import re import json as pyjson from typing import List, Optional, Any from inspect import signature from functools import wraps from hashlib import sha256 from urllib.parse import urlparse, quote, unquote from html import escape, unescape from datetime import datetime from dateparser import parse as dateparser import requests from base32_crockford import encode as base32_encode # type: ignore from w3lib.encoding import html_body_declared_encoding, http_content_type_encoding try: import chardet detect_encoding = lambda rawdata: chardet.detect(rawdata)["encoding"] except ImportError: detect_encoding = lambda rawdata: "utf-8" ### Parsing Helpers # All of these are (str) -> str # shortcuts to: https://docs.python.org/3/library/urllib.parse.html#url-parsing scheme = lambda url: urlparse(url).scheme.lower() without_scheme = lambda url: urlparse(url)._replace(scheme='').geturl().strip('//') without_query = lambda url: urlparse(url)._replace(query='').geturl().strip('//') without_fragment = lambda url: urlparse(url)._replace(fragment='').geturl().strip('//') without_path = lambda url: urlparse(url)._replace(path='', fragment='', query='').geturl().strip('//') path = lambda url: urlparse(url).path basename = lambda url: urlparse(url).path.rsplit('/', 1)[-1] domain = lambda url: urlparse(url).netloc query = lambda url: urlparse(url).query fragment = lambda url: urlparse(url).fragment extension = lambda url: basename(url).rsplit('.', 1)[-1].lower() if '.' in basename(url) else '' base_url = lambda url: without_scheme(url) # uniq base url used to dedupe links without_www = lambda url: url.replace('://www.', '://', 1) without_trailing_slash = lambda url: url[:-1] if url[-1] == '/' else url.replace('/?', '?') hashurl = lambda url: base32_encode(int(sha256(base_url(url).encode('utf-8')).hexdigest(), 16))[:20] urlencode = lambda s: s and quote(s, encoding='utf-8', errors='replace') urldecode = lambda s: s and unquote(s) htmlencode = lambda s: s and escape(s, quote=True) htmldecode = lambda s: s and unescape(s) short_ts = lambda ts: str(parse_date(ts).timestamp()).split('.')[0] ts_to_date = lambda ts: ts and parse_date(ts).strftime('%Y-%m-%d %H:%M') ts_to_iso = lambda ts: ts and parse_date(ts).isoformat() URL_REGEX = re.compile( r'http[s]?://' # start matching from allowed schemes r'(?:[a-zA-Z]|[0-9]' # followed by allowed alphanum characters r'|[$-_@.&+]|[!*\(\),]' # or allowed symbols r'|(?:%[0-9a-fA-F][0-9a-fA-F]))' # or allowed unicode bytes r'[^\]\[\(\)<>\""\'\s]+', # stop parsing at these symbols re.IGNORECASE, ) COLOR_REGEX = re.compile(r'\[(?P\d+)(;(?P\d+)(;(?P\d+))?)?m') def is_static_file(url: str): # TODO: the proper way is with MIME type detection + ext, not only extension from .config import STATICFILE_EXTENSIONS return extension(url).lower() in STATICFILE_EXTENSIONS def enforce_types(func): """ Enforce function arg and kwarg types at runtime using its python3 type hints """ # TODO: check return type as well @wraps(func) def typechecked_function(*args, **kwargs): sig = signature(func) def check_argument_type(arg_key, arg_val): try: annotation = sig.parameters[arg_key].annotation except KeyError: annotation = None if annotation is not None and annotation.__class__ is type: if not isinstance(arg_val, annotation): raise TypeError( '{}(..., {}: {}) got unexpected {} argument {}={}'.format( func.__name__, arg_key, annotation.__name__, type(arg_val).__name__, arg_key, str(arg_val)[:64], ) ) # check args for arg_val, arg_key in zip(args, sig.parameters): check_argument_type(arg_key, arg_val) # check kwargs for arg_key, arg_val in kwargs.items(): check_argument_type(arg_key, arg_val) return func(*args, **kwargs) return typechecked_function def docstring(text: Optional[str]): """attach the given docstring to the decorated function""" def decorator(func): if text: func.__doc__ = text return func return decorator @enforce_types def str_between(string: str, start: str, end: str=None) -> str: """(12345, , ) -> 12345""" content = string.split(start, 1)[-1] if end is not None: content = content.rsplit(end, 1)[0] return content @enforce_types def parse_date(date: Any) -> Optional[datetime]: """Parse unix timestamps, iso format, and human-readable strings""" if date is None: return None if isinstance(date, datetime): return date if isinstance(date, (float, int)): date = str(date) if isinstance(date, str): return dateparser(date) raise ValueError('Tried to parse invalid date! {}'.format(date)) @enforce_types def download_url(url: str, timeout: int=None) -> str: """Download the contents of a remote url and return the text""" from .config import TIMEOUT, CHECK_SSL_VALIDITY, WGET_USER_AGENT timeout = timeout or TIMEOUT response = requests.get( url, headers={'User-Agent': WGET_USER_AGENT}, verify=CHECK_SSL_VALIDITY, timeout=timeout, ) content_type = response.headers.get('Content-Type', '') encoding = http_content_type_encoding(content_type) or html_body_declared_encoding(response.text) if encoding is not None: response.encoding = encoding return response.text @enforce_types def chrome_args(**options) -> List[str]: """helper to build up a chrome shell command with arguments""" from .config import CHROME_OPTIONS options = {**CHROME_OPTIONS, **options} cmd_args = [options['CHROME_BINARY']] if options['CHROME_HEADLESS']: cmd_args += ('--headless',) if not options['CHROME_SANDBOX']: # assume this means we are running inside a docker container # in docker, GPU support is limited, sandboxing is unecessary, # and SHM is limited to 64MB by default (which is too low to be usable). cmd_args += ( '--no-sandbox', '--disable-gpu', '--disable-dev-shm-usage', '--disable-software-rasterizer', ) if not options['CHECK_SSL_VALIDITY']: cmd_args += ('--disable-web-security', '--ignore-certificate-errors') if options['CHROME_USER_AGENT']: cmd_args += ('--user-agent={}'.format(options['CHROME_USER_AGENT']),) if options['RESOLUTION']: cmd_args += ('--window-size={}'.format(options['RESOLUTION']),) if options['TIMEOUT']: cmd_args += ('--timeout={}'.format((options['TIMEOUT']) * 1000),) if options['CHROME_USER_DATA_DIR']: cmd_args.append('--user-data-dir={}'.format(options['CHROME_USER_DATA_DIR'])) return cmd_args def ansi_to_html(text): """ Based on: https://stackoverflow.com/questions/19212665/python-converting-ansi-color-codes-to-html """ from .config import COLOR_DICT TEMPLATE = '
' text = text.replace('[m', '
') def single_sub(match): argsdict = match.groupdict() if argsdict['arg_3'] is None: if argsdict['arg_2'] is None: _, color = 0, argsdict['arg_1'] else: _, color = argsdict['arg_1'], argsdict['arg_2'] else: _, color = argsdict['arg_3'], argsdict['arg_2'] return TEMPLATE.format(COLOR_DICT[color][0]) return COLOR_REGEX.sub(single_sub, text) class AttributeDict(dict): """Helper to allow accessing dict values via Example.key or Example['key']""" def __init__(self, *args, **kwargs): super().__init__(*args, **kwargs) # Recursively convert nested dicts to AttributeDicts (optional): # for key, val in self.items(): # if isinstance(val, dict) and type(val) is not AttributeDict: # self[key] = AttributeDict(val) def __getattr__(self, attr: str) -> Any: return dict.__getitem__(self, attr) def __setattr__(self, attr: str, value: Any) -> None: return dict.__setitem__(self, attr, value) class ExtendedEncoder(pyjson.JSONEncoder): """ Extended json serializer that supports serializing several model fields and objects """ def default(self, obj): cls_name = obj.__class__.__name__ if hasattr(obj, '_asdict'): return obj._asdict() elif isinstance(obj, bytes): return obj.decode() elif isinstance(obj, datetime): return obj.isoformat() elif isinstance(obj, Exception): return '{}: {}'.format(obj.__class__.__name__, obj) elif cls_name in ('dict_items', 'dict_keys', 'dict_values'): return tuple(obj) return pyjson.JSONEncoder.default(self, obj)