Add example in ruby (#11717)

examples directory was missing an example in ruby, this PR aims to fix this.

Closes #11717

COPYBARA_INTEGRATE_REVIEW=https://github.com/protocolbuffers/protobuf/pull/11717 from mlitwiniuk:ruby_example 14a5d1a34a
PiperOrigin-RevId: 514756892

examples/Makefile

@@ -10,11 +10,12 @@ go:     add_person_go     list_people_go
 gotest: add_person_gotest list_people_gotest
 java:   add_person_java   list_people_java
 python: add_person_python list_people_python
+ruby:   add_person_ruby   list_people_ruby
 
 clean:
-	rm -f add_person_cpp list_people_cpp add_person_java list_people_java add_person_python list_people_python
+	rm -f add_person_cpp list_people_cpp add_person_java list_people_java add_person_python list_people_python add_person_ruby list_people_ruby
 	rm -f javac_middleman AddPerson*.class ListPeople*.class com/example/tutorial/protos/*.class
-	rm -f protoc_middleman addressbook.pb.cc addressbook.pb.h addressbook_pb2.py com/example/tutorial/protos/*.java
+	rm -f protoc_middleman protoc_middleman_ruby addressbook.pb.cc addressbook.pb.h addressbook_pb2.py addressbook_pb.rb com/example/tutorial/protos/*.java
 	rm -f *.pyc
 	rm -f go/tutorialpb/*.pb.go add_person_go list_people_go
 	rm -f protoc_middleman_dart dart_tutorial/*.pb*.dart
@@ -39,6 +40,10 @@ protoc_middleman_dart: addressbook.proto
 	pub get
 	@touch protoc_middleman_dart
 
+protoc_middleman_ruby: addressbook.proto
+	protoc $$PROTO_PATH --ruby_out=. addressbook.proto
+	@touch protoc_middleman_ruby
+
 add_person_cpp: add_person.cc protoc_middleman
 	pkg-config --cflags protobuf  # fails if protobuf is not installed
 	c++ -std=c++14 add_person.cc addressbook.pb.cc -o add_person_cpp `pkg-config --cflags --libs protobuf`
@@ -90,3 +95,15 @@ list_people_python: list_people.py protoc_middleman
 	@echo '#! /bin/sh' > list_people_python
 	@echo './list_people.py "$$@"' >> list_people_python
 	@chmod +x list_people_python
+
+add_person_ruby: add_person.rb protoc_middleman_ruby
+	@echo "Writing shortcut script add_person_ruby..."
+	@echo '#! /bin/sh' > add_person_ruby
+	@echo './add_person.rb "$$@"' >> add_person_ruby
+	@chmod +x add_person_ruby
+
+list_people_ruby: list_people.rb protoc_middleman_ruby
+	@echo "Writing shortcut script list_people_ruby..."
+	@echo '#! /bin/sh' > list_people_ruby
+	@echo './list_people.rb "$$@"' >> list_people_ruby
+	@chmod +x list_people_ruby

examples/add_person.rb

@@ -0,0 +1,77 @@
+#! /usr/bin/env ruby
+
+# See README.md for information and build instructions.
+
+require './addressbook_pb'
+require 'pry'
+
+# creates Person object and fills it with data from user input
+def prompt_for_address()
+  person = Tutorial::Person.newlD()
+
+  puts "Enter person ID number:"
+  person.id = STDIN.gets.chomp.to_i
+  puts "Enter name:"
+  person.name = STDIN.gets.chomp
+
+  puts "Enter email address (blank for none):"
+  email = STDIN.gets.chomp
+
+  if email != ""
+    person.email = email
+  end
+
+  loop do
+    puts "Enter a phone number (or leave blank to finish):"
+    number = STDIN.gets.chomp
+
+    if number == ""
+      break
+    end
+
+    phone_number = Tutorial::Person::PhoneNumber.new(number: number)
+    puts "Is this a mobile, home or work phone?"
+    type = STDIN.gets.chomp
+
+    case type
+    when "mobile"
+      phone_number.type = :MOBILE
+    when "home"
+      phone_number.type = :HOME
+    when "work"
+      phone_number.type = :WORK
+    else
+      puts "Unknown phone type; leaving as default value."
+    end
+    person.phones.push(phone_number)
+  end
+  person
+end
+
+# Main procedure:  Reads the entire address book from a file,
+#   adds one person based on user input, then writes it back out to the same
+#   file.
+if ARGV.length != 1
+  puts "Usage: #{$0} ADDRESS_BOOK_FILE"
+  exit(-1)
+end
+
+address_book = Tutorial::AddressBook.new()
+if File.exist?(ARGV[0])
+  # Read the existing address book if it exists
+  f = File.open(ARGV[0], "rb")
+  address_book = Tutorial::AddressBook.decode(f.read)
+  f.close
+else
+  puts "#{$PROGRAM_NAME}: File not found. Creating new file."
+end
+
+person = prompt_for_address
+
+# Add an address.
+address_book.people.push(person)
+
+# Write the new address book back to disk.
+f = File.open(ARGV[0], "wb")
+f.write(Tutorial::AddressBook.encode(address_book))
+f.close

examples/list_people.rb

@@ -0,0 +1,42 @@
+#! /usr/bin/env ruby
+
+require './addressbook_pb'
+require 'pry'
+
+# Iterates though all people in the AddressBook and prints info about them.
+def list_people(address_book)
+  address_book.people.each do |person|
+    puts "Person ID: #{person.id}"
+    puts "  Name: #{person.name}"
+    if person.email != ""
+      puts "  Email: #{person.email}"
+    end
+
+    person.phones.each do |phone_number|
+      type =
+        case phone_number.type
+        when :MOBILE
+          "Mobile phone"
+        when :HOME
+          "Home phone"
+        when :WORK
+          "Work phone"
+        end
+      puts "  #{type} #: #{phone_number.number}"
+    end
+  end
+end
+
+# Main procedure:  Reads the entire address book from a file and prints all
+#   the information inside.
+if ARGV.length != 1
+  puts "Usage: #{$PROGRAM_NAME} ADDRESS_BOOK_FILE"
+  exit(-1)
+end
+
+# Read the existing address book.
+f = File.open(ARGV[0], "rb")
+address_book = Tutorial::AddressBook.decode(f.read)
+f.close
+
+list_people(address_book)