fix: fix the headers issue (#671)

* fix: fix the headers issue

* chore: fix linting

* chore: fix lint

.ruby-version

@@ -0,0 +1 @@
+2.7.2

lib/twilio-ruby/base/client_base.rb

@@ -27,10 +27,9 @@ def initialize(username = nil, password = nil, account_sid = nil, region = nil,
       ##
       # Makes a request to the Twilio API using the configured http client
       # Authentication information is automatically added if none is provided
-      # rubocop:disable Lint/ShadowedArgument
       def request(host, port, method, uri, params = {}, data = {}, headers = {}, auth = nil, timeout = nil) # rubocop:disable Metrics/MethodLength
         auth ||= @auth
-        headers = generate_headers(method)
+        headers = generate_headers(method, headers)
         uri = build_uri(uri)
 
         if @logger
@@ -68,7 +67,6 @@ def request(host, port, method, uri, params = {}, data = {}, headers = {}, auth
 
         response
       end
-      # rubocop:enable Lint/ShadowedArgument
 
       ##
       # Build the final request uri
@@ -105,9 +103,8 @@ def validate_ssl_certificate
         raise RestError.new 'Unexpected response from certificate endpoint', response
       end
 
-      def generate_headers(method)
+      def generate_headers(method, headers)
         ruby_config = RbConfig::CONFIG
-        headers = {}
         headers['User-Agent'] =
           "twilio-ruby/#{Twilio::VERSION} (#{ruby_config['host_os']} #{ruby_config['host_cpu']}) Ruby/#{RUBY_VERSION}"
         headers['Accept-Charset'] = 'utf-8'

spec/rest/client_spec.rb

@@ -221,7 +221,7 @@ def initialize(client)
 
     it 'use default user agent format' do
       @client.request('host', 'port', 'GET', 'https://api.twilio.com')
-      expect(@client.http_client.last_request.headers['User-Agent']).to match %r{^twilio-ruby/[0-9.]+(-rc\.[0-9]+)?\s\([\w-]+\s\w+\)\sRuby/[^\s]+$}
+      expect(@client.http_client.last_request.headers['User-Agent']).to match %r{^twilio-ruby/[0-9.]+(-rc\.[0-9]+)?\s\([\w.-]+\s\w+\)\sRuby/[^\s]+$}
     end
 
     it 'add user agent extensions' do
@@ -231,5 +231,11 @@ def initialize(client)
       actual_extensions = @client.http_client.last_request.headers['User-Agent'].split(/ /).last(extensions.size)
       expect(actual_extensions).to match_array(extensions)
     end
+
+    it 'preserve headers passed' do
+      headers = Twilio::Values.of({ 'X-Twilio-Webhook-Enabled' => 'true' })
+      @client.request('host', 'port', 'GET', 'https://api.twilio.com', nil, nil, headers)
+      expect(@client.http_client.last_request.headers['X-Twilio-Webhook-Enabled']).to eq('true')
+    end
   end
 end