Add Slack::Messages::Formatting#escape (#454)

Author: marfoldi

CHANGELOG.md

@@ -1,6 +1,7 @@
 ### 2.2.0 (Next)
 
 * Your contribution here.
+* [#454](https://github.com/slack-ruby/slack-ruby-client/pull/454): Added `Slack::Messages::Formatting#escape` - [@marfoldi](https://github.com/marfoldi).
 * [#452](https://github.com/slack-ruby/slack-ruby-client/pull/452): Automatically generate Web API multi-argument requirements from docs - [@jmanian](https://github.com/jmanian).
 * [#448](https://github.com/slack-ruby/slack-ruby-client/pull/448), [#453](https://github.com/slack-ruby/slack-ruby-client/pull/453): Automatically convert more Web API arguments to JSON-encoded strings - [@jmanian](https://github.com/jmanian).
 

README.md

@@ -585,7 +585,7 @@ The `verify!` call may raise `Slack::Events::Request::MissingSigningSecret`, `Sl
 
 ### Message Parsing
 
-All text in Slack uses the same [system of escaping](https://api.slack.com/docs/formatting): chat messages, direct messages, file comments, etc. Use [Slack::Messages::Formatting](lib/slack/messages/formatting.rb) to unescape incoming messages. This comes handy, for example, you want to treat all input to a real time bot as plain text.
+All text in Slack uses the same [system of escaping](https://api.slack.com/docs/formatting): chat messages, direct messages, file comments, etc. Use [Slack::Messages::Formatting](lib/slack/messages/formatting.rb) to escape or unescape messages. This comes handy, for example, you want to treat all input to a real time bot as plain text.
 
 ```ruby
 Slack::Messages::Formatting.unescape('Hello & <world>'))
@@ -610,6 +610,12 @@ Slack::Messages::Formatting.unescape('‘hello’'))
   # => "'hello'"
 ```
 
+
+```ruby
+Slack::Messages::Formatting.escape('Hello & <world>')
+  # => 'Hello &amp; &lt;world&gt;'
+```
+
 ### Command-Line Client
 
 The slack command-line client returns JSON data from the Slack API.

lib/slack/messages/formatting.rb

@@ -24,6 +24,17 @@ def unescape(message)
               end
             end)
         end
+
+        #
+        # Escape a message.
+        # @see https://api.slack.com/reference/surfaces/formatting#escaping
+        #
+        def escape(message)
+          message
+            .gsub('&', '&')
+            .gsub('>', '>')
+            .gsub('<', '&lt;')
+        end
       end
     end
   end

spec/slack/messages/formatting_spec.rb

@@ -61,4 +61,14 @@
       expect(formatting.unescape('‘hello’')).to eq "'hello'"
     end
   end
+
+  context '#escape' do
+    it 'plain text' do
+      expect(formatting.escape('plain text')).to eq 'plain text'
+    end
+
+    it 'escapes a message' do
+      expect(formatting.escape('Hello & <world>')).to eq 'Hello &amp; &lt;world&gt;'
+    end
+  end
 end