summaryrefslogtreecommitdiff
path: root/contrib/headless_pianobar
blob: 20f8a5476e679e8c0b3f3c6ec402398c55d87da4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
#!/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=${CHECK_PERIOD:-"1"}

# This variable will set how many lines of pianobar's output to print when
# re-connecting to pianobar.
OUTPUT_LINES=${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 [[ $? == "1" || "$INPUT" == $'\004' ]]
        then
                quit
	elif [ "$INPUT" == "" ]
	then
		echo "" > $HOME/.config/pianobar/ctl
	else
		echo -n $INPUT > $HOME/.config/pianobar/ctl
	fi
done