RailsConf 2023

Aaron Patterson

May 03, 2023

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Transcript

1. None

2. It's the Final Keynote!

3. Increase Creativity!

4. Modern Dev Environments Programmer Efficiency in 2023?

5. Artificial Intelligence

6. ChatGPT

7. GitHub Copilot

8. Editors

9. VSCode

10. Language Servers

11. None

12. Technical Content

13. Hi, I'm Aaron!

14. @tenderlove @[email protected]

15. None
16. None

17. —Eileen Uchitelle “I remain on the Rails core team for

    you. To make Rails better for the community”

18. —Aaron “Notice me Senpai!’

19. RAILS CONF!!!!

20. Bona Fide Mycologist

21. None
22. None
23. None
24. None
25. None

26. I don’t value my time

27. Other Hobbies

28. None
29. None

30. I love programming

31. http://youtube.com/ tenderlovescoolstuff

32. http://youtube.com/ tenderlovescoolstuff CLICK HERE!!

33. Rails monkey patched that??

34. That’s not your active job!

35. I’m not saying it was Active Support, but it definitely

    was.

36. I am old 㻝

37. I am old 㻝

38. None

39. The best time to be a programmer is now.

40. Syntax Highlighting 㷠

41. Garbage Collection

42. None

43. Convention over Configuration

44. Making Decisions For Us

45. Example Spring Java Bean This is how we programmed in

    the early 2000's <!-- target bean to be referenced by name --> <bean id="testBean" class="org.springframework.beans.TestBean" scope="prototype"> <property name="age" value="10"/> <property name="spouse"> <bean class="org.springframework.beans.TestBean"> <property name="age" value="11"/> </bean> </property> </bean> <!-- will result in 10, which is the value of property 'age' of bean 'testBean' --> <util:property-path id="name" path="testBean.age"/>

46. Meetings about column names

47. Design documents about DAOs

48. Data Access Object

49. Rails: Follow the Convention and everything Just Works

50. Less Code Fewer Decisions Fewer Distractions

51. 㻑

52. Thinking Sucks!

53. Think about your app, not primary key names

54. THEY DID What??

55. Artificial Intelligence Chatgpt GitHub Copilot BARD Bing chat

56. Fake Intelligence, Real Problems

57. Licensing Issues?

58. Ethics?

59. Believable Bullshit

60. Could be true?

61. Someone, Probably “AI users are only wasting their own time”

62. None
63. None

64. -- VPP (Very Patient Person) Hi, large language models like

    ChatGPT don't actually “know" exactly how to use command line tools like GitHub CLI, so they make up command invocations that sound plausible but may or may not exist.
65. None

66. Drudgery

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68. None

69. — Me, in the future “Copilot, please fix these tests”

70. None

71. Red, Green, Refactor Adding the Feature / Tests Fixing the

    Tests Refactor the Code
72. None

73. Spend Less Time on “Boring” Tasks

74. None

75. Editors

76. None

77. Awkward!

78. Language Server

79. Language Server Protocol (LSP)

80. Language Server is a Program

81. clangd Language Server Protocol

82. clangd Language Server Protocol

83. Language Server Protocol

84. Rack

85. Technical Content

86. Developing a Language Server

87. None

88. VSCode Extension

89. None

90. Configuring Vim Add clangd support # Tell Vim to find

    vim-lsp packadd vim-lsp # Use clangd if available if executable('clangd') au User lsp_setup call lsp#register_server({ \ 'name': 'clangd', \ 'cmd': ['clangd'], \ 'allowlist': ['c'], \ }) endif Use the “clangd” command Only enable it on C files

91. Check Syntax But only check syntax on Save def foo

    if end

92. Communicate via STDIN / STDOUT or TCP

93. Typical Order of Operations Open foo.rb Ruby LSP Open bar.rb

94. Language Server Protocol Just JSON with a header Content-Length: 1234\r\n

    Content-Type: application/vscode-jsonrpc; charset=utf-8\r\n \r\n { cool:"stuff",live:"stream"...} Content-Type is optional!

95. Not Request / Response

96. Events, encoded as JSON

97. Respond to events with `id`

98. Event Message Reader Read Messages from $stdin and Parse module

    LSP class Reader def initialize @io = $stdin.binmode end def read buffer = @io.gets("\r\n\r\n") content_length = buffer.match(/Content-Length: (\d+)/i)[1].to_i message = @io.read(content_length) JSON.parse message, symbolize_names: true end end end Read Header in to a Buffer Get Content Length Read JSON event and parse

99. Event Message Writer Write Hash as JSON to $stdout module

    LSP class Writer def initialize @io = $stdout.binmode end def write response str = JSON.dump(response.merge("jsonrpc" => "2.0")) @io.write "Content-Length: #{str.bytesize}\r\n" @io.write "\r\n" @io.write str @io.flush end end end Add Required Key Calculate and write length Send JSON Body

100. Event Loop module LSP def self.run reader = Reader.new writer

     = Writer.new # Handle events subscriber = LSP::Events.new loop do # Read an event message = reader.read # Ask the handler to handle the event subscriber.handle message[:method], message, writer end end end

101. First Event “initialize” event Content-Length: 2683\r\n \r\n {"id":1,"jsonrpc":"2.0","method":"initialize","params":{"rootUri":"file:///Users/aaron/git/lsp-stream","capabilities":{"workspace": {"workspaceFolders":false,"configuration":true,"symbol":{"dynamicRegistration":false},"applyEdit":true},"window": {"workDoneProgress":false},"textDocument":{"callHierarchy":{"dynamicRegistration":false},"rename":

     {"prepareSupport":true,"dynamicRegistration":false,"prepareSupportDefaultBehavior":1},"codeAction": {"isPreferredSupport":true,"disabledSupport":true,"codeActionLiteralSupport":{"codeActionKind":{"valueSet": ["","quickfix","refactor","refactor.extract","refactor.inline","refactor.rewrite","source","source.organizeImports"]}},"dynamicRegistration":false },"completion":{"completionItem":{"snippetSupport":false,"resolveSupport":{"properties":["additionalTextEdits"]},"documentationFormat": ["markdown","plaintext"]},"dynamicRegistration":false,"completionItemKind":{"valueSet": [10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,1,2,3,4,5,6,7,8,9]}},"formatting":{"dynamicRegistration":false},"codeLens": {"dynamicRegistration":false},"inlayHint":{"dynamicRegistration":false},"hover":{"dynamicRegistration":false,"contentFormat": ["markdown","plaintext"]},"rangeFormatting":{"dynamicRegistration":false},"declaration": {"dynamicRegistration":false,"linkSupport":true},"references":{"dynamicRegistration":false},"typeHierarchy": {"dynamicRegistration":false},"foldingRange":{"rangeLimit":5000,"dynamicRegistration":false,"lineFoldingOnly":true},"documentSymbol": {"symbolKind":{"valueSet": [10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,1,2,3,4,5,6,7,8,9]},"dynamicRegistration":false,"labelSupport":false,"hierarchicalDocumentSymb olSupport":false},"publishDiagnostics":{"relatedInformation":true},"synchronization": {"dynamicRegistration":false,"willSaveWaitUntil":false,"willSave":false,"didSave":true},"documentHighlight": {"dynamicRegistration":false},"implementation":{"dynamicRegistration":false,"linkSupport":true},"typeDefinition": {"dynamicRegistration":false,"linkSupport":true},"semanticTokens":{"serverCancelSupport":false,"requests": {"full":false,"range":false},"multilineTokenSupport":false,"dynamicRegistration":false,"overlappingTokenSupport":false,"tokenTypes": ["type","class","enum","interface","struct","typeParameter","parameter","variable","property","enumMember","event","function","method","macro","ke yword","modifier","comment","string","number","regexp","operator"],"tokenModifiers":[],"formats":["relative"]},"signatureHelp": {"dynamicRegistration":false},"definition":{"dynamicRegistration":false,"linkSupport":true}}},"rootPath":"/Users/aaron/git/lsp- stream","clientInfo":{"name":"vim-lsp"},"processId":51035,"trace":"off"}}

102. First Event “initialize” event Content-Length: 2683\r\n \r\n {"id":1,"jsonrpc":"2.0","method":"initialize","params":{"rootUri":"file:///Users/aaron/git/lsp-stream","capabilities":{"workspace": {"workspaceFolders":false,"configuration":true,"symbol":{"dynamicRegistration":false},"applyEdit":true},"window": {"workDoneProgress":false},"textDocument":{"callHierarchy":{"dynamicRegistration":false},"rename":

     {"prepareSupport":true,"dynamicRegistration":false,"prepareSupportDefaultBehavior":1},"codeAction": {"isPreferredSupport":true,"disabledSupport":true,"codeActionLiteralSupport":{"codeActionKind":{"valueSet": ["","quickfix","refactor","refactor.extract","refactor.inline","refactor.rewrite","source","source.organizeImports"]}},"dynamicRegistration":false },"completion":{"completionItem":{"snippetSupport":false,"resolveSupport":{"properties":["additionalTextEdits"]},"documentationFormat": ["markdown","plaintext"]},"dynamicRegistration":false,"completionItemKind":{"valueSet": [10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,1,2,3,4,5,6,7,8,9]}},"formatting":{"dynamicRegistration":false},"codeLens": {"dynamicRegistration":false},"inlayHint":{"dynamicRegistration":false},"hover":{"dynamicRegistration":false,"contentFormat": ["markdown","plaintext"]},"rangeFormatting":{"dynamicRegistration":false},"declaration": {"dynamicRegistration":false,"linkSupport":true},"references":{"dynamicRegistration":false},"typeHierarchy": {"dynamicRegistration":false},"foldingRange":{"rangeLimit":5000,"dynamicRegistration":false,"lineFoldingOnly":true},"documentSymbol": {"symbolKind":{"valueSet": [10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,1,2,3,4,5,6,7,8,9]},"dynamicRegistration":false,"labelSupport":false,"hierarchicalDocumentSymb olSupport":false},"publishDiagnostics":{"relatedInformation":true},"synchronization": {"dynamicRegistration":false,"willSaveWaitUntil":false,"willSave":false,"didSave":true},"documentHighlight": {"dynamicRegistration":false},"implementation":{"dynamicRegistration":false,"linkSupport":true},"typeDefinition": {"dynamicRegistration":false,"linkSupport":true},"semanticTokens":{"serverCancelSupport":false,"requests": {"full":false,"range":false},"multilineTokenSupport":false,"dynamicRegistration":false,"overlappingTokenSupport":false,"tokenTypes": ["type","class","enum","interface","struct","typeParameter","parameter","variable","property","enumMember","event","function","method","macro","ke yword","modifier","comment","string","number","regexp","operator"],"tokenModifiers":[],"formats":["relative"]},"signatureHelp": {"dynamicRegistration":false},"definition":{"dynamicRegistration":false,"linkSupport":true}}},"rootPath":"/Users/aaron/git/lsp- stream","clientInfo":{"name":"vim-lsp"},"processId":51035,"trace":"off"}}

103. Event Handling Dispatch to methods based on event names module

     LSP class Events DISPATCH = { "initialize" => :on_initialize, "textDocument/didSave" => :did_save } def handle method, message, writer send(DISPATCH.fetch(method) { :unknown }, message, writer) end def on_initialize message, writer # ... end end end Map event names to methods Look up methods and call them

104. Initialize Message Tells the editor what features your server supports

     (server § editor) module LSP class Events def on_initialize message, writer result = { "capabilities" => { "textDocumentSync" => { "openClose" => true, "change" => 1,"save" => true } } } writer.write(id: message[:id], result: result) end end end Open / Close Change Save

105. Document Was Saved Editor § Server {"method":"textDocument/didSave","params":{ "textDocument":{ "uri":"file:///Users/aaron/git/minitest/test.rb"}}}

106. Document Was Saved Editor § Server {"method":"textDocument/didSave","params":{ "textDocument":{ "uri":"file:///Users/aaron/git/minitest/test.rb"}}}

107. Document Was Saved Editor § Server {"method":"textDocument/didSave","params":{ "textDocument":{ "uri":"file:///Users/aaron/git/minitest/test.rb"}}}

108. Save Events Parse the File, Report Document Diagnostics module LSP

     class Events def did_save message, writer doc = message.dig(:params, :textDocument) file = doc[:uri].delete_prefix("file://") result = { :uri => doc[:uri], :diagnostics => [ ] } error = check_syntax file if error line_number = error.message[/(?<=:)\d+/].to_i line = File.readlines(file)[line_number - 1] result = { :uri => doc[:uri], :diagnostics => [ { "range" => { "start" => { "character" => 0, "line" => line_number - 1 }, "end" => { "character" => line.bytesize, "line" => line_number - 1 }, }, "message" => error.message.lines.first, "severity" => 1 }, ], } end writer.write(method: "textDocument/publishDiagnostics", params: result) end end end Set our default response Check Syntax Extract the Line Information Construct Error Report Send Error Report

109. Checking Syntax Try compiling the file def check_syntax file RubyVM::InstructionSequence.compile_file(file)

     nil rescue SyntaxError => e e # only return syntax errors rescue Exception nil # ignore anything else end

110. That’s It!

111. Entire Language Server It fits on one slide! #!/Users/aaron/.rubies/arm64/ruby-trunk/bin/ruby require

     "json" module LSP class Writer def initialize @io = $stdout.binmode end def write response str = JSON.dump(response.merge("jsonrpc" => "2.0")) @io.write "Content-Length: #{str.bytesize}\r\n" @io.write "\r\n" @io.write str @io.flush end end class Reader def initialize @io = $stdin.binmode end def read buffer = @io.gets("\r\n\r\n") content_length = buffer.match(/Content-Length: (\d+)/i)[1].to_i message = @io.read(content_length) JSON.parse message, symbolize_names: true end end class Events DISPATCH = { "initialize" => :on_initialize, "textDocument/didSave" => :did_save } def handle method, message, writer send DISPATCH.fetch(method) { :unknown }, message, writer end def on_initialize message, writer result = { "capabilities" => { "textDocumentSync" => { "openClose" => true, "change" => 1,"save" => true } } } writer.write(id: message[:id], result: result) end
112. None

113. Implement Other Events

114. Implement other Checks

115. Language Server Protocol https://microsoft.github.io/language-server-protocol/

116. https://gist.github.com/tenderlove/ 9a18be7a27ba7a074a8ba8fbf554e794

117. None

118. Application Record So Many Generated Methods! class User < ApplicationRecord

     end

119. Routes Files Even More Generated Methods! Rails.application.routes.draw do resources :users

     resources :posts end

120. Tapioca https://github.com/Shopify/tapioca

121. — Me, in my head, but now out loud at

     RailsConf “What if Rails had a built-in Language Server?”

122. Prototype: Refreshing https://github.com/tenderlove/refreshing

123. Hover Info for Active Record

124. None

125. Jump to “Definition”

126. None

127. Hover Info for URL Helpers

128. None

129. NICE!

130. Jump to Definition for URL Helpers 㷉

131. None

132. Automatic Refreshing and Error Highlighting

133. None

134. We’re all TDD’ing our views though, right?

135. More Ideas!

136. Ruby LSP Rails https://github.com/Shopify/ruby-lsp-rails

137. Language Server Hacks

138. App Must Be Running

139. Fetching Active Record Columns Check that the constant inherits from

     Active Record if token && token =~ /^[A-Z]/ begin const = Object.const_get(token) value = "# #{const.name}\n" if const < ActiveRecord::Base name_header = "Column Name" type_header = "Column Type" info = [[name_header, type_header]] + const.columns.map { |column| ["`" + column.name.to_s + "`", column.type.to_s] } max_name_len = info.map(&:first).sort_by(&:length).last.length max_type_len = info.map(&:last).sort_by(&:length).last.length name_header, type_header = *info.shift value << ("| " + name_header.ljust(max_name_len)) value << (" | " + type_header.ljust(max_type_len) + " |\n") value << ("| " + ("-" * max_name_len)) value << (" | " + ("-" * max_type_len) + " |\n") info.each do |name, type| value << ("| " + name.ljust(max_name_len)) value << (" | " + type.ljust(max_type_len) + " |\n") end end rescue NameError end end

140. Fetching Active Record Columns Check that the constant inherits from

     Active Record if token && token =~ /^[A-Z]/ begin const = Object.const_get(token) value = "# #{const.name}\n" if const < ActiveRecord::Base name_header = "Column Name" type_header = "Column Type" info = [[name_header, type_header]] + const.columns.map { |column| ["`" + column.name.to_s + "`", column.type.to_s] } max_name_len = info.map(&:first).sort_by(&:length).last.length max_type_len = info.map(&:last).sort_by(&:length).last.length name_header, type_header = *info.shift value << ("| " + name_header.ljust(max_name_len)) value << (" | " + type_header.ljust(max_type_len) + " |\n") value << ("| " + ("-" * max_name_len)) value << (" | " + ("-" * max_type_len) + " |\n") info.each do |name, type| value << ("| " + name.ljust(max_name_len)) value << (" | " + type.ljust(max_type_len) + " |\n") end end rescue NameError end end

141. Fetching Active Record Columns Check that the constant inherits from

     Active Record if token && token =~ /^[A-Z]/ begin const = Object.const_get(token) value = "# #{const.name}\n" if const < ActiveRecord::Base name_header = "Column Name" type_header = "Column Type" info = [[name_header, type_header]] + const.columns.map { |column| ["`" + column.name.to_s + "`", column.type.to_s] } max_name_len = info.map(&:first).sort_by(&:length).last.length max_type_len = info.map(&:last).sort_by(&:length).last.length name_header, type_header = *info.shift value << ("| " + name_header.ljust(max_name_len)) value << (" | " + type_header.ljust(max_type_len) + " |\n") value << ("| " + ("-" * max_name_len)) value << (" | " + ("-" * max_type_len) + " |\n") info.each do |name, type| value << ("| " + name.ljust(max_name_len)) value << (" | " + type.ljust(max_type_len) + " |\n") end end rescue NameError end end

142. URL Helper Information “rake routes” already knows this info! value

     = '' if token && token =~ /^([a-z_]+)(_path|_url)$/ # check if it's a route helper if Rails.application.routes.named_routes.key?($1) route = Rails.application.routes.named_routes.get($1) controller = route.requirements[:controller] action = route.requirements[:action] value = "* URI Pattern: `#{route.path.spec}`\n* Controller#Action: `#{controller} ##{action}`" else value = "Something else" end else # Other Stuff end

143. URL Helper Information “rake routes” already knows this info! value

     = '' if token && token =~ /^([a-z_]+)(_path|_url)$/ # check if it's a route helper if Rails.application.routes.named_routes.key?($1) route = Rails.application.routes.named_routes.get($1) controller = route.requirements[:controller] action = route.requirements[:action] value = "* URI Pattern: `#{route.path.spec}`\n* Controller#Action: `#{controller} ##{action}`" else value = "Something else" end else # Other Stuff end

144. URL Helper Information “rake routes” already knows this info! value

     = '' if token && token =~ /^([a-z_]+)(_path|_url)$/ # check if it's a route helper if Rails.application.routes.named_routes.key?($1) route = Rails.application.routes.named_routes.get($1) controller = route.requirements[:controller] action = route.requirements[:action] value = "* URI Pattern: `#{route.path.spec}`\n* Controller#Action: `#{controller} ##{action}`" else value = "Something else" end else # Other Stuff end

145. Helper Definitions

146. None

147. Route Source Location bin/rails routes -E [aaron@tc-lan-adapter㷊 ~/g/blogsite (main)]$ bin/rails

     routes -E --[ Route 1 ]-------------------------- Prefix | users Verb | GET URI | /users(.:format) Controller#Action | users#index Source Location | config/routes.rb:6 --[ Route 2 ]-------------------------- Prefix | Verb | POST URI | /users(.:format) Controller#Action | users#create Source Location | config/routes.rb:6 --[ Route 3 ]-------------------------- Prefix | new_user Verb | GET URI | /users/new(.:format) Controller#Action | users#new Source Location | config/routes.rb:6 Rails 7.1!

148. Route Source Location Language Server Lookup if Rails.application.routes.named_routes.key?($1) route =

     Rails.application.routes.named_routes.get($1) file, line = route.source_location.split(':') file = File.join(@root, file) char = File.readlines(file)[line.to_i - 1].index(/[^\s]/) uri = "file://" + file result = { :uri => uri, :range => { start: { line: line.to_i - 1, character: char }, end: { line: line.to_i, character: 0 } } } writer.write(id: request[:id], result: result) end Find the source line Figure out the column Send info back to editor

149. Error Information

150. ERB is converted to Ruby Exceptions in the generated code

     must be mapped to the source <p style="color: green"><%= notice %></p> <h1>Users</h1> <div id="users"> <% @users.each do |user| %> <%= render user %> <p> <%= link_to "Show this user", user %> </p> <% end %> </div> <%= link_to "New user", new_user_path %> Source ERB #coding:ASCII-8BIT _erbout = +''; _erbout.<< "<p style=\"color: green\">".freeze; _erbout.<<(( notice ).to_s); _erbout.<< "</p>\n\n<h1>Users</ h1>\n\n<div id=\"users\">\n ".freeze ; @users.each do |user| ; _erbout.<< "\n ".freeze ; _erbout.<<(( render user ).to_s); _erbout.<< "\n <p>\n ".freeze ; _erbout.<<(( link_to "Show this user", user ).to_s); _erbout.<< "\n </p>\n ".freeze ; end ; _erbout.<< "\n</div>\n\n".freeze ; _erbout.<<(( link_to "New user", new_user_path ).to_s); _erbout.<< "\n".freeze ; _erbout Evaluated Ruby
151. None
152. None
153. None
154. None
155. None

156. Thank you Mame!

157. None

158. Language Server Integration Simply Monkey Patch Rails! (Sorry Eileen) class

     ActionDispatch::DebugView def send_exception ex resp = { uri: "file://" + ex.file_name, diagnostics: [ "range" => { "start" => { "character" => 0, "line" => (ex.line_number.to_i - 1) }, "end" => { "character" => 65536, "line" => (ex.line_number.to_i - 1) }, }, "severity" => 1, "message" => ex.message ] } Refreshing::LSP::ERROR_QUEUE << [:error, resp] end end

159. Language Server Integration Cont. Pop off the queue and send

     to the editor Thread.new do while item = ERROR_QUEUE.pop type, val = *item if type == :clear subscriber.files.each do |file, version| val = { uri: file, version: version, diagnostics: [] } writer.write(method: "textDocument/publishDiagnostics", params: val) end else val[:version] = subscriber.files[val[:uri]] writer.write(method: "textDocument/publishDiagnostics", params: val) end end end

160. This is a Rube Goldberg Machine Ruby Goldberg?

161. My Pitch.

162. None

163. Different Servers Have Different Features

164. None
165. None

166. Rails Should Include a Language Server

167. Only One

168. I might not value my time, but I highly value

     yours

169. Thank You!

170. Increased Creativity!

171. Thank You! 㷉