Option to store scopes from response header on client

CHANGELOG.md

@@ -1,6 +1,7 @@
 ### 0.18.0 (Next)
 
 * Your contribution here.
+* [#382](https://github.com/slack-ruby/slack-ruby-client/pull/382): Add option to extract OAuth scopes from Web response headers - [@jmanian](https://github.com/jmanian).
 * [#380](https://github.com/slack-ruby/slack-ruby-client/pull/380): Updates to server error classes and hierarchy - [@jmanian](https://github.com/jmanian).
 
 ### 0.17.0 (2021/03/07)

README.md

@@ -239,6 +239,7 @@ open_timeout        | Optional connection open timeout in seconds.
 default_page_size   | Optional page size for paginated requests, default is _100_.
 default_max_retries | Optional number of retries for paginated requests, default is _100_.
 adapter             | Optional HTTP adapter to use, defaults to `Faraday.default_adapter`.
+store_scopes        | Option to populate `oauth_scopes` on the client from the response headers after a request.
 
 You can also pass request options, including `timeout` and `open_timeout` into individual calls.
 

lib/slack-ruby-client.rb

@@ -31,6 +31,7 @@
 require_relative 'slack/web/api/errors/server_error'
 require_relative 'slack/web/faraday/response/raise_error'
 require_relative 'slack/web/faraday/response/wrap_error'
+require_relative 'slack/web/faraday/response/store_scopes'
 require_relative 'slack/web/faraday/connection'
 require_relative 'slack/web/faraday/request'
 require_relative 'slack/web/api/mixins'

lib/slack/web/client.rb

@@ -6,7 +6,7 @@ class Client
       include Faraday::Request
       include Api::Endpoints
 
-      attr_accessor(*Config::ATTRIBUTES)
+      attr_accessor(*Config::ATTRIBUTES, :oauth_scopes)
 
       def initialize(options = {})
         Slack::Web::Config::ATTRIBUTES.each do |key|

lib/slack/web/config.rb

@@ -17,6 +17,7 @@ module Config
         default_page_size
         default_max_retries
         adapter
+        store_scopes
       ].freeze
 
       attr_accessor(*Config::ATTRIBUTES)
@@ -34,6 +35,7 @@ def reset
         self.default_page_size = 100
         self.default_max_retries = 100
         self.adapter = ::Faraday.default_adapter
+        self.store_scopes = nil
       end
     end
 

lib/slack/web/faraday/connection.rb

@@ -28,6 +28,7 @@ def connection
                 connection.use ::FaradayMiddleware::Mashify, mash_class: Slack::Messages::Message
                 connection.use ::FaradayMiddleware::ParseJson
                 connection.use ::Slack::Web::Faraday::Response::WrapError
+                connection.use ::Slack::Web::Faraday::Response::StoreScopes, client: self if store_scopes
                 connection.response :logger, logger if logger
                 connection.adapter adapter
               end

lib/slack/web/faraday/response/store_scopes.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+module Slack
+  module Web
+    module Faraday
+      module Response
+        class StoreScopes < ::Faraday::Response::Middleware
+          attr_accessor :client
+
+          def initialize(app = nil, options = {})
+            super(app)
+            self.client = options[:client]
+          end
+
+          def on_complete(env)
+            raw_scopes = env.response_headers[:'x-oauth-scopes']
+            client.oauth_scopes = raw_scopes&.split(',')
+          end
+        end
+      end
+    end
+  end
+end

spec/lib/slack/web/faraday/response/store_scopes_spec.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+require 'spec_helper'
+
+RSpec.describe Slack::Web::Faraday::Response::StoreScopes do
+  let(:store_scopes_obj) { described_class.new(app, client: client) }
+  let(:app) { proc {} }
+  let(:client) { Slack::Web::Client.new }
+  let(:env) { instance_double(Faraday::Env, response_headers: response_headers) }
+
+  describe '#on_complete' do
+    subject(:on_complete) { store_scopes_obj.on_complete(env) }
+
+    context 'with no x-oauth-scopes header' do
+      let(:response_headers) { Faraday::Utils::Headers.new }
+
+      it 'does not set oauth_scopes on the client' do
+        on_complete
+        expect(client.oauth_scopes).to be_nil
+      end
+    end
+
+    context 'with x-oauth-scopes in an unexpected format' do
+      let(:raw_scopes) { 'this is not what scopes look like' }
+      let(:response_headers) { Faraday::Utils::Headers.new('x-oauth-scopes': raw_scopes) }
+
+      it 'does not crash' do
+        on_complete
+        expect(client.oauth_scopes).to contain_exactly(raw_scopes)
+      end
+    end
+
+    context 'with x-oauth-scopes in an expected format' do
+      let(:scopes) { %w[chat:write chat:write.public chat:write:user commands identity.basic] }
+      let(:response_headers) { Faraday::Utils::Headers.new('x-oauth-scopes': scopes.join(',')) }
+
+      it 'parses the scopes into an array' do
+        on_complete
+        expect(client.oauth_scopes).to match_array(scopes)
+      end
+    end
+  end
+end