Clear Bash quoting with JSON

Question

I looked at similar questions before, but does not exactly answer my issue.

I'm using cURL to send a JSON request, like this:

curl -X POST  -H "Content-Type:application/json" "$HOST" -d '{"uri": "'"$URI"'", "identityKeyValue":"'"`date +%s`"'", "identityKeyType": "bar", "status": "'$STATUS'", "statusDetail": "'"$STATUS_DETAIL"'", "exclusionKeys": [], "monitoredEntity": {"name": "foobar"}, "timestamp":'"`date +%s`"', "metadata": {} }'

It works, but it is very ugly (I'm talking about the part after -d), but I couldn't find something better meeting the following:

1. Supports variable substitution (like $STATUS)
2. Support command substitution (like `date +%s`)

Since it's JSON, it obviously needs a lot of doublequotes (")

The command does not have to be one line. I want readability & clarity rather than this messy/hacky look. What do you suggest?

Answer 1

break it up into multiple steps, and use a printf template:

fmt='{"uri": "%s", "identityKeyValue":"%s", "identityKeyType": "bar", "status": "%s", "statusDetail": "%s", "exclusionKeys": [], "monitoredEntity": {"name": "foobar"}, "timestamp":%d, "metadata": {}}'
time=$(date +%s)
data=$(printf "$fmt" "$URI" $time "$STATUS" "$STATUS_DETAIL" $time)
curl -X POST  -H "Content-Type:application/json" "$HOST" -d "$data"

Also, get out of the habit of using ALL_CAPS_VARNAMES: one day you'll accidentally use PATH and then wonder why your program broke.