Code Smells: Your Refactoring Cheat Codes

Sure, the TDD cycle is red-green-refactor but what exactly are we refactoring? We just wrote the code, it's green, and it seems reasonable to us. Let's move onto the next test. We're have a deadline, remember?

Whether we're working with code we just wrote or opening up a project for the first time, being able to listen to the hints the code is trying to give you about how it wants to be constructed is the most direct path toward successful refactoring. What the code is telling you nuanced however: no code smell is absolute and none in itself is an indication of a problem. How do we know we need to refactor? What are the code smells telling us to do? How do we balance our short terms needs of shipping our software with the long term maintainability of the code base? In this talk we'll talk through some of the classical code smells and dive into examples of how to put these smells to work for you.

Transcript

1. Code Smells: r Refactoring Cheat Codes
2. @jpignata
4. Code smells are heuristics for refactoring.
6. Our design communicates to us through resistance.
7. Our code is difficult to understand
8. Our code is difficult to test
9. Our code is difficult to change
10. Our code is difficult to reuse
11. This resistance is valuable feedback.
12. Code smells are hints from our software about how to reduce this resistance.
13. This is one way our design emerges.
14. Application Push Daemon Google Cloud Messaging API Android Device UDP HTTPS
15. Application Push Daemon Google Cloud Messaging API Android Device UDP HTTPS
16. queue = Queue.new client = HTTPClient.new socket = UDPSocket.new 10.times do Thread.new do while data = queue.pop client.post("https://android.googleapis.com/gcm/send", data, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end socket.bind("0.0.0.0", 6889) while data = socket.recvfrom(4096) case data[0].split.first when "PING" socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) queue << json end end
17. PING it responds with PONG SEND it delivers the message to the Google Cloud Messaging API Commands
18. $ ruby ./pushd.rb
19. $ nc -u 127.0.0.1 6889 PING
20. $ nc -u 127.0.0.1 6889 PING PONG
21. PING ✔ it responds with PONG SEND it delivers the message to the Google Cloud Messaging API Commands
22. $ nc -u 127.0.0.1 6889 SEND AP91bQd65Z5IA8p "Steve: What is up?"
24. PING ✔ it responds with PONG SEND ✔ it delivers the message to the Google Cloud Messaging API Commands
25. describe "Push Daemon" do let(:socket) { UDPSocket.new } before(:all) do Thread.new { load "./pushd.rb" } end describe "commands" do describe "PING" do it "responds with PONG" end describe "SEND" do it "delivers the message to the Google Cloud Messaging API" end end end
26. it "responds with PONG" do socket.send("PING", 0, "127.0.0.1", 6889) response, _ = socket.recvfrom(8) response.should eq("PONG") end
27. it "delivers the message to the Google Cloud Messaging API" do stub_request :post, "https://android.googleapis.com/gcm/send" socket.send('SEND t0k3n "Steve: What is up?"', 0, "127.0.0.1", 6889) assert_requested :post, "https://android.googleapis.com/gcm/send", { body: { "registration_ids" => ["t0k3n"], "data" => { "alert" => "Steve: What is up?" } }.to_json } end
28. jp@oeuf:~/workspace/mwrc(master)$ rspec Push Daemon commands PING responds with PONG SEND delivers the message to the Google Cloud Messaging API Finished in 0.06854 seconds 2 examples, 0 failures
29. queue = Queue.new client = HTTPClient.new socket = UDPSocket.new 10.times do Thread.new do while data = queue.pop client.post("https://android.googleapis.com/gcm/send", data, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end socket.bind("0.0.0.0", 6889) while data = socket.recvfrom(4096) case data[0].split.first when "PING" socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) queue << json end end
30. Long Method C S
31. queue = Queue.new client = HTTPClient.new socket = UDPSocket.new 10.times do Thread.new do while data = queue.pop client.post("https://android.googleapis.com/gcm/send", data, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end socket.bind("0.0.0.0", 6889) while data = socket.recvfrom(4096) case data[0].split.first when "PING" socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) queue << json end end Collaborator Instantiation [
32. queue = Queue.new client = HTTPClient.new socket = UDPSocket.new
33. queue = Queue.new client = HTTPClient.new socket = UDPSocket.new 10.times do Thread.new do while data = queue.pop client.post("https://android.googleapis.com/gcm/send", data, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end socket.bind("0.0.0.0", 6889) while data = socket.recvfrom(4096) case data[0].split.first when "PING" socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) queue << json end end Thread Pool Initialization [ Collaborator Instantiation [
34. 10.times do Thread.new do while data = queue.pop # ... end end end
35. queue = Queue.new client = HTTPClient.new socket = UDPSocket.new 10.times do Thread.new do while data = queue.pop client.post("https://android.googleapis.com/gcm/send", data, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end socket.bind("0.0.0.0", 6889) while data = socket.recvfrom(4096) case data[0].split.first when "PING" socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) queue << json end end Thread Pool Initialization [ Service Request Creation and Delivery [ Collaborator Instantiation [
36. client.post("https://android.googleapis.com/gcm/send", data, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" })
37. queue = Queue.new client = HTTPClient.new socket = UDPSocket.new 10.times do Thread.new do while data = queue.pop client.post("https://android.googleapis.com/gcm/send", data, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end socket.bind("0.0.0.0", 6889) while data = socket.recvfrom(4096) case data[0].split.first when "PING" socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) queue << json end end Thread Pool Initialization [ Service Request Creation and Delivery [ [ Server Socket Setup Collaborator Instantiation [
38. socket.bind("0.0.0.0", 6889)
39. queue = Queue.new client = HTTPClient.new socket = UDPSocket.new 10.times do Thread.new do while data = queue.pop client.post("https://android.googleapis.com/gcm/send", data, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end socket.bind("0.0.0.0", 6889) while data = socket.recvfrom(4096) case data[0].split.first when "PING" socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) queue << json end end Thread Pool Initialization [ Service Request Creation and Delivery [ [ Server Socket Setup [ Command Dispatch Collaborator Instantiation [
40. case data[0].split.first when "PING" # ... when "SEND" # ... end end
41. queue = Queue.new client = HTTPClient.new socket = UDPSocket.new 10.times do Thread.new do while data = queue.pop client.post("https://android.googleapis.com/gcm/send", data, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end socket.bind("0.0.0.0", 6889) while data = socket.recvfrom(4096) case data[0].split.first when "PING" socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) queue << json end end Thread Pool Initialization [ Service Request Creation and Delivery [ [ Server Socket Setup [ Command Dispatch [ Parameter Extraction Collaborator Instantiation [
42. data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } })
43. queue = Queue.new client = HTTPClient.new socket = UDPSocket.new 10.times do Thread.new do while data = queue.pop client.post("https://android.googleapis.com/gcm/send", data, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end socket.bind("0.0.0.0", 6889) while data = socket.recvfrom(4096) case data[0].split.first when "PING" socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) queue << json end end Thread Pool Initialization [ Service Request Creation and Delivery [ [ Server Socket Setup [ Command Dispatch [ Parameter Extraction Collaborator Instantiation [
44. Replace Method with Method Object R f r
45. class PushDaemon end
46. queue = Queue.new client = HTTPClient.new socket = UDPSocket.new 10.times do Thread.new do while data = queue.pop client.post("https://android.googleapis.com/gcm/send", data, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end socket.bind("0.0.0.0", 6889) while data = socket.recvfrom(4096) case data[0].split.first when "PING" socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) queue << json end end
47. class PushDaemon def initialize @queue = Queue.new @client = HTTPClient.new @socket = UDPSocket.new end end
48. 10.times do Thread.new do while json = queue.pop client.post("https://android.googleapis.com/gcm/send", json, "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" ) end end end socket.bind("0.0.0.0", 6889) while data = socket.recvfrom(4096) case data[0].split.first when "PING" socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) queue << json end end
49. def start 10.times do Thread.new do while json = @queue.pop @client.post("https://android.googleapis.com/gcm/send", json, "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" ) end end end @socket.bind("0.0.0.0", 6889) while data = @socket.recvfrom(4096) case data[0].split.first when "PING" @socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @queue << json end end end
50. Extract Method R f r
51. def start 10.times do Thread.new do while json = @queue.pop @client.post("https://android.googleapis.com/gcm/send", json, "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" ) end end end @socket.bind("0.0.0.0", 6889) while data = @socket.recvfrom(4096) case data[0].split.first when "PING" @socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @queue << json end end end [ Spawn Workers [ Bind [ Loop and Process Incoming Requests
52. def start spawn_workers bind loop { process_request } end
53. def spawn_workers 10.times do Thread.new do while json = @queue.pop @client.post("https://android.googleapis.com/gcm/send", json, "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" ) end end end end
54. def bind @socket.bind("0.0.0.0", 6889) end
55. def process_request data = @socket.recvfrom(4096) case data[0].split.first when "PING" @socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @queue << json end end
56. class PushDaemon def initialize @queue = Queue.new @client = HTTPClient.new @socket = UDPSocket.new end def start spawn_workers bind loop { process_request } end private def spawn_workers; end def bind; end def process_request; end end
57. ➡ Update authorization key ➡ Increase thread pool size ➡ Swap HTTP client ➡ Use a different transport protocol ➡ Modify wire protocol format ➡ Add commands ➡ Add a different push notification service ➡ Move UDP port ➡ Use x-www-form-urlencoded instead of JSON ➡ Lower maximum payload size ➡ Bind to a specific interface address ➡ Update push service URL
58. Divergent Change C S
59. Extract Class R f r
60. def spawn_workers 10.times do Thread.new do while json = @queue.pop @client.post("https://android.googleapis.com/gcm/send", json, "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" ) end end end end
61. class Worker def initialize @queue = Queue.new @client = HTTPClient.new end end
62. class PushDaemon def initialize @queue = Queue.new @client = HTTPClient.new @socket = UDPSocket.new end end
63. class PushDaemon def initialize @worker = Worker.new @socket = UDPSocket.new end end
64. def process_request data = @socket.recvfrom(4096) case data[0].split.first when "PING" @socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @queue << json end end
65. class Worker def initialize @queue = Queue.new @client = HTTPClient.new end def <<(json) @queue << json end end
66. def process_request data = @socket.recvfrom(4096) case data[0].split.first when "PING" @socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @queue << json end end
67. def process_request data = @socket.recvfrom(4096) case data[0].split.first when "PING" @socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end
68. def spawn_workers 10.times do Thread.new do while json = @queue.pop @client.post("https://android.googleapis.com/gcm/send", json, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end end
69. class Worker def initialize @queue = Queue.new @client = HTTPClient.new end def spawn(count) count.times do Thread.new do while json = @queue.pop @client.post("https://android.googleapis.com/gcm/send", json, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end end def <<(json) @queue << json end end
70. class PushDaemon def initialize @worker = Worker.new @socket = UDPSocket.new end def start spawn_workers bind loop { process_request } end private def spawn_workers; end def bind; end def process_request; end end
71. class PushDaemon def initialize @worker = Worker.new @socket = UDPSocket.new end def start @worker.spawn(10) bind loop { process_request } end private def bind; end def process_request; end end
72. class PushDaemon def initialize @worker = Worker.new @socket = UDPSocket.new end def start @worker.spawn(10) bind loop { process_request } end private def bind; end def process_request; end end
73. def bind @socket.bind("0.0.0.0", 6889) end def process_request data = @socket.recvfrom(4096) case data[0].split.first when "PING" @socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end [ Bind [ Receive [ Send
74. class UDPServer def initialize @socket = UDPSocket.new end end
75. def bind @socket.bind("0.0.0.0", 6889) end def process_request data = @socket.recvfrom(4096) case data[0].split.first when "PING" @socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end [ Bind [ Receive [ Send
76. class UDPServer def initialize @socket = UDPSocket.new end def bind(port) @socket.bind("0.0.0.0", port) end def receive @socket.recvfrom(4096) end def send(message, address, port) @socket.send(message, 0, address, port) end end
77. class PushDaemon def initialize @worker = Worker.new @socket = UDPSocket.new end def start @worker.spawn(10) bind loop { process_request } end private def bind; end def process_request; end end
78. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new end def start @worker.spawn(10) bind loop { process_request } end private def bind; end def process_request; end end
79. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new end def start @worker.spawn(10) bind loop { process_request } end private def bind; end def process_request; end end
80. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new end def start @worker.spawn(10) @server.bind(6889) loop { process_request } end private def process_request; end end
81. def process_request data = @socket.recvfrom(4096) case data[0].split.first when "PING" @socket.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @queue << json end end
82. def process_request data = @server.receive case data[0].split.first when "PING" @server.send("PONG", data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @queue << json end end
83. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new end def start @worker.spawn(10) @server.bind(6889) loop { process_request } end private def process_request data = @server.receive case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
84. Inappropriate Intimacy C S
85. PushDaemon UDPServer bind(port) receive data
86. PushDaemon UDPServer listen(port) call(data)
87. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new end def start @worker.spawn(10) @server.bind(6889) loop { process_request } end private def process_request data = @server.receive case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
88. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.bind(6889) loop { process_request } end private def process_request data = @server.receive case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
89. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.bind(6889) loop { process_request } end private def process_request data = @server.receive case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
90. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.bind(6889) @server.listen end private def process_request data = @server.receive case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
91. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.bind(6889) @server.listen end private def process_request data = @server.receive case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
92. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end private def process_request data = @server.receive case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
93. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end private def process_request data = @server.receive case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
94. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def process_request(data) case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
95. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def process_request(data) case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
96. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(data) case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
97. class UDPServer def initialize @socket = UDPSocket.new end def bind(port) @socket.bind("0.0.0.0", port) end def receive @socket.recvfrom(4096) end def send(message, address, port) @socket.send(message, 0, address, port) end end
98. class UDPServer def initialize(app) @app = app @socket = UDPSocket.new end def bind(port) @socket.bind("0.0.0.0", port) end def receive @socket.recvfrom(4096) end def send(message, address, port) @socket.send(message, 0, address, port) end end
99. class UDPServer def initialize(app) @app = app @socket = UDPSocket.new end def bind(port) @socket.bind("0.0.0.0", port) end def receive @socket.recvfrom(4096) end def send(message, address, port) @socket.send(message, 0, address, port) end end
100. class UDPServer def initialize(app) @app = app @socket = UDPSocket.new end def listen(port) @socket.bind("0.0.0.0", port) loop { @app.call(receive) } end def receive @socket.recvfrom(4096) end def send(message, address, port) @socket.send(message, 0, address, port) end end
101. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(data) case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
102. Case Statement C S
103. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(data) case data[0].split.first when "PING" @server.send("PONG", 0, data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end end
104. Replace Conditional with Polymorphism R f r
105. def call(data) case data[0].split.first when "PING" @server.send("PONG", data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end
106. module Jobs class Ping def initialize(data, server) @data = data @server = server end def run @server.send("PONG", @data[1][3], @data[1][1]) end end end
107. def call(data) case data[0].split.first when "PING" @server.send("PONG", data[1][3], data[1][1]) when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end
108. def call(data) case data[0].split.first when "PING" Jobs::Ping.new(data, @server).run when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end
109. def call(data) case data[0].split.first when "PING" Jobs::Ping.new(data, @server).run when "SEND" data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) @worker << json end end
110. module Jobs class Send def initialize(data, server) @data = data @server = server end def run @data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) end end end
111. def call(data) case data[0].split.first when "PING" Jobs::Ping.new(data, @server).run when "SEND" json = Jobs::Send.new(data, @server).run @worker << json end end
112. class Worker def initialize @queue = Queue.new @client = HTTPClient.new end def spawn(count) count.times do Thread.new do while json = @queue.pop @client.post("https://android.googleapis.com/gcm/send", json, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end end def <<(json) @queue << json end end
113. class Worker def initialize @queue = Queue.new @client = HTTPClient.new end def spawn(count) count.times do Thread.new do while json = @queue.pop @client.post("https://android.googleapis.com/gcm/send", json, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end end def <<(json) @queue << json end end
114. module Jobs class Send def self.client @client ||= HTTPClient.new end def initialize(data, server) @data = data @server = server end def run @data[0][5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) self.class.client.post("https://android.googleapis.com/gcm/send", json, { "Authorization" => "key=AIzaSyCABSTd47XeIH-ERx9rvHUSF9DIJ7DCwdk", "Content-Type" => "application/json" }) end end end
115. class Worker def initialize @queue = Queue.new end def spawn(count) count.times do Thread.new { work } end end def <<(job) @queue << job end private def work while job = @queue.pop job.run end end end
116. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(data) case data[0].split.first when "PING" Jobs::Ping.new(data, @server).run when "SEND" json = Jobs::Send.new(data, @server).run @worker << json end end end
117. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(data) job = case data[0].split.first when "PING" Jobs::Ping.new(data, @server) when "SEND" Jobs::Send.new(data, @server) end if job @worker << job end end end
118. Move Creation Knowledge to Factory R f r
119. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.bind(6889) @server.listen end def call(data) job = case data[0].split.first when "PING" Jobs::Ping.new(data, @server) when "SEND" Jobs::Send.new(data, @server) end if job @worker << job end end end
120. module Jobs def self.factory(data, server) case data[0].split.first when "PING" Jobs::Ping.new(data, server) when "SEND" Jobs::Send.new(data, server) end end end
121. module Jobs JOBS = { "PING" => Ping, "SEND" => Send } def self.factory(data, server) command = data[0].split.first.upcase klass = JOBS[command] if klass klass.new(data, server) end end end
122. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.bind(6889) @server.listen end def call(data) job = case data[0].split.first when "PING" Jobs::Ping.new(data, @server) when "SEND" Jobs::Send.new(data, @server) end if job @worker << job end end end
123. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(data) job = Jobs.factory(data, @server) if job @worker << job end end end
124. module Jobs class Ping def initialize(data, server) @data = data @server = server end def run @server.send("PONG", @data[1][3], @data[1][1]) end end end
125. Data Clumps C S
126. ["PING", ["AF_INET", 61370, "localhost", "127.0.0.1"]] data[1][3] data[1][1] [ [
127. class Client def initialize(sockaddr) @addrinfo = Addrinfo.new(sockaddr) end def address @addrinfo.ip_address end def port @addrinfo.ip_port end end
128. class UDPServer def initialize(app) @app = app @socket = UDPSocket.new end def listen(port) @socket.bind("0.0.0.0", port) loop { @app.call(receive) } end def receive @socket.recvfrom(4096) end def send(message, address, port) @socket.send(message, 0, address, port) end end
129. class UDPServer def initialize(app) @app = app @socket = UDPSocket.new end def listen(port) @socket.bind("0.0.0.0", port) loop do message, sockaddr = @socket.recvfrom(4096) client = Client.new(sockaddr) @app.call(client, message) end end def send(message, address, port) @socket.send(message, 0, address, port) end end
130. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(data) job = Jobs.factory(data, @server) if job @worker << job end end end
131. Uncommunicative Name C S
132. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(data) job = Jobs.factory(data, @server) if job @worker << job end end end
133. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(client, message) job = Jobs.factory(client, message, @server) if job @worker << job end end end
134. module Jobs class Ping def initialize(client, message, server) @client = client @message = message @server = server end def run @server.send("PONG", @client.address, @client.port) end end end
135. Feature Envy C S
136. Extracted objects tend to attract behavior.
137. class Client def initialize(sockaddr) @addrinfo = Addrinfo.new(sockaddr) end def address @addrinfo.ip_address end def port @addrinfo.ip_port end end
138. class Client def initialize(sockaddr, server) @addrinfo = Addrinfo.new(sockaddr) @server = server end def address @addrinfo.ip_address end def port @addrinfo.ip_port end end
139. class Client def initialize(sockaddr, server) @addrinfo = Addrinfo.new(sockaddr) @server = server end def send(message) @server.send(message, address, port) end def address @addrinfo.ip_address end def port @addrinfo.ip_port end end
140. class UDPServer def initialize(app) @app = app @socket = UDPSocket.new end def listen @socket.bind("0.0.0.0", port) loop do message, sockaddr = @socket.recvfrom(4096) client = Client.new(sockaddr) @app.call(client, message) end end def send(message, address, port) @socket.send(message, 0, address, port) end end
141. class UDPServer def initialize(app) @app = app @socket = UDPSocket.new end def listen @socket.bind("0.0.0.0", port) loop do message, sockaddr = @socket.recvfrom(4096) client = Client.new(sockaddr, self) @app.call(client, message) end end def send(message, address, port) @socket.send(message, 0, address, port) end end
142. module Jobs class Ping def initialize(client, message, server) @client = client @message = message @server = server end def run @server.send("PONG", @client.address, @client.port) end end end
143. module Jobs class Ping def initialize(client, message, server) @client = client @message = message @server = server end def run @client.send("PONG") end end end
144. module Jobs class Ping def initialize(client, message, server) @client = client @message = message @server = server end def run @client.send("PONG") end end end
145. module Jobs class Ping def initialize(client, message) @client = client @message = message end def run @client.send("PONG") end end end
146. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(client, message) job = Jobs.factory(client, message, @server) if job @worker << job end end end
147. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(client, message) job = Jobs.factory(client, message) if job @worker << job end end end
148. module Jobs class Send def self.client @client ||= HTTPClient.new end def initialize(client, message) @client = client @message = message end def run @message[5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) self.class.client.post("https://android.googleapis.com/gcm/send", json, { "Authorization" => "key=AIzaSyCABSTd47XeIH-ERx9rvHUSF9DIJ7DCwdk", "Content-Type" => "application/json" }) end end end
149. Same Name, Different Meaning C S
150. module Jobs class Send def self.client @client ||= HTTPClient.new end def initialize(client, message) @client = client @message = message end def run @message[5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) self.class.client.post("https://android.googleapis.com/gcm/send", json, { "Authorization" => "key=AIzaSyCABSTd47XeIH-ERx9rvHUSF9DIJ7DCwdk", "Content-Type" => "application/json" }) end end end HTTP Client [ Server Client [
151. module Jobs class Send def self.client @client ||= HTTPClient.new end def initialize(client, message) @client = client @message = message end def run @message[5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) json = JSON.generate({ "registration_ids" => [$1], "data" => { "alert" => $2 } }) self.class.client.post("https://android.googleapis.com/gcm/send", json, { "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" }) end end end
152. class PushNotification def self.client @client ||= HTTPClient.new end def initialize(registration_id, alert) @registration_id = registration_id @alert = alert end def deliver self.class.client.post("https://android.googleapis.com/gcm/send", to_json, "Authorization" => "key=AIzaSyCABSTd47XeIH", "Content-Type" => "application/json" ) end def to_json { "registration_ids" => [@registration_id], "data" => { "alert" => @alert } }.to_json end end
153. module Jobs class Send def initialize(client, message) @client = client @message = message end def run @message[5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/) PushNotification.new($1, $2).deliver end end end
154. Primitive Obsession C S
155. We’re using simple data types to represent complex ideas.
156. @message[5..-1].match(/([a-zA-Z0-9_\-]*) "([^"]*)/)
157. COMMAND [parameters]
158. parameter “second parameter”
159. Shellwords
160. class Request def initialize(message) @tokens = Shellwords.split(message) end def command @tokens[0].to_s.upcase end def parameters Array(@tokens[1..-1]) end end
161. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(client, message) job = Jobs.factory(client, message) if job @worker << job end end end
162. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(client, message) request = Request.new(message) job = Jobs.factory(client, request) if job @worker << job end end end
163. module Jobs JOBS = { "PING" => Ping, "SEND" => Send } def self.factory(client, message) command = message.split.first.upcase klass = JOBS[command] if klass klass.new(client, message) end end end
164. module Jobs JOBS = { "PING" => Ping, "SEND" => Send } def self.factory(client, request) klass = JOBS[request.command] if klass klass.new(client, request) end end end
165. module Jobs class Send def initialize(client, request) @client = client @request = request end def run PushNotification.new(registration_id, alert).deliver end private def registration_id @request.parameters[0] end def alert @request.parameters[1] end end end
166. Nil Checks C S
167. module Jobs JOBS = { "PING" => Ping, "SEND" => Send } def self.factory(client, request) klass = JOBS[request.command] if klass klass.new(client, request) end end end Possible nil from hash [
168. class PushDaemon def initialize @server = UDPServer.new(self) @worker = Worker.new end def start @worker.spawn(10) @server.listen(6889) end def call(client, message) request = Request.new(message) job = Jobs.factory(client, request) if job @worker << job end end end Possible nil from factory [
169. nil communicates that an unknown command has been requested
170. Introduce Null Object R f r
171. module Jobs class NullJob def initialize(client, request) end def run end end end
172. module Jobs JOBS = { "PING" => Ping, "SEND" => Send } def self.factory(client, request) klass = JOBS[request.command] if klass klass.new(client, request) end end end
173. module Jobs JOBS = { "PING" => Ping, "SEND" => Send } JOBS.default = NullJob def self.factory(client, request) JOBS[request.command].new(client, request) end end
174. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(client, message) request = Request.new(message) job = Jobs.factory(client, request) if job @worker << job end end end
175. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(client, message) request = Request.new(message) job = Jobs.factory(client, request) @worker << job end end
176. module Jobs class Ping def initialize(client, request) @client = client @request = request end def run @client.send("PONG") end def >>(worker) worker << self end end end
177. module Jobs class NullJob def initialize(client, request) end def run end def >>(worker) end end end
178. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(client, message) request = Request.new(message) job = Jobs.factory(client, request) @worker << job end end
179. class PushDaemon def initialize @worker = Worker.new @server = UDPServer.new(self) end def start @worker.spawn(10) @server.listen(6889) end def call(client, message) request = Request.new(message) job = Jobs.factory(client, request) job >> @worker end end
180. jpignata / mwrc
181. Thanks! @jpignata tx.pignata.com