4 Ways to Parse a JSON API with Ruby

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4 Ways to Parse a JSON API with Ruby

The Ruby Toolboxlists no less than 25 HTTP clients . Let’s look at how to retrieve and parse JSON results from a RESTful API using the four most popular Ruby HTTP libraries.

The fourcode snippets below will:

Define a URL to be parsed. We’ll use the Spotfiy API because it allows requests without authentication. Make an HTTP GET request to that URL. Parse the JSON result.

Each snippet is a different path to the same destination; if you pp the result from any of them,you’ll see a hash with Spotify search results:

net/http

net/http is built into the Ruby standard library. There’s no gem to install and no dependencies to cause headaches down the road. If you value stability over speed of development, this is the right choice for you (for example, the twilio-ruby gem is built on net/http).

Unsurprisingly, using Net/http can require more work than using the gems built on top of it. For example, you have to create a URI object before making the HTTP request.

Ruby

require 'net/http'require 'json'url = 'https://api.spotify.com/v1/search?type=artist&q=tycho'uri = URI(url)response = Net::HTTP.get(uri)JSON.parse(response) require'net/http'require'json' url='https://api.spotify.com/v1/search?type=artist&q=tycho'uri=URI(url)response=Net::HTTP.get(uri)JSON.parse(response) HTTParty

net/http feels cumbersome andspartanat times. HTTParty was built on top of net/http in order to “Make HTTP fun again.” It adds a lot of convenience methods and can be used for all manners of HTTP requests. For instance, HTTParty is a strong choice if you need to build a webscraper.

It also works quite nicely with RESTful APIs. Check out how calling parsed_response on a response parses the JSON without explicitly using the JSON library:

Shell

gem install httparty gem installhttparty

Ruby

require 'httparty'url = 'https://api.spotify.com/v1/search?type=artist&q=tycho'response = HTTParty.get(url)response.parsed_response require'httparty' url='https://api.spotify.com/v1/search?type=artist&q=tycho'response=HTTParty.get(url)response.parsed_response

HTTParty also offers a command line interface — useful during development when trying to understand the structure of HTTP responses.

rest-client

rest-client is also built upon net/http but it’s designed solely for interacting with RESTful APIs. Unlike HTTParty, you’ll still need the JSON library to parse the response.

Shell

gem install rest-client gem installrest-client

Ruby

require 'rest-client'require 'json'url = 'https://api.spotify.com/v1/search?type=artist&q=tycho'response = RestClient.get(url)JSON.parse(response) require'rest-client'require'json' url='https://api.spotify.com/v1/search?type=artist&q=tycho'response=RestClient.get(url)JSON.parse(response) Faraday

Faraday is for developers who crave control. It has middleware to control all aspects of the request/response cycle. While rest-client and HTTParty lock you into net/http, Faraday lets you choose from seven HTTP Clients. For instance, you can use EventMachine for asynchronous request. (For the others, check out the github repo ).

That customization means that our Faraday code snippet is more involved. Before we make our HTTP request and parse our results, we have to:

Choose an HTTP adapter. The default is net/http. Identify the response type. In this case we’ll use JSON, but you could also use XML or CSV .

Shell

gem install faradaygem install faraday_middleware gem installfaradaygem installfaraday_middleware

Ruby

require 'faraday'require 'faraday_middleware'url = 'https://api.spotify.com/v1'conn = Faraday.new(url: url) do |faraday| faraday.adapter Faraday.default_adapter faraday.response :jsonendresponse = conn.get('search', type: 'artist', q: 'tycho')response.body require'faraday'require'faraday_middleware' url='https://api.spotify.com/v1' conn=Faraday.new(url:url)do|faraday| faraday.adapterFaraday.default_adapter faraday.response:jsonend response=conn.get('search',type:'artist',q:'tycho')response.body

You’ll notice that we pass our queryas optional parameters on the get method instead of concatanating them into theURL string. And because we’ve already told Faradaythat the response is going to be JSON, we can call response . body and get back a parsed hash.

Wrapping Up

The Ruby ecosystem offers a ton of options for interacting with JSON APIs. While these approaches are similar for the simplest of GET requests, the differences become more apparent as your HTTP requests grow in complexity. Play around and see which one best fits your needs.

Did we miss your favorite library? Let us know in the comments or contact me below.

Many thanks to Phil Nash and Matt Makai for their contributions to this post.

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