B3 Rails Cheatsheet

b3_rails_cheatsheet.md

B3 Rails Cheatsheet

Faraday

• Docs

Getting a basic response:

  response = Faraday.get({url})

Re-use your connection to the same API, while handling different endpoints:

  conn = Faraday.new({base url})
  
  response1 = conn.get("/api/v1/thing/1")
  data = JSON.parse(response1.body)
  
  response2 = conn.post("api/v1/other-thing", {name: 'John', age: '30'})
  data2 = JSON.parse(response2.body)

Postman

• Docs
• Used as a specialized browser for making & testing HTTP requests, organizable by collection.

Testing APIs

• When consuming an API, it is best to mock the request so that we can save on HTTP requests to different services. This is because some API providers will limit the # of requests to their endpoints in total, or per hour/day.
• Lesson

Webmock

• Docs

1. Make sure webmock is installed in the Gemfile's :test group. Run bundle install.
2. Add require 'webmock/rspec' to spec_helper.rb file
3. Add the stub_request and .to_return methods to your test. Ex:

stub_request(:method, "the API endpoint")
.to_return(status: ###, body: ..., headers: {#optional}) 

Optionally, add a fixture file andFile.read it into your test. You can use Postman to get the raw data. When you run your test, Webmock will give you helpful error messages with the code to add. Usually (though not always) you can copy-paste that code and remove the headers info.

VCR

• Docs
• Use VCR to automatically store fixture files inside of named "cassettes".
• Configuration-heavy, but can configure per-block or per-test suite.

1. Add gem "vcr" to our :test block in Gemfile, run bundle.
2. Add this codeblock to rails_helper.rb:

# VCR configuration
VCR.configure do |config|
  config.cassette_library_dir = "spec/fixtures/vcr_cassettes"
  config.hook_into :webmock
end

3. Add either a :vcr flag to a test, or set up VCR.use_cassette('name') to tests that you'll want to use VCR fixture data for.

• If using the :vcr flag per-test, add following to config block:

config.configure_rspec_metadata!

4. If you are using API keys as part of your requests, remember to put config.filter_sensitive_data in the VCR configuration in rails_helper. NOTE - filter_sensitive_data takes two params: first is what it will turn the second into. Example:

config.filter_sensitive_data("<hidden_key>") { ENV["KEY_TO_FIND_IN_DOCUMENT"] }

• VCR cassettes can expire, where manual fixture files have to be manually deleted. You can do per-cassette expiration, or global in the config block. Per-cassettes will override the global configuration.

# Per-cassette expiration: 

VCR.use_cassette('name_of_cassette', re_record_interval: 7.days) do 
   # test code goes here 
end

# Globally, in VCR config block:

config.default_cassette_options = { re_record_interval: 7.days }

Refactoring

• Rules for Developers, by Sandi Metz
• Lesson on Facades, Services, and refactoring
• Four pillars of OOP - which ones are most at play in regard to Facades/Services patterns, and why?
  1. Inheritance
  2. Abstraction
  3. Encapsulation
  4. Polymorphism

Building APIs in Rails

Customizing JSON - Serialization

Error Handling

Basic Authentication

Sessions, Cookies, Authorization

Service-Oriented Architecture (microservices)

Writing good READMEs

Background Workers

Caching