improved raw mqtt parser that converts directly to the usual 'full' j…

…son representation

app/grammars/raw_message.tt

@@ -2,31 +2,47 @@ grammar RawMessage
   rule message
     '{' message_body '}' {
       def to_hash
-        message_body.to_hash
+        { data: [ message_body.to_hash ] }
       end
     }
   end
 
   rule message_body
     (pairs:pair*) {
       def to_hash
-        pairs.elements.inject({}) {|m, p| m.merge(p.to_hash) }
+        pairs.elements.inject({ recorded_at: nil, sensors: [] }) { |accum, pair_node|
+          pair = pair_node.to_value
+          if pair[:key] == :t
+            accum.merge(recorded_at: pair[:value])
+          else
+            new_sensors_list = accum[:sensors] + [{id: pair[:key], value: pair[:value]}]
+            accum.merge(sensors: new_sensors_list)
+          end
+        }
       end
     }
   end
 
   rule pair
-    key ':' value (','?) {
-      def to_hash
-        { key.to_sym => value.to_number }
+    pair:(timestamp_pair / value_pair) ","? {
+      def to_value
+        pair.to_value
+      end
+    }
+  end
+
+  rule timestamp_pair
+    't:' timestamp {
+      def to_value
+        { key: :t, value: timestamp.text_value }
       end
     }
   end
 
-  rule key
-    key:(number / 't') {
-      def to_sym
-        key.text_value.to_sym
+  rule value_pair
+    number ':' value {
+      def to_value
+         { key: number.text_value, value: value.text_value }
       end
     }
   end
@@ -37,21 +53,30 @@ grammar RawMessage
 
   rule float
     float:(number decimal_part) {
-      def to_number
-        float.text_value.to_f
+      def to_value
+        float.text_value
       end
     }
   end
 
   rule number
-    number:[0-9]+ {
-      def to_number
-        number.text_value.to_i
+    number:[\-0-9]+ {
+      def to_value
+        number.text_value
       end
     }
   end
 
   rule decimal_part
     '.' number
   end
+
+  rule timestamp
+    timestamp:([0-9] 4..4 '-' [0-9] 2..2 '-' [0-9] 2..2 'T' [0-9] 2..2 ':' [0-9] 2..2 ':' [0-9] 2..2 'Z') {
+      def to_value
+        Time.parse(timestamp.text_value)
+      end
+    }
+  end
+
 end

app/lib/raw_mqtt_message_parser.rb

@@ -6,7 +6,7 @@ def initialize
   end
 
   def parse(message)
-    parser.parse(self.convert_to_ascii(message)).to_hash
+    parser.parse(self.convert_to_ascii(message))&.to_hash
   end
 
   private