#!/usr/bin/env bash

# Admin API key goes here
KEY="YOUR_ADMIN_API_KEY"

# Split the key into ID and SECRET
TMPIFS=$IFS
IFS=':' read ID SECRET <<< "$KEY"
IFS=$TMPIFS

# Prepare header and payload
NOW=$(date +'%s')
FIVE_MINS=$(($NOW + 300))
HEADER="{\"alg\": \"HS256\",\"typ\": \"JWT\", \"kid\": \"$ID\"}"
PAYLOAD="{\"iat\":$NOW,\"exp\":$FIVE_MINS,\"aud\": \"/v2/admin/\"}"

# Helper function for perfoming base64 URL encoding
base64_url_encode() {
    declare input=${1:-$(</dev/stdin)}
    # Use `tr` to URL encode the output from base64.
    printf '%s' "${input}" | base64 | tr -d '=' | tr '+' '-' |  tr '/' '_'
}

# Prepare the token body
header_base64=$(base64_url_encode "$HEADER")
payload_base64=$(base64_url_encode "$PAYLOAD")

header_payload="${header_base64}.${payload_base64}"

# Create the signature
signature=$(printf '%s' "${header_payload}" | openssl dgst -binary -sha256 -mac HMAC -macopt hexkey:$SECRET | base64_url_encode)

# Concat payload and signature into a valid JWT token
TOKEN="${header_payload}.${signature}"

# Make an authenticated request to create a post
curl -H "Authorization: Ghost $TOKEN" \
-H "Content-Type: application/json" \
-d '{"posts":[{"title":"Hello world"}]}' \
"http://localhost:2368/ghost/api/v2/admin/posts/"
