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Merged
Code0x58 merged 1 commit into from
Dec 9, 2020
Merged

Provide better exception messages + better slice support #6

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9 changes: 6 additions & 3 deletions .travis.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ language: python

jobs:
include:
- python: 3.9
- python: 3.8
- python: 3.7
- python: 3.6
Expand All @@ -10,7 +11,7 @@ jobs:
- python: 2.7
- python: pypy3
- python: pypy
- name: "Python: 3.7"
- name: "Python: 2.7"
os: osx
osx_image: xcode11.2 # Python 3.7.4 running on macOS 10.14.4
language: shell # 'language: python' is an error on Travis CI macOS
Expand All @@ -22,5 +23,7 @@ jobs:
- python -m pip install --upgrade pip
env: PATH=/c/Python38:/c/Python38/Scripts:$PATH

install: python -m pip install . pytest
script: python -m pytest
install: python -m pip install --upgrade . pytest==4.6.1 pytest-cov==2.8.1 codecov==2.1.10
script: python -m pytest -vv --cov=jsonstore --cov-append
after_success:
- codecov
6 changes: 5 additions & 1 deletion README.rst
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@@ -1,4 +1,4 @@
|PyPi Package| |Build Status| |Codacy Rating|
|PyPi Package| |Build Status| |Codacy Rating| |Coverage Report|

jsonstore
=========
Expand Down Expand Up @@ -47,6 +47,8 @@ Basics
assert store['a_list', -1] == 3
# you can use slices in lists
assert len(store['a_list', 1:]) == 2
del store['a_list', :2]
assert store.a_list == [3]

# deep copies are made when assigning values
my_list = ['fun']
Expand Down Expand Up @@ -95,3 +97,5 @@ file until all of the transactions have been closed.
:target: https://www.codacy.com/app/evilumbrella-github/python-jsonstore?utm_source=github.com&utm_medium=referral&utm_content=Code0x58/python-jsonstore&utm_campaign=Badge_Grade
.. |PyPi Package| image:: https://badge.fury.io/py/python-jsonstore.svg
:target: https://pypi.org/project/python-jsonstore/
.. |Coverage Report| image:: https://codecov.io/gh/Code0x58/python-jsonstore/branch/master/graph/badge.svg
:target: https://codecov.io/gh/Code0x58/python-jsonstore
125 changes: 74 additions & 51 deletions jsonstore.py
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Expand Up @@ -12,6 +12,13 @@

__all__ = ["JsonStore"]

STRING_TYPES = (str,)
INT_TYPES = (int,)
if sys.version_info < (3,):
STRING_TYPES += (unicode,)
INT_TYPES += (long,)
VALUE_TYPES = (bool, int, float, type(None)) + INT_TYPES


class JsonStore(object):
"""A class to provide object based access to a JSON file"""
Expand Down Expand Up @@ -81,9 +88,10 @@ def __getattr__(self, key):
raise AttributeError(key)

@classmethod
def _valid_object(cls, obj, parents=None):
def _verify_object(cls, obj, parents=None):
"""
Determine if the object can be encoded into JSON
Raise an exception if the object is not suitable for assignment.

"""
# pylint: disable=unicode-builtin,long-builtin
if isinstance(obj, (dict, list)):
Expand All @@ -94,85 +102,100 @@ def _valid_object(cls, obj, parents=None):
parents.append(obj)

if isinstance(obj, dict):
return all(
cls._valid_string(k) and cls._valid_object(v, parents)
for k, v in obj.items()
)
for k, v in obj.items():
if not cls._valid_string(k):
# this is necessary because of the JSON serialisation
raise TypeError("a dict has non-string keys")
cls._verify_object(v, parents)
elif isinstance(obj, (list, tuple)):
return all(cls._valid_object(o, parents) for o in obj)
for o in obj:
cls._verify_object(o, parents)
else:
return cls._valid_value(obj)

@classmethod
def _valid_value(cls, value):
if isinstance(value, (bool, int, float, type(None))):
return True
elif sys.version_info < (3,) and isinstance(value, long):
if isinstance(value, VALUE_TYPES):
return True
else:
return cls._valid_string(value)

@classmethod
def _valid_string(cls, value):
if isinstance(value, str):
if isinstance(value, STRING_TYPES):
return True
elif sys.version_info < (3,):
return isinstance(value, unicode)
else:
return False

def __setattr__(self, key, value):
if not self._valid_object(value):
raise AttributeError
self._data[key] = deepcopy(value)
@classmethod
def _canonical_key(cls, key):
"""Convert a set/get/del key into the canonical form."""
if cls._valid_string(key):
return tuple(key.split("."))

if isinstance(key, (tuple, list)):
key = tuple(key)
if not key:
raise TypeError("key must be a string or non-empty tuple/list")
return key

raise TypeError("key must be a string or non-empty tuple/list")

def __setattr__(self, attr, value):
self._verify_object(value)
self._data[attr] = deepcopy(value)
self._do_auto_commit()

def __delattr__(self, key):
del self._data[key]
def __delattr__(self, attr):
del self._data[attr]

def __get_obj(self, full_path):
"""
Returns the object which is under the given path
"""
if isinstance(full_path, (tuple, list)):
steps = full_path
else:
steps = full_path.split(".")
def __get_obj(self, steps):
"""Returns the object which is under the given path."""
path = []
obj = self._data
if not full_path:
return obj
for step in steps:
path.append(step)
if isinstance(obj, dict) and not self._valid_string(step):
# this is necessary because of the JSON serialisation
raise TypeError("%s is a dict and %s is not a string" % (path, step))
try:
obj = obj[step]
except KeyError:
raise KeyError(".".join(path))
except (KeyError, IndexError, TypeError) as e:
raise type(e)("unable to get %s from %s: %s" % (step, path, e))
path.append(step)
return obj

def __setitem__(self, name, value):
path, _, key = name.rpartition(".")
if self._valid_object(value):
dictionary = self.__get_obj(path)
dictionary[key] = deepcopy(value)
self._do_auto_commit()
else:
raise AttributeError
def __setitem__(self, key, value):
steps = self._canonical_key(key)
path, step = steps[:-1], steps[-1]
self._verify_object(value)
container = self.__get_obj(path)
if isinstance(container, dict) and not self._valid_string(step):
raise TypeError("%s is a dict and %s is not a string" % (path, step))
try:
container[step] = deepcopy(value)
except (IndexError, TypeError) as e:
raise type(e)("unable to set %s from %s: %s" % (step, path, e))
self._do_auto_commit()

def __getitem__(self, key):
obj = self.__get_obj(key)
if obj is self._data:
raise KeyError
steps = self._canonical_key(key)
obj = self.__get_obj(steps)
return deepcopy(obj)

def __delitem__(self, name):
if isinstance(name, (tuple, list)):
path = name[:-1]
key = name[-1]
else:
path, _, key = name.rpartition(".")
def __delitem__(self, key):
steps = self._canonical_key(key)
path, step = steps[:-1], steps[-1]
obj = self.__get_obj(path)
del obj[key]
try:
del obj[step]
except (KeyError, IndexError, TypeError) as e:
raise type(e)("unable to delete %s from %s: %s" % (step, path, e))

def __contains__(self, key):
return key in self._data
steps = self._canonical_key(key)
try:
self.__get_obj(steps)
return True
except (KeyError, IndexError, TypeError):
# this is rather permissive as the types are dynamic
return False
42 changes: 37 additions & 5 deletions test_jsonstore.py
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Expand Up @@ -105,19 +105,39 @@ def test_assign_valid_types(self):
self.assertRaises(KeyError, self._getitem(name))
self.assertRaises(AttributeError, self._getattr(name))

def test_slices(self):
self.store.list = [1, 2, 3]
self.store["list", :2] = ["a", "b"]
self.assertEqual(self.store["list", 1:], ["b", 3])
del self.store["list", :1]
self.assertEqual(self.store.list, ["b", 3])

def test_assign_invalid_types(self):
for method in (self._setattr, self._setitem):

def assign(value):
return method("key", value)

self.assertRaises(AttributeError, assign(set()))
self.assertRaises(AttributeError, assign(object()))
self.assertRaises(AttributeError, assign(None for i in range(2)))
self.assertRaises(TypeError, assign(set()))
self.assertRaises(TypeError, assign(object()))
self.assertRaises(TypeError, assign(None for i in range(2)))
self.assertRaises(TypeError, assign({1: 1}))

def test_assign_bad_keys(self):
# FIXME: a ValueError would make more sense
self.assertRaises(AttributeError, self._setitem(1, 2))
value = 1
# the root object is a dict, so a string key is needed
self.assertRaises(TypeError, self._setitem(1, value))
self.assertRaises(TypeError, self._setitem((1, "a"), value))

self.store["dict"] = {}
self.store["list"] = []
self.assertRaises(TypeError, self._setitem((), value))
self.assertRaises(TypeError, self._setitem(("dict", 1), value))
self.assertRaises(TypeError, self._setitem(("dict", slice(1)), value))
self.assertRaises(TypeError, self._setitem(("list", "a"), value))
self.assertRaises(TypeError, self._setitem(("list", slice("a")), value))
self.assertRaises(IndexError, self._setitem(("list", 1), value))


def test_retrieve_values(self):
for name, value in self.TEST_DATA:
Expand Down Expand Up @@ -177,6 +197,7 @@ def test_nested_getitem(self):
assert self.store[["list", 0, "key", -1]] == "last"
self.assertRaises(TypeError, self._getitem("list.0.key.1"))
assert len(self.store["list", 0, "key", 1:]) == 2
self.assertRaises(IndexError, self._getitem(("list", 1)))

def test_del(self):
self.store.key = None
Expand All @@ -187,6 +208,17 @@ def test_del(self):
del self.store["key"]
self.assertRaises(KeyError, self._getitem("key"))

with self.assertRaises(KeyError):
del self.store["missing"]

self.store.list = []
with self.assertRaises(IndexError):
del self.store["list", 1]

self.store.dict = {}
with self.assertRaises(TypeError):
del self.store["dict", slice("a")]

def test_context_and_deserialisation(self):
store_file = mktemp()
for name, value in self.TEST_DATA:
Expand Down