playlist_downloader

#!/bin/bash
function usage() {
    echo "Usage: $0 <playlist-id>"
    exit 1
}
function download() {
    local tempfile=`tempfile` || usage
    local formated_tempfile=`tempfile` || usage
    curl -s "https://gdata.youtube.com/feeds/api/playlists/$1?max-results=$2&start-index=$3" > $tempfile
    xmllint --format $tempfile > $formated_tempfile
    rm $tempfile
    echo $formated_tempfile
}
function get_number_of_videos() {
    number_of_videos=`grep totalResults $1 | sed -re "s/[^[:digit:]]*([[:digit:]]+)[^[:digit:]]*/\1/"`
    declare -i number_of_videos
}
function parse_file() {
    for line in `grep 'media:player' $1`; do
        [ $line == '<media:player' ] && continue
        echo `echo $line | cut -d '=' -f 3 | cut -d '&' -f 1`
    done
    rm $1
}

if [ $# != 1 ]; then usage; fi

max_results=50
index=1

part_one=`download $1 $max_results $index`
get_number_of_videos $part_one

i=1
while [ $index -le $number_of_videos ]
do
    file=`download $1 $max_results $index`
    for id in `parse_file $file`; do
        echo "Downloading $i out of $number_of_videos ($id)"
        youtube-dl $id -x --audio-format mp3 -c -i -t
        let i+=1
    done
    let index+=$max_results
done