forked from s3lph/matemat
Documentation of the RequestArgument class.
This commit is contained in:
parent
118de8bf95
commit
8898abc77b
2 changed files with 159 additions and 6 deletions
|
@ -1,121 +1,273 @@
|
|||
|
||||
from typing import List, Optional, Tuple, Union
|
||||
from typing import Iterator, List, Optional, Tuple, Union
|
||||
|
||||
|
||||
class RequestArgument(object):
|
||||
"""
|
||||
Container class for HTTP request arguments that simplifies dealing with
|
||||
- scalar and array arguments:
|
||||
Automatically converts between single values and arrays where necessary: Arrays with one element can be
|
||||
accessed as scalars, and scalars can be iterated, yielding themselves as a single item.
|
||||
- UTF-8 strings and binary data (e.g. file uploads):
|
||||
All data can be retrieved both as a str (if utf-8 decoding is possible) and a bytes object.
|
||||
|
||||
The objects returned from iteration or indexing are immutable views of (parts of) this object.
|
||||
|
||||
Usage example:
|
||||
|
||||
qsargs = urllib.parse.parse_qs(qs, strict_parsing=True, keep_blank_values=True, errors='strict')
|
||||
args: Dict[str, RequestArgument] = dict()
|
||||
for k, vs in qsargs:
|
||||
args[k] = RequestArgument(k)
|
||||
for v in vs:
|
||||
# text/plain usually is a sensible choice for values decoded from urlencoded strings
|
||||
# IF ALREADY IN STRING FORM (which parse_qs does)!
|
||||
args[k].append('text/plain', v)
|
||||
|
||||
if 'username' in args and args['username'].is_scalar:
|
||||
username: str = args['username'].get_str()
|
||||
else:
|
||||
raise ValueError()
|
||||
|
||||
"""
|
||||
|
||||
def __init__(self,
|
||||
name: str,
|
||||
value: Union[Tuple[str, Union[bytes, str]], List[Tuple[str, Union[bytes, str]]]] = None) -> None:
|
||||
"""
|
||||
Create a new RequestArgument with a name and optionally an initial value.
|
||||
|
||||
:param name: The name for this argument, as provided via GET or POST.
|
||||
:param value: The initial value, if any. Optional, initializes with empty array if omitted.
|
||||
"""
|
||||
# Assign name
|
||||
self.__name: str = name
|
||||
# Initialize value
|
||||
self.__value: Union[Tuple[str, Union[bytes, str]], List[Tuple[str, Union[bytes, str]]]] = None
|
||||
# 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
|
||||
|
||||
@property
|
||||
def is_array(self) -> bool:
|
||||
"""
|
||||
:return: True, if the value is a (possibly empty) array, False otherwise.
|
||||
"""
|
||||
return isinstance(self.__value, list)
|
||||
|
||||
@property
|
||||
def is_scalar(self) -> bool:
|
||||
"""
|
||||
:return: True, if the value is a single scalar value, False otherwise.
|
||||
"""
|
||||
return not isinstance(self.__value, list)
|
||||
|
||||
@property
|
||||
def is_view(self) -> bool:
|
||||
"""
|
||||
:return: True, if this instance is an immutable view, False otherwise.
|
||||
"""
|
||||
return False
|
||||
|
||||
@property
|
||||
def name(self) -> str:
|
||||
"""
|
||||
:return: The name of this argument.
|
||||
"""
|
||||
return self.__name
|
||||
|
||||
def get_str(self, index: int = None) -> Optional[str]:
|
||||
def get_str(self, index: int = None) -> 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.
|
||||
|
||||
:param index: For array values: The index of the value to retrieve. For scalar values: None (default).
|
||||
: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.
|
||||
"""
|
||||
if self.is_array:
|
||||
# instance is an array value
|
||||
if index is None:
|
||||
# Needs an index for array values
|
||||
raise ValueError('index must not be None')
|
||||
# Type hint; access array element
|
||||
v: Tuple[str, Union[bytes, str]] = self.__value[index]
|
||||
if isinstance(v[1], str):
|
||||
# The value already is a string, return
|
||||
return v[1]
|
||||
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')
|
||||
|
||||
def get_bytes(self, index: int = None) -> Optional[bytes]:
|
||||
def get_bytes(self, index: int = None) -> 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.
|
||||
|
||||
:param index: For array values: The index of the value to retrieve. For scalar values: None (default).
|
||||
: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.
|
||||
"""
|
||||
if self.is_array:
|
||||
# instance is an array value
|
||||
if index is None:
|
||||
# Needs an index for array values
|
||||
raise ValueError('index must not be None')
|
||||
# Type hint; access array element
|
||||
v: Tuple[str, Union[bytes, str]] = self.__value[index]
|
||||
if isinstance(v[1], bytes):
|
||||
# The value already is a bytes object, return
|
||||
return v[1]
|
||||
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')
|
||||
|
||||
def get_content_type(self, index: int = None) -> Optional[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.
|
||||
|
||||
:param index: For array values: The index of the value to retrieve. For scalar values: None (default).
|
||||
: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.
|
||||
"""
|
||||
if self.is_array:
|
||||
# instance is an array value
|
||||
if index is None:
|
||||
# Needs an index for array values
|
||||
raise ValueError('index must not be None')
|
||||
# Type hint; access array element
|
||||
v: Tuple[str, Union[bytes, str]] = self.__value[index]
|
||||
# Return the content type of the requested value
|
||||
return v[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')
|
||||
# Return the content type of the scalar value
|
||||
return self.__value[0]
|
||||
|
||||
def append(self, ctype: str, value: Union[str, bytes]):
|
||||
"""
|
||||
Append a value to this instance. Turns an empty argument into a scalar and a scalar into an array.
|
||||
|
||||
:param ctype: The Content-Type, as provided in the request.
|
||||
:param value: The scalar value to append, either a string or bytes object.
|
||||
:raises TypeError: If called on an immutable view.
|
||||
"""
|
||||
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):
|
||||
def __len__(self) -> int:
|
||||
"""
|
||||
:return: Number of values for this argument.
|
||||
"""
|
||||
return len(self.__value) if self.is_array else 1
|
||||
|
||||
def __iter__(self):
|
||||
def __iter__(self) -> Iterator['RequestArgument']:
|
||||
"""
|
||||
Iterate the values of this argument. Each value is accessible as if it were a scalar RequestArgument in turn,
|
||||
although they are immutable.
|
||||
|
||||
: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
|
||||
_value: List[Tuple[str, Union[bytes, str]]] = self.__value
|
||||
for v in _value:
|
||||
# If this is an array, 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).
|
||||
: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 ValueError('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])
|
||||
|
||||
|
||||
class _View(RequestArgument):
|
||||
"""
|
||||
This class represents an immutable view of a (subset of a) RequestArgument object. Should not be instantiated
|
||||
directly.
|
||||
"""
|
||||
|
||||
def __init__(self, name: str, value: Union[Tuple[str, Union[bytes, str]], List[Tuple[str, Union[bytes, str]]]]):
|
||||
def __init__(self, name: str, value: Union[Tuple[str, Union[bytes, str]], List[Tuple[str, Union[bytes, str]]]])\
|
||||
-> None:
|
||||
"""
|
||||
Create a new immutable view of a (subset of a) RequestArgument.
|
||||
|
||||
:param name: The name for this argument, same as in the original RequestArgument.
|
||||
:param value: The values to represent in this view, obtained by e.g. indexing or slicing.
|
||||
"""
|
||||
super().__init__(name, value)
|
||||
|
||||
@property
|
||||
def is_view(self) -> bool:
|
||||
"""
|
||||
:return: True, if this instance is an immutable view, False otherwise.
|
||||
"""
|
||||
return True
|
||||
|
|
|
@ -69,6 +69,7 @@ def _parse_multipart(body: bytes, boundary: str) -> List[RequestArgument]:
|
|||
args[name] = RequestArgument(name)
|
||||
args[name].append(hdr['Content-Type'].strip(), part)
|
||||
if not has_name:
|
||||
# Content-Disposition header without name attribute
|
||||
raise ValueError('mutlipart/form-data part without name attribute')
|
||||
|
||||
return list(args.values())
|
||||
|
|
Loading…
Reference in a new issue