Tweaks to DecimalField

rest_framework/fields.py

@@ -521,7 +521,12 @@ class DecimalField(Field):
         return value
 
     def to_representation(self, value):
-        if isinstance(value, decimal.Decimal):
+        if value in (None, ''):
+            return None
+
+        if not isinstance(value, decimal.Decimal):
+            value = decimal.Decimal(value)
+
         context = decimal.getcontext().copy()
         context.prec = self.max_digits
         quantized = value.quantize(
@@ -532,10 +537,6 @@ class DecimalField(Field):
             return quantized
         return '{0:f}'.format(quantized)
 
-        if not self.coerce_to_string:
-            return value
-        return '%.*f' % (self.max_decimal_places, value)
-
 
 # Date & time fields...