Fix rubocop failures

lib/mattermost/session.rb

@@ -54,7 +54,15 @@ module Mattermost
     end
 
     def params
-      Rack::Utils.parse_query(@oauth_uri.query).symbolize_keys
+      Rack::Utils.parse_query(oauth_uri.query).symbolize_keys
+    end
+
+    def get(path, options = {})
+      self.class.get(path, options.merge(headers: @headers))
+    end
+
+    def post(path, options = {})
+      self.class.post(path, options.merge(headers: @headers))
     end
 
     private
@@ -63,11 +71,12 @@ module Mattermost
       return unless oauth_uri
       return unless token_uri
 
-      self.token = request_token
+      @token = request_token
       @headers = {
-        "Authorization": "Bearer #{self.token}"
+        Authorization: "Bearer #{@token}"
       }
-      self.token
+
+      @token
     end
 
     def destroy
@@ -75,35 +84,32 @@ module Mattermost
     end
 
     def oauth_uri
+      return @oauth_uri if defined?(@oauth_uri)
+
+      @oauth_uri = nil
+
       response = get("/api/v3/oauth/gitlab/login", follow_redirects: false)
       return unless 300 <= response.code && response.code < 400
 
       redirect_uri = response.headers['location']
       return unless redirect_uri
 
-      @oauth_uri ||= URI.parse(redirect_uri)
+      @oauth_uri = URI.parse(redirect_uri)
     end
 
     def token_uri
       @token_uri ||=
-        if @oauth_uri
+        if oauth_uri
           authorization.authorize.redirect_uri if pre_auth.authorizable?
         end
     end
 
     def request_token
-      response = get(@token_uri, follow_redirects: false)
+      response = get(token_uri, follow_redirects: false)
+
       if 200 <= response.code && response.code < 400
         response.headers['token']
       end
     end
-
-    def get(path, options = {})
-      self.class.get(path, options.merge(headers: @headers))
-    end
-
-    def post(path, options = {})
-      self.class.post(path, options.merge(headers: @headers))
-    end
   end
 end