convert to modular Sinatra app

This attempts to fix an issue with the `request.body` not being a
StringIO instance, but wrapped depending on the application server
in use.

For Webrick, the raw request body seems not to be accessible anymore,
which is a shame. Switching to Puma helps a bit, but getting the raw
body still requires accessing an instance variabale from Rack::Lint...

Dockerfile

@@ -24,4 +24,4 @@ COPY . .
 
 EXPOSE 3000
 
-CMD ["bundle", "exec", "ruby", "/app/app.rb"]
+CMD ["bundle", "exec", "rackup", "--host=0.0.0.0", "--port=3000", "--env=production"]

Gemfile

@@ -4,7 +4,7 @@ git_source(:github) { |name| "https://github.com/#{name}.git" }
 
 gem "sinatra"
 gem "sisimai", "~> 5.0.2"
-gem "webrick"
+gem "puma"
 gem "rackup"
 
 group :test do

Gemfile.lock

@@ -6,9 +6,10 @@ GEM
     byebug (11.1.3)
     coderay (1.1.3)
     diff-lcs (1.5.1)
-    method_source (1.0.0)
+    method_source (1.1.0)
     mustermann (3.0.0)
       ruby2_keywords (~> 0.0.1)
+    nio4r (2.7.1)
     oj (3.16.3)
       bigdecimal (>= 3.0)
     pry (0.14.2)
@@ -17,6 +18,8 @@ GEM
     pry-byebug (3.10.1)
       byebug (~> 11.0)
       pry (>= 0.13, < 0.15)
+    puma (6.4.2)
+      nio4r (~> 2.0)
     rack (3.0.10)
     rack-protection (4.0.0)
       base64 (>= 0.1.0)
@@ -58,12 +61,12 @@ PLATFORMS
 
 DEPENDENCIES
   pry-byebug
+  puma
   rack-test
   rackup
   rspec
   sinatra
   sisimai (~> 5.0.2)
-  webrick
 
 BUNDLED WITH
    2.5.6

README.md

@@ -13,7 +13,7 @@ Download the code, install the dependencies and start the server.
 $ git clone https://github.com/digineo/sisimai-web
 $ cd sisimai-web
 $ bundle install
-$ bundle exec ruby app.rb
+$ bundle exec rackup --host 127.0.0.1 --port 3000
 ```
 
 ## Installation with Docker

config.ru

@@ -0,0 +1,2 @@
+require_relative "lib/sisimai_web/app"
+run SisimaiWeb::App

lib/sisimai_web/app.rb

@@ -0,0 +1,38 @@
+require "sinatra"
+require "sisimai"
+require "sisimai/fact"
+require "oj"
+
+require_relative "./classifier"
+
+module SisimaiWeb
+  class App < Sinatra::Application
+    set :host,        "0.0.0.0"
+    set :port,        3001
+    set :environment, "production"
+
+    post "/" do
+      result = SisimaiWeb.classify(raw_body)
+
+      status 200
+      headers "Content-Type" => "application/json"
+      body result.to_json
+    end
+
+    private
+
+    def raw_body
+      body = request.body
+      body = case body
+      when StringIO
+        body
+      when Rack::Lint::Wrapper::InputWrapper
+        body.instance_variable_get(:@input)
+      else
+        raise ArgumentError, "don't know how to access raw body"
+      end
+
+      body.tap(&:rewind).read
+    end
+  end
+end

lib/sisimai_web/classifier.rb

@@ -0,0 +1,20 @@
+require "sisimai"
+require "sisimai/fact"
+
+module SisimaiWeb
+  def self.classify(message)
+    fact = Sisimai::Fact.rise(data: message, vacation: true, delivered: true)&.first
+    return unless fact
+
+    fact.damn.merge("softbounce" => to_softbounce(fact))
+  end
+
+  # Sisimai::Fact has deprecated and will remove #softbounce in v5.1.0.
+  # For backward compatibility we'll keep it though.
+  def self.to_softbounce(fact)
+    return  0 if fact.hardbounce
+    return -1 if %w[delivered feedback vacation].include?(fact.reason)
+
+    1
+  end
+end

spec/spec_helper.rb

@@ -2,13 +2,13 @@
 require "rack/test"
 
 ENV["RACK_ENV"] = "test"
-require_relative "../app.rb"
+require_relative "../lib/sisimai_web/app.rb"
 
 module TestHelper
   include Rack::Test::Methods
 
   def app
-    Sinatra::Application
+    SisimaiWeb::App
   end
 
   def read_fixture(name)