Add to_json method to messages, don't freeze it anymore

lib/rackstash/message.rb

@@ -42,11 +42,6 @@ module Rackstash
       @time = dup_freeze(time)
       @progname = dup_freeze(progname)
       @formatter = formatter
-
-      # Freeze the newly created message to ensure it can't be changed.
-      # All passed values are also effectively frozen, making the Message an
-      # immutable object.
-      freeze
     end
 
     def severity_label
@@ -56,8 +51,14 @@ module Rackstash
     def to_s
       cleanup @formatter.call(severity_label, @time, @progname, @message)
     end
-    alias_method :to_str, :to_s
-    alias_method :as_json, :to_s
+
+    alias :as_json :to_s
+    # Messages are implicitly conversible to Strings
+    alias :to_str :to_s
+
+    def to_json
+      as_json.to_json
+    end
 
     private
 

spec/rackstash/message_spec.rb

@@ -180,11 +180,24 @@ describe Rackstash::Message do
       expect(message.to_s).to eql '#<StandardError: An error>'
     end
 
-  end
+    it 'is aliased to to_str' do
+      message = Rackstash::Message.new('hello world')
+      expect(message.to_str).to eql 'hello world'
+    end
 
-  describe '#frozen?' do
-    it 'is always true' do
-      expect(Rackstash::Message.new('Beep boop')).to be_frozen
+    it 'is aliased to as_json' do
+      message = Rackstash::Message.new('hello world')
+      expect(message.as_json).to eql 'hello world'
     end
   end
+
+  it 'formats the message as JSON' do
+    message = Rackstash::Message.new('hello world')
+    as_json = 'hello world'
+
+    expect(message).to receive(:as_json).and_return(as_json)
+    expect(as_json).to receive(:to_json).and_return('"json string"')
+
+    expect(message.to_json).to eql '"json string"'
+  end
 end