Using jq with an unknown amount of arguments from shell script? - json

Question

I'm about to lose my mind working with jq for the first time today. I've tried every ever so dirty way to make this work somehow. Let's get down to business:
I'm trying to further develop the pretty barebones API for Unifi Controllers for some use cases:
https://dl.ui.com/unifi/6.0.41/unifi_sh_api
Here's some mock up data (the real json data is thousands of lines):
{
"meta": {
"rc": "ok"
},
"data": [
{
"_id": "61a0da77f730e404af0edc3c",
"ip": "10.19.31.120",
"mac": "ff:ec:ff:89:ff:58",
"name": "Test-Accesspoint"
}
]
}
Here is my advancedapi.sh
#!/bin/bash
source unifiapi.sh
unifi_login 1>dev/null
if [ "$1" ];
then
command=$1
shift
else
echo "Please enter command"
exit
fi
#jq -r '.data[] | "\(.name),\(.mac)"'
assembleKeys(){
c="0"
seperator=";"
keys=$(for i in "$#"
do
c=$(expr $c + 1)
if [ $c -gt 1 ];
then
echo -n "${seperator}\(.${i})"
else
echo -n "\(.${i})"
fi
done
echo)
}
assembleJQ(){
c=0
jq=$(echo -en 'jq -r -j \x27.data[] | '
for i in "$#"
do
if [ "$c" != "0" ];
then
echo -en ",\x22 \x22,"
fi
c=1
echo -en ".$i"
done
echo -en ",\x22\\\n\x22\x27")
echo "$jq"
}
getDeviceKeys(){
assembleJQ "$#"
#unifi_list_devices | jq -r '.data[]' | jq -r "${keys}"
#export keys=mac
#export second=name
#unifi_list_devices | jq -r -j --arg KEYS "$keys" --arg SECOND "$second" '.data[] | .[$KEYS]," ",.[$SECOND],"\n"'
unifi_list_devices | $jq
#unifi_list_devices | jq -r -j '.data[] | .mac," ",.name,"\n"'
}
"$command" $#
Users should be able to call any function from the API with as many arguments as they want.
So basically this:
#export keys=mac
#export second=name
#unifi_list_devices | jq -r -j --arg KEYS "$keys" --arg SECOND "$second" '.data[] | .[$KEYS]," ",.[$SECOND],"\n"'
which works, but only with a limited number of arguments. I want to pass $# to jq.
I'm trying to get the name and mac-address of a device by calling:
./advancedapi.sh getDeviceKeys mac name
this should return the mac-address and name of the device. But it only gives me this:
jq -r -j '.data[] | .mac," ",.name,"\n"'
jq: error: syntax error, unexpected INVALID_CHARACTER, expecting $end (Unix shell quoting issues?) at <top-level>, line 1:
'.data[]
jq: 1 compile error
The top-most line being the jq command, which works perfectly fine when called manually.
The assembleKeys function was my attempt at generating a string that looks like this:
jq -r '.data[] | "\(.name),\(.mac)"'
Can anyone explain to me, preferably in-depth, how to do this? I'm going insane here!
Thanks!

Answer 1

I want to pass $# to jq.
There are actually many ways to do this, but the simplest might be using the --args command-line option, as illustrated here:
File: check
#/bin/bash
echo "${#}"
jq -n '$ARGS.positional' --args "${#}"
Example run:
./check 1 2 3
1 2 3
[
"1",
"2",
"3"
]
Projection
Here's an example that might be closer to what you're looking for.
Using your sample JSON:
File: check2
#/bin/bash
jq -r '
def project($array):
. as $in | reduce $array[] as $k ([]; . + [$in[$k]]);
$ARGS.positional,
(.data[] | project($ARGS.positional))
| #csv
' input.json --args "${#}"
./check2 name mac
"name","mac"
"Test-Accesspoint","ff:ec:ff:89:ff:58"

Answer 2

There is error in the json (red highlighted commas)(that commas are not needed)
$
$ cat j.json | jq -r '.data[] | "\(.name)█\(.mac)█\(.ip)█\(._id)"'
Test-Accesspoint█ff:ec:ff:89:ff:58█10.19.31.120█61a0da77f730e404af0edc3c
$ cat j.json
{
"meta": {
"rc": "ok"
},
"data": [
{
"_id": "61a0da77f730e404af0edc3c",
"ip": "10.19.31.120",
"mac": "ff:ec:ff:89:ff:58",
"name": "Test-Accesspoint"
}
]
}
$
If the api have given this json you should probably edit it, before piping it into jq [maybe with sed or something like it]