add gem-stat command … (#1707)

thanks to @dannytatom for the original gem-stats rubygems plugin, which
inspired this Pry command.

it returns some general statistics about a rubygem when given a name.
note that rubygems rate limits the requests, and thanks to that this
command can be a "Fail Whale" although the error is handled gracefully.

This commit depends on pull request:
https://github.com/pry/pry/pull/1701

CHANGELOG.md

@@ -1,7 +1,12 @@
-### 0.11.3
+### HEAD
 
 #### Features
 
+* Add a new command, "gem-stat", inspired by the rubygem of a similar
+  name (gem-stats) by [@dannytatom](https://github.com/dannytatom).
+
+See pull request [#1705](https://github.com/pry/pry/pull/1705].
+
 * Add Pry::Platform#known_engines, returns an Array of Ruby engines
   (MRI, JRuby, Rubinius) that Pry is known to run on.
 
@@ -13,6 +18,18 @@ See pull request [#1694](https://github.com/pry/pry/pull/1694).
 
 See pull request [#1701](https://github.com/pry/pry/pull/1701).
 
+#### Pry developers
+
+* Optionally skip a spec on specific Ruby engine(s) by providing `expect_failure: [:mri, :jruby]`
+  as a metadata Hash to the example group.
+
+See pull request [#1694](https://github.com/pry/pry/pull/1694).
+
+
+### 0.11.3
+
+#### Features
+
 * Add Pry::Testable, an improved modular replacement for PryTestHelpers.
   **breaking change**.
 
@@ -56,13 +73,6 @@ See pull request [#1691](https://github.com/pry/pry/pull/1691).
 See pull request [#1674](https://github.com/pry/pry/pull/1674).
 
 
-#### Pry developers
-
-* Optionally skip a spec on specific Ruby engine(s) by providing `expect_failure: [:mri, :jruby]`
-  as a metadata Hash to the example group.
-
-See pull request [#1694](https://github.com/pry/pry/pull/1694).
-
 ### 0.11.0
 
 * Add alias 'whereami[?!]+' for 'whereami' command. ([#1597](https://github.com/pry/pry/pull/1597))

lib/pry/commands/gem_stats.rb

@@ -0,0 +1,81 @@
+class Pry::Command::GemStat < Pry::ClassCommand
+  require 'json'
+  require 'net/http'
+  STAT_HOST = "rubygems.org"
+  STAT_PORT = 443
+  STAT_PATH = "/api/v1/gems/%s.json"
+  FAIL_WHALE = <<-FAILWHALE
+W     W      W
+W        W  W     W
+              '.  W
+  .-""-._     \ \.--|
+ /       "-..__) .-'
+|     _         /
+\'-.__,   .__.,'
+ `'----'._\--'
+VVVVVVVVVVVVVVVVVVVVV
+FAILWHALE
+
+  match 'gem-stat'
+  description 'Show the statistics of a gem (requires internet connection)'
+  group 'Gems'
+  command_options argument_required: true
+  banner <<-BANNER
+    gem-stats name
+
+    Show the statistics of a gem.
+    Requires an internet connection.
+  BANNER
+
+  def process(name)
+    client = Net::HTTP.start STAT_HOST, STAT_PORT, use_ssl: true
+    res = client.get STAT_PATH % URI.encode_www_form_component(name)
+    case res
+    when Net::HTTPOK
+      _pry_.pager.page format_gem(JSON.parse(res.body))
+    when Net::HTTPServiceUnavailable
+      _pry_.pager.page <<-FAILURE
+#{bright_blue(FAIL_WHALE)}
+#{bright_red('Ruby On Rails')}
+#{bright_red('Net::HTTPServiceUnavailable')}
+      FAILURE
+    else
+      raise Pry::CommandError, "Bad response (#{res.class})"
+    end
+  ensure
+    client.finish if client
+  end
+
+  private
+  def format_gem(h)
+    h = Pry::Config.from_hash(h, nil)
+    format_str = unindent <<-FORMAT
+    %{name} %{version}
+    --
+    Total Downloads   : %{downloads}
+    Version Downloads : %{version_downloads}
+
+    #{red('Dependencies')} (runtime)
+    --
+    %{rdependencies}
+
+    #{red('Dependencies')} (development)
+    %{ddependencies}
+    FORMAT
+    format_str % {name: green(h.name),
+                  version: bold("v#{h.version}"),
+                  downloads: h.downloads,
+                  version_downloads: h.version_downloads,
+                  rdependencies: format_dependencies(h.dependencies.runtime),
+                  ddependencies: format_dependencies(h.dependencies.development)}
+  end
+
+  def format_dependencies(rdeps)
+    rdeps.empty? ?
+      bold("None") :
+      with_line_numbers(rdeps.map {|h|
+        "%{name} (%{requirements})" % {name: h["name"], requirements: h["requirements"]}
+      }.join($/), 1, :bold)
+  end
+  Pry::Commands.add_command(self)
+end