Add a Bitbucket client for the OAuth2 API

lib/bitbucket/client.rb

+module Bitbucket
+  class Client
+    def initialize(options = {})
+      @connection = options.fetch(:connection, Connection.new(options))
+    end
+
+    private
+
+    attr_reader :connection
+  end
+end

lib/bitbucket/connection.rb

+module Bitbucket
+  class Connection
+    DEFAULT_API_VERSION = '2.0'
+    DEFAULT_BASE_URI    = 'https://api.bitbucket.org/'
+    DEFAULT_QUERY       = {}
+
+    def initialize(options = {})
+      @api_version = options.fetch(:api_version, DEFAULT_API_VERSION)
+      @base_uri    = options.fetch(:base_uri, DEFAULT_BASE_URI)
+      @query       = options.fetch(:query, DEFAULT_QUERY)
+
+      @token         = options.fetch(:token)
+      @expires_at    = options.fetch(:expires_at)
+      @expires_in    = options.fetch(:expires_in)
+      @refresh_token = options.fetch(:refresh_token)
+
+      @client     = OAuth2::Client.new(provider.app_id, provider.app_secret, options)
+      @connection = OAuth2::AccessToken.new(@client, @token, refresh_token: @refresh_token, expires_at: @expires_at, expires_in: @expires_in)
+    end
+
+    def query(params = {})
+      @query.update(params)
+    end
+
+    def get(path, query = {})
+      refresh! if expired?
+
+      response = connection.get(build_url(path), params: @query.merge(query))
+      response.parsed
+    end
+
+    def expired?
+      connection.expired?
+    end
+
+    def refresh!
+      response = connection.refresh!
+
+      @token         = response.token
+      @expires_at    = response.expires_at
+      @expires_in    = response.expires_in
+      @refresh_token = response.refresh_token
+
+      @connection = OAuth2::AccessToken.new(@client, @token, refresh_token: @refresh_token, expires_at: @expires_at, expires_in: @expires_in)
+    end
+
+    private
+
+    attr_reader :connection, :expires_at, :expires_in, :refresh_token, :token
+
+    def build_url(path)
+      return path if path.starts_with?(root_url)
+
+      "#{root_url}#{path}"
+    end
+
+    def root_url
+      @root_url ||= "#{@base_uri}#{@api_version}"
+    end
+
+    def provider
+      Gitlab.config.omniauth.providers.find { |provider| provider.name == 'bitbucket' }
+    end
+
+    def options
+      OmniAuth::Strategies::Bitbucket.default_options[:client_options].deep_symbolize_keys
+    end
+  end
+end