Add support for preprocessed JSON strings (with optimizations) in encoder

In some situations, you may have a large python dictionary you need to JSONify but one of the values inside the dict is already a JSON string. This is common when pulling an object from a database, for example, where one of the fields is a JSON blob/string. Previously you would have to deserialize and then reserialize that string just to serialize the high level object, but obviously this is unnecessarily slow. This changes adds a method/type that can be used to wrap a str and tell the serializer to just pass it through instead.

1 files changed, 10 insertions, 0 deletions

diff --git a/simplejson/encoder.py b/simplejson/encoder.py
index 5b9bda7..9a4c0c5 100644
--- a/simplejson/encoder.py
+++ b/simplejson/encoder.py
@@ -39,6 +39,10 @@ for i in [0x2028, 0x2029]:
 
 FLOAT_REPR = repr
 
+class RawJSON(object):
+    def __init__(self, encoded_json):
+        self.encoded_json = encoded_json
+
 def encode_basestring(s, _PY3=PY3, _q=u('"')):
     """Return a JSON representation of a Python string
 
@@ -464,6 +468,8 @@ def _make_iterencode(markers, _default, _encoder, _indent, _floatstr,
             if (isinstance(value, string_types) or
                 (_PY3 and isinstance(value, binary_type))):
                 yield buf + _encoder(value)
+            elif isinstance(value, RawJSON):
+                yield buf + value.encoded_json
             elif value is None:
                 yield buf + 'null'
             elif value is True:
@@ -582,6 +588,8 @@ def _make_iterencode(markers, _default, _encoder, _indent, _floatstr,
             if (isinstance(value, string_types) or
                 (_PY3 and isinstance(value, binary_type))):
                 yield _encoder(value)
+            elif isinstance(value, RawJSON):
+                yield value.encoded_json
             elif value is None:
                 yield 'null'
             elif value is True:
@@ -624,6 +632,8 @@ def _make_iterencode(markers, _default, _encoder, _indent, _floatstr,
         if (isinstance(o, string_types) or
             (_PY3 and isinstance(o, binary_type))):
             yield _encoder(o)
+        elif isinstance(o, RawJSON):
+            buf + o.encoded_json
         elif o is None:
             yield 'null'
         elif o is True: