How to construct JSON in KSH/BASH script? [closed] - json

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Sample input JSON is given below:
I want the code to construct the JSON object static/dynamically in KSH/BASH
Example :
```{
"param1": "value1",
"param2": "value2",
"param3": "value3"
}```
Nested JSON:
```{
"param1": "value1",
"param2": "value2",
"param3": {
"param4": "value4",
"param5": "value5"
}
}```

Answer 1

Using jq to generate your JSON will save you when the input data contains things like quotation marks.
simple JSON object
json=$(
jq -n \
--arg "$param1" "$value1" \
--arg "$param2" "$value2" \
--arg "$param3" "$value3" \
'$ARGS.named'
)
nested
nestedJson=$(
jq -n \
--arg "$param1" "$value1" \
--arg "$param2" "$value2" \
--arg "$param3" "$value3" \
--argjson "nested" "$json" \
'$ARGS.named'
)
dynamic: use bash associative arrays
declare -A data=([param4]="value4" [param5]="value5")
jq_args=(
-n
--arg "$param1" "$value1"
--arg "$param2" "$value2"
)
for key in "${!data[#]}"; do
jq_args+=( --arg "$key" "${data[$key]}" )
done
dynamicJson=$( jq "${jq_args[#]}" '$ARGS.named'

Answer 2

Preparing the JSON in KSH/Bash
json=$(cat <<-END
{
"${param1}": "${value1}",
"${param2}": "${value2}",
"${param3}": "${value3}"
}
END
)
Preparing the Nested-JSON in KSH/Bash
nestedJson=$(cat <<-END
{
"${param1}": "${value1}",
"${param2}": "${value2}",
"${param3}": "${value3}",
"nested" : ${json}
}
END
)
Dynamic JSON:
array=("param4:value4", "param5:value5")
dynamicJSON=$(cat <<-END
{
"${param1}": "${value1}",
"${param2}": "${value2}"
}
END
)
for element in ${array[#]}
do
key="$(cut -d":" -f1 <<<"$element")"
val="$(cut -d":" -f2 <<<"$element")"
dynamicJSON=$( sed '$s/}/,\n'"\"$key\""':'"\"$val\""'}/' <<<"$dynamicJSON")
done

Answer 3

You can reference environment variables directory in your jq program
using env.varname
$ export fname="foo"
$ export lname="bar"
$ export location="baz"
$ SAMPLE_JSON='{
"first_name": "",
"last_lname": "",
"location": "",
"key": "value"
}'
$ jq '{
"first_name":env.fname,
"last_lname":env.lname,
"location":env.location,
"key": .key
}' <<<"$SAMPLE_JSON"
{
"first_name": "foo",
"last_lname": "bar",
"location": "baz",
"key": "value"
}
Nested
SAMPLE_JSON='{
"param1": "value1",
"param2": "value2",
"param3": {
"param4": "value4",
"param5": "value5"
}
}'
jq '{
"param1": env.fname,
"param2": env.lname,
"param3": {
"param4": .param3.param4,
"param5": env.location
}
}' <<<"$SAMPLE_JSON"
{
"param1": "foo",
"param2": "bar",
"param3": {
"param4": "value4",
"param5": "baz"
}
}