[Fix rubocop#5973] Add Style/IpAddresses cop

.rubocop.yml

@@ -29,6 +29,11 @@ Style/FormatStringToken:
   Exclude:
     - spec/**/*
 
+Style/IpAddresses:
+  # The test for this cop includes strings that would cause offenses
+  Exclude:
+  - spec/rubocop/cop/style/ip_addresses_spec.rb
+
 Layout/EndOfLine:
   EnforcedStyle: lf
 

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### New features
 
+* [#5973](https://github.com/bbatsov/rubocop/issues/5973): Add new `Style/IpAddresses` cop. ([@dvandersluis][])
 * [#5843](https://github.com/bbatsov/rubocop/issues/5843): Add configuration options to `Naming/MemoizedInstanceVariableName` cop to allow leading underscores. ([@leklund][])
 * [#5843](https://github.com/bbatsov/rubocop/issues/5843): Add `EnforcedStyleForLeadingUnderscores` to `Naming/MemoizedInstanceVariableName` cop to allow leading underscores. ([@leklund][])
 

config/default.yml

@@ -1139,6 +1139,12 @@ Style/InverseMethods:
     :select: :reject
     :select!: :reject!
 
+Style/IpAddresses:
+  # Allow strings to be whitelisted
+  Whitelist:
+    - "::"
+    # :: is a valid IPv6 address, but could potentially be legitimately in code
+
 Style/Lambda:
   EnforcedStyle: line_count_dependent
   SupportedStyles:

config/disabled.yml

@@ -82,6 +82,10 @@ Style/InlineComment:
   Description: 'Avoid trailing inline comments.'
   Enabled: false
 
+Style/IpAddresses:
+  Description: "Don't include literal IP addresses in code."
+  Enabled: false
+
 Style/MethodCallWithArgsParentheses:
   Description: 'Use parentheses for method calls with arguments.'
   StyleGuide: '#method-invocation-parens'

lib/rubocop.rb

@@ -441,6 +441,7 @@
 require_relative 'rubocop/cop/style/infinite_loop'
 require_relative 'rubocop/cop/style/inverse_methods'
 require_relative 'rubocop/cop/style/inline_comment'
+require_relative 'rubocop/cop/style/ip_addresses'
 require_relative 'rubocop/cop/style/lambda'
 require_relative 'rubocop/cop/style/lambda_call'
 require_relative 'rubocop/cop/style/line_end_concatenation'

lib/rubocop/cop/style/ip_addresses.rb

@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+require 'resolv'
+
+module RuboCop
+  module Cop
+    module Style
+      # This cop checks for hardcoded IP addresses, which can make code
+      # brittle. IP addresses are likely to need to be changed when code
+      # is deployed to a different server or environment, which may break
+      # a deployment if forgotten. Prefer setting IP addresses in ENV or
+      # other configuration.
+      #
+      # @example
+      #
+      #   # bad
+      #   ip_address = '127.59.241.29'
+      #
+      #   # good
+      #   ip_address = ENV['DEPLOYMENT_IP_ADDRESS']
+      class IpAddresses < Cop
+        include StringHelp
+
+        IPV6_MAX_SIZE = 45 # IPv4-mapped IPv6 is the longest
+        MSG = 'Do not hardcode IP addresses.'.freeze
+
+        def offense?(node)
+          contents = node.source[1...-1]
+
+          return false if whitelist.include?(contents.downcase)
+
+          # To try to avoid doing two regex checks on every string,
+          # shortcut out if the string does not look like an IP address
+          return false unless could_be_ip?(contents)
+
+          contents =~ ::Resolv::IPv4::Regex || contents =~ ::Resolv::IPv6::Regex
+        end
+
+        # Dummy implementation of method in ConfigurableEnforcedStyle that is
+        # called from StringHelp.
+        def opposite_style_detected; end
+
+        # Dummy implementation of method in ConfigurableEnforcedStyle that is
+        # called from StringHelp.
+        def correct_style_detected; end
+
+        private
+
+        def whitelist
+          whitelist = cop_config['Whitelist']
+          Array(whitelist).map(&:downcase)
+        end
+
+        def could_be_ip?(str)
+          # If the string is too long, it can't be an IP
+          return false if too_long?(str)
+
+          # If the string doesn't start with a colon or hexadecimal char,
+          # we know it's not an IP address
+          starts_with_hex_or_colon?(str)
+        end
+
+        def too_long?(str)
+          str.size > IPV6_MAX_SIZE
+        end
+
+        def starts_with_hex_or_colon?(str)
+          first_char = str[0].ord
+          (48..58).cover?(first_char) || (65..70).cover?(first_char) ||
+            (97..102).cover?(first_char)
+        end
+      end
+    end
+  end
+end

manual/cops.md

@@ -445,6 +445,7 @@ In the following section you find all available cops:
 * [Style/InfiniteLoop](cops_style.md#styleinfiniteloop)
 * [Style/InlineComment](cops_style.md#styleinlinecomment)
 * [Style/InverseMethods](cops_style.md#styleinversemethods)
+* [Style/IpAddresses](cops_style.md#styleipaddresses)
 * [Style/Lambda](cops_style.md#stylelambda)
 * [Style/LambdaCall](cops_style.md#stylelambdacall)
 * [Style/LineEndConcatenation](cops_style.md#stylelineendconcatenation)

manual/cops_style.md

@@ -2552,6 +2552,34 @@ Name | Default value | Configurable values
 InverseMethods | `{:any?=>:none?, :even?=>:odd?, :===>:!=, :=~=>:!~, :<=>:>=, :>=>:<=}` | 
 InverseBlocks | `{:select=>:reject, :select!=>:reject!}` | 
 
+## Style/IpAddresses
+
+Enabled by default | Supports autocorrection
+--- | ---
+Disabled | No
+
+This cop checks for hardcoded IP addresses, which can make code
+brittle. IP addresses are likely to need to be changed when code
+is deployed to a different server or environment, which may break
+a deployment if forgotten. Prefer setting IP addresses in ENV or
+other configuration.
+
+### Examples
+
+```ruby
+# bad
+ip_address = '127.59.241.29'
+
+# good
+ip_address = ENV['DEPLOYMENT_IP_ADDRESS']
+```
+
+### Configurable attributes
+
+Name | Default value | Configurable values
+--- | --- | ---
+Whitelist | `::` | Array
+
 ## Style/Lambda
 
 Enabled by default | Supports autocorrection

spec/rubocop/cop/style/ip_addresses_spec.rb

@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::Style::IpAddresses, :config do
+  subject(:cop) { described_class.new(config) }
+
+  let(:cop_config) { {} }
+
+  context 'IPv4' do
+    it 'registers an offense for a valid address' do
+      expect_offense(<<-RUBY.strip_indent)
+        '255.255.255.255'
+        ^^^^^^^^^^^^^^^^^ Do not hardcode IP addresses.
+      RUBY
+    end
+
+    it 'does not register an offense for an invalid address' do
+      expect_no_offenses('"578.194.591.059"')
+    end
+
+    it 'does not register an offense for an address inside larger text' do
+      expect_no_offenses('"My IP is 192.168.1.1"')
+    end
+  end
+
+  context 'IPv6' do
+    it 'registers an offense for a valid address' do
+      expect_offense(<<-RUBY.strip_indent)
+        '2001:0db8:85a3:0000:0000:8a2e:0370:7334'
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Do not hardcode IP addresses.
+      RUBY
+    end
+
+    it 'registers an offense for an address with 0s collapsed' do
+      expect_offense(<<-RUBY.strip_indent)
+        '2001:db8:85a3::8a2e:370:7334'
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Do not hardcode IP addresses.
+      RUBY
+    end
+
+    it 'registers an offense for a shortened address' do
+      expect_offense(<<-RUBY.strip_indent)
+        '2001:db8::1'
+        ^^^^^^^^^^^^^ Do not hardcode IP addresses.
+      RUBY
+    end
+
+    it 'registers an offense for a very short address' do
+      expect_offense(<<-RUBY.strip_indent)
+        '1::'
+        ^^^^^ Do not hardcode IP addresses.
+      RUBY
+    end
+
+    it 'registers an offense for the loopback address' do
+      expect_offense(<<-RUBY.strip_indent)
+        '::1'
+        ^^^^^ Do not hardcode IP addresses.
+      RUBY
+    end
+
+    it 'does not register an offense for an invalid address' do
+      expect_no_offenses('"2001:db8::1xyz"')
+    end
+
+    context 'the unspecified address :: (shortform of 0:0:0:0:0:0:0:0)' do
+      it 'does not register an offense' do
+        expect_no_offenses('"::"')
+      end
+
+      context 'when it is removed from the whitelist' do
+        let(:cop_config) { { 'Whitelist' => [] } }
+
+        it 'registers an offense' do
+          expect_offense(<<-RUBY.strip_indent)
+            '::'
+            ^^^^ Do not hardcode IP addresses.
+          RUBY
+        end
+      end
+    end
+  end
+
+  context 'with whitelist' do
+    let(:cop_config) { { 'Whitelist' => ['a::b'] } }
+
+    it 'does not register an offense for a whitelisted address' do
+      expect_no_offenses('"a::b"')
+    end
+
+    it 'does not register an offense if the case differs' do
+      expect_no_offenses('"A::B"')
+    end
+  end
+end