1 files changed, 125 insertions, 0 deletions
diff --git a/yt_dlp/postprocessor/metadataparser.py b/yt_dlp/postprocessor/metadataparser.py
new file mode 100644
index 0000000..1d60542
--- /dev/null
+++ b/yt_dlp/postprocessor/metadataparser.py
@@ -0,0 +1,125 @@
+import re
+
+from .common import PostProcessor
+from ..utils import Namespace, filter_dict, function_with_repr
+
+
+class MetadataParserPP(PostProcessor):
+    def __init__(self, downloader, actions):
+        super().__init__(downloader)
+        self._actions = []
+        for f in actions:
+            action, *args = f
+            assert action in self.Actions
+            self._actions.append(action(self, *args))
+
+    @classmethod
+    def validate_action(cls, action, *data):
+        """Each action can be:
+                (Actions.INTERPRET, from, to) OR
+                (Actions.REPLACE, field, search, replace)
+        """
+        if action not in cls.Actions:
+            raise ValueError(f'{action!r} is not a valid action')
+        action(cls, *data)  # So this can raise error to validate
+
+    @staticmethod
+    def field_to_template(tmpl):
+        if re.match(r'[a-zA-Z_]+$', tmpl):
+            return f'%({tmpl})s'
+
+        from ..YoutubeDL import YoutubeDL
+        err = YoutubeDL.validate_outtmpl(tmpl)
+        if err:
+            raise err
+        return tmpl
+
+    @staticmethod
+    def format_to_regex(fmt):
+        r"""
+        Converts a string like
+           '%(title)s - %(artist)s'
+        to a regex like
+           '(?P<title>.+)\ \-\ (?P<artist>.+)'
+        """
+        if not re.search(r'%\(\w+\)s', fmt):
+            return fmt
+        lastpos = 0
+        regex = ''
+        # replace %(..)s with regex group and escape other string parts
+        for match in re.finditer(r'%\((\w+)\)s', fmt):
+            regex += re.escape(fmt[lastpos:match.start()])
+            regex += rf'(?P<{match.group(1)}>.+)'
+            lastpos = match.end()
+        if lastpos < len(fmt):
+            regex += re.escape(fmt[lastpos:])
+        return regex
+
+    def run(self, info):
+        for f in self._actions:
+            f(info)
+        return [], info
+
+    @function_with_repr
+    def interpretter(self, inp, out):
+        def f(info):
+            data_to_parse = self._downloader.evaluate_outtmpl(template, info)
+            self.write_debug(f'Searching for {out_re.pattern!r} in {template!r}')
+            match = out_re.search(data_to_parse)
+            if match is None:
+                self.to_screen(f'Could not interpret {inp!r} as {out!r}')
+                return
+            for attribute, value in filter_dict(match.groupdict()).items():
+                info[attribute] = value
+                self.to_screen(f'Parsed {attribute} from {template!r}: {value!r}')
+
+        template = self.field_to_template(inp)
+        out_re = re.compile(self.format_to_regex(out))
+        return f
+
+    @function_with_repr
+    def replacer(self, field, search, replace):
+        def f(info):
+            val = info.get(field)
+            if val is None:
+                self.to_screen(f'Video does not have a {field}')
+                return
+            elif not isinstance(val, str):
+                self.report_warning(f'Cannot replace in field {field} since it is a {type(val).__name__}')
+                return
+            self.write_debug(f'Replacing all {search!r} in {field} with {replace!r}')
+            info[field], n = search_re.subn(replace, val)
+            if n:
+                self.to_screen(f'Changed {field} to: {info[field]}')
+            else:
+                self.to_screen(f'Did not find {search!r} in {field}')
+
+        search_re = re.compile(search)
+        return f
+
+    Actions = Namespace(INTERPRET=interpretter, REPLACE=replacer)
+
+
+class MetadataFromFieldPP(MetadataParserPP):
+    @classmethod
+    def to_action(cls, f):
+        match = re.match(r'(?s)(?P<in>.*?)(?<!\\):(?P<out>.+)$', f)
+        if match is None:
+            raise ValueError(f'it should be FROM:TO, not {f!r}')
+        return (
+            cls.Actions.INTERPRET,
+            match.group('in').replace('\\:', ':'),
+            match.group('out'),
+        )
+
+    def __init__(self, downloader, formats):
+        super().__init__(downloader, [self.to_action(f) for f in formats])
+
+
+# Deprecated
+class MetadataFromTitlePP(MetadataParserPP):
+    def __init__(self, downloader, titleformat):
+        super().__init__(downloader, [(self.Actions.INTERPRET, 'title', titleformat)])
+        self.deprecation_warning(
+            'yt_dlp.postprocessor.MetadataFromTitlePP is deprecated '
+            'and may be removed in a future version. Use yt_dlp.postprocessor.MetadataFromFieldPP instead')