "$2")"
else
u="$1"
fi
# After ensuring the URL is well-formed, `blastoff' needs to transform
# it according to the transform rules of RFC 3986 (see Section 5.2.2), which
# turns relative references into absolute references that bollux can use
# in its request to the server. That's followed by a check that the
# protocol is set, defaulting to Gemini if it isn't.
#
# Implementation detail: because Bash is really stupid when it comes to
# arrays, the URL functions u* (see below) work with an array defined
# with `local -a' and passed by name, not by value. Thus, the
# `utransform url ...' instead of `urltransform "${url[@]}"' or
# similar. In addition, the `ucdef' and `ucset' functions take the name
# of the array element as parameters, not the element itself.
local -a url
run utransform url "$BOLLUX_URL" "$u"
if ! ucdef url[1]; then
run ucset url[1] "$BOLLUX_PROTO"
fi
# To try and keep `bollux' as extensible as possible, I've written it
# only to expect two functions for every protocol it supports:
# `x_request' and `x_response', where `x' is the name of the protocol
# (the first element of the built `url' array). `declare -F' looks only
# for functions in the current scope, failing if it doesn't exist.
#
# In between `x_request' and `x_response', `blastoff' normalizes the
# line endings to UNIX-style (LF) for ease of display.
{
if declare -F "${url[1]}_request" >/dev/null 2>&1; then
run "${url[1]}_request" "$url"
else
die 99 "No request handler for '${url[1]}'"
fi
} | run normalize | {
if declare -F "${url[1]}_response" >/dev/null 2>&1; then
run "${url[1]}_response" "$url"
else
log d \
"No response handler for '${url[1]}';" \
" passing thru"
passthru
fi
}
}
# $BASH_SOURCE is an array that stores the "stack" of source calls in bash. If
# the first element of that array is "bollux", that means the user called this
# script, instead of sourcing it. In that case, and ONLY in that case, should
# bollux actually enter the main loop of the program. Otherwise, allow the
# sourcing environment to simply source this script.
#
# This is basically the equivalent of python's 'if __name__ == "__main__":'
# block.
if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then
${DEBUG:-false} && set -x
run bollux "$@"
fi