dmi2json

#!/bin/bash

#
# convert the output of dmidecode into JSON
#
# labels are stripped of all non alphanumeric text
# we look for LABEL: VALUE (splitting on the ':')
# if there is no ':' then it is a VALUE
#
# because sections repeat, each instance is cached
# in a tmp directory and dumped at the end of processing
#

unset TAG OLDTAG HANDLE OLDHANDLE PREFIX

quote() { 
    WHAT="$*"
    [[ ${WHAT} ]]       || return   # skip if blank
    WHAT="${WHAT/[[:space:]]/}"
    WHAT=$(echo $WHAT | tr -d '\t') # remove tabs
    [[ $WHAT && ${IGNORE[${WHAT,,}]} ]] && WHAT=""
    [[ $WHAT || $LABEL ]] || return

    # enforce quoting on values that could look like numbers
    [[ $LABEL =~ BIOSRevision || $LABEL =~ Version || $LABEL =~ Description || $LABEL =~ Address || $LABEL =~ Serial || $LABEL == "Rank" ]] && echo -n "${PREFIX}\"$WHAT\"" && return
    [[ $* =~ ^[0-9]+(.[0-9])?$ ]] && echo -n "${PREFIX}$WHAT" || echo -n "${PREFIX}\"$WHAT\""
}

fail() { echo >&2 $* ; exit 1 ; }

emit() {
    [[ $FILENAME ]] || fail "no filename set"
    echo -n -e "$*" >> $FILENAME
}

show() { echo "  {" ; cat $1 ; echo ; echo "  }" ; }


TMPDIR=$(mktemp -d)

REJECT="^(Inactive|Table|End Of Table|SMBIOS|Group Associations|OEM-specific Type|#|[0-9])"

declare -A IGNORE=(
	["unknown"]=true
	["unspecified"]=true
	["to be filled by o.e.m."]=true
	["not provided"]=true
	["not specified"]=true
	["not present"]=true
	["no module installed"]=true
	["0123456789"]=true
	["1234567890"]=true
	["<out of spec>"]=true
)

while IFS= read -r LINE
do
    [[ $LINE ]] || continue
    if [[ $LINE =~ $REJECT ]]; then
    	while IFS= read -r LINE
		do
			[[ -z $LINE ]] && break
		done
		continue
    fi
    [[ $LINE =~ ^Handle ]]  && HANDLE="${LINE:7:6}" && continue
    [[ $LINE =~ ^[A-Z] ]]   && TAG=${LINE//[[:space:]]/} && continue
    unset SKIP

    # LABEL is all text to left of ":"
    # VALUE is all text to right of ":"
    LABEL=${LINE%%:*}
    VALUE=${LINE##*:}

    # if no ':' they'll be the same, and therefore text represents VALUE
    [[ $VALUE == $LABEL ]] && unset LABEL
    [[ $LABEL && $VALUE ]] && BOTH=true || unset BOTH

    # trim whitespace and undesirables as needed
    LABEL=${LABEL//[()\"\.\/[:space:]-]/}
    VALUE=${VALUE//\"/}

    mkdir $TMPDIR/$TAG > /dev/null 2>&1

    # TAG represents top level structure that starts at beginning of the line
    if [[ $TAG != $OLDTAG || $HANDLE != $OLDHANDLE ]]; then
        # clean up prior tag
        [[ $PREFIX ]] && emit "\n${PREFIX}]\n" # prefix means list mode

        mkdir $TMPDIR/$TAG > /dev/null 2>&1
        FILENAME=$TMPDIR/$TAG/$HANDLE

        unset LAST
        unset PREFIX
        OLDTAG=$TAG
        OLDHANDLE=$HANDLE
    fi

    # if just a VALUE element then we are "SOLO"
    # which represents a list element
    [[ $VALUE && -z $LABEL ]] && SOLO=true || unset SOLO
    [[ $SOLO && $LAST ]] && SKIP=true && VALUE=" " && unset SOLO # errant line we can live without

    # did we encounter an end of list?
    [[ $LABEL && $VALUE && $PREFIX ]] && emit "\n${PREFIX}],\n" && unset PREFIX 

    # we can't comma separate list items until we know there's another entry
    # on the next line, which we won't know until then
    # so we save actual line endings until the *beginning* of the next line
    # and tack one on at the end of the section to clean up

    [[ $SOLO && $PRIOR ]]    && emit ",\n" # mid list 
    [[ $SOLO && $LAST ]]     && emit ","   # special case 
    [[ -z $VALUE && $LAST ]] && emit ",\n" 
    [[ $SKIP ]]              && emit ",\n"
    [[ $BOTH && $LAST ]]     && emit ",\n"

    # print item name
    [[ $LABEL ]] && emit "$PREFIX      \"$LABEL\": "

    # print item value, or if none, start a new list 
    [[ -n $VALUE ]] && emit "$(quote "$VALUE")" || emit  "[\n"
    [[ $LABEL && -z $VALUE ]] && PREFIX="          " 

    # to compare prior states
    LAST=$BOTH
    PRIOR=$SOLO
done

TAGS=$(ls $TMPDIR | wc -l)

echo "{"
cd $TMPDIR
for TAG in *
do
    let "TAGS--"
    echo "  \"$TAG\":"
    CNT=$(ls $TMPDIR/$TAG | wc -l)
    [[ $CNT -eq 1 ]] && [[ $TAGS -gt 0 ]] && show $TMPDIR/$TAG/* && echo -e "\n," && continue
    [[ $CNT -eq 1 ]] && [[ $TAGS -eq 0 ]] && show $TMPDIR/$TAG/* && continue
    echo "  ["
    for FILE in $TMPDIR/$TAG/*
    do
        show $FILE
        let "CNT--"
        [[ $CNT -gt 0 ]] && echo ","
    done
    echo
    echo "  ]"
    [[ $TAGS -gt 0 ]] && echo ","
done
echo "}"

rm -rf $TMPDIR