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| -rwxr-xr-x | contrib/headless_pianobar | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/contrib/headless_pianobar b/contrib/headless_pianobar new file mode 100755 index 0000000..b9483c9 --- /dev/null +++ b/contrib/headless_pianobar @@ -0,0 +1,160 @@ +#!/bin/bash +# +# headless_pianobar +# +# Copyright (c) 2012 Daniel Thau +# +# Permission is hereby granted, free of charge, to any person obtaining a copy of +# this software and associated documentation files (the "Software"), to deal in +# the Software without restriction, including without limitation the rights to +# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies +# of the Software, and to permit persons to whom the Software is furnished to do +# so, subject to the following conditions: +# +# The above copyright notice and this permission notice shall be included in all +# copies or substantial portions of the Software. +# +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +# SOFTWARE. +# +### Description/instructions: +# +# This script to allow pianobar to run headlessly as well as re-connect to +# pianobar's UI. +# +# When this script is launched, if pianobar isn't running, it will launch +# pianobar (in the background) and then immediately connect to pianobar's UI to +# allow the user to do things such as log in. If pianobar is running, this +# script will simply connect to pianobar's UI. +# +# If you close this script with ctrl-c or by closing the terminal, pianobar +# should continue running in the background. +# +# To close pianobar, press the key mapped to close pianobar ('q' by default). +# This script should detect that pianobar died and close as well. +# +### Known issues/limitations: +# +# When the user is at a text input field - such as login or naming a station - +# mappings to quit pianobar ('q' by default) will not quit pianobar. Moreover, +# techniques such as ctrl-c or closing the terminal will not quit pianobar +# either, as they only quit this script and leave pianobar running headlessly. +# To quit pianobar from this situation, one must either complete the text entry +# and get pianobar to a state where it will accept the quit mapping, or one +# must kill pianobar from outside of this script through commands such as +# `kill`. +# +# This script was initially intended to be bourne-shell compatible and +# portable, however one major limitation was found: the bourne shell does not +# seem to have a good way to read a single character at a time such as can be +# done with bash's "-n" flag. Thus this script is dependent on less portable +# techniques and currently requires bash. + + +# This script regularly checks whether or not pianobar is running in the +# background in order to detect when it closes. This variable sets how long of +# a delay there will be between checks (in seconds). +CHECK_PERIOD="1" + +# This variable will set how many lines of pianobar's output to print when +# re-connecting to pianobar. +OUTPUT_LINES="30" + +# Ensure the ctrl fifo exists. +if [ ! -p $HOME/.config/pianobar/ctl ] +then + echo "pianobar ctl fifo not present at $HOME/.config/pianobar/ctl" + echo -n "Create? (y/N) " + read YN + if [ "$YN" = "y" ] || [ "$YN" = "yes" ] || [ "$YN" = "Y" ] || [ "$YN" = "YES" ] + then + mkdir -p $HOME/.config/pianobar/ + mkfifo $HOME/.config/pianobar/ctl + if [ ! -p $HOME/.config/pianobar/ctl ] + then + echo "Failed to create fifo, aborting" + exit 1 + fi + else + exit 1 + fi +fi + +# Launch pianobar if it is not already running. +if ! ps -u $(id -u) -o comm | grep -q "^pianobar$" +then + echo "pianobar not running, launching pianobar" + nohup pianobar &>$HOME/.config/pianobar/out &disown + sleep 1 +fi + +# Sanity check: ensure pianobar's output can be read. +if [ ! -f $HOME/.config/pianobar/out ] +then + echo "pianobar does not seem to be outputting to $HOME/.config/pianobar/out, try killing it and starting $0 again" + exit 2 +fi + +# Function to cleanly quit. Ensures that the two backgrounded processes (the +# output, tail, and the check, running()) both exit along with the parent (this +# script itself) +quit(){ + # tail and running() might both die when the parent dies as there was no + # nohup, but double-check just to make sure. Don't want to leave a mess + # behind. + if [ ! -z $TAILPID ] + then + kill $TAILPID 2>/dev/null + fi + if [ ! -z $RUNNINGPID ] + then + kill $RUNNINGPID 2>/dev/null + fi + trap - HUP INT TERM + kill $$ + exit 0 +} + +# Check on a regular basis that pianobar is still running. +# If pianobar stops running, stop this script as well. +running(){ + while ps -u $(id -u) -o comm | grep -q "^pianobar$" + do + sleep $CHECK_PERIOD + done + echo "pianobar died, quitting" + quit +} + +# Ensure quit() is called to clean up when exiting +trap quit HUP INT TERM + +# Print pianobar's output. +tail -n$OUTPUT_LINES -f $HOME/.config/pianobar/out & +TAILPID=$! + +# Run running() in the background to detect when pianobar closes. +running & +RUNNINGPID=$! + +# Get input from user, character by character, and feed it to pianobar's ctl +# fifo. Note that no newline character is given with `read`. Rather, one +# simply gets an empty variable back. Detect this situation and pass a newline +# along to pianobar. Otherwise, send the character read from input to +# pianobar. +IFS="" +while /bin/true +do + read -n1 -s INPUT + if [ "$INPUT" == "" ] + then + echo "" > $HOME/.config/pianobar/ctl + else + echo -n $INPUT > $HOME/.config/pianobar/ctl + fi +done |