util.py

# -*- coding: utf-8 -*-

# Copyright 2017-2023 Mike Fährmann
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.

"""Utility functions and classes"""

import re
import os
import sys
import json
import time
import random
import getpass
import hashlib
import binascii
import datetime
import functools
import itertools
import subprocess
import urllib.parse
from http.cookiejar import Cookie
from email.utils import mktime_tz, parsedate_tz
from . import text, version, exception


def bencode(num, alphabet="0123456789"):
    """Encode an integer into a base-N encoded string"""
    data = ""
    base = len(alphabet)
    while num:
        num, remainder = divmod(num, base)
        data = alphabet[remainder] + data
    return data


def bdecode(data, alphabet="0123456789"):
    """Decode a base-N encoded string ( N = len(alphabet) )"""
    num = 0
    base = len(alphabet)
    for c in data:
        num *= base
        num += alphabet.index(c)
    return num


def advance(iterable, num):
    """"Advance 'iterable' by 'num' steps"""
    iterator = iter(iterable)
    next(itertools.islice(iterator, num, num), None)
    return iterator


def repeat(times):
    """Return an iterator that returns None"""
    if times < 0:
        return itertools.repeat(None)
    return itertools.repeat(None, times)


def unique(iterable):
    """Yield unique elements from 'iterable' while preserving order"""
    seen = set()
    add = seen.add
    for element in iterable:
        if element not in seen:
            add(element)
            yield element


def unique_sequence(iterable):
    """Yield sequentially unique elements from 'iterable'"""
    last = None
    for element in iterable:
        if element != last:
            last = element
            yield element


def contains(values, elements, separator=" "):
    """Returns True if at least one of 'elements' is contained in 'values'"""
    if isinstance(values, str):
        values = values.split(separator)

    if not isinstance(elements, (tuple, list)):
        return elements in values

    for e in elements:
        if e in values:
            return True
    return False


def raises(cls):
    """Returns a function that raises 'cls' as exception"""
    def wrap(*args):
        raise cls(*args)
    return wrap


def identity(x):
    """Returns its argument"""
    return x


def true(_):
    """Always returns True"""
    return True


def false(_):
    """Always returns False"""
    return False


def noop():
    """Does nothing"""


def md5(s):
    """Generate MD5 hexdigest of 's'"""
    if not s:
        s = b""
    elif isinstance(s, str):
        s = s.encode()
    return hashlib.md5(s).hexdigest()


def sha1(s):
    """Generate SHA1 hexdigest of 's'"""
    if not s:
        s = b""
    elif isinstance(s, str):
        s = s.encode()
    return hashlib.sha1(s).hexdigest()


def generate_token(size=16):
    """Generate a random token with hexadecimal digits"""
    data = random.getrandbits(size * 8).to_bytes(size, "big")
    return binascii.hexlify(data).decode()


def format_value(value, suffixes="kMGTPEZY"):
    value = format(value)
    value_len = len(value)
    index = value_len - 4
    if index >= 0:
        offset = (value_len - 1) % 3 + 1
        return (value[:offset] + "." + value[offset:offset+2] +
                suffixes[index // 3])
    return value


def combine_dict(a, b):
    """Recursively combine the contents of 'b' into 'a'"""
    for key, value in b.items():
        if key in a and isinstance(value, dict) and isinstance(a[key], dict):
            combine_dict(a[key], value)
        else:
            a[key] = value
    return a


def transform_dict(a, func):
    """Recursively apply 'func' to all values in 'a'"""
    for key, value in a.items():
        if isinstance(value, dict):
            transform_dict(value, func)
        else:
            a[key] = func(value)


def filter_dict(a):
    """Return a copy of 'a' without "private" entries"""
    return {k: v for k, v in a.items() if k[0] != "_"}


def delete_items(obj, keys):
    """Remove all 'keys' from 'obj'"""
    for key in keys:
        if key in obj:
            del obj[key]


def enumerate_reversed(iterable, start=0, length=None):
    """Enumerate 'iterable' and return its elements in reverse order"""
    if length is None:
        length = len(iterable)

    try:
        iterable = zip(range(start-1+length, start-1, -1), reversed(iterable))
    except TypeError:
        iterable = list(zip(range(start, start+length), iterable))
        iterable.reverse()

    return iterable


def number_to_string(value, numbers=(int, float)):
    """Convert numbers (int, float) to string; Return everything else as is."""
    return str(value) if value.__class__ in numbers else value


def to_string(value):
    """str() with "better" defaults"""
    if not value:
        return ""
    if value.__class__ is list:
        try:
            return ", ".join(value)
        except Exception:
            return ", ".join(map(str, value))
    return str(value)


def datetime_to_timestamp(dt):
    """Convert naive UTC datetime to timestamp"""
    return (dt - EPOCH) / SECOND


def datetime_to_timestamp_string(dt):
    """Convert naive UTC datetime to timestamp string"""
    try:
        return str((dt - EPOCH) // SECOND)
    except Exception:
        return ""


def json_default(obj):
    if isinstance(obj, CustomNone):
        return None
    return str(obj)


json_loads = json._default_decoder.decode
json_dumps = json.JSONEncoder(default=json_default).encode


def dump_json(obj, fp=sys.stdout, ensure_ascii=True, indent=4):
    """Serialize 'obj' as JSON and write it to 'fp'"""
    json.dump(
        obj, fp,
        ensure_ascii=ensure_ascii,
        indent=indent,
        default=json_default,
        sort_keys=True,
    )
    fp.write("\n")


def dump_response(response, fp, headers=False, content=True, hide_auth=True):
    """Write the contents of 'response' into a file-like object"""

    if headers:
        request = response.request
        req_headers = request.headers.copy()
        res_headers = response.headers.copy()
        outfmt = """\
{request.method} {request.url}
Status: {response.status_code} {response.reason}

Request Headers
---------------
{request_headers}
"""
        if request.body:
            outfmt += """
Request Body
------------
{request.body}
"""
        outfmt += """
Response Headers
----------------
{response_headers}
"""
        if hide_auth:
            authorization = req_headers.get("Authorization")
            if authorization:
                atype, sep, _ = str(authorization).partition(" ")
                req_headers["Authorization"] = atype + " ***" if sep else "***"

            cookie = req_headers.get("Cookie")
            if cookie:
                req_headers["Cookie"] = ";".join(
                    c.partition("=")[0] + "=***"
                    for c in cookie.split(";")
                )

            set_cookie = res_headers.get("Set-Cookie")
            if set_cookie:
                res_headers["Set-Cookie"] = re.sub(
                    r"(^|, )([^ =]+)=[^,;]*", r"\1\2=***", set_cookie,
                )

        fmt_nv = "{}: {}".format

        fp.write(outfmt.format(
            request=request,
            response=response,
            request_headers="\n".join(
                fmt_nv(name, value)
                for name, value in req_headers.items()
            ),
            response_headers="\n".join(
                fmt_nv(name, value)
                for name, value in res_headers.items()
            ),
        ).encode())

    if content:
        if headers:
            fp.write(b"\nContent\n-------\n")
        fp.write(response.content)


def extract_headers(response):
    headers = response.headers
    data = dict(headers)

    hcd = headers.get("content-disposition")
    if hcd:
        name = text.extr(hcd, 'filename="', '"')
        if name:
            text.nameext_from_url(name, data)

    hlm = headers.get("last-modified")
    if hlm:
        data["date"] = datetime.datetime(*parsedate_tz(hlm)[:6])

    return data


@functools.lru_cache(maxsize=None)
def git_head():
    try:
        out, err = Popen(
            ("git", "rev-parse", "--short", "HEAD"),
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            cwd=os.path.dirname(os.path.abspath(__file__)),
        ).communicate()
        if out and not err:
            return out.decode().rstrip()
    except (OSError, subprocess.SubprocessError):
        pass
    return None


def expand_path(path):
    """Expand environment variables and tildes (~)"""
    if not path:
        return path
    if not isinstance(path, str):
        path = os.path.join(*path)
    return os.path.expandvars(os.path.expanduser(path))


def remove_file(path):
    try:
        os.unlink(path)
    except OSError:
        pass


def remove_directory(path):
    try:
        os.rmdir(path)
    except OSError:
        pass


def set_mtime(path, mtime):
    try:
        if isinstance(mtime, str):
            mtime = mktime_tz(parsedate_tz(mtime))
        os.utime(path, (time.time(), mtime))
    except Exception:
        pass


def cookiestxt_load(fp, cookiejar):
    """Parse a Netscape cookies.txt file and add its Cookies to 'cookiejar'"""
    set_cookie = cookiejar.set_cookie

    for line in fp:

        line = line.lstrip(" ")
        # strip '#HttpOnly_'
        if line.startswith("#HttpOnly_"):
            line = line[10:]
        # ignore empty lines and comments
        if not line or line[0] in ("#", "$", "\n"):
            continue
        # strip trailing '\n'
        if line[-1] == "\n":
            line = line[:-1]

        domain, domain_specified, path, secure, expires, name, value = \
            line.split("\t")

        if not name:
            name = value
            value = None

        set_cookie(Cookie(
            0, name, value,
            None, False,
            domain,
            domain_specified == "TRUE",
            domain.startswith("."),
            path, False,
            secure == "TRUE",
            None if expires == "0" or not expires else expires,
            False, None, None, {},
        ))


def cookiestxt_store(fp, cookies):
    """Write 'cookies' in Netscape cookies.txt format to 'fp'"""
    write = fp.write
    write("# Netscape HTTP Cookie File\n\n")

    for cookie in cookies:
        if not cookie.domain:
            continue

        if cookie.value is None:
            name = ""
            value = cookie.name
        else:
            name = cookie.name
            value = cookie.value

        write("\t".join((
            cookie.domain,
            "TRUE" if cookie.domain.startswith(".") else "FALSE",
            cookie.path,
            "TRUE" if cookie.secure else "FALSE",
            "0" if cookie.expires is None else str(cookie.expires),
            name,
            value + "\n",
        )))


def code_to_language(code, default=None):
    """Map an ISO 639-1 language code to its actual name"""
    return CODES.get((code or "").lower(), default)


def language_to_code(lang, default=None):
    """Map a language name to its ISO 639-1 code"""
    if lang is None:
        return default
    lang = lang.capitalize()
    for code, language in CODES.items():
        if language == lang:
            return code
    return default


CODES = {
    "ar": "Arabic",
    "bg": "Bulgarian",
    "ca": "Catalan",
    "cs": "Czech",
    "da": "Danish",
    "de": "German",
    "el": "Greek",
    "en": "English",
    "es": "Spanish",
    "fi": "Finnish",
    "fr": "French",
    "he": "Hebrew",
    "hu": "Hungarian",
    "id": "Indonesian",
    "it": "Italian",
    "ja": "Japanese",
    "ko": "Korean",
    "ms": "Malay",
    "nl": "Dutch",
    "no": "Norwegian",
    "pl": "Polish",
    "pt": "Portuguese",
    "ro": "Romanian",
    "ru": "Russian",
    "sv": "Swedish",
    "th": "Thai",
    "tr": "Turkish",
    "vi": "Vietnamese",
    "zh": "Chinese",
}


class HTTPBasicAuth():
    __slots__ = ("authorization",)

    def __init__(self, username, password):
        self.authorization = b"Basic " + binascii.b2a_base64(
            username.encode("latin1") + b":" + str(password).encode("latin1")
        )[:-1]

    def __call__(self, request):
        request.headers["Authorization"] = self.authorization
        return request


class LazyPrompt():
    __slots__ = ()

    def __str__(self):
        return getpass.getpass()


class CustomNone():
    """None-style type that supports more operations than regular None"""
    __slots__ = ()

    def __getattribute__(self, _):
        return self

    def __getitem__(self, _):
        return self

    def __iter__(self):
        return self

    def __call__(self, *args, **kwargs):
        return self

    @staticmethod
    def __next__():
        raise StopIteration

    @staticmethod
    def __bool__():
        return False

    @staticmethod
    def __len__():
        return 0

    @staticmethod
    def __format__(_):
        return "None"

    @staticmethod
    def __str__():
        return "None"

    __repr__ = __str__


NONE = CustomNone()
EPOCH = datetime.datetime(1970, 1, 1)
SECOND = datetime.timedelta(0, 1)
WINDOWS = (os.name == "nt")
SENTINEL = object()
USERAGENT = "gallery-dl/" + version.__version__
EXECUTABLE = getattr(sys, "frozen", False)
SPECIAL_EXTRACTORS = {"oauth", "recursive", "generic"}
GLOBALS = {
    "contains" : contains,
    "parse_int": text.parse_int,
    "urlsplit" : urllib.parse.urlsplit,
    "datetime" : datetime.datetime,
    "timedelta": datetime.timedelta,
    "abort"    : raises(exception.StopExtraction),
    "terminate": raises(exception.TerminateExtraction),
    "restart"  : raises(exception.RestartExtraction),
    "hash_sha1": sha1,
    "hash_md5" : md5,
    "re"       : re,
}


if EXECUTABLE and hasattr(sys, "_MEIPASS"):
    # https://github.com/pyinstaller/pyinstaller/blob/develop/doc
    # /runtime-information.rst#ld_library_path--libpath-considerations
    _popen_env = os.environ.copy()

    orig = _popen_env.get("LD_LIBRARY_PATH_ORIG")
    if orig is None:
        _popen_env.pop("LD_LIBRARY_PATH", None)
    else:
        _popen_env["LD_LIBRARY_PATH"] = orig

    orig = _popen_env.get("DYLD_LIBRARY_PATH_ORIG")
    if orig is None:
        _popen_env.pop("DYLD_LIBRARY_PATH", None)
    else:
        _popen_env["DYLD_LIBRARY_PATH"] = orig

    del orig

    class Popen(subprocess.Popen):
        def __init__(self, args, **kwargs):
            kwargs["env"] = _popen_env
            subprocess.Popen.__init__(self, args, **kwargs)
else:
    Popen = subprocess.Popen


def compile_expression(expr, name="<expr>", globals=None):
    code_object = compile(expr, name, "eval")
    return functools.partial(eval, code_object, globals or GLOBALS)


def import_file(path):
    """Import a Python module from a filesystem path"""
    path, name = os.path.split(path)

    name, sep, ext = name.rpartition(".")
    if not sep:
        name = ext

    if path:
        path = expand_path(path)
        sys.path.insert(0, path)
        try:
            return __import__(name)
        finally:
            del sys.path[0]
    else:
        return __import__(name)


def build_duration_func(duration, min=0.0):
    if not duration:
        if min:
            return lambda: min
        return None

    if isinstance(duration, str):
        lower, _, upper = duration.partition("-")
        lower = float(lower)
    else:
        try:
            lower, upper = duration
        except TypeError:
            lower, upper = duration, None

    if upper:
        upper = float(upper)
        return functools.partial(
            random.uniform,
            lower if lower > min else min,
            upper if upper > min else min,
        )
    else:
        if lower < min:
            lower = min
        return lambda: lower


def build_extractor_filter(categories, negate=True, special=None):
    """Build a function that takes an Extractor class as argument
    and returns True if that class is allowed by 'categories'
    """
    if isinstance(categories, str):
        categories = categories.split(",")

    catset = set()  # set of categories / basecategories
    subset = set()  # set of subcategories
    catsub = []     # list of category-subcategory pairs

    for item in categories:
        category, _, subcategory = item.partition(":")
        if category and category != "*":
            if subcategory and subcategory != "*":
                catsub.append((category, subcategory))
            else:
                catset.add(category)
        elif subcategory and subcategory != "*":
            subset.add(subcategory)

    if special:
        catset |= special
    elif not catset and not subset and not catsub:
        return true if negate else false

    tests = []

    if negate:
        if catset:
            tests.append(lambda extr:
                         extr.category not in catset and
                         extr.basecategory not in catset)
        if subset:
            tests.append(lambda extr: extr.subcategory not in subset)
    else:
        if catset:
            tests.append(lambda extr:
                         extr.category in catset or
                         extr.basecategory in catset)
        if subset:
            tests.append(lambda extr: extr.subcategory in subset)

    if catsub:
        def test(extr):
            for category, subcategory in catsub:
                if category in (extr.category, extr.basecategory) and \
                        subcategory == extr.subcategory:
                    return not negate
            return negate
        tests.append(test)

    if len(tests) == 1:
        return tests[0]
    if negate:
        return lambda extr: all(t(extr) for t in tests)
    else:
        return lambda extr: any(t(extr) for t in tests)


def build_proxy_map(proxies, log=None):
    """Generate a proxy map"""
    if not proxies:
        return None

    if isinstance(proxies, str):
        if "://" not in proxies:
            proxies = "http://" + proxies.lstrip("/")
        return {"http": proxies, "https": proxies}

    if isinstance(proxies, dict):
        for scheme, proxy in proxies.items():
            if "://" not in proxy:
                proxies[scheme] = "http://" + proxy.lstrip("/")
        return proxies

    if log:
        log.warning("invalid proxy specifier: %s", proxies)


def build_predicate(predicates):
    if not predicates:
        return lambda url, kwdict: True
    elif len(predicates) == 1:
        return predicates[0]
    return functools.partial(chain_predicates, predicates)


def chain_predicates(predicates, url, kwdict):
    for pred in predicates:
        if not pred(url, kwdict):
            return False
    return True


class RangePredicate():
    """Predicate; True if the current index is in the given range(s)"""

    def __init__(self, rangespec):
        self.ranges = ranges = self._parse(rangespec)
        self.index = 0

        if ranges:
            # technically wrong, but good enough for now
            # and evaluating min/max for a large range is slow
            self.lower = min(r.start for r in ranges)
            self.upper = max(r.stop for r in ranges) - 1
        else:
            self.lower = 0
            self.upper = 0

    def __call__(self, _url, _kwdict):
        self.index = index = self.index + 1

        if index > self.upper:
            raise exception.StopExtraction()

        for range in self.ranges:
            if index in range:
                return True
        return False

    @staticmethod
    def _parse(rangespec):
        """Parse an integer range string and return the resulting ranges

        Examples:
            _parse("-2,4,6-8,10-")      -> [(1,3), (4,5), (6,9), (10,INTMAX)]
            _parse(" - 3 , 4-  4, 2-6") -> [(1,4), (4,5), (2,7)]
            _parse("1:2,4:8:2")         -> [(1,1), (4,7,2)]
        """
        ranges = []
        append = ranges.append

        if isinstance(rangespec, str):
            rangespec = rangespec.split(",")

        for group in rangespec:
            if not group:
                continue

            elif ":" in group:
                start, _, stop = group.partition(":")
                stop, _, step = stop.partition(":")
                append(range(
                    int(start) if start.strip() else 1,
                    int(stop) if stop.strip() else sys.maxsize,
                    int(step) if step.strip() else 1,
                ))

            elif "-" in group:
                start, _, stop = group.partition("-")
                append(range(
                    int(start) if start.strip() else 1,
                    int(stop) + 1 if stop.strip() else sys.maxsize,
                ))

            else:
                start = int(group)
                append(range(start, start+1))

        return ranges


class UniquePredicate():
    """Predicate; True if given URL has not been encountered before"""
    def __init__(self):
        self.urls = set()

    def __call__(self, url, _):
        if url.startswith("text:"):
            return True
        if url not in self.urls:
            self.urls.add(url)
            return True
        return False


class FilterPredicate():
    """Predicate; True if evaluating the given expression returns True"""

    def __init__(self, expr, target="image"):
        if not isinstance(expr, str):
            expr = "(" + ") and (".join(expr) + ")"
        name = "<{} filter>".format(target)
        self.expr = compile_expression(expr, name)

    def __call__(self, _, kwdict):
        try:
            return self.expr(kwdict)
        except exception.GalleryDLException:
            raise
        except Exception as exc:
            raise exception.FilterError(exc)