111 lines
3.0 KiB
Bash
Executable File
111 lines
3.0 KiB
Bash
Executable File
#!/bin/sh
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# This script is an example captcha script.
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# It takes the text to recognize in the captcha image as a parameter.
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# It return the image binary as a result. ejabberd support PNG, JPEG and GIF.
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# The whole idea of the captcha script is to let server admins adapt it to
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# their own needs. The goal is to be able to make the captcha generation as
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# unique as possible, to make the captcha challenge difficult to bypass by
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# a bot.
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# Server admins are thus supposed to write and use their own captcha generators.
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# This script relies on ImageMagick.
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# It is NOT compliant with ImageMagick forks like GraphicsMagick.
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INPUT=$1
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if test -n ${BASH_VERSION:-''} ; then
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get_random ()
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{
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R=$RANDOM
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}
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else
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for n in `od -A n -t u2 -N 48 /dev/urandom`; do RL="$RL$n "; done
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get_random ()
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{
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R=${RL%% *}
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RL=${RL#* }
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}
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fi
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get_random
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WAVE1_AMPLITUDE=$((2 + $R % 5))
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get_random
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WAVE1_LENGTH=$((50 + $R % 25))
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get_random
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WAVE2_AMPLITUDE=$((2 + $R % 5))
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get_random
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WAVE2_LENGTH=$((50 + $R % 25))
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get_random
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WAVE3_AMPLITUDE=$((2 + $R % 5))
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get_random
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WAVE3_LENGTH=$((50 + $R % 25))
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get_random
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W1_LINE_START_Y=$((10 + $R % 40))
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get_random
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W1_LINE_STOP_Y=$((10 + $R % 40))
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get_random
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W2_LINE_START_Y=$((10 + $R % 40))
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get_random
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W2_LINE_STOP_Y=$((10 + $R % 40))
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get_random
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W3_LINE_START_Y=$((10 + $R % 40))
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get_random
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W3_LINE_STOP_Y=$((10 + $R % 40))
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get_random
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B1_LINE_START_Y=$(($R % 40))
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get_random
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B1_LINE_STOP_Y=$(($R % 40))
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get_random
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B2_LINE_START_Y=$(($R % 40))
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get_random
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B2_LINE_STOP_Y=$(($R % 40))
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#B3_LINE_START_Y=$(($R % 40))
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#B3_LINE_STOP_Y=$(($R % 40))
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get_random
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B1_LINE_START_X=$(($R % 20))
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get_random
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B1_LINE_STOP_X=$((100 + $R % 40))
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get_random
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B2_LINE_START_X=$(($R % 20))
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get_random
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B2_LINE_STOP_X=$((100 + $R % 40))
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#B3_LINE_START_X=$(($R % 20))
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#B3_LINE_STOP_X=$((100 + $R % 40))
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get_random
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RAND_A=$(($R % 10 + 40))
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get_random
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RAND_B=$(($R % 14))
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get_random
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RAND_C=$(($R % 10 + 60))
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get_random
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RAND_D=$(($R % 20))
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convert -size 180x60 xc:none -pointsize 40 \
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\( -clone 0 -stroke plasma:fractal \
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-strokewidth 1 -draw \
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"line $B1_LINE_START_X,$B1_LINE_START_Y $B1_LINE_STOP_X,$B1_LINE_STOP_Y" \
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-strokewidth 1 -draw \
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"line $B2_LINE_START_X,$B2_LINE_START_Y $B2_LINE_STOP_X,$B2_LINE_STOP_Y" \
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-wave "$WAVE2_AMPLITUDE"x"$WAVE2_LENGTH" \) \
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\( -clone 0 -stroke plasma:fractal \
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-strokewidth 2 -draw "line 0,$W1_LINE_START_Y 140,$W1_LINE_STOP_Y" \
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-strokewidth 2 -draw "line 0,$W2_LINE_START_Y 140,$W2_LINE_STOP_Y" \
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-strokewidth 2 -draw "line 0,$W3_LINE_START_Y 140,$W3_LINE_STOP_Y" \
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-wave "$WAVE3_AMPLITUDE"x"$WAVE3_LENGTH" \) \
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\( -clone 0 -fill plasma:fractal \
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-stroke plasma:fractal -strokewidth 3 -annotate "2x0+0+$RAND_A" "$INPUT" \
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-stroke plasma:fractal -strokewidth 4 -annotate "2x0+0+$RAND_A" "$INPUT" \
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-roll +$ROLL_X+0 \
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-wave "$WAVE1_AMPLITUDE"x"$WAVE1_LENGTH" \
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-roll -$ROLL_X+0 \
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-distort Perspective "0,0,0,0 0,$RAND_C,0,80 80,0,80,5 80,80,80,55" \
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-rotate "+$RAND_D" \) \
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\( -size 140x60 xc: +noise Random -alpha set -channel A -evaluate set 40% \) \
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-compose add \
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-flatten -crop 140x60 +repage -quality 500 -depth 11 png:-
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