1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
import abc
import io
import itertools
import os
import pathlib
from typing import Any, BinaryIO, Iterable, Iterator, NoReturn, Text, Optional
from typing import runtime_checkable, Protocol
from typing import Union
StrPath = Union[str, os.PathLike[str]]
__all__ = ["ResourceReader", "Traversable", "TraversableResources"]
class ResourceReader(metaclass=abc.ABCMeta):
"""Abstract base class for loaders to provide resource reading support."""
@abc.abstractmethod
def open_resource(self, resource: Text) -> BinaryIO:
"""Return an opened, file-like object for binary reading.
The 'resource' argument is expected to represent only a file name.
If the resource cannot be found, FileNotFoundError is raised.
"""
# This deliberately raises FileNotFoundError instead of
# NotImplementedError so that if this method is accidentally called,
# it'll still do the right thing.
raise FileNotFoundError
@abc.abstractmethod
def resource_path(self, resource: Text) -> Text:
"""Return the file system path to the specified resource.
The 'resource' argument is expected to represent only a file name.
If the resource does not exist on the file system, raise
FileNotFoundError.
"""
# This deliberately raises FileNotFoundError instead of
# NotImplementedError so that if this method is accidentally called,
# it'll still do the right thing.
raise FileNotFoundError
@abc.abstractmethod
def is_resource(self, path: Text) -> bool:
"""Return True if the named 'path' is a resource.
Files are resources, directories are not.
"""
raise FileNotFoundError
@abc.abstractmethod
def contents(self) -> Iterable[str]:
"""Return an iterable of entries in `package`."""
raise FileNotFoundError
class TraversalError(Exception):
pass
@runtime_checkable
class Traversable(Protocol):
"""
An object with a subset of pathlib.Path methods suitable for
traversing directories and opening files.
Any exceptions that occur when accessing the backing resource
may propagate unaltered.
"""
@abc.abstractmethod
def iterdir(self) -> Iterator["Traversable"]:
"""
Yield Traversable objects in self
"""
def read_bytes(self) -> bytes:
"""
Read contents of self as bytes
"""
with self.open('rb') as strm:
return strm.read()
def read_text(self, encoding: Optional[str] = None) -> str:
"""
Read contents of self as text
"""
with self.open(encoding=encoding) as strm:
return strm.read()
@abc.abstractmethod
def is_dir(self) -> bool:
"""
Return True if self is a directory
"""
@abc.abstractmethod
def is_file(self) -> bool:
"""
Return True if self is a file
"""
def joinpath(self, *descendants: StrPath) -> "Traversable":
"""
Return Traversable resolved with any descendants applied.
Each descendant should be a path segment relative to self
and each may contain multiple levels separated by
``posixpath.sep`` (``/``).
"""
if not descendants:
return self
names = itertools.chain.from_iterable(
path.parts for path in map(pathlib.PurePosixPath, descendants)
)
target = next(names)
matches = (
traversable for traversable in self.iterdir() if traversable.name == target
)
try:
match = next(matches)
except StopIteration:
raise TraversalError(
"Target not found during traversal.", target, list(names)
)
return match.joinpath(*names)
def __truediv__(self, child: StrPath) -> "Traversable":
"""
Return Traversable child in self
"""
return self.joinpath(child)
@abc.abstractmethod
def open(self, mode='r', *args, **kwargs):
"""
mode may be 'r' or 'rb' to open as text or binary. Return a handle
suitable for reading (same as pathlib.Path.open).
When opening as text, accepts encoding parameters such as those
accepted by io.TextIOWrapper.
"""
@property
@abc.abstractmethod
def name(self) -> str:
"""
The base name of this object without any parent references.
"""
class TraversableResources(ResourceReader):
"""
The required interface for providing traversable
resources.
"""
@abc.abstractmethod
def files(self) -> "Traversable":
"""Return a Traversable object for the loaded package."""
def open_resource(self, resource: StrPath) -> io.BufferedReader:
return self.files().joinpath(resource).open('rb')
def resource_path(self, resource: Any) -> NoReturn:
raise FileNotFoundError(resource)
def is_resource(self, path: StrPath) -> bool:
return self.files().joinpath(path).is_file()
def contents(self) -> Iterator[str]:
return (item.name for item in self.files().iterdir())
|
