read_json

# Export json file into environment.
#
# Should work in Bash or KSH93, Python 2 or 3.
# POSIX shells cannot export arrays, so json list
# values will only be usable in immediate environment.
#
# Goes to a lot of trouble to avoid eval --
# export_json is cleaner, but must eval arbitrary code!
#
# Child elements are separated with _ like so:
#   { "parent": { "child": 2 } }
# becomes:
#   export parent_child=2
#
# Subshells cannot affect parent environment, so source this:
# . read_json file.json

if [[ -z "$1" ]]; then
    echo "No JSON file specified."
    return 2
fi

if [[ ! -e "$1" ]]; then
    echo "Specified file not found."
    return 4
fi

if [[ -n "$BASH_VERSION" ]]; then
    readopts='-ra'
elif [[ -n "$KSH_VERSION" ]]; then
    readopts='-rA'
else
    echo "Only runs in Bash or KSH93."
    exit 8
fi

# Some unfortunate OS do not support process substitution
tmp_file=/tmp/$1.$$
mkfifo $tmp_file

python -c "
from __future__ import print_function
import json

rs=chr(30) #record separator
gs=chr(29) #group separator

def print_dict(obj, prefix=''):
    if isinstance(obj, dict):
        for k, v in obj.items():
            if isinstance(v, (dict, list)):
                new_prefix = '{}{}_'.format(prefix, k)
                print_dict(v, new_prefix)
            else:
                print('{}{}{}{}'.format(prefix, k, rs, v))
    if isinstance(obj, list):
        if isinstance(obj[0], (dict, list)):
            for idx, v in enumerate(obj):
                new_prefix = '{}{}_'.format(prefix, idx)
                print_dict(v, new_prefix)
        else:
            print('{}ARRAY{}{}{}LIST' \
                  .format(prefix, rs, gs.join(str(x) for x in obj), rs))

with open('$1') as f:
    print_dict(json.load(f))
" >$tmp_file &

while IFS=$'\x1e' read var val type; do
    if [[ "$type" == LIST ]]; then
        IFS=$'\x1d' read -d '' "$readopts" "$var" <<<$val
    else
        typeset -x "$var"="$val"
    fi
done <$tmp_file

rm -f $tmp_file