Converting JSON response to key value pair using jq - bash

Question

So, I am getting a response from an API that I am calling in a shell script in the following form
[{"id":100000004,"name":"Customs Clearance Requested"},{"id":100000005,"name":"Customs Cleared"},{"id":100000006,"name":"Cargo Loaded to Vessel"}]
I want to create a map out of it that will help me lookup the id's from a name and use it in the shell script. So something like map["Customs Clearance Requested"] would give me 100000004 which I can use further. Can this be done using jq? I am pretty new to shell scripting and jq and got stuck with above thing

Answer 1

json='[{"id":100000004,"name":"Customs Clearance Requested"},{"id":100000005,"name":"Customs Cleared"},{"id":100000006,"name":"Cargo Loaded to Vessel"}]'
declare -A map
while IFS= read -r -d '' name && IFS= read -r -d '' value; do
map[$name]=$value
done < <(jq -j '.[] | "\(.name)\u0000\(.id)\u0000"' <<<"$json")
declare -p map # demo purposes: print the map we created as output
...emits as output:
declare -A map=(["Cargo Loaded to Vessel"]="100000006" ["Customs Clearance Requested"]="100000004" ["Customs Cleared"]="100000005" )
...which you can query exactly as requested:
$ echo "${map['Cargo Loaded to Vessel']}"
100000006

Answer 2

You could use the select function, e.g.:
data='[{"id":100000004,"name":"Customs Clearance Requested"},{"id":100000005,"name":"Customs Cleared"},{"id":100000006,"name":"Cargo Loaded to Vessel"}]'
jq 'map(select(.["name"] == "Customs Clearance Requested"))' <<< $data
It will get all elements which name equals "Customs Clearance Requested", e.g.:
[
{
"id": 100000004,
"name": "Customs Clearance Requested"
}
]
If you want to get the id field:
jq 'map(select(.["name"] == "Customs Clearance Requested")["id"])' <<< $data
This will output:
[
100000004
]
Please note that it will return an array and not a single element because the search does not know how many results will be found.
If you want to generalize this in a shell function, you could write:
function get_id_from_name
{
# $1=name to search for
local filter=$(printf 'map(select(.["name"] == "%s")["id"])' "$1")
jq "$filter"
}
Then call it like that:
get_id_from_name "Customs Clearance Requested" <<< $data
If your data is stored in a file, you could call it this way:
get_id_from_name "Customs Clearance Requested" < /path/to/file.json

Answer 3

The following is very similar to #CharlesDuffy's excellent answer but does not assume that the .name and .id values are NUL-free (i.e., do not have any "\u0000" characters):
declare -A map
while read -r name
do
name=$(sed -e 's/^"//' -e 's/"$//' <<< "$name")
read -r id
map[$name]="$id"
done < <(echo "$json" | jq -c '.[]|.name,.id')
The point is that the -j option is like -r (i.e., produces "raw output"), whereas the -c option produces JSON.
This means that if you don't want the .id values as JSON strings, then the above won't be a solution; also, if the .name values contain double-quotes, then you might want to deal with the occurrences of \".