In the last lesson we walked through a HTTParty RubyGem guide and we learned how to integrate built in classes from the gem to call an API. If you need something more specific, it's a good idea to create a separate class to manage the API processes. That's what we are going to do in this lesson, while still leveraging some of the key modules supplied by HTTParty.

require 'rubygems'
require 'httparty'

class StackExchange
  include HTTParty
  base_uri 'api.stackexchange.com'
end

In this code, we are creating a class called StackExchance. As the first step we are including the HTTParty module so that this class can access the methods provided by the gem. Next, we are setting the base_uri, which is the stackexchange API URI's path.

Since this is our custom class, let's create an initializer that takes in the arguments service and page. Inside of the initialize method we will store our API query inside of the @options instance variable. Inside of the query we're passing in the service and page that we want returned.

def initialize(service, page)
  @options = { query: {site: service, page: page}}
end

Next, we are going to create some additional custom methods. If you remember the previous lesson, we got a large amount of information when we used the body method. To be more specific, we are going to create a method called questions that will simply return the questions from Stack Overflow.

def questions
  self.class.get('/2.2/questions', @options)
end

In this method, the string that we passed is the API endpoint. Every web application's documentation provides this endpoint value for you, so you have to look through it to find out what it is. From there we're passing in the query from our @options.

Next, we'll have a method called users that's similar to the questions method. This will allow us to query the list of users from Stack Overflow.

def users
  self.class.get('/2.2/users', @options)
end

Now that we have all our methods, let's create an instance of our class.

stack_exchange = StackExchange.new('stackoverflow', 1)
puts stack_exchange.questions

In this code, we are passing two arguments because our initialize method takes two parameters. The first is a service called stackoverflow and we can find this information about services in the API's documentation. The second parameter is the page, and we want only results from the first page so we pass in 1.

Next, we are calling the questions method.

If you execute this code, the output is:

If you look through the results you'll see that the API contains a list of questions and their related URLs. You can copy the link attribute and paste it in the browser to see if it is working, if you access the URL in the browser you'll see the question returned from the API:

If you go back to the output, we can see other attributes too such as: title, tags, owner, display name and just about everything else you need to access the stack overflow questions.

Let's test if the users method is working by updating the call to the following:

stack_exchange = StackExchange.new('stackoverflow', 1) 
puts stack_exchange.users

If you run the program now the output will bring up all the users.

Note that it brings up the list of users on the first page and includes different attributes such as: gravatar, account id, last accessed date and last modified date.

So, that's how you create a custom API Connector in Ruby while using the HTTParty gem.