module Restforce::Concerns::Connection

def connection
  @connection ||= Faraday.new(options[:instance_url],
                              connection_options) do |builder|
    # Parses JSON into Hashie::Mash structures.
    unless (options[:mashify] == false)
      builder.use    Restforce::Middleware::Mashify, self, options
    end
    # Handles multipart file uploads for blobs.
    builder.use      Restforce::Middleware::Multipart
    # Converts the request into JSON.
    builder.request  :json
    # Handles reauthentication for 403 responses.
    if authentication_middleware
      builder.use    authentication_middleware, self, options
    end
    # Sets the oauth token in the headers.
    builder.use      Restforce::Middleware::Authorization, self, options
    # Ensures the instance url is set.
    builder.use      Restforce::Middleware::InstanceURL, self, options
    # Caches GET requests.
    builder.use      Restforce::Middleware::Caching, cache, options if cache
    # Follows 30x redirects.
    builder.use      FaradayMiddleware::FollowRedirects
    # Raises errors for 40x responses.
    builder.use      Restforce::Middleware::RaiseError
    # Parses returned JSON response into a hash.
    builder.response :json, content_type: /\bjson$/
    # Log request/responses
    builder.use      Restforce::Middleware::Logger,
                     Restforce.configuration.logger,
                     options if Restforce.log?
    # Compress/Decompress the request/response
    builder.use      Restforce::Middleware::Gzip, self, options
    builder.adapter  adapter
  end
end