Allow pass the content via stdin

For example:

```
cat test/fixtures/merge.yml | flatito
```

exe/flatito

@@ -6,7 +6,8 @@ require "flatito"
 require "optparse"
 
 # If no arguments are given, print help
-ARGV << "-h" if ARGV.empty?
+stdin = $stdin.read unless $stdin.tty?
+ARGV << "-h" if ARGV.empty? && !stdin
 
 options = {}
 OptionParser.new do |opts|
@@ -43,8 +44,10 @@ OptionParser.new do |opts|
   end
 end.parse!
 
-begin
+Flatito::Config.prepare_with_options(options)
+
+if stdin
+  Flatito.flat_content(stdin, options)
+else
   Flatito.search(ARGV, options)
-rescue Interrupt
-  warn "\nInterrupted"
 end

lib/flatito.rb

@@ -9,9 +9,20 @@
 require_relative "flatito/yaml_with_line_number"
 require_relative "flatito/renderer"
 require_relative "flatito/regex_from_search"
+require_relative "flatito/print_items"
+require_relative "flatito/config"
 
 module Flatito
-  def self.search(paths, options)
-    Finder.new(paths, options).call
+  class << self
+    def search(paths, options = {})
+      Finder.new(paths, options).call
+    rescue Interrupt
+      warn "\nInterrupted"
+    end
+
+    def flat_content(content, options = {})
+      items = FlattenYaml.items_from_content(content)
+      PrintItems.call(options[:search], items)
+    end
   end
 end

lib/flatito/config.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module Flatito
+  module Config
+    @stdout = $stdout
+    @stderr = $stderr
+    @stdin  = $stdin
+
+    class << self
+      attr_accessor :renderer, :stdout, :stder, :stdin
+
+      def prepare_with_options(options)
+        self.renderer = Renderer.build(options)
+      end
+    end
+  end
+end

lib/flatito/finder.rb

@@ -8,14 +8,13 @@ class Finder
 
     DEFAULT_EXTENSIONS = %w[json yml yaml].freeze
 
-    attr_reader :paths, :search, :extensions, :options, :renderer
+    attr_reader :paths, :search, :extensions, :options
 
     def initialize(paths, options = {})
       @paths = paths
       @search = options[:search]
       @extensions = prepare_extensions(options[:extensions] || DEFAULT_EXTENSIONS)
       @options = options
-      @renderer = Renderer.build(options)
     end
 
     def call
@@ -36,14 +35,13 @@ def call
 
     private
 
-    def flat_and_filter(pathname)
-      items = FlattenYaml.new(pathname).items
-      items = filter_by_search(items) if search
-
-      return unless items.any?
+    def renderer
+      Config.renderer
+    end
 
-      renderer.print_pathname(pathname)
-      renderer.print_items(items)
+    def flat_and_filter(pathname)
+      items = FlattenYaml.items_from_path(pathname)
+      PrintItems.call(search, items, pathname)
     end
 
     def prepare_extensions(extensions)

lib/flatito/flatten_yaml.rb

@@ -3,8 +3,21 @@
 module Flatito
   class FlattenYaml
     Item = Struct.new(:key, :value, :line, keyword_init: true)
-    def initialize(pathname)
-      @pathname = pathname
+    class << self
+      def items_from_path(pathname)
+        content = File.read(pathname)
+        new(content).items
+      end
+
+      def items_from_content(content)
+        new(content).items
+      end
+    end
+
+    attr_reader :content
+
+    def initialize(content)
+      @content = content
     end
 
     def items
@@ -31,7 +44,7 @@ def with_line_numbers
       handler = YAMLWithLineNumber::TreeBuilder.new
       handler.parser = Psych::Parser.new(handler)
 
-      handler.parser.parse(File.read(@pathname))
+      handler.parser.parse(content)
       YAMLWithLineNumber::VisitorsToRuby.create.accept(handler.root)
     rescue Psych::SyntaxError
       warn "Invalid YAML #{@pathname}"

lib/flatito/print_items.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module Flatito
+  class PrintItems
+    def self.call(search, items, pathname = nil)
+      items = filter_by_search(items) if search
+      return unless items.any?
+
+      renderer.print_pathname(pathname) if pathname
+      renderer.print_items(items)
+    end
+
+    def self.renderer
+      Config.renderer
+    end
+  end
+end

lib/flatito/renderer.rb

@@ -8,16 +8,12 @@ class Renderer
     include RegexFromSearch
 
     def self.build(options)
-      if tty?
+      if Config.stdout.tty?
         Renderer::TTY.new(options)
       else
         Renderer::Plain.new(options)
       end
     end
-
-    def self.tty?
-      $stdout.tty?
-    end
   end
 
   class Base
@@ -33,7 +29,7 @@ def print_file_progress(pathname); end
     def ending; end
 
     def print_pathname(pathname)
-      puts colorize(pathname.to_s, :light_blue)
+      stdout.puts colorize(pathname.to_s, :light_blue)
     end
 
     def print_items(items)
@@ -42,8 +38,8 @@ def print_items(items)
       items.each do |item|
         print_item(item, line_number_padding)
       end
-      puts
-      flush
+      stdout.puts
+      stdout.flush
     end
 
     def print_item(item, line_number_padding)
@@ -54,15 +50,11 @@ def print_item(item, line_number_padding)
                 ""
               end
 
-      puts "#{line_number} #{matched_string(item.key)} #{value}"
+      stdout.puts "#{line_number} #{matched_string(item.key)} #{value}"
     end
 
     private
 
-    def flush
-      stdout.flush
-    end
-
     def regex
       @regex ||= Regexp.new(search)
     end
@@ -85,7 +77,7 @@ def truncate(string, max = 50)
     end
 
     def stdout
-      $stdout
+      Config.stdout
     end
 
     def colorize(string, color)
@@ -95,7 +87,7 @@ def colorize(string, color)
 
   class Renderer::Plain < Base
     def ending
-      puts
+      stdout.puts
     end
   end
 
@@ -128,19 +120,19 @@ def print_pathname(pathname)
     def ending
       clear_line
       show_cursor
-      puts
+      stdout.puts
     end
 
     def hide_cursor
-      print HIDE_CURSOR
+      stdout.print HIDE_CURSOR
     end
 
     def show_cursor
-      print SHOW_CURSOR
+      stdout.print SHOW_CURSOR
     end
 
     def clear_line
-      print CLEAR_LINE
+      stdout.print CLEAR_LINE
     end
 
     private

test/flatito/config_test.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class Flatito::ConfigTest < Minitest::Test
+  class DummyTTY < StringIO
+    def tty?
+      true
+    end
+  end
+
+  class DummyNotTTY < StringIO
+    def tty?
+      false
+    end
+  end
+
+  test "when stdout is tty set renderer as tty" do
+    Flatito::Config.stdout = DummyTTY.new
+    Flatito::Config.prepare_with_options({})
+
+    assert_kind_of Flatito::Renderer::TTY, Flatito::Config.renderer
+  end
+
+  test "when stdout is not tty set renderer as plain" do
+    Flatito::Config.stdout = DummyNotTTY.new
+    Flatito::Config.prepare_with_options({})
+
+    assert_kind_of Flatito::Renderer::Plain, Flatito::Config.renderer
+  end
+end

test/flatito/flatten_yaml_test.rb

@@ -4,7 +4,7 @@
 
 class Flatito::FlattenYamlTest < Minitest::Test
   test "a json" do
-    items = Flatito::FlattenYaml.new("test/fixtures/a.json").items
+    items = Flatito::FlattenYaml.items_from_path("test/fixtures/a.json")
 
     assert_equal 5, items.size
     assert_equal "one", items[0].key
@@ -13,7 +13,7 @@ class Flatito::FlattenYamlTest < Minitest::Test
   end
 
   test "no nested" do
-    items = Flatito::FlattenYaml.new("test/fixtures/no_nested.yml").items
+    items = Flatito::FlattenYaml.items_from_path("test/fixtures/no_nested.yml")
 
     assert_equal 3, items.size
     assert_equal "one", items[0].key
@@ -22,7 +22,7 @@ class Flatito::FlattenYamlTest < Minitest::Test
   end
 
   test "nested" do
-    items = Flatito::FlattenYaml.new("test/fixtures/nested.yml").items
+    items = Flatito::FlattenYaml.items_from_path("test/fixtures/nested.yml")
 
     assert_equal 3, items.size
     assert_equal "nested1.one", items[0].key
@@ -39,7 +39,7 @@ class Flatito::FlattenYamlTest < Minitest::Test
   end
 
   test "with merging hashes" do
-    items = Flatito::FlattenYaml.new("test/fixtures/merge.yml").items
+    items = Flatito::FlattenYaml.items_from_path("test/fixtures/merge.yml")
 
     assert_equal 3, items.size
 
@@ -57,7 +57,7 @@ class Flatito::FlattenYamlTest < Minitest::Test
   end
 
   test "multiline values" do
-    items = Flatito::FlattenYaml.new("test/fixtures/multiline.yml").items
+    items = Flatito::FlattenYaml.items_from_path("test/fixtures/multiline.yml")
 
     assert_equal "en.long_message", items[0].key
     assert_equal 2, items[0].line
@@ -67,12 +67,22 @@ class Flatito::FlattenYamlTest < Minitest::Test
   end
 
   test "with ruby objects" do
-    items = Flatito::FlattenYaml.new("test/fixtures/with_ruby_objects.yml").items
+    items = Flatito::FlattenYaml.items_from_path("test/fixtures/with_ruby_objects.yml")
 
     assert_equal 3, items.size
 
     assert_equal "two", items[1].key
     assert_equal "[object: OpenStruct]", items[1].value
     assert_equal 2, items[1].line
   end
+
+  test "items from content with duplicated keys" do
+    content = File.read("test/fixtures/no_nested.yml")
+    items = Flatito::FlattenYaml.items_from_content(content)
+
+    assert_equal 3, items.size
+    assert_equal "one", items[0].key
+    assert_equal "One", items[0].value
+    assert_equal 1, items[0].line
+  end
 end