Merge pull request #53 from lxxxvi/allow-writing-to-STDOUT

Allow writing to stdout

README.md

@@ -12,7 +12,7 @@
 
 Finally it orders the configurations **alphabetically** within these groups.
 
-## Example
+## Main example
 
 ### Input `.rubocop.yml`:
 
@@ -84,28 +84,65 @@ gem install ruboclean
 ## Command synopsis
 
 ```shell
-ruboclean [path] [--silent] [--preserve-comments] [--preserve-paths] [--verify]
+ruboclean [path] \
+  [--output=/path/to/file.yml] \
+  [--silent] \
+  [--preserve-comments] \
+  [--preserve-paths] \
+  [--verify]
 ```
 
 ### Parameters
 
-| Parameter                        | Description                                                                                                                           |
-|:---------------------------------|:--------------------------------------------------------------------------------------------------------------------------------------|
-| `path`                           | Can be a directory that contains a `.rubocop.yml`, or a path to a `.rubocop.yml` directly. Defaults to the current working directory. |
-| `--output=[/path/to/output.yml]` | Output path, where the result is written to. Can be either absolute or relative of the current working directory                      |
-| `--silent`                       | Suppress any output displayed on the screen when executing the command.                                                               |
-| `--preserve-comments`            | Preserves **preceding** comments for each top-level entry in the configuration. Inline comments are **not** preserved.                |
-| `--preserve-paths`               | Skips the path cleanup that are applied against `Include:` and `Exclude:` configuration.                                              |
-| `--verify`                       | Executes in dry-run mode. Exits with 1 if changes are needed, otherwise 0.                                                            |
+#### `path`
 
-### Examples
+Can be a directory that contains a `.rubocop.yml`, or a path to a `.rubocop.yml` directly.
+Defaults to the current working directory.
+
+##### Examples
 
 ```shell
 ruboclean                             # uses `.rubocop.yml` of current working directory
 ruboclean /path/to/dir                # uses `.rubocop.yml` of /path/to/dir
 ruboclean /path/to/dir/.rubocop.yml
 ```
 
+#### `--output=/path/to/file.yml`
+
+Output path where the result is written to.
+Can be absolute or relative to the current working directory.
+`--output=STDOUT` prints it to STDOUT and not to a file.
+
+##### Examples
+
+```shell
+ruboclean --output=/absolute/path.yml
+ruboclean --output=relative/path.yml    # relative to current working directory
+ruboclean --output=STDOUT               # does not write anything to a file
+```
+
+#### `--silent`
+
+Suppress any log output displayed on the screen when executing the command.
+It still prints to STDOUT if used in combination with `--output=STDOUT`.
+
+#### `--preserve-comments`
+
+Preserves **preceding** comments for each top-level entry in the configuration.
+Inline comments are **not** preserved.
+
+See main example above for explanation.
+
+#### `--preserve-paths`
+
+Skips the path cleanup that are applied against `Include:` and `Exclude:` configurations.
+
+See main example above for explanation.
+
+#### `--verify`
+
+Executes in dry-run mode. Exits with `1` if changes are needed, otherwise `0`.
+
 ## Development
 
 After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.

lib/ruboclean.rb

@@ -6,6 +6,7 @@
 require "ruboclean/grouper"
 require "ruboclean/path_cleanup"
 require "ruboclean/runner"
+require "ruboclean/stream_writer"
 require "ruboclean/to_yaml_converter"
 require "ruboclean/version"
 

lib/ruboclean/runner.rb

@@ -16,7 +16,7 @@ def run!
       load_file.then(&method(:order))
                .then(&method(:cleanup_paths))
                .then(&method(:convert_to_yaml))
-               .then(&method(:write_file!))
+               .then(&method(:write_stream!))
                .then(&method(:changed?))
     end
 
@@ -62,12 +62,14 @@ def convert_to_yaml(configuration_hash)
       ToYamlConverter.new(configuration_hash, cli_arguments.preserve_comments?, source_yaml).to_yaml
     end
 
-    def write_file!(target_yaml)
+    def write_stream!(target_yaml)
       target_yaml.tap do |content|
-        target_file_pathname.write(content) unless verify?
+        StreamWriter.new(target_file_pathname, content).write! unless verify?
       end
     end
 
+    # TODO: Find a better place to compute source_file_pathname and target_file_pathname
+    #       Preferrably it should happen early in the lifecycle, as it includes (and raises) argument validations
     def source_file_pathname
       @source_file_pathname ||= find_source_file_pathname
     end

lib/ruboclean/stream_writer.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module Ruboclean
+  # Orders the items within the groups alphabetically
+  class StreamWriter
+    def initialize(target_file_pathname, content)
+      @target_file_pathname = target_file_pathname
+      @content = content
+    end
+
+    def write!
+      if stdout?
+        puts content
+      else
+        target_file_pathname.write(content)
+      end
+    end
+
+    private
+
+    attr_reader :target_file_pathname, :content
+
+    def stdout?
+      target_file_pathname.basename.to_s == "STDOUT"
+    end
+  end
+end

test/ruboclean/runner_test.rb

@@ -104,7 +104,7 @@ def test_run_with_output_argument_absolute_path
     end
 
     def test_run_with_output_argument_relative_path # rubocop:disable Metrics/MethodLength
-      # we need to read it here, because we're leaving the working directory soon
+      # we need to read it here, because we're leaving the working directory (see `Dir.chdir` below)
       expected_target_file_content = fixture_file_path("00_expected_output.yml").read
 
       using_fixture_files("00_input.yml") do |fixture_path|
@@ -124,6 +124,16 @@ def test_run_with_output_argument_relative_path # rubocop:disable Metrics/Method
       end
     end
 
+    def test_run_with_output_argument_stdout
+      using_fixture_files("00_input.yml") do |fixture_path|
+        arguments = [fixture_path, "--output=STDOUT"]
+
+        assert_output(fixture_file_path("00_expected_output.yml").read) do
+          Ruboclean::Runner.new(arguments).run!
+        end
+      end
+    end
+
     def test_run_with_output_argument_overrides_a_file
       using_fixture_files("00_input.yml") do |fixture_path|
         output_pathname = Pathname.new(fixture_path).dirname.join("custom_output_path.yml")

test/ruboclean/stream_writer_test.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+module Ruboclean
+  class StreamWriterTest < BaseTest
+    def test_writes_to_path
+      Tempfile.create do |tmpfile|
+        target_file_pathname = Pathname.new(tmpfile)
+        Ruboclean::StreamWriter.new(target_file_pathname, "magnificent file output").write!
+
+        assert_equal "magnificent file output", target_file_pathname.read
+      end
+    end
+
+    def test_writes_to_stdout
+      target_file_pathname = Pathname.new("STDOUT")
+
+      assert_output("magnificent STDOUT output\n") do
+        Ruboclean::StreamWriter.new(target_file_pathname, "magnificent STDOUT output").write!
+      end
+    end
+  end
+end