HackerspaceSG membership payment via PayPal Rest API

paypal-payout.sh

#!/usr/bin/env bash

##
# Update your configuration here
# You may get your `client_id` and `client_secret` from developer.paypal.com
# For membership level, please refer to http://hackerspace.sg/membership
##

endpoint=api.paypal.com
client_id=$client_id
client_secret=$client_secret
membership_level="128.00"
receiver=luther@hackerspace.sg

##
# Configurations ends here
# Do not edit beyond this line
################################

require () {
    for i
    do
        if ! command -v $i > /dev/null
        then
            echo command $i not found >&2
            exit 1
        fi
    done
}

getAccessToken() {
  test "token.json" == "$(find token.json -mtime -14400s)" ||
  curl -s -XPOST "https://$endpoint/v1/oauth2/token" \
    -u "$client_id:$client_secret" \
    -H "Accept: application/json" \
    -d "grant_type=client_credentials" \
    | json | tee token.json
}

makePayout() {
  local timeid=$(date +%Y%m%d%H%M%S)
  local month=${month:-${timeid:0:6}}
  local email_subject="HSG Membership $month"
  local access_token="$(json -f token.json access_token)"

  curl -s -XPOST "https://$endpoint/v1/payments/payouts?sync_mode=true" \
    -H "Content-Type:application/json" \
    -H "Authorization: Bearer $access_token" \
    -d '{
        "sender_batch_header": {
            "sender_batch_id": "'$timeid'",
            "email_subject": "'"$email_subject"'",
            "recipient_type": "EMAIL"
        },
        "items": [
            {
                "recipient_type": "EMAIL",
                "amount": {
                    "value": "'$membership_level'",
                    "currency": "SGD"
                },
                "note": "PayPal payment via Rest API: '$month' '$membership_level' SGD",
                "sender_item_id": "'$timeid'",
                "receiver": "'$receiver'"
            }
        ]
    }' \
    | json | tee payout-$month.json
}

require json curl tee date
getAccessToken
makePayout