clean_links_mapper.py

# Some code here has been modified from:
# https://github.com/kallewesterling/CleanText/
# --------------------------------------------------------
from typing import Optional

import regex as re

from ..base_op import OPERATORS, Mapper


@OPERATORS.register_module('clean_links_mapper')
class CleanLinksMapper(Mapper):
    """Mapper to clean links like http/https/ftp in text samples."""

    _batched_op = True

    def __init__(self,
                 pattern: Optional[str] = None,
                 repl: str = '',
                 *args,
                 **kwargs):
        """
        Initialization method.

        :param pattern: regular expression pattern to search for within text.
        :param repl: replacement string, default is empty string.
        :param args: extra args
        :param kwargs: extra args
        """
        super().__init__(*args, **kwargs)
        if pattern is None:
            self.pattern = r'(?i)\b('
            self.pattern += r'(?:[a-z][\w-]+:(?:\/{1,3}|'
            self.pattern += r'[a-z0-9%])|www\d{0,3}[.]|'
            self.pattern += r'[a-z0-9.\-]+[.][a-z]{2,4}\/)'
            self.pattern += r'(?:[^\s()<>]+|\(([^\s()<>]+|'
            self.pattern += r'(\([^\s()<>]+\)))*\))'
            self.pattern += r'+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|'
            self.pattern += r'[^\s`!()\[\]{};:\'\".,<>?«»“”‘’])'
            self.pattern += r')'
        else:
            self.pattern = pattern
            if ((len(pattern) > 2) and
                (pattern.startswith("r'") and pattern.endswith("'")
                 or pattern.startswith('r"') and pattern.endswith('"'))):
                self.pattern = pattern[2:-1]
        self.repl = repl

    def process_batched(self, samples):
        for idx, text in enumerate(samples[self.text_key]):
            if not re.search(self.pattern, text, flags=re.DOTALL):
                continue

            samples[self.text_key][idx] = re.sub(pattern=self.pattern,
                                                 repl=self.repl,
                                                 string=text,
                                                 flags=re.DOTALL)
        return samples