Wordpress API in Ruby

config.ru

require 'JdbcActiveRecordExample'

run Sinatra::Application

Gemfile

gem 'jdbc-mysql'
gem 'activerecord-jdbcmysql-adapter'
gem 'puma'
gem 'sinatra'

JdbcActiveRecordExample.rb

require "jdbc/mysql"
require "java"
require 'sinatra'
require 'active_record'
require 'json'

# Change the following to reflect your database settings
ActiveRecord::Base.establish_connection(
  adapter: 'jdbcmysql',
  username: 'root',
  password: '123456',
  database: 'test2'
)

class Post < ActiveRecord::Base
	self.table_name = 'wp_posts'
	self.primary_key = 'ID'
	belongs_to :author, class_name: 'User', foreign_key: 'post_author'
end
class User < ActiveRecord::Base
	self.table_name = 'wp_users'
	self.primary_key = 'ID'
	has_many :posts, class_name: 'Post', foreign_key: 'post_author'


end

get '/authors' do 
	content_type 'json'
	User.all.to_json
end

get '/authors/:id' do 
	content_type 'json'
	User.find(params[:id]).to_json
end

get '/authors/:author_id/posts' do
	content_type 'json'
	user = User.find(params[:author_id])
	if user
		user.posts.to_json
	else
		[].to_json
	end
end

The DB schema is the Wordpress database. The example is not production ready of course ;), it's just a proof of concept.