]>
Commit | Line | Data |
---|---|---|
69bec673 | 1 | import collections.abc |
2 | import contextlib | |
32abfb00 | 3 | import http.cookies |
69bec673 | 4 | import inspect |
5 | import itertools | |
6 | import re | |
ffbd4f2a | 7 | import xml.etree.ElementTree |
69bec673 | 8 | |
9 | from ._utils import ( | |
10 | IDENTITY, | |
11 | NO_DEFAULT, | |
12 | LazyList, | |
0b6f829b | 13 | deprecation_warning, |
69bec673 | 14 | is_iterable_like, |
15 | try_call, | |
16 | variadic, | |
17 | ) | |
18 | ||
19 | ||
20 | def traverse_obj( | |
21 | obj, *paths, default=NO_DEFAULT, expected_type=None, get_all=True, | |
0b6f829b | 22 | casesense=True, is_user_input=NO_DEFAULT, traverse_string=False): |
69bec673 | 23 | """ |
24 | Safely traverse nested `dict`s and `Iterable`s | |
25 | ||
26 | >>> obj = [{}, {"key": "value"}] | |
27 | >>> traverse_obj(obj, (1, "key")) | |
f9fb3ce8 | 28 | 'value' |
69bec673 | 29 | |
30 | Each of the provided `paths` is tested and the first producing a valid result will be returned. | |
31 | The next path will also be tested if the path branched but no results could be found. | |
32abfb00 SS |
32 | Supported values for traversal are `Mapping`, `Iterable`, `re.Match`, |
33 | `xml.etree.ElementTree` (xpath) and `http.cookies.Morsel`. | |
69bec673 | 34 | Unhelpful values (`{}`, `None`) are treated as the absence of a value and discarded. |
35 | ||
36 | The paths will be wrapped in `variadic`, so that `'key'` is conveniently the same as `('key', )`. | |
37 | ||
38 | The keys in the path can be one of: | |
39 | - `None`: Return the current object. | |
40 | - `set`: Requires the only item in the set to be a type or function, | |
32abfb00 SS |
41 | like `{type}`/`{type, type, ...}/`{func}`. If a `type`, return only |
42 | values of this type. If a function, returns `func(obj)`. | |
69bec673 | 43 | - `str`/`int`: Return `obj[key]`. For `re.Match`, return `obj.group(key)`. |
44 | - `slice`: Branch out and return all values in `obj[key]`. | |
45 | - `Ellipsis`: Branch out and return a list of all values. | |
46 | - `tuple`/`list`: Branch out and return a list of all matching values. | |
47 | Read as: `[traverse_obj(obj, branch) for branch in branches]`. | |
48 | - `function`: Branch out and return values filtered by the function. | |
49 | Read as: `[value for key, value in obj if function(key, value)]`. | |
50 | For `Iterable`s, `key` is the index of the value. | |
51 | For `re.Match`es, `key` is the group number (0 = full match) | |
52 | as well as additionally any group names, if given. | |
32abfb00 | 53 | - `dict`: Transform the current object and return a matching dict. |
69bec673 | 54 | Read as: `{key: traverse_obj(obj, path) for key, path in dct.items()}`. |
32abfb00 SS |
55 | - `any`-builtin: Take the first matching object and return it, resetting branching. |
56 | - `all`-builtin: Take all matching objects and return them as a list, resetting branching. | |
69bec673 | 57 | |
58 | `tuple`, `list`, and `dict` all support nested paths and branches. | |
59 | ||
60 | @params paths Paths which to traverse by. | |
61 | @param default Value to return if the paths do not match. | |
62 | If the last key in the path is a `dict`, it will apply to each value inside | |
63 | the dict instead, depth first. Try to avoid if using nested `dict` keys. | |
64 | @param expected_type If a `type`, only accept final values of this type. | |
65 | If any other callable, try to call the function on each result. | |
66 | If the last key in the path is a `dict`, it will apply to each value inside | |
67 | the dict instead, recursively. This does respect branching paths. | |
68 | @param get_all If `False`, return the first matching result, otherwise all matching ones. | |
69 | @param casesense If `False`, consider string dictionary keys as case insensitive. | |
70 | ||
0b6f829b | 71 | `traverse_string` is only meant to be used by YoutubeDL.prepare_outtmpl and is not part of the API |
69bec673 | 72 | |
69bec673 | 73 | @param traverse_string Whether to traverse into objects as strings. |
74 | If `True`, any non-compatible object will first be | |
75 | converted into a string and then traversed into. | |
76 | The return value of that path will be a string instead, | |
77 | not respecting any further branching. | |
78 | ||
79 | ||
80 | @returns The result of the object traversal. | |
81 | If successful, `get_all=True`, and the path branches at least once, | |
82 | then a list of results is returned instead. | |
83 | If no `default` is given and the last path branches, a `list` of results | |
84 | is always returned. If a path ends on a `dict` that result will always be a `dict`. | |
85 | """ | |
0b6f829b SS |
86 | if is_user_input is not NO_DEFAULT: |
87 | deprecation_warning('The is_user_input parameter is deprecated and no longer works') | |
88 | ||
69bec673 | 89 | casefold = lambda k: k.casefold() if isinstance(k, str) else k |
90 | ||
91 | if isinstance(expected_type, type): | |
92 | type_test = lambda val: val if isinstance(val, expected_type) else None | |
93 | else: | |
94 | type_test = lambda val: try_call(expected_type or IDENTITY, args=(val,)) | |
95 | ||
96 | def apply_key(key, obj, is_last): | |
97 | branching = False | |
98 | result = None | |
99 | ||
100 | if obj is None and traverse_string: | |
101 | if key is ... or callable(key) or isinstance(key, slice): | |
102 | branching = True | |
103 | result = () | |
104 | ||
105 | elif key is None: | |
106 | result = obj | |
107 | ||
108 | elif isinstance(key, set): | |
69bec673 | 109 | item = next(iter(key)) |
32abfb00 SS |
110 | if len(key) > 1 or isinstance(item, type): |
111 | assert all(isinstance(item, type) for item in key) | |
112 | if isinstance(obj, tuple(key)): | |
69bec673 | 113 | result = obj |
114 | else: | |
115 | result = try_call(item, args=(obj,)) | |
116 | ||
117 | elif isinstance(key, (list, tuple)): | |
118 | branching = True | |
119 | result = itertools.chain.from_iterable( | |
120 | apply_path(obj, branch, is_last)[0] for branch in key) | |
121 | ||
122 | elif key is ...: | |
123 | branching = True | |
32abfb00 SS |
124 | if isinstance(obj, http.cookies.Morsel): |
125 | obj = dict(obj, key=obj.key, value=obj.value) | |
69bec673 | 126 | if isinstance(obj, collections.abc.Mapping): |
127 | result = obj.values() | |
ffbd4f2a | 128 | elif is_iterable_like(obj) or isinstance(obj, xml.etree.ElementTree.Element): |
69bec673 | 129 | result = obj |
130 | elif isinstance(obj, re.Match): | |
131 | result = obj.groups() | |
132 | elif traverse_string: | |
133 | branching = False | |
134 | result = str(obj) | |
135 | else: | |
136 | result = () | |
137 | ||
138 | elif callable(key): | |
139 | branching = True | |
32abfb00 SS |
140 | if isinstance(obj, http.cookies.Morsel): |
141 | obj = dict(obj, key=obj.key, value=obj.value) | |
69bec673 | 142 | if isinstance(obj, collections.abc.Mapping): |
143 | iter_obj = obj.items() | |
ffbd4f2a | 144 | elif is_iterable_like(obj) or isinstance(obj, xml.etree.ElementTree.Element): |
69bec673 | 145 | iter_obj = enumerate(obj) |
146 | elif isinstance(obj, re.Match): | |
147 | iter_obj = itertools.chain( | |
148 | enumerate((obj.group(), *obj.groups())), | |
149 | obj.groupdict().items()) | |
150 | elif traverse_string: | |
151 | branching = False | |
152 | iter_obj = enumerate(str(obj)) | |
153 | else: | |
154 | iter_obj = () | |
155 | ||
156 | result = (v for k, v in iter_obj if try_call(key, args=(k, v))) | |
157 | if not branching: # string traversal | |
158 | result = ''.join(result) | |
159 | ||
160 | elif isinstance(key, dict): | |
161 | iter_obj = ((k, _traverse_obj(obj, v, False, is_last)) for k, v in key.items()) | |
162 | result = { | |
163 | k: v if v is not None else default for k, v in iter_obj | |
164 | if v is not None or default is not NO_DEFAULT | |
165 | } or None | |
166 | ||
167 | elif isinstance(obj, collections.abc.Mapping): | |
32abfb00 SS |
168 | if isinstance(obj, http.cookies.Morsel): |
169 | obj = dict(obj, key=obj.key, value=obj.value) | |
69bec673 | 170 | result = (try_call(obj.get, args=(key,)) if casesense or try_call(obj.__contains__, args=(key,)) else |
171 | next((v for k, v in obj.items() if casefold(k) == key), None)) | |
172 | ||
173 | elif isinstance(obj, re.Match): | |
174 | if isinstance(key, int) or casesense: | |
175 | with contextlib.suppress(IndexError): | |
176 | result = obj.group(key) | |
177 | ||
178 | elif isinstance(key, str): | |
179 | result = next((v for k, v in obj.groupdict().items() if casefold(k) == key), None) | |
180 | ||
181 | elif isinstance(key, (int, slice)): | |
ffbd4f2a | 182 | if is_iterable_like(obj, (collections.abc.Sequence, xml.etree.ElementTree.Element)): |
69bec673 | 183 | branching = isinstance(key, slice) |
184 | with contextlib.suppress(IndexError): | |
185 | result = obj[key] | |
186 | elif traverse_string: | |
187 | with contextlib.suppress(IndexError): | |
188 | result = str(obj)[key] | |
189 | ||
ffbd4f2a SS |
190 | elif isinstance(obj, xml.etree.ElementTree.Element) and isinstance(key, str): |
191 | xpath, _, special = key.rpartition('/') | |
32abfb00 | 192 | if not special.startswith('@') and not special.endswith('()'): |
ffbd4f2a SS |
193 | xpath = key |
194 | special = None | |
195 | ||
196 | # Allow abbreviations of relative paths, absolute paths error | |
197 | if xpath.startswith('/'): | |
198 | xpath = f'.{xpath}' | |
199 | elif xpath and not xpath.startswith('./'): | |
200 | xpath = f'./{xpath}' | |
201 | ||
202 | def apply_specials(element): | |
203 | if special is None: | |
204 | return element | |
205 | if special == '@': | |
206 | return element.attrib | |
207 | if special.startswith('@'): | |
208 | return try_call(element.attrib.get, args=(special[1:],)) | |
209 | if special == 'text()': | |
210 | return element.text | |
32abfb00 | 211 | raise SyntaxError(f'apply_specials is missing case for {special!r}') |
ffbd4f2a SS |
212 | |
213 | if xpath: | |
214 | result = list(map(apply_specials, obj.iterfind(xpath))) | |
215 | else: | |
216 | result = apply_specials(obj) | |
217 | ||
69bec673 | 218 | return branching, result if branching else (result,) |
219 | ||
220 | def lazy_last(iterable): | |
221 | iterator = iter(iterable) | |
222 | prev = next(iterator, NO_DEFAULT) | |
223 | if prev is NO_DEFAULT: | |
224 | return | |
225 | ||
226 | for item in iterator: | |
227 | yield False, prev | |
228 | prev = item | |
229 | ||
230 | yield True, prev | |
231 | ||
232 | def apply_path(start_obj, path, test_type): | |
233 | objs = (start_obj,) | |
234 | has_branched = False | |
235 | ||
236 | key = None | |
237 | for last, key in lazy_last(variadic(path, (str, bytes, dict, set))): | |
69bec673 | 238 | if not casesense and isinstance(key, str): |
239 | key = key.casefold() | |
240 | ||
3699eeb6 SS |
241 | if key in (any, all): |
242 | has_branched = False | |
243 | filtered_objs = (obj for obj in objs if obj not in (None, {})) | |
244 | if key is any: | |
245 | objs = (next(filtered_objs, None),) | |
246 | else: | |
247 | objs = (list(filtered_objs),) | |
248 | continue | |
249 | ||
69bec673 | 250 | if __debug__ and callable(key): |
251 | # Verify function signature | |
252 | inspect.signature(key).bind(None, None) | |
253 | ||
254 | new_objs = [] | |
255 | for obj in objs: | |
256 | branching, results = apply_key(key, obj, last) | |
257 | has_branched |= branching | |
258 | new_objs.append(results) | |
259 | ||
260 | objs = itertools.chain.from_iterable(new_objs) | |
261 | ||
262 | if test_type and not isinstance(key, (dict, list, tuple)): | |
263 | objs = map(type_test, objs) | |
264 | ||
265 | return objs, has_branched, isinstance(key, dict) | |
266 | ||
267 | def _traverse_obj(obj, path, allow_empty, test_type): | |
268 | results, has_branched, is_dict = apply_path(obj, path, test_type) | |
269 | results = LazyList(item for item in results if item not in (None, {})) | |
270 | if get_all and has_branched: | |
271 | if results: | |
272 | return results.exhaust() | |
273 | if allow_empty: | |
274 | return [] if default is NO_DEFAULT else default | |
275 | return None | |
276 | ||
277 | return results[0] if results else {} if allow_empty and is_dict else None | |
278 | ||
279 | for index, path in enumerate(paths, 1): | |
280 | result = _traverse_obj(obj, path, index == len(paths), True) | |
281 | if result is not None: | |
282 | return result | |
283 | ||
284 | return None if default is NO_DEFAULT else default | |
285 | ||
286 | ||
287 | def get_first(obj, *paths, **kwargs): | |
288 | return traverse_obj(obj, *((..., *variadic(keys)) for keys in paths), **kwargs, get_all=False) | |
289 | ||
290 | ||
291 | def dict_get(d, key_or_keys, default=None, skip_false_values=True): | |
292 | for val in map(d.get, variadic(key_or_keys)): | |
293 | if val is not None and (val or not skip_false_values): | |
294 | return val | |
295 | return default |