adm-ntuh-net/ntuh/dojango/util/__init__.py
2024-12-12 10:19:16 +08:00

246 lines
9 KiB
Python
Executable file

import os
import datetime
from decimal import Decimal
from dojango.conf import settings # using the app-specific settings
from django.core.serializers.json import DateTimeAwareJSONEncoder
from django.db.models import Model
from django.db.models import ImageField, FileField
from django.db.models.query import QuerySet
from django.http import HttpResponse
from django.template.loader import render_to_string
from django.utils import simplejson as json
from django.utils.functional import Promise
try:
# we need it, if we want to serialize query- and model-objects
# of google appengine within json_encode
from google import appengine
except:
appengine = None
try:
# this is just available since django version 1.0
# google appengine does not provide this function yet!
from django.utils.encoding import force_unicode
except Exception:
import types
# code copied from django version 1.0
class DjangoUnicodeDecodeError(UnicodeDecodeError):
def __init__(self, obj, *args):
self.obj = obj
UnicodeDecodeError.__init__(self, *args)
def __str__(self):
original = UnicodeDecodeError.__str__(self)
return '%s. You passed in %r (%s)' % (original, self.obj,
type(self.obj))
def force_unicode(s, encoding='utf-8', strings_only=False, errors='strict'):
"""
Similar to smart_unicode, except that lazy instances are resolved to
strings, rather than kept as lazy objects.
If strings_only is True, don't convert (some) non-string-like objects.
"""
if strings_only and isinstance(s, (types.NoneType, int, long, datetime.datetime, datetime.date, datetime.time, float)):
return s
try:
if not isinstance(s, basestring,):
if hasattr(s, '__unicode__'):
s = unicode(s)
else:
try:
s = unicode(str(s), encoding, errors)
except UnicodeEncodeError:
if not isinstance(s, Exception):
raise
# If we get to here, the caller has passed in an Exception
# subclass populated with non-ASCII data without special
# handling to display as a string. We need to handle this
# without raising a further exception. We do an
# approximation to what the Exception's standard str()
# output should be.
s = ' '.join([force_unicode(arg, encoding, strings_only,
errors) for arg in s])
elif not isinstance(s, unicode):
# Note: We use .decode() here, instead of unicode(s, encoding,
# errors), so that if s is a SafeString, it ends up being a
# SafeUnicode at the end.
s = s.decode(encoding, errors)
except UnicodeDecodeError, e:
raise DjangoUnicodeDecodeError(s, *e.args)
return s
def extract_nodelist_options(nodelist, context=None):
"""
Returns a dict containing the key=value options listed within the nodelist.
The value can be a python dict, list, tuple, or number/string literal.
"""
ret={}
if context:
rendered = nodelist.render(context)
else:
rendered = nodelist.render({})
if rendered.find('=')>0:
for key,val in [ opt.strip().split("=") for opt in rendered.split("\n") if opt.find('=')>-1 ]:
ret[key.strip()]=eval(val.strip())
return ret
def debug(request):
"Returns context variables helpful for debugging."
context_extras = {}
if settings.DEBUG:
context_extras['DEBUG'] = True
return context_extras
def json_encode(data):
"""
The main issues with django's default json serializer is that properties that
had been added to an object dynamically are being ignored (and it also has
problems with some models).
"""
def _any(data):
ret = None
# Opps, we used to check if it is of type list, but that fails
# i.e. in the case of django.newforms.utils.ErrorList, which extends
# the type "list". Oh man, that was a dumb mistake!
if isinstance(data, list):
ret = _list(data)
# Same as for lists above.
elif appengine and isinstance(data, appengine.ext.db.Query):
ret = _list(data)
elif isinstance(data, dict):
ret = _dict(data)
elif isinstance(data, Decimal):
# json.dumps() cant handle Decimal
ret = str(data)
elif isinstance(data, QuerySet):
# Actually its the same as a list ...
ret = _list(data)
elif isinstance(data, Model):
ret = _model(data)
elif appengine and isinstance(data, appengine.ext.db.Model):
ret = _googleModel(data)
# here we need to encode the string as unicode (otherwise we get utf-16 in the json-response)
elif isinstance(data, basestring):
ret = unicode(data)
# see http://code.djangoproject.com/ticket/5868
elif isinstance(data, Promise):
ret = force_unicode(data)
elif isinstance(data, datetime.datetime):
# For dojo.date.stamp we convert the dates to use 'T' as separator instead of space
# i.e. 2008-01-01T10:10:10 instead of 2008-01-01 10:10:10
ret = str(data).replace(' ', 'T')
elif isinstance(data, datetime.date):
ret = str(data)
elif isinstance(data, datetime.time):
ret = "T" + str(data)
else:
# always fallback to a string!
ret = data
return ret
def _model(data):
ret = {}
# If we only have a model, we only want to encode the fields.
for f in data._meta.fields:
# special FileField handling (they can't be json serialized)
if isinstance(f, ImageField) or isinstance(f, FileField):
ret[f.attname] = unicode(getattr(data, f.attname))
else:
ret[f.attname] = _any(getattr(data, f.attname))
# And additionally encode arbitrary properties that had been added.
fields = dir(data.__class__) + ret.keys()
# ignoring _state and delete properties
add_ons = [k for k in dir(data) if k not in fields and k not in ('delete', '_state',)]
for k in add_ons:
ret[k] = _any(getattr(data, k))
return ret
def _googleModel(data):
ret = {}
ret['id'] = data.key().id()
for f in data.fields():
ret[f] = _any(getattr(data, f))
return ret
def _list(data):
ret = []
for v in data:
ret.append(_any(v))
return ret
def _dict(data):
ret = {}
for k,v in data.items():
ret[k] = _any(v)
return ret
ret = _any(data)
return json.dumps(ret, cls=DateTimeAwareJSONEncoder)
def json_decode(json_string):
"""
This function is just for convenience/completeness (because we have json_encode).
Sometimes you want to convert a json-string to a python object.
It throws a ValueError, if the JSON String is invalid.
"""
return json.loads(json_string)
def to_json_response(data, func_name=None, use_iframe=False):
"""
This functions creates a http response object. It mainly set the right
headers for you.
If you pass a func_name to it, it'll surround the json data with a function name.
"""
data = json_encode(data)
# as of dojo version 1.2.0, prepending {}&&\n is the most secure way!!!
# for dojo version < 1.2.0 you have to set DOJANGO_DOJO_SECURE_JSON = False
# in your settings file!
if settings.DOJO_SECURE_JSON:
data = "{}&&\n" + data
# don't wrap it into a function, if we use an iframe
if func_name and not use_iframe:
data = "%s(%s)" % (func_name, data)
mimetype = "application/json"
if use_iframe:
mimetype = "text/html"
data = render_to_string("dojango/json_iframe.html", {'json_data': data})
ret = HttpResponse(data, mimetype=mimetype+"; charset=%s" % settings.DEFAULT_CHARSET)
# The following are for IE especially
ret['Pragma'] = "no-cache"
ret['Cache-Control'] = "must-revalidate"
ret['If-Modified-Since'] = str(datetime.datetime.now())
return ret
def to_dojo_data(items, identifier='id', num_rows=None):
"""Return the data as the dojo.data API defines.
The dojo.data API expects the data like so:
{identifier:"whatever",
items: [
{name:"Lenin", id:3, ....},
]
}
The identifier is optional.
"""
ret = {'items':items}
if identifier:
ret['identifier'] = identifier
if num_rows:
ret['numRows'] = num_rows
return ret
def is_number(s):
"""Is this the right way for checking a number.
Maybe there is a better pythonic way :-)"""
try:
int(s)
return True
except TypeError:
pass
except ValueError:
pass
return False