I convert python dicts with simplejson, but I'd like to customise the output for some defined keys.
for example, I'd like the keys callback and scope to be always rendered with no surrounding quotes so the javascript can interpret the data and not read it as a string.
example desired output :
"data":{
"name":"Julien"
,"callback":function() {alert('hello, world');}
,"params":{
"target":"div2"
,"scope":this
}
}
Notice the callback and scope keys have no surrounding quotes in their values.
I've tried create a custom class and subclass JSONencoder with no luck.
class JsonSpecialKey(object):
def __init__(self, data):
self.data = data
class JsonSpecialEncoder(simplejson.JSONEncoder):
def default(self, obj):
if isinstance (obj, JsonSpecialKey):
# how to remove quotes ??
return obj.data
return simplejson.JSONEncoder.default(self, obj)
d = {'testKey':JsonSpecialKey('function() {alert(123);}')}
print simplejson.dumps(d, cls=JsonSpecialEncoder, ensure_ascii=False, indent=4)
I know the resulting JSON may be invalid in the JSON recommendations but it is important to some JS applications.
I've tried some regex workarounds but it's getting complex for multilines and inline functions with data inside.
Thank you !
I succeed by modifying json code
import json
from json.encoder import encode_basestring_ascii ,encode_basestring,FLOAT_REPR,INFINITY,c_make_encoder
class JsonSpecialKey(object):
def __init__(self, data):
self.data = data
def _make_iterencode(markers, _default, _encoder, _indent, _floatstr,
_key_separator, _item_separator, _sort_keys, _skipkeys, _one_shot,
## HACK: hand-optimized bytecode; turn globals into locals
ValueError=ValueError,
dict=dict,
float=float,
id=id,
int=int,
isinstance=isinstance,
list=list,
str=str,
tuple=tuple,
):
if _indent is not None and not isinstance(_indent, str):
_indent = ' ' * _indent
def _iterencode_list(lst, _current_indent_level):
if not lst:
yield '[]'
return
if markers is not None:
markerid = id(lst)
if markerid in markers:
raise ValueError("Circular reference detected")
markers[markerid] = lst
buf = '['
if _indent is not None:
_current_indent_level += 1
newline_indent = '\n' + _indent * _current_indent_level
separator = _item_separator + newline_indent
buf += newline_indent
else:
newline_indent = None
separator = _item_separator
first = True
for value in lst:
if first:
first = False
else:
buf = separator
if isinstance(value, str):
yield buf + _encoder(value)
elif value is None:
yield buf + 'null'
elif value is True:
yield buf + 'true'
elif value is False:
yield buf + 'false'
elif isinstance(value, int):
yield buf + str(value)
elif isinstance(value, float):
yield buf + _floatstr(value)
elif isinstance(value, JsonSpecialKey):
yield buf + value.data
else:
yield buf
if isinstance(value, (list, tuple)):
chunks = _iterencode_list(value, _current_indent_level)
elif isinstance(value, dict):
chunks = _iterencode_dict(value, _current_indent_level)
else:
chunks = _iterencode(value, _current_indent_level)
for chunk in chunks:
yield chunk
if newline_indent is not None:
_current_indent_level -= 1
yield '\n' + _indent * _current_indent_level
yield ']'
if markers is not None:
del markers[markerid]
def _iterencode_dict(dct, _current_indent_level):
if not dct:
yield '{}'
return
if markers is not None:
markerid = id(dct)
if markerid in markers:
raise ValueError("Circular reference detected")
markers[markerid] = dct
yield '{'
if _indent is not None:
_current_indent_level += 1
newline_indent = '\n' + _indent * _current_indent_level
item_separator = _item_separator + newline_indent
yield newline_indent
else:
newline_indent = None
item_separator = _item_separator
first = True
if _sort_keys:
items = sorted(dct.items(), key=lambda kv: kv[0])
else:
items = dct.items()
for key, value in items:
if isinstance(key, str):
pass
# JavaScript is weakly typed for these, so it makes sense to
# also allow them. Many encoders seem to do something like this.
elif isinstance(key, float):
key = _floatstr(key)
elif key is True:
key = 'true'
elif key is False:
key = 'false'
elif key is None:
key = 'null'
elif isinstance(key, int):
key = str(key)
elif _skipkeys:
continue
else:
raise TypeError("key " + repr(key) + " is not a string")
if first:
first = False
else:
yield item_separator
yield _encoder(key)
yield _key_separator
if isinstance(value, str):
yield _encoder(value)
elif value is None:
yield 'null'
elif value is True:
yield 'true'
elif value is False:
yield 'false'
elif isinstance(value, int):
yield str(value)
elif isinstance(value, float):
yield _floatstr(value)
elif isinstance(value, JsonSpecialKey):
yield value.data
else:
if isinstance(value, (list, tuple)):
chunks = _iterencode_list(value, _current_indent_level)
elif isinstance(value, dict):
chunks = _iterencode_dict(value, _current_indent_level)
else:
chunks = _iterencode(value, _current_indent_level)
for chunk in chunks:
yield chunk
if newline_indent is not None:
_current_indent_level -= 1
yield '\n' + _indent * _current_indent_level
yield '}'
if markers is not None:
del markers[markerid]
def _iterencode(o, _current_indent_level):
if isinstance(o, str):
yield _encoder(o)
elif o is None:
yield 'null'
elif o is True:
yield 'true'
elif o is False:
yield 'false'
elif isinstance(o, int):
yield str(o)
elif isinstance(o, float):
yield _floatstr(o)
elif isinstance(o, JsonSpecialKey):
yield o.data
elif isinstance(o, (list, tuple)):
for chunk in _iterencode_list(o, _current_indent_level):
yield chunk
elif isinstance(o, dict):
for chunk in _iterencode_dict(o, _current_indent_level):
yield chunk
else:
if markers is not None:
markerid = id(o)
if markerid in markers:
raise ValueError("Circular reference detected")
markers[markerid] = o
o = _default(o)
for chunk in _iterencode(o, _current_indent_level):
yield chunk
if markers is not None:
del markers[markerid]
return _iterencode
class JsonSpecialEncoder(json.JSONEncoder):
def iterencode(self, o, _one_shot=False):
"""Encode the given object and yield each string
representation as available.
For example::
for chunk in JSONEncoder().iterencode(bigobject):
mysocket.write(chunk)
"""
if self.check_circular:
markers = {}
else:
markers = None
if self.ensure_ascii:
_encoder = encode_basestring_ascii
else:
_encoder = encode_basestring
def floatstr(o, allow_nan=self.allow_nan,
_repr=FLOAT_REPR, _inf=INFINITY, _neginf=-INFINITY):
# Check for specials. Note that this type of test is processor
# and/or platform-specific, so do tests which don't depend on the
# internals.
if o != o:
text = 'NaN'
elif o == _inf:
text = 'Infinity'
elif o == _neginf:
text = '-Infinity'
else:
return _repr(o)
if not allow_nan:
raise ValueError(
"Out of range float values are not JSON compliant: " +
repr(o))
return text
_iterencode = _make_iterencode(
markers, self.default, _encoder, self.indent, floatstr,
self.key_separator, self.item_separator, self.sort_keys,
self.skipkeys, _one_shot)
return _iterencode(o, 0)
d = {'testKey':JsonSpecialKey('function() {alert(123);}')}
print (json.dumps(d, cls=JsonSpecialEncoder, ensure_ascii=False, indent=4))
EDITED:precision of the code I modified
from json.encode I took the function _make_iterencode
adding something like
elif isinstance(value, JsonSpecialKey):
yield buf + value.data
at three places
from JsonEncoder I took the method iterencode
but I just forced the _iterencode to be my custom function _make_iterencode
_iterencode = _make_iterencode(
markers, self.default, _encoder, self.indent, floatstr,
self.key_separator, self.item_separator, self.sort_keys,
self.skipkeys, _one_shot)
I hope it's clear