from __future__ import generators
import decimal, re, inspect
import copy
try:
# yaml isn't standard with python. It shouldn't be required if it
# isn't used.
import yaml
except ImportError:
yaml = None
# Fallback since `any` isn't in Python <2.5
try:
any
except NameError:
def any(iterable):
for element in iterable:
if element:
return True
return False
from django.db.models.query import QuerySet
from django.db.models import Model, permalink
from django.utils import simplejson
from django.utils.xmlutils import SimplerXMLGenerator
from django.utils.encoding import smart_unicode
from django.core.urlresolvers import reverse, NoReverseMatch
from django.core.serializers.json import DateTimeAwareJSONEncoder
from django.http import HttpResponse
from django.core import serializers
from utils import HttpStatusCode, Mimer
from validate_jsonp import is_valid_jsonp_callback_value
try:
import cStringIO as StringIO
except ImportError:
import StringIO
try:
import cPickle as pickle
except ImportError:
import pickle
# Allow people to change the reverser (default `permalink`).
reverser = permalink
class Emitter(object):
"""
Super emitter. All other emitters should subclass
this one. It has the `construct` method which
conveniently returns a serialized `dict`. This is
usually the only method you want to use in your
emitter. See below for examples.
`RESERVED_FIELDS` was introduced when better resource
method detection came, and we accidentially caught these
as the methods on the handler. Issue58 says that's no good.
"""
EMITTERS = { }
RESERVED_FIELDS = set([ 'read', 'update', 'create',
'delete', 'model', 'anonymous',
'allowed_methods', 'fields', 'exclude' ])
def __init__(self, payload, typemapper, handler, fields=(), anonymous=True):
self.typemapper = typemapper
self.data = payload
self.handler = handler
self.fields = fields
self.anonymous = anonymous
if isinstance(self.data, Exception):
raise
def method_fields(self, handler, fields):
if not handler:
return { }
ret = dict()
for field in fields - Emitter.RESERVED_FIELDS:
t = getattr(handler, str(field), None)
if t and callable(t):
ret[field] = t
return ret
def construct(self):
"""
Recursively serialize a lot of types, and
in cases where it doesn't recognize the type,
it will fall back to Django's `smart_unicode`.
Returns `dict`.
"""
def _any(thing, fields=None):
"""
Dispatch, all types are routed through here.
"""
ret = None
if isinstance(thing, QuerySet):
ret = _qs(thing, fields)
elif isinstance(thing, (tuple, list, set)):
ret = _list(thing, fields)
elif isinstance(thing, dict):
ret = _dict(thing, fields)
elif isinstance(thing, decimal.Decimal):
ret = str(thing)
elif isinstance(thing, Model):
ret = _model(thing, fields)
elif isinstance(thing, HttpResponse):
raise HttpStatusCode(thing)
elif inspect.isfunction(thing):
if not inspect.getargspec(thing)[0]:
ret = _any(thing())
elif hasattr(thing, '__emittable__'):
f = thing.__emittable__
if inspect.ismethod(f) and len(inspect.getargspec(f)[0]) == 1:
ret = _any(f())
elif repr(thing).startswith("<django.db.models.fields.related.RelatedManager"):
ret = _any(thing.all())
else:
ret = smart_unicode(thing, strings_only=True)
return ret
def _fk(data, field):
"""
Foreign keys.
"""
return _any(getattr(data, field.name))
def _related(data, fields=None):
"""
Foreign keys.
"""
return [ _model(m, fields) for m in data.iterator() ]
def _m2m(data, field, fields=None):
"""
Many to many (re-route to `_model`.)
"""
return [ _model(m, fields) for m in getattr(data, field.name).iterator() ]
def _model(data, fields=None):
"""
Models. Will respect the `fields` and/or
`exclude` on the handler (see `typemapper`.)
"""
ret = { }
handler = self.in_typemapper(type(data), self.anonymous)
get_absolute_uri = False
if handler or fields:
v = lambda f: getattr(data, f.attname)
if handler:
fields = getattr(handler, 'fields')
if not fields or hasattr(handler, 'fields'):
"""
Fields was not specified, try to find teh correct
version in the typemapper we were sent.
"""
mapped = self.in_typemapper(type(data), self.anonymous)
get_fields = set(mapped.fields)
exclude_fields = set(mapped.exclude).difference(get_fields)
if 'absolute_uri' in get_fields:
get_absolute_uri = True
if not get_fields:
get_fields = set([ f.attname.replace("_id", "", 1)
for f in data._meta.fields + data._meta.virtual_fields])
if hasattr(mapped, 'extra_fields'):
get_fields.update(mapped.extra_fields)
# sets can be negated.
for exclude in exclude_fields:
if isinstance(exclude, basestring):
get_fields.discard(exclude)
elif isinstance(exclude, re._pattern_type):
for field in get_fields.copy():
if exclude.match(field):
get_fields.discard(field)
else:
get_fields = set(fields)
met_fields = self.method_fields(handler, get_fields)
for f in data._meta.local_fields + data._meta.virtual_fields:
if f.serialize and not any([ p in met_fields for p in [ f.attname, f.name ]]):
if not f.rel:
if f.attname in get_fields:
ret[f.attname] = _any(v(f))
get_fields.remove(f.attname)
else:
if f.attname[:-3] in get_fields:
ret[f.name] = _fk(data, f)
get_fields.remove(f.name)
for mf in data._meta.many_to_many:
if mf.serialize and mf.attname not in met_fields:
if mf.attname in get_fields:
ret[mf.name] = _m2m(data, mf)
get_fields.remove(mf.name)
# try to get the remainder of fields
for maybe_field in get_fields:
if isinstance(maybe_field, (list, tuple)):
model, fields = maybe_field
inst = getattr(data, model, None)
if inst:
if hasattr(inst, 'all'):
ret[model] = _related(inst, fields)
elif callable(inst):
if len(inspect.getargspec(inst)[0]) == 1:
ret[model] = _any(inst(), fields)
else:
ret[model] = _model(inst, fields)
elif maybe_field in met_fields:
# Overriding normal field which has a "resource method"
# so you can alter the contents of certain fields without
# using different names.
ret[maybe_field] = _any(met_fields[maybe_field](data))
else:
maybe = getattr(data, maybe_field, None)
if maybe is not None:
if callable(maybe):
if len(inspect.getargspec(maybe)[0]) <= 1:
ret[maybe_field] = _any(maybe())
else:
ret[maybe_field] = _any(maybe)
else:
handler_f = getattr(handler or self.handler, maybe_field, None)
if handler_f:
ret[maybe_field] = _any(handler_f(data))
else:
for f in data._meta.fields:
ret[f.attname] = _any(getattr(data, f.attname))
fields = dir(data.__class__) + ret.keys()
add_ons = [k for k in dir(data) if k not in fields]
for k in add_ons:
ret[k] = _any(getattr(data, k))
# resouce uri
if self.in_typemapper(type(data), self.anonymous):
handler = self.in_typemapper(type(data), self.anonymous)
if hasattr(handler, 'resource_uri'):
url_id, fields = handler.resource_uri(data)
try:
ret['resource_uri'] = reverser( lambda: (url_id, fields) )()
except NoReverseMatch, e:
pass
if hasattr(data, 'get_api_url') and 'resource_uri' not in ret:
try: ret['resource_uri'] = data.get_api_url()
except: pass
# absolute uri
if hasattr(data, 'get_absolute_url') and get_absolute_uri:
try: ret['absolute_uri'] = data.get_absolute_url()
except: pass
return ret
def _qs(data, fields=None):
"""
Querysets.
"""
return [ _any(v, fields) for v in data ]
def _list(data, fields=None):
"""
Lists.
"""
return [ _any(v, fields) for v in data ]
def _dict(data, fields=None):
"""
Dictionaries.
"""
return dict([ (k, _any(v, fields)) for k, v in data.iteritems() ])
# Kickstart the seralizin'.
return _any(self.data, self.fields)
def in_typemapper(self, model, anonymous):
for klass, (km, is_anon) in self.typemapper.iteritems():
if model is km and is_anon is anonymous:
return klass
def render(self):
"""
This super emitter does not implement `render`,
this is a job for the specific emitter below.
"""
raise NotImplementedError("Please implement render.")
def stream_render(self, request, stream=True):
"""
Tells our patched middleware not to look
at the contents, and returns a generator
rather than the buffered string. Should be
more memory friendly for large datasets.
"""
yield self.render(request)
@classmethod
def get(cls, format):
"""
Gets an emitter, returns the class and a content-type.
"""
if cls.EMITTERS.has_key(format):
return cls.EMITTERS.get(format)
raise ValueError("No emitters found for type %s" % format)
@classmethod
def register(cls, name, klass, content_type='text/plain'):
"""
Register an emitter.
Parameters::
- `name`: The name of the emitter ('json', 'xml', 'yaml', ...)
- `klass`: The emitter class.
- `content_type`: The content type to serve response as.
"""
cls.EMITTERS[name] = (klass, content_type)
@classmethod
def unregister(cls, name):
"""
Remove an emitter from the registry. Useful if you don't
want to provide output in one of the built-in emitters.
"""
return cls.EMITTERS.pop(name, None)
class XMLEmitter(Emitter):
def _to_xml(self, xml, data):
if isinstance(data, (list, tuple)):
for item in data:
xml.startElement("resource", {})
self._to_xml(xml, item)
xml.endElement("resource")
elif isinstance(data, dict):
for key, value in data.iteritems():
xml.startElement(key, {})
self._to_xml(xml, value)
xml.endElement(key)
else:
xml.characters(smart_unicode(data))
def render(self, request):
stream = StringIO.StringIO()
xml = SimplerXMLGenerator(stream, "utf-8")
xml.startDocument()
xml.startElement("response", {})
self._to_xml(xml, self.construct())
xml.endElement("response")
xml.endDocument()
return stream.getvalue()
Emitter.register('xml', XMLEmitter, 'text/xml; charset=utf-8')
Mimer.register(lambda *a: None, ('text/xml',))
class JSONEmitter(Emitter):
"""
JSON emitter, understands timestamps.
"""
def render(self, request):
cb = request.GET.get('callback', None)
seria = simplejson.dumps(self.construct(), cls=DateTimeAwareJSONEncoder, ensure_ascii=False, indent=4)
# Callback
if cb and is_valid_jsonp_callback_value(cb):
return '%s(%s)' % (cb, seria)
return seria
Emitter.register('json', JSONEmitter, 'application/json; charset=utf-8')
Mimer.register(simplejson.loads, ('application/json',))
class YAMLEmitter(Emitter):
"""
YAML emitter, uses `safe_dump` to omit the
specific types when outputting to non-Python.
"""
def render(self, request):
return yaml.safe_dump(self.construct())
if yaml: # Only register yaml if it was import successfully.
Emitter.register('yaml', YAMLEmitter, 'application/x-yaml; charset=utf-8')
Mimer.register(lambda s: dict(yaml.load(s)), ('application/x-yaml',))
class PickleEmitter(Emitter):
"""
Emitter that returns Python pickled.
"""
def render(self, request):
return pickle.dumps(self.construct())
Emitter.register('pickle', PickleEmitter, 'application/python-pickle')
"""
WARNING: Accepting arbitrary pickled data is a huge security concern.
The unpickler has been disabled by default now, and if you want to use
it, please be aware of what implications it will have.
Read more: http://nadiana.com/python-pickle-insecure
Uncomment the line below to enable it. You're doing so at your own risk.
"""
# Mimer.register(pickle.loads, ('application/python-pickle',))
class DjangoEmitter(Emitter):
"""
Emitter for the Django serialized format.
"""
def render(self, request, format='xml'):
if isinstance(self.data, HttpResponse):
return self.data
elif isinstance(self.data, (int, str)):
response = self.data
else:
response = serializers.serialize(format, self.data, indent=True)
return response
Emitter.register('django', DjangoEmitter, 'text/xml; charset=utf-8')