Clean code again

Transcript

1. CLEAN CODE again Percy Lam
5. OBJECTIVES Readable Simple Extendable Efficient
6. 1 2 # artstack/app/models/user.rb 3 4 class User < ActiveRecord::Base 5 6 def self.search_users_ac(term) 7 User.joins(:profile) 8 .where("CONCAT(profiles.first_name, ' ', profiles.last_name) 9 LIKE ? OR users.username LIKE ?", '%'+term+'%', '%'+ 10 term+'%') 11 .limit(10) 12 end 13 14 end
7. NAMING • Pronounceable • Searchable • Avoid abbreviations
8. Searchable Names ok() book token stroke cookie smoking
9. 1 # artstack/app/models/social_share.rb 2 3 class SocialShare 4 5 def self.tw_share_work_by_link(current_tw_user, work, 6 artwork_link) 7 if current_tw_user 8 message = "#{work.title} by #{work.artist} #{artwork_link} 9 @theArtStack #art" 10 current_tw_user.update(message) 11 end 12 end 13 14 end
10. Functions should… DO ONE THING!!
11. 1 # artstack/app/controllers/api_controller.rb 2 3 class ApiController < ApplicationController 4 5 def register 6 if params[:fb_id] && params[:fb_access_token] && params[:fb_expires] 7 begin 8 user = User.find_by_facebook_uid(current_facebook_user.id) 9 if user 10 result = {:code => -2, :result => 11 'There exists an account associated to the same Facebook account. Please 12 tap Sign In instead.'} 13 14 if facebook_login(user)[:code] == 1 15 result[:user] = facebook_login 16 end 17 18 render :json => result 19 return 20 end 21 22 unless current_facebook_user && current_facebook_user.id == params[:fb_id].to_i 23 render :json => {:code => -2, :result => 'Account not associated with 24 Facebook yet. Please Sign In with password.'} 25 return 26 end 27 28 user = User.create(:show_welcome => false, :facebook_uid => params[:fb_id], : 29 signup_source => 'm') 30 user.before_connect(current_facebook_user) # simulate normal web facebook 31 connect flow, which to help create profile 32 33 begin 34 user.save! 35 rescue Exception => e 36 ExceptionLog.log(e, request) 37 render :json => {:code => -2, :result => 'Account not saved due to server 38 hiccups. Please try again later.'}
12. 39 return 40 end 41 42 user.signup_follow(current_facebook_user) # simulate web user session creation, 43 auto follow users 44 user.profile.reload 45 46 add_device_token_to_user(params, user) 47 app_token = app_key ? UserApp.find_or_create_by_app_key_id_and_user_id(app_key. 48 id, user.id) : nil 49 app_token = app_token.try(:token) 50 51 render :json => { 52 :code => 1, 53 :result => 'Success', 54 :next_step_url => url_for(:controller => :settings, :action => :recommended, : 55 only_path => false, :app_token => app_token), 56 :first_name => user.profile.first_name, 57 :profile_url => user_profile_path(user, :only_path => false), 58 :sharing_url => url_for(:controller => :home, :action => :index, 59 :referrals => user.public_invitation_key, :only_path => false, :host => 60 ArtStack::DomainHost), 61 :app_token => app_token, 62 :id => user.id, 63 :avatar_url => user.profile.avatar_url(:thumb), 64 :follow_require_approval => user.follow_require_approval, 65 } 66 return 67 68 rescue => e 69 ExceptionLog.log(e, request) 70 render :json => {:code => -1, :result => 'Access token not correct'} 71 return 72 end 73 end 74 75 if params[:email] && params[:password] && params[:first_name] && params[:last_name] 76 # register by email and password 77 end 78 end
13. Function should… • be small • do one thing • reveal the intent by its name • use descriptive names
14. 1 class FacebookRegisterHandler 2 3 def initialize(fb_user, params, request, controller) 4 @fb_user = fb_user 5 @params = params 6 @request = request 7 @controller = controller 8 9 begin 10 if validate_fb_user 11 unless check_if_user_already_exists 12 create_user 13 end 14 end 15 rescue => e 16 access_token_error_message 17 ExceptionLog.log(e, request) 18 end 19 end 20 21 private 22 23 def validate_fb_user 24 if @fb_user.valid? 25 true 26 else 27 fb_id_invalid_message 28 return false 29 end 30 end 31 32 def check_if_user_already_exists 33 @user = User.find_by_facebook_uid(@fb_user.id) 34 35 if @user 36 add_device_token_to_user 37 account_already_exists_message 38 end 39 end 40
15. 41 def create_user 42 @user = User.create( 43 :show_welcome => false, 44 :facebook_uid => @fb_user.id, 45 :signup_source => 'm') 46 47 @user.before_connect(@fb_user) 48 49 begin 50 @user.save! 51 @user.signup_follow(@fb_user) 52 @user.profile.reload 53 add_device_token_to_user 54 success_message 55 56 rescue Exception => e 57 ExceptionLog.log(e, @request) 58 server_error_message 59 end 60 end 61 62 def success_message 63 @json = { 64 :code => 1, 65 :result => 'Success', 66 :next_step_url => h.url_for( 67 :controller => :settings, 68 :action => :recommended, 69 :only_path => false, 70 :app_token => app_token), 71 :first_name => @user.profile.first_name, 72 :profile_url => h.user_profile_path(@user, :only_path => false), 73 :sharing_url => h.url_for( 74 :controller => :home, 75 :action => :index, 76 :referrals => @user.public_invitation_key, 77 :only_path => false, 78 :host => ArtStack::DomainHost), 79 :app_token => app_token,
16. 80 :id => @user.id, 81 :avatar_url => @user.profile.avatar_url(:thumb), 82 :follow_require_approval => @user.follow_require_approval, 83 } 84 end 85 86 def fb_id_invalid_message 87 @json = { 88 :code => -2, 89 :result => 'Account not associated with Facebook yet. Please Sign In with 90 password.' 91 } 92 end 93 94 def account_already_exists_message 95 @json = { 96 :code => -2, 97 :result => 'There exists an account associated to the same Facebook account. 98 Please tap Sign In instead.', 99 :user => { 100 :code => 1, 101 :result => 'Success', 102 :id => @user.id, 103 :first_name => @user.profile.first_name, 104 :profile_url => h.user_profile_path(@user, :only_path => false), 105 :sharing_url => h.url_for(:controller => :home, :action => :index, 106 :referrals => @user.public_invitation_key, :only_path => false, 107 :host => ArtStack::DomainHost), 108 :avatar_url => @user.profile.avatar_url(:thumb), 109 :app_token => app_token, 110 :follow_require_approval => @user.follow_require_approval, 111 } 112 } 113 end 114 115 end
17. Excessively long identifiers
18. Excessively long identifiers 1 # artstack/app/models/work.rb 2 3 class Work < ActiveRecord::Base 4 5 def update_artwork(params, opts = {}) 6 work_tags = []; 7 artist_tags = []; 8 updated_tags = [] 9 current_user = opts[:current_user] 10 11 # Get original tags of artwork 12 original_work_taggings = ActsAsTaggableOn::Tagging.select('tag_id, 13 context') 14 .where(:taggable_id => self.id, :taggable_type => :Work) 15 original_work_tagging_hash = original_work_taggings.index_by(&:tag_id) 16 original_work_tags = ActsAsTaggableOn::Tag.select('id, name') 17 .find(original_work_taggings.map(&:tag_id)) 18 .map { |ft| { :name => ft.name, :context => 19 original_work_tagging_hash[ft.id][:context] } } 20 .reject { |t| t[:context] == 'dimensions' } 21 22 # Get original tags of artist 23 original_artist_taggings = ActsAsTaggableOn::Tagging.select('tag_id, 24 context') 25 .where(:taggable_id => self.artist.id, :taggable_type => :Artist) 26 original_artist_tagging_hash = original_artist_taggings.index_by(&:tag_id) 27 original_artist_tags = ActsAsTaggableOn::Tag.select('id, name') 28 .find(original_artist_taggings.map(&:tag_id)) 29 .map { |ft| { :name => ft.name ,:context => 30 original_artist_tagging_hash[ft.id][:context] } }
19. 31 32 # Set artwork type to the first medium matching ArtStack::ArtworkTypes 33 if params['medium_list'] && params["artwork_type_list"].blank? 34 artwork_types = ArtStack::ArtworkTypes.map(&:downcase) 35 mediums = params['medium_list'].split(';') 36 mediums.each do |medium| 37 if index = artwork_types.find_index { |type| type.singularize == 38 medium.strip.downcase.singularize } 39 params["artwork_type_list"] = ArtStack::ArtworkTypes[index] 40 break 41 end 42 end 43 end 44 45 # Add free tag 'Work in progress' 46 if params['work_in_progress'] == 'true' 47 params['tag_list'] += ';Work in progress' 48 end 49 50 # Construct array of tags input 51 ArtStack::TagTypes.each do |tag_type| 52 tag_list = tag_type.singularize + "_list" 53 if ArtStack::ArtistAndArtworkSharedTagTypes.include? tag_type 54 tag_list_param = (params[:artist_attributes] && params[: 55 artist_attributes][tag_list] && params[: 56 artist_attributes][tag_list]) || params[tag_list] 57 next if tag_list_param.blank? 58 tag_list_param = tag_list_param.split(/\;/) if tag_list_param.is_a? 59 String 60
20. • Function should be small • (Rule of thumb: < one screen size) • Code width < 80 ~ 100 characters
21. Long Parameter List
22. Long Parameter List 1 class ToPeopleJsonFromHashHandler 2 3 def user_followed_self 4 @result = a.to_users_feed_json_from_hash( 5 @activity[:followable_type], @activity[:followable], [@activity[:object] 6 ], @user) 7 8 header = I18n.t('application.feed.double_avatar.user_followed_self_html', 9 :user => a.link_to_user(@activity[:object], true, true, false, true), 10 :second_user => a.link_to_user(@activity[:followable], true, true, 11 false, true) 12 ) 13 14 header_short = I18n.t('application.feed.double_avatar. 15 user_followed_self_html', 16 :user => a.link_to_user(@activity[:object], true, false, false, true), 17 :second_user => a.link_to_user(@activity[:followable], true, false, 18 false, true) 19 ) 20 21 { 22 :header => header, 23 :header_short => header_short, 24 :first_avatar => @activity[:object], 25 :second_avatar => @activity[:followable] 26 } 27 end 28 29 end
23. Misplaced Responsibility
24. Misplaced Responsibility 1 # artstack/app/models/user.rb 2 3 class User < ActiveRecord::Base 4 5 # return utc offset which has the required local time in the 6 range [-11, 13] 7 8 def self.get_utc_offset_by_local(local) 9 now = Time.now.utc.hour 10 result = local - now 11 12 if result < -11 13 result + 24 14 elsif result > 13 15 result - 24 16 else 17 result 18 end 19 end 20 21 end
25. Feature Envy
26. 1 class FollowableTag < ActiveRecord::Base 2 3 def self.update_exhibitions_from_mutual_art 4 from_date = (Date.today.at_beginning_of_month - 1.day).strftime('%Y/%m/%d') 5 to_date = (Date.today + 90.day).strftime('%Y/%m/%d') 6 mutual_art_url = "http://api.mutualart. 7 com/UpcomingExhibitions?username=mutualart@artstack. 8 com&password=2561A01O43Rbb5R&FromDate=#{from_date}&ToDate=#{ 9 to_date}" 10 response = JSON.load(open(mutual_art_url, :read_timeout => 300)) 11 12 exhibitions = response['Items'] || [] 13 exhibitions.each do |exh| 14 title = exh['Title'] 15 16 followable_tag = FollowableTag.followable_tag(title, 'exhibitions', true) 17 followable_tag.link_galleries_from_mutual_art 18 19 info = followable_tag.info 20 info.started_at = Date.parse(exh['StartDate']) if (exh['StartDate'] && !info. 21 started_at) 22 info.ended_at = Date.parse(exh['EndDate']) if (exh['EndDate'] && !info.ended_at) 23 info.institution = exh['Organization']['Name'] if (exh['Organization'].try('[]', 24 'Name') && !info.institution) 25 info.website = exh['Link'] if (exh['Link'] && !info.website) 26 27 if exh['Address'] && exh['Street'] 28 address = ([exh['Street']] + exh['Address'].split('/').reverse) 29 .collect{|str| str.gsub(/\s+/, " ").strip}.reject{|str| str.blank?}.uniq 30 .join(', ') 31 count = info.places.count 32 if count == 0 33 info.places << FollowableTagInfoPlace.create(:address => address) 34 elsif count == 1 35 place = info.places.first 36 if place.address != address 37 place.address = address 38 place.save 39 end 40 end
27. REMOVE ALL DEAD CODES
28. AVOID LARGE CLASSES
29. REPLACE MAGIC NUMBER WITH NAME CONSTANTS
30. 0 20 40 60 80 100 120 140 160 180 200 Ideal Productivity vs time
31. END