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Reworked RequestArgument API to somewhat more lax concerning 0-indices, potentially leading to safer code.

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s3lph 2018-06-29 18:29:51 +02:00
parent 73c7dbe89f
commit 21a927046d
2 changed files with 94 additions and 149 deletions
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119
matemat/webserver/requestargs.py
View file

@ -43,35 +43,31 @@ class RequestArgument(object):
# Assign name
self.__name: str = name
# Initialize value
self.__value: Union[Tuple[str, Union[bytes, str]], List[Tuple[str, Union[bytes, str]]]] = []
self.__value: List[Tuple[str, Union[bytes, str]]] = []
# Default to empty array
if value is None:
self.__value = []
else:
if isinstance(value, list):
if len(value) == 1:
# An array of length 1 will be reduced to a scalar
self.__value = value[0]
else:
# Store the array
self.__value = value
else:
# Scalar value, simply store
self.__value = value
# Turn scalar into an array before storing
self.__value = [value]
@property
def is_array(self) -> bool:
"""
:return: True, if the value is a (possibly empty) array, False otherwise.
"""
return isinstance(self.__value, list)
return len(self.__value) != 1
@property
def is_scalar(self) -> bool:
"""
:return: True, if the value is a single scalar value, False otherwise.
"""
return not isinstance(self.__value, list)
return len(self.__value) == 1
@property
def is_view(self) -> bool:
@ -87,23 +83,19 @@ class RequestArgument(object):
"""
return self.__name
def get_str(self, index: int = None) -> str:
def get_str(self, index: int = 0) -> str:
"""
Attempts to return a value as a string. If this instance is an scalar, no index must be provided. If this
instance is an array, an index must be provided.
Attempts to return a value as a string. The index defaults to 0.
:param index: For array values: The index of the value to retrieve. For scalar values: None (default).
:param index: The index of the value to retrieve. Default: 0.
:return: An UTF-8 string representation of the requested value.
:raises UnicodeDecodeError: If the value cannot be decoded into an UTF-8 string.
:raises IndexError: If the index is out of bounds.
:raises ValueError: If this is an array value, and no index is provided, or if this is a scalar value and an
index is provided.
:raises ValueError: If the index is not an int.
:raises TypeError: If the requested value is neither a str nor a bytes object.
"""
if self.is_array:
# instance is an array value
if index is None:
# Needs an index for array values
if not isinstance(index, int):
# Index must be an int
raise ValueError('index must not be None')
# Type hint; access array element
v: Tuple[str, Union[bytes, str]] = self.__value[index]
@ -113,35 +105,20 @@ class RequestArgument(object):
elif isinstance(v[1], bytes):
# The value is a bytes object, attempt to decode
return v[1].decode('utf-8')
else:
# instance is a scalar value
if index is not None:
# Must not have an index for array values
raise ValueError('index must be None')
if isinstance(self.__value[1], str):
# The value already is a string, return
return self.__value[1]
elif isinstance(self.__value[1], bytes):
# The value is a bytes object, attempt to decode
return self.__value[1].decode('utf-8')
raise TypeError('Value is neither a str nor bytes')
def get_bytes(self, index: int = None) -> bytes:
def get_bytes(self, index: int = 0) -> bytes:
"""
Attempts to return a value as a bytes object. If this instance is an scalar, no index must be provided. If
this instance is an array, an index must be provided.
Attempts to return a value as a bytes object. The index defaults to 0.
:param index: For array values: The index of the value to retrieve. For scalar values: None (default).
:param index: The index of the value to retrieve. Default: 0.
:return: A bytes object representation of the requested value. Strings will be encoded as UTF-8.
:raises IndexError: If the index is out of bounds.
:raises ValueError: If this is an array value, and no index is provided, or if this is a scalar value and an
index is provided.
:raises ValueError: If the index is not an int.
:raises TypeError: If the requested value is neither a str nor a bytes object.
"""
if self.is_array:
# instance is an array value
if index is None:
# Needs an index for array values
if not isinstance(index, int):
# Index must be a int
raise ValueError('index must not be None')
# Type hint; access array element
v: Tuple[str, Union[bytes, str]] = self.__value[index]
@ -151,48 +128,25 @@ class RequestArgument(object):
elif isinstance(v[1], str):
# The value is a string, encode first
return v[1].encode('utf-8')
else:
# instance is a scalar value
if index is not None:
# Must not have an index for array values
raise ValueError('index must be None')
if isinstance(self.__value[1], bytes):
# The value already is a bytes object, return
return self.__value[1]
elif isinstance(self.__value[1], str):
# The value is a string, encode first
return self.__value[1].encode('utf-8')
raise TypeError('Value is neither a str nor bytes')
def get_content_type(self, index: int = None) -> Optional[str]:
def get_content_type(self, index: int = 0) -> str:
"""
Attempts to retrieve a value's Content-Type. If this instance is an scalar, no index must be provided. If this
instance is an array, an index must be provided.
Attempts to retrieve a value's Content-Type. The index defaults to 0.
:param index: For array values: The index of the value to retrieve. For scalar values: None (default).
:param index: The index of the value to retrieve. Default: 0.
:return: The Content-Type of the requested value, as sent by the client. Not necessarily trustworthy.
:raises IndexError: If the index is out of bounds.
:raises ValueError: If this is an array value, and no index is provided, or if this is a scalar value and an
index is provided.
:raises ValueError: If the index is not an int.
"""
if self.is_array:
# instance is an array value
if index is None:
if not isinstance(index, int):
# Needs an index for array values
raise ValueError('index must not be None')
# Type hint; access array element
va: Tuple[str, Union[bytes, str]] = self.__value[index]
# Return the content type of the requested value
return va[0]
else:
# instance is a scalar value
if index is not None:
# Must not have an index for array values
raise ValueError('index must be None')
# Type hint
vs: Tuple[str, Union[bytes, str]] = self.__value
# Return the content type of the scalar value
return vs[0]
def append(self, ctype: str, value: Union[str, bytes]):
"""
@ -205,21 +159,13 @@ class RequestArgument(object):
if self.is_view:
# This is an immutable view, raise exception
raise TypeError('A RequestArgument view is immutable!')
if len(self) == 0:
# Turn an empty argument into a scalar
self.__value = ctype, value
else:
# First turn the scalar into a one-element array ...
if self.is_scalar:
self.__value = [self.__value]
# ... then append the new value
self.__value.append((ctype, value))
def __len__(self) -> int:
"""
:return: Number of values for this argument.
"""
return len(self.__value) if self.is_array else 1
return len(self.__value)
def __iter__(self) -> Iterator['RequestArgument']:
"""
@ -228,29 +174,18 @@ class RequestArgument(object):
:return: An iterator that yields immutable views of the values.
"""
if self.is_scalar:
# If this is a scalar, yield an immutable view of the single value
yield _View(self.__name, self.__value)
else:
# Typing helper
vs: List[Tuple[str, Union[bytes, str]]] = self.__value
for v in vs:
# If this is an array, yield an immutable scalar view for each (ctype, value) element in the array
for v in self.__value:
# Yield an immutable scalar view for each (ctype, value) element in the array
yield _View(self.__name, v)
def __getitem__(self, index: Union[int, slice]):
"""
Index the argument with either an int or a slice. The returned values are represented as immutable
RequestArgument views. Scalar arguments may be indexed with int(0).
RequestArgument views.
:param index: The index or slice.
:return: An immutable view of the indexed elements of this argument.
"""
if self.is_scalar:
# Scalars may only be indexed with 0
if index == 0:
# Return an immutable view of the single scalar value
return _View(self.__name, self.__value)
raise IndexError('Scalar RequestArgument only indexable with 0')
# Pass the index or slice through to the array, packing the result in an immutable view
return _View(self.__name, self.__value[index])

62
matemat/webserver/test/test_requestargs.py
View file

@ -43,13 +43,17 @@ class TestRequestArguments(unittest.TestCase):
self.assertEqual(b'bar', ra.get_bytes())
# Content-Type must be set correctly
self.assertEqual('text/plain', ra.get_content_type())
# Using indices must result in an error
with self.assertRaises(ValueError):
# Using 0 indices must yield the same results
self.assertEqual('bar', ra.get_str(0))
with self.assertRaises(ValueError):
self.assertEqual('bar', ra.get_bytes(0))
with self.assertRaises(ValueError):
self.assertEqual('bar', ra.get_content_type(0))
self.assertEqual(b'bar', ra.get_bytes(0))
self.assertEqual('text/plain', ra.get_content_type(0))
# Using other indices must result in an error
with self.assertRaises(IndexError):
ra.get_str(1)
with self.assertRaises(IndexError):
ra.get_bytes(1)
with self.assertRaises(IndexError):
ra.get_content_type(1)
# Must not be a view
self.assertFalse(ra.is_view)
@ -69,13 +73,17 @@ class TestRequestArguments(unittest.TestCase):
self.assertEqual(b'bar', ra.get_bytes())
# Content-Type must be set correctly
self.assertEqual('text/plain', ra.get_content_type())
# Using indices must result in an error
with self.assertRaises(ValueError):
# Using 0 indices must yield the same results
self.assertEqual('bar', ra.get_str(0))
with self.assertRaises(ValueError):
self.assertEqual('bar', ra.get_bytes(0))
with self.assertRaises(ValueError):
self.assertEqual('bar', ra.get_content_type(0))
self.assertEqual(b'bar', ra.get_bytes(0))
self.assertEqual('text/plain', ra.get_content_type(0))
# Using other indices must result in an error
with self.assertRaises(IndexError):
ra.get_str(1)
with self.assertRaises(IndexError):
ra.get_bytes(1)
with self.assertRaises(IndexError):
ra.get_content_type(1)
# Must not be a view
self.assertFalse(ra.is_view)
@ -96,13 +104,18 @@ class TestRequestArguments(unittest.TestCase):
self.assertEqual(b'\x00\x80\xff\xfe', ra.get_bytes())
# Content-Type must be set correctly
self.assertEqual('application/octet-stream', ra.get_content_type())
# Using indices must result in an error
with self.assertRaises(ValueError):
self.assertEqual('bar', ra.get_str(0))
with self.assertRaises(ValueError):
self.assertEqual('bar', ra.get_bytes(0))
with self.assertRaises(ValueError):
self.assertEqual('bar', ra.get_content_type(0))
# Using 0 indices must yield the same results
with self.assertRaises(UnicodeDecodeError):
ra.get_str(0)
self.assertEqual(b'\x00\x80\xff\xfe', ra.get_bytes(0))
self.assertEqual('application/octet-stream', ra.get_content_type(0))
# Using other indices must result in an error
with self.assertRaises(IndexError):
ra.get_str(1)
with self.assertRaises(IndexError):
ra.get_bytes(1)
with self.assertRaises(IndexError):
ra.get_content_type(1)
# Must not be a view
self.assertFalse(ra.is_view)
@ -120,13 +133,10 @@ class TestRequestArguments(unittest.TestCase):
self.assertEqual(2, len(ra))
self.assertFalse(ra.is_scalar)
self.assertTrue(ra.is_array)
# Retrieving values without an index must fail
with self.assertRaises(ValueError):
ra.get_str()
with self.assertRaises(ValueError):
ra.get_bytes()
with self.assertRaises(ValueError):
ra.get_content_type()
# Retrieving values without an index must yield the first element
self.assertEqual('bar', ra.get_str())
self.assertEqual(b'bar', ra.get_bytes())
self.assertEqual('text/plain', ra.get_content_type())
# The first value must be representable both as str and bytes, and have ctype text/plain
self.assertEqual('bar', ra.get_str(0))
self.assertEqual(b'bar', ra.get_bytes(0))