Allow StripeClient to be configured per instance

This changes allows for each instance of StripeClient to have its own
configuration object instead of relying on the global config. Each
instance can be configured to override any global config values
previously set.

lib/stripe.rb

@@ -62,6 +62,8 @@ module Stripe
   class << self
     extend Forwardable
 
+    attr_reader :configuration
+
     # User configurable options
     def_delegators :@configuration, :api_key, :api_key=
     def_delegators :@configuration, :api_version, :api_version=

lib/stripe/connection_manager.rb

@@ -15,8 +15,10 @@ class ConnectionManager
     # by `StripeClient` to determine whether a connection manager should be
     # garbage collected or not.
     attr_reader :last_used
+    attr_reader :config
 
-    def initialize
+    def initialize(config = Stripe.configuration)
+      @config = config
       @active_connections = {}
       @last_used = Util.monotonic_time
 
@@ -117,17 +119,17 @@ def execute_request(method, uri, body: nil, headers: nil, query: nil)
       # reused Go's default for `DefaultTransport`.
       connection.keep_alive_timeout = 30
 
-      connection.open_timeout = Stripe.open_timeout
-      connection.read_timeout = Stripe.read_timeout
+      connection.open_timeout = config.open_timeout
+      connection.read_timeout = config.read_timeout
       if connection.respond_to?(:write_timeout=)
-        connection.write_timeout = Stripe.write_timeout
+        connection.write_timeout = config.write_timeout
       end
 
       connection.use_ssl = uri.scheme == "https"
 
-      if Stripe.verify_ssl_certs
+      if config.verify_ssl_certs
         connection.verify_mode = OpenSSL::SSL::VERIFY_PEER
-        connection.cert_store = Stripe.ca_store
+        connection.cert_store = config.ca_store
       else
         connection.verify_mode = OpenSSL::SSL::VERIFY_NONE
         warn_ssl_verify_none
@@ -141,10 +143,10 @@ def execute_request(method, uri, body: nil, headers: nil, query: nil)
     # out those pieces to make passing them into a new connection a little less
     # ugly.
     private def proxy_parts
-      if Stripe.proxy.nil?
+      if config.proxy.nil?
         [nil, nil, nil, nil]
       else
-        u = URI.parse(Stripe.proxy)
+        u = URI.parse(config.proxy)
         [u.host, u.port, u.user, u.password]
       end
     end

lib/stripe/oauth.rb

@@ -7,8 +7,8 @@ module OAuthOperations
 
       def self.execute_resource_request(method, url, params, opts)
         opts = Util.normalize_opts(opts)
-        opts[:client] ||= StripeClient.active_client
-        opts[:api_base] ||= Stripe.connect_base
+        opts[:client] ||= opts[:client] || StripeClient.active_client
+        opts[:api_base] ||= opts[:client].config.connect_base
 
         super(method, url, params, opts)
       end
@@ -29,7 +29,8 @@ def self.get_client_id(params = {})
     end
 
     def self.authorize_url(params = {}, opts = {})
-      base = opts[:connect_base] || Stripe.connect_base
+      client = opts[:client] || StripeClient.active_client
+      base = opts[:connect_base] || client.config.connect_base
 
       path = "/oauth/authorize"
       path = "/express" + path if opts[:express]

lib/stripe/resources/account.rb

@@ -45,12 +45,8 @@ def resource_url
     end
 
     # @override To make id optional
-    def self.retrieve(id = ARGUMENT_NOT_PROVIDED, opts = {})
-      id = if id.equal?(ARGUMENT_NOT_PROVIDED)
-             nil
-           else
-             Util.check_string_argument!(id)
-           end
+    def self.retrieve(id = nil, opts = {})
+      Util.check_string_argument!(id) if id
 
       # Account used to be a singleton, where this method's signature was
       # `(opts={})`. For the sake of not breaking folks who pass in an OAuth
@@ -136,11 +132,10 @@ def deauthorize(client_id = nil, opts = {})
         client_id: client_id,
         stripe_user_id: id,
       }
+      opts = @opts.merge(Util.normalize_opts(opts))
       OAuth.deauthorize(params, opts)
     end
 
-    ARGUMENT_NOT_PROVIDED = Object.new
-
     private def serialize_additional_owners(legal_entity, additional_owners)
       original_value =
         legal_entity

lib/stripe/resources/file.rb

@@ -25,8 +25,9 @@ def self.create(params = {}, opts = {})
         end
       end
 
+      config = opts[:client]&.config || Stripe.configuration
       opts = {
-        api_base: Stripe.uploads_base,
+        api_base: config.uploads_base,
         content_type: MultipartEncoder::MULTIPART_FORM_DATA,
       }.merge(Util.normalize_opts(opts))
       super