Summary of Clean Code: A Handbook of Agile Software Craftsmanship: by Robert C Martin See Part I: http://www.slideshare.net/JaneChung12/how-to-write-better-code-indepth-best-practices-for-writing-readable-simple-extendable-and-efficient-code-part-i References: Clean Code: A Handbook of Agile Software Craftsmanship: by Robert C Martin (http://www.amazon.com/Clean-Code-Handbook- Software-Craftsmanship/dp/0132350882) Design Patterns: Elements of Reusable Object-Oriented Software by Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides The Clean Code Talks - "Global State and Singletons" https://www.youtube.com/watch?v=-FRm3VPhseI

1. CLEAN CODE
again
Percy Lam
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2. Skygear.io

3. Skygear.io

4. Skygear.io

5. OBJECTIVES
Readable Simple Extendable Efficient
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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
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7. NAMING
• Pronounceable
• Searchable
• Avoid abbreviations
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8. Searchable Names
ok()
book
token
stroke
cookie
smoking
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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
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10. Functions should…
DO ONE THING!!
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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.'}
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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
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13. Function should…
• be small
• do one thing
• reveal the intent by its name
• use descriptive names
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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
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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, Skygear.io

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
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17. Excessively long identifiers
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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] } }
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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
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20. • Function should be small
• (Rule of thumb: < one screen size)
• Code width < 80 ~ 100 characters
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21. Long Parameter List
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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 Skygear.io

23. Misplaced Responsibility
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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
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25. Feature Envy
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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
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27. REMOVE ALL DEAD CODES
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28. AVOID LARGE CLASSES
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29. REPLACE MAGIC NUMBER
WITH NAME CONSTANTS
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30. 0
20
40
60
80
100
120
140
160
180
200
Ideal Productivity vs time
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31. Brought to you by Oursky
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