Add extractor helpers (#10653)

Authored by: Grub4K

test/test_traversal.py

@@ -4,8 +4,18 @@
 
 import pytest
 
-from yt_dlp.utils import dict_get, int_or_none, str_or_none
-from yt_dlp.utils.traversal import traverse_obj
+from yt_dlp.utils import (
+    ExtractorError,
+    determine_ext,
+    dict_get,
+    int_or_none,
+    str_or_none,
+)
+from yt_dlp.utils.traversal import (
+    traverse_obj,
+    require,
+    subs_list_to_dict,
+)
 
 _TEST_DATA = {
     100: 100,
@@ -420,6 +430,71 @@ def test_traversal_morsel(self):
         assert traverse_obj(morsel, [(None,), any]) == morsel, \
             'Morsel should not be implicitly changed to dict on usage'
 
+    def test_traversal_filter(self):
+        data = [None, False, True, 0, 1, 0.0, 1.1, '', 'str', {}, {0: 0}, [], [1]]
+
+        assert traverse_obj(data, [..., filter]) == [True, 1, 1.1, 'str', {0: 0}, [1]], \
+            '`filter` should filter falsy values'
+
+
+class TestTraversalHelpers:
+    def test_traversal_require(self):
+        with pytest.raises(ExtractorError):
+            traverse_obj(_TEST_DATA, ['None', {require('value')}])
+        assert traverse_obj(_TEST_DATA, ['str', {require('value')}]) == 'str', \
+            '`require` should pass through non `None` values'
+
+    def test_subs_list_to_dict(self):
+        assert traverse_obj([
+            {'name': 'de', 'url': 'https://example.com/subs/de.vtt'},
+            {'name': 'en', 'url': 'https://example.com/subs/en1.ass'},
+            {'name': 'en', 'url': 'https://example.com/subs/en2.ass'},
+        ], [..., {
+            'id': 'name',
+            'url': 'url',
+        }, all, {subs_list_to_dict}]) == {
+            'de': [{'url': 'https://example.com/subs/de.vtt'}],
+            'en': [
+                {'url': 'https://example.com/subs/en1.ass'},
+                {'url': 'https://example.com/subs/en2.ass'},
+            ],
+        }, 'function should build subtitle dict from list of subtitles'
+        assert traverse_obj([
+            {'name': 'de', 'url': 'https://example.com/subs/de.ass'},
+            {'name': 'de'},
+            {'name': 'en', 'content': 'content'},
+            {'url': 'https://example.com/subs/en'},
+        ], [..., {
+            'id': 'name',
+            'data': 'content',
+            'url': 'url',
+        }, all, {subs_list_to_dict}]) == {
+            'de': [{'url': 'https://example.com/subs/de.ass'}],
+            'en': [{'data': 'content'}],
+        }, 'subs with mandatory items missing should be filtered'
+        assert traverse_obj([
+            {'url': 'https://example.com/subs/de.ass', 'name': 'de'},
+            {'url': 'https://example.com/subs/en', 'name': 'en'},
+        ], [..., {
+            'id': 'name',
+            'ext': ['url', {lambda x: determine_ext(x, default_ext=None)}],
+            'url': 'url',
+        }, all, {subs_list_to_dict(ext='ext')}]) == {
+            'de': [{'url': 'https://example.com/subs/de.ass', 'ext': 'ass'}],
+            'en': [{'url': 'https://example.com/subs/en', 'ext': 'ext'}],
+        }, '`ext` should set default ext but leave existing value untouched'
+        assert traverse_obj([
+            {'name': 'en', 'url': 'https://example.com/subs/en2', 'prio': True},
+            {'name': 'en', 'url': 'https://example.com/subs/en1', 'prio': False},
+        ], [..., {
+            'id': 'name',
+            'quality': ['prio', {int}],
+            'url': 'url',
+        }, all, {subs_list_to_dict(ext='ext')}]) == {'en': [
+            {'url': 'https://example.com/subs/en1', 'ext': 'ext'},
+            {'url': 'https://example.com/subs/en2', 'ext': 'ext'},
+        ]}, '`quality` key should sort subtitle list accordingly'
+
 
 class TestDictGet:
     def test_dict_get(self):

yt_dlp/extractor/common.py

@@ -573,13 +573,13 @@ class InfoExtractor:
 
     def _login_hint(self, method=NO_DEFAULT, netrc=None):
         password_hint = f'--username and --password, --netrc-cmd, or --netrc ({netrc or self._NETRC_MACHINE}) to provide account credentials'
+        cookies_hint = 'See  https://github.com/yt-dlp/yt-dlp/wiki/FAQ#how-do-i-pass-cookies-to-yt-dlp  for how to manually pass cookies'
         return {
             None: '',
-            'any': f'Use --cookies, --cookies-from-browser, {password_hint}',
+            'any': f'Use --cookies, --cookies-from-browser, {password_hint}. {cookies_hint}',
             'password': f'Use {password_hint}',
-            'cookies': (
-                'Use --cookies-from-browser or --cookies for the authentication. '
-                'See  https://github.com/yt-dlp/yt-dlp/wiki/FAQ#how-do-i-pass-cookies-to-yt-dlp  for how to manually pass cookies'),
+            'cookies': f'Use --cookies-from-browser or --cookies for the authentication. {cookies_hint}',
+            'session_cookies': f'Use --cookies for the authentication (--cookies-from-browser might not work). {cookies_hint}',
         }[method if method is not NO_DEFAULT else 'any' if self.supports_login() else 'cookies']
 
     def __init__(self, downloader=None):

yt_dlp/utils/_utils.py

@@ -1984,11 +1984,30 @@ def urljoin(base, path):
     return urllib.parse.urljoin(base, path)
 
 
-def int_or_none(v, scale=1, default=None, get_attr=None, invscale=1):
+def partial_application(func):
+    sig = inspect.signature(func)
+
+    @functools.wraps(func)
+    def wrapped(*args, **kwargs):
+        try:
+            sig.bind(*args, **kwargs)
+        except TypeError:
+            return functools.partial(func, *args, **kwargs)
+        else:
+            return func(*args, **kwargs)
+
+    return wrapped
+
+
+@partial_application
+def int_or_none(v, scale=1, default=None, get_attr=None, invscale=1, base=None):
     if get_attr and v is not None:
         v = getattr(v, get_attr, None)
+    if invscale == 1 and scale < 1:
+        invscale = int(1 / scale)
+        scale = 1
     try:
-        return int(v) * invscale // scale
+        return (int(v) if base is None else int(v, base=base)) * invscale // scale
     except (ValueError, TypeError, OverflowError):
         return default
 
@@ -2006,9 +2025,13 @@ def str_to_int(int_str):
         return int_or_none(int_str)
 
 
+@partial_application
 def float_or_none(v, scale=1, invscale=1, default=None):
     if v is None:
         return default
+    if invscale == 1 and scale < 1:
+        invscale = int(1 / scale)
+        scale = 1
     try:
         return float(v) * invscale / scale
     except (ValueError, TypeError):

yt_dlp/utils/traversal.py

@@ -1,18 +1,35 @@
+from __future__ import annotations
+
+import collections
 import collections.abc
 import contextlib
+import functools
 import http.cookies
 import inspect
 import itertools
 import re
+import typing
 import xml.etree.ElementTree
 
 from ._utils import (
     IDENTITY,
     NO_DEFAULT,
+    ExtractorError,
     LazyList,
     deprecation_warning,
+    get_elements_html_by_class,
+    get_elements_html_by_attribute,
+    get_elements_by_attribute,
+    get_element_html_by_attribute,
+    get_element_by_attribute,
+    get_element_html_by_id,
+    get_element_by_id,
+    get_element_html_by_class,
+    get_elements_by_class,
+    get_element_text_and_html_by_tag,
     is_iterable_like,
     try_call,
+    url_or_none,
     variadic,
 )
 
@@ -54,6 +71,7 @@ def traverse_obj(
                             Read as: `{key: traverse_obj(obj, path) for key, path in dct.items()}`.
         - `any`-builtin:    Take the first matching object and return it, resetting branching.
         - `all`-builtin:    Take all matching objects and return them as a list, resetting branching.
+        - `filter`-builtin: Return the value if it is truthy, `None` otherwise.
 
         `tuple`, `list`, and `dict` all support nested paths and branches.
 
@@ -247,6 +265,10 @@ def apply_path(start_obj, path, test_type):
                     objs = (list(filtered_objs),)
                 continue
 
+            if key is filter:
+                objs = filter(None, objs)
+                continue
+
             if __debug__ and callable(key):
                 # Verify function signature
                 inspect.signature(key).bind(None, None)
@@ -277,13 +299,143 @@ def _traverse_obj(obj, path, allow_empty, test_type):
         return results[0] if results else {} if allow_empty and is_dict else None
 
     for index, path in enumerate(paths, 1):
-        result = _traverse_obj(obj, path, index == len(paths), True)
+        is_last = index == len(paths)
+        try:
+            result = _traverse_obj(obj, path, is_last, True)
             if result is not None:
                 return result
+        except _RequiredError as e:
+            if is_last:
+                # Reraise to get cleaner stack trace
+                raise ExtractorError(e.orig_msg, expected=e.expected) from None
 
     return None if default is NO_DEFAULT else default
 
 
+def value(value, /):
+    return lambda _: value
+
+
+def require(name, /, *, expected=False):
+    def func(value):
+        if value is None:
+            raise _RequiredError(f'Unable to extract {name}', expected=expected)
+
+        return value
+
+    return func
+
+
+class _RequiredError(ExtractorError):
+    pass
+
+
+@typing.overload
+def subs_list_to_dict(*, ext: str | None = None) -> collections.abc.Callable[[list[dict]], dict[str, list[dict]]]: ...
+
+
+@typing.overload
+def subs_list_to_dict(subs: list[dict] | None, /, *, ext: str | None = None) -> dict[str, list[dict]]: ...
+
+
+def subs_list_to_dict(subs: list[dict] | None = None, /, *, ext=None):
+    """
+    Convert subtitles from a traversal into a subtitle dict.
+    The path should have an `all` immediately before this function.
+
+    Arguments:
+    `ext`      The default value for `ext` in the subtitle dict
+
+    In the dict you can set the following additional items:
+    `id`       The subtitle id to sort the dict into
+    `quality`  The sort order for each subtitle
+    """
+    if subs is None:
+        return functools.partial(subs_list_to_dict, ext=ext)
+
+    result = collections.defaultdict(list)
+
+    for sub in subs:
+        if not url_or_none(sub.get('url')) and not sub.get('data'):
+            continue
+        sub_id = sub.pop('id', None)
+        if sub_id is None:
+            continue
+        if ext is not None and not sub.get('ext'):
+            sub['ext'] = ext
+        result[sub_id].append(sub)
+    result = dict(result)
+
+    for subs in result.values():
+        subs.sort(key=lambda x: x.pop('quality', 0) or 0)
+
+    return result
+
+
+@typing.overload
+def find_element(*, attr: str, value: str, tag: str | None = None, html=False): ...
+
+
+@typing.overload
+def find_element(*, cls: str, html=False): ...
+
+
+@typing.overload
+def find_element(*, id: str, tag: str | None = None, html=False): ...
+
+
+@typing.overload
+def find_element(*, tag: str, html=False): ...
+
+
+def find_element(*, tag=None, id=None, cls=None, attr=None, value=None, html=False):
+    # deliberately using `id=` and `cls=` for ease of readability
+    assert tag or id or cls or (attr and value), 'One of tag, id, cls or (attr AND value) is required'
+    if not tag:
+        tag = r'[\w:.-]+'
+
+    if attr and value:
+        assert not cls, 'Cannot match both attr and cls'
+        assert not id, 'Cannot match both attr and id'
+        func = get_element_html_by_attribute if html else get_element_by_attribute
+        return functools.partial(func, attr, value, tag=tag)
+
+    elif cls:
+        assert not id, 'Cannot match both cls and id'
+        assert tag is None, 'Cannot match both cls and tag'
+        func = get_element_html_by_class if html else get_elements_by_class
+        return functools.partial(func, cls)
+
+    elif id:
+        func = get_element_html_by_id if html else get_element_by_id
+        return functools.partial(func, id, tag=tag)
+
+    index = int(bool(html))
+    return lambda html: get_element_text_and_html_by_tag(tag, html)[index]
+
+
+@typing.overload
+def find_elements(*, cls: str, html=False): ...
+
+
+@typing.overload
+def find_elements(*, attr: str, value: str, tag: str | None = None, html=False): ...
+
+
+def find_elements(*, tag=None, cls=None, attr=None, value=None, html=False):
+    # deliberately using `cls=` for ease of readability
+    assert cls or (attr and value), 'One of cls or (attr AND value) is required'
+
+    if attr and value:
+        assert not cls, 'Cannot match both attr and cls'
+        func = get_elements_html_by_attribute if html else get_elements_by_attribute
+        return functools.partial(func, attr, value, tag=tag or r'[\w:.-]+')
+
+    assert not tag, 'Cannot match both cls and tag'
+    func = get_elements_html_by_class if html else get_elements_by_class
+    return functools.partial(func, cls)
+
+
 def get_first(obj, *paths, **kwargs):
     return traverse_obj(obj, *((..., *variadic(keys)) for keys in paths), **kwargs, get_all=False)