GH - Layered GitHub API client

This is a highly flexible, layered, low-level GitHub client library, trying to get out of your way and let you get to the GitHub data as simple as possible. Unless you add layers, you will end up with Hashes and Arrays. The approach and API should be familiar from projects like Rack or Faraday.

Simple example:

require 'gh'
puts GH['users/rkh']['name']

This will by default use all the middleware that ships with GH, in the following order:

• GH::Remote - sends HTTP requests to GitHub and parses the response
• GH::Normalizer - renames fields consistenly, adds hypermedia links if possible
• GH::LazyLoader - will load missing fields when accessed (handy for dealing with incomplete data without sending to many requests)
• GH::MergeCommit - adds infos about merge commits to pull request payloads
• GH::LinkFollower - will add content of hypermedia links as fields (lazyly), allows you to traverse relations
• GH::Pagination - adds support for transparent pagination
• GH::Instrumentation - let's you instrument gh

The following middleware is not included by default:

• GH::Cache - caches the responses (will use Rails cache if in Rails, in-memory cache otherwise)

Main Entry Points

Every layer has two main entry points:

• [key] - loads data from GitHub
• load(data) - takes data and applies modifications (handy for dealing with service hook payloads)

These two methods are exposed by any instance of a layer and the GH constant.

Using a Single Layer

You can initialize and use any layer on its own:

gh = GH::Remote.new
puts gh['users/rkh']['name']

Layers know which other layer they should usually wrap (Remote wraps no other layer, LazyLoader and LinkFollower wrap Normalizer by default, anything else wraps Remote), so you can initialize them right away:

gh = GH::LazyLoader.new

You can also pass the layer that should be wrapped as an argument:

gh = GH::LazyLoader.new(GH::LinkFollower.new)

Creating Your Own Stack

For convinience a stack DSL is provided:

# Same as GH::Normalizer.new(GH::Cache.new)
gh = GH::Stack.build do
  use GH::Normalizer
  use GH::Cache
end

puts gh['users/rkh']['name']

You can also create reusable Stack instances:

stack = GH::Stack.new do
  use GH::Normalizer
  use GH::Cache
end

gh = stack.build username: 'rkh', password: 'abc123'
puts gh['user']['name']

One such instance (with the standard setup) can be accessed as GH::DefaultStack

Scoping

With the main goal to separate authentication from other logic, the gh library supports scopting:

GH.with GH::LazyLoader.new do
  puts GH['users/rkh']['name']
end

That way, you could create a stack with, for instance, an access token:

authenticated = GH::DefaultStack.build token: 'e72e16c7e42f292c6912e7710c838347ae178b4a'

GH.with(authenticated) do
  # ...
end

Since this is rather common, you can pass options directly to with:

GH.with(username: 'rkh', password: 'abc123') do
  # ...
end

Scoping is thread-safe.

Is this production ready?

I hope so, we use it in production for Travis CI. The work on this library has been funded by the Travis Love Campaign.