Keep video IDs verbatim if possible (Closes #571)

[yt-dlp.git] / youtube_dl / utils.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import gzip
import io
import locale
import os
import re
import sys
import zlib
import email.utils
import json

try:
    import urllib.request as compat_urllib_request
except ImportError: # Python 2
    import urllib2 as compat_urllib_request

try:
    import urllib.error as compat_urllib_error
except ImportError: # Python 2
    import urllib2 as compat_urllib_error

try:
    import urllib.parse as compat_urllib_parse
except ImportError: # Python 2
    import urllib as compat_urllib_parse

try:
    from urllib.parse import urlparse as compat_urllib_parse_urlparse
except ImportError: # Python 2
    from urlparse import urlparse as compat_urllib_parse_urlparse

try:
    import http.cookiejar as compat_cookiejar
except ImportError: # Python 2
    import cookielib as compat_cookiejar

try:
    import html.entities as compat_html_entities
except ImportError: # Python 2
    import htmlentitydefs as compat_html_entities

try:
    import html.parser as compat_html_parser
except ImportError: # Python 2
    import HTMLParser as compat_html_parser

try:
    import http.client as compat_http_client
except ImportError: # Python 2
    import httplib as compat_http_client

try:
    from urllib.parse import parse_qs as compat_parse_qs
except ImportError: # Python 2
    # HACK: The following is the correct parse_qs implementation from cpython 3's stdlib.
    # Python 2's version is apparently totally broken
    def _unquote(string, encoding='utf-8', errors='replace'):
        if string == '':
            return string
        res = string.split('%')
        if len(res) == 1:
            return string
        if encoding is None:
            encoding = 'utf-8'
        if errors is None:
            errors = 'replace'
        # pct_sequence: contiguous sequence of percent-encoded bytes, decoded
        pct_sequence = b''
        string = res[0]
        for item in res[1:]:
            try:
                if not item:
                    raise ValueError
                pct_sequence += item[:2].decode('hex')
                rest = item[2:]
                if not rest:
                    # This segment was just a single percent-encoded character.
                    # May be part of a sequence of code units, so delay decoding.
                    # (Stored in pct_sequence).
                    continue
            except ValueError:
                rest = '%' + item
            # Encountered non-percent-encoded characters. Flush the current
            # pct_sequence.
            string += pct_sequence.decode(encoding, errors) + rest
            pct_sequence = b''
        if pct_sequence:
            # Flush the final pct_sequence
            string += pct_sequence.decode(encoding, errors)
        return string

    def _parse_qsl(qs, keep_blank_values=False, strict_parsing=False,
                encoding='utf-8', errors='replace'):
        qs, _coerce_result = qs, unicode
        pairs = [s2 for s1 in qs.split('&') for s2 in s1.split(';')]
        r = []
        for name_value in pairs:
            if not name_value and not strict_parsing:
                continue
            nv = name_value.split('=', 1)
            if len(nv) != 2:
                if strict_parsing:
                    raise ValueError("bad query field: %r" % (name_value,))
                # Handle case of a control-name with no equal sign
                if keep_blank_values:
                    nv.append('')
                else:
                    continue
            if len(nv[1]) or keep_blank_values:
                name = nv[0].replace('+', ' ')
                name = _unquote(name, encoding=encoding, errors=errors)
                name = _coerce_result(name)
                value = nv[1].replace('+', ' ')
                value = _unquote(value, encoding=encoding, errors=errors)
                value = _coerce_result(value)
                r.append((name, value))
        return r

    def compat_parse_qs(qs, keep_blank_values=False, strict_parsing=False,
                encoding='utf-8', errors='replace'):
        parsed_result = {}
        pairs = _parse_qsl(qs, keep_blank_values, strict_parsing,
                        encoding=encoding, errors=errors)
        for name, value in pairs:
            if name in parsed_result:
                parsed_result[name].append(value)
            else:
                parsed_result[name] = [value]
        return parsed_result

try:
    compat_str = unicode # Python 2
except NameError:
    compat_str = str

try:
    compat_chr = unichr # Python 2
except NameError:
    compat_chr = chr

std_headers = {
    'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64; rv:10.0) Gecko/20100101 Firefox/10.0',
    'Accept-Charset': 'ISO-8859-1,utf-8;q=0.7,*;q=0.7',
    'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
    'Accept-Encoding': 'gzip, deflate',
    'Accept-Language': 'en-us,en;q=0.5',
}
def preferredencoding():
    """Get preferred encoding.

    Returns the best encoding scheme for the system, based on
    locale.getpreferredencoding() and some further tweaks.
    """
    try:
        pref = locale.getpreferredencoding()
        u'TEST'.encode(pref)
    except:
        pref = 'UTF-8'

    return pref

if sys.version_info < (3,0):
    def compat_print(s):
        print(s.encode(preferredencoding(), 'xmlcharrefreplace'))
else:
    def compat_print(s):
        assert type(s) == type(u'')
        print(s)

def htmlentity_transform(matchobj):
    """Transforms an HTML entity to a character.

    This function receives a match object and is intended to be used with
    the re.sub() function.
    """
    entity = matchobj.group(1)

    # Known non-numeric HTML entity
    if entity in compat_html_entities.name2codepoint:
        return compat_chr(compat_html_entities.name2codepoint[entity])

    mobj = re.match(u'(?u)#(x?\\d+)', entity)
    if mobj is not None:
        numstr = mobj.group(1)
        if numstr.startswith(u'x'):
            base = 16
            numstr = u'0%s' % numstr
        else:
            base = 10
        return compat_chr(int(numstr, base))

    # Unknown entity in name, return its literal representation
    return (u'&%s;' % entity)

compat_html_parser.locatestarttagend = re.compile(r"""<[a-zA-Z][-.a-zA-Z0-9:_]*(?:\s+(?:(?<=['"\s])[^\s/>][^\s/=>]*(?:\s*=+\s*(?:'[^']*'|"[^"]*"|(?!['"])[^>\s]*))?\s*)*)?\s*""", re.VERBOSE) # backport bugfix
class IDParser(compat_html_parser.HTMLParser):
    """Modified HTMLParser that isolates a tag with the specified id"""
    def __init__(self, id):
        self.id = id
        self.result = None
        self.started = False
        self.depth = {}
        self.html = None
        self.watch_startpos = False
        self.error_count = 0
        compat_html_parser.HTMLParser.__init__(self)

    def error(self, message):
        if self.error_count > 10 or self.started:
            raise compat_html_parser.HTMLParseError(message, self.getpos())
        self.rawdata = '\n'.join(self.html.split('\n')[self.getpos()[0]:]) # skip one line
        self.error_count += 1
        self.goahead(1)

    def loads(self, html):
        self.html = html
        self.feed(html)
        self.close()

    def handle_starttag(self, tag, attrs):
        attrs = dict(attrs)
        if self.started:
            self.find_startpos(None)
        if 'id' in attrs and attrs['id'] == self.id:
            self.result = [tag]
            self.started = True
            self.watch_startpos = True
        if self.started:
            if not tag in self.depth: self.depth[tag] = 0
            self.depth[tag] += 1

    def handle_endtag(self, tag):
        if self.started:
            if tag in self.depth: self.depth[tag] -= 1
            if self.depth[self.result[0]] == 0:
                self.started = False
                self.result.append(self.getpos())

    def find_startpos(self, x):
        """Needed to put the start position of the result (self.result[1])
        after the opening tag with the requested id"""
        if self.watch_startpos:
            self.watch_startpos = False
            self.result.append(self.getpos())
    handle_entityref = handle_charref = handle_data = handle_comment = \
    handle_decl = handle_pi = unknown_decl = find_startpos

    def get_result(self):
        if self.result is None:
            return None
        if len(self.result) != 3:
            return None
        lines = self.html.split('\n')
        lines = lines[self.result[1][0]-1:self.result[2][0]]
        lines[0] = lines[0][self.result[1][1]:]
        if len(lines) == 1:
            lines[-1] = lines[-1][:self.result[2][1]-self.result[1][1]]
        lines[-1] = lines[-1][:self.result[2][1]]
        return '\n'.join(lines).strip()

def get_element_by_id(id, html):
    """Return the content of the tag with the specified id in the passed HTML document"""
    parser = IDParser(id)
    try:
        parser.loads(html)
    except compat_html_parser.HTMLParseError:
        pass
    return parser.get_result()


def clean_html(html):
    """Clean an HTML snippet into a readable string"""
    # Newline vs <br />
    html = html.replace('\n', ' ')
    html = re.sub('\s*<\s*br\s*/?\s*>\s*', '\n', html)
    # Strip html tags
    html = re.sub('<.*?>', '', html)
    # Replace html entities
    html = unescapeHTML(html)
    return html


def sanitize_open(filename, open_mode):
    """Try to open the given filename, and slightly tweak it if this fails.

    Attempts to open the given filename. If this fails, it tries to change
    the filename slightly, step by step, until it's either able to open it
    or it fails and raises a final exception, like the standard open()
    function.

    It returns the tuple (stream, definitive_file_name).
    """
    try:
        if filename == u'-':
            if sys.platform == 'win32':
                import msvcrt
                msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
            return (sys.stdout, filename)
        stream = open(encodeFilename(filename), open_mode)
        return (stream, filename)
    except (IOError, OSError) as err:
        # In case of error, try to remove win32 forbidden chars
        filename = re.sub(u'[/<>:"\\|\\\\?\\*]', u'#', filename)

        # An exception here should be caught in the caller
        stream = open(encodeFilename(filename), open_mode)
        return (stream, filename)


def timeconvert(timestr):
    """Convert RFC 2822 defined time string into system timestamp"""
    timestamp = None
    timetuple = email.utils.parsedate_tz(timestr)
    if timetuple is not None:
        timestamp = email.utils.mktime_tz(timetuple)
    return timestamp

def sanitize_filename(s, restricted=False, is_id=False):
    """Sanitizes a string so it could be used as part of a filename.
    If restricted is set, use a stricter subset of allowed characters.
    Set is_id if this is not an arbitrary string, but an ID that should be kept if possible
    """
    def replace_insane(char):
        if char == '?' or ord(char) < 32 or ord(char) == 127:
            return ''
        elif char == '"':
            return '' if restricted else '\''
        elif char == ':':
            return '_-' if restricted else ' -'
        elif char in '\\/|*<>':
            return '_'
        if restricted and (char in '!&\'()[]{}$;`^,#' or char.isspace()):
            return '_'
        if restricted and ord(char) > 127:
            return '_'
        return char

    result = u''.join(map(replace_insane, s))
    if not is_id:
        while '__' in result:
            result = result.replace('__', '_')
        result = result.strip('_')
        # Common case of "Foreign band name - English song title"
        if restricted and result.startswith('-_'):
            result = result[2:]
        if not result:
            result = '_'
    return result

def orderedSet(iterable):
    """ Remove all duplicates from the input iterable """
    res = []
    for el in iterable:
        if el not in res:
            res.append(el)
    return res

def unescapeHTML(s):
    """
    @param s a string
    """
    assert type(s) == type(u'')

    result = re.sub(u'(?u)&(.+?);', htmlentity_transform, s)
    return result

def encodeFilename(s):
    """
    @param s The name of the file
    """

    assert type(s) == type(u'')

    # Python 3 has a Unicode API
    if sys.version_info >= (3, 0):
        return s

    if sys.platform == 'win32' and sys.getwindowsversion()[0] >= 5:
        # Pass u'' directly to use Unicode APIs on Windows 2000 and up
        # (Detecting Windows NT 4 is tricky because 'major >= 4' would
        # match Windows 9x series as well. Besides, NT 4 is obsolete.)
        return s
    else:
        return s.encode(sys.getfilesystemencoding(), 'ignore')

class DownloadError(Exception):
    """Download Error exception.

    This exception may be thrown by FileDownloader objects if they are not
    configured to continue on errors. They will contain the appropriate
    error message.
    """
    pass


class SameFileError(Exception):
    """Same File exception.

    This exception will be thrown by FileDownloader objects if they detect
    multiple files would have to be downloaded to the same file on disk.
    """
    pass


class PostProcessingError(Exception):
    """Post Processing exception.

    This exception may be raised by PostProcessor's .run() method to
    indicate an error in the postprocessing task.
    """
    pass

class MaxDownloadsReached(Exception):
    """ --max-downloads limit has been reached. """
    pass


class UnavailableVideoError(Exception):
    """Unavailable Format exception.

    This exception will be thrown when a video is requested
    in a format that is not available for that video.
    """
    pass


class ContentTooShortError(Exception):
    """Content Too Short exception.

    This exception may be raised by FileDownloader objects when a file they
    download is too small for what the server announced first, indicating
    the connection was probably interrupted.
    """
    # Both in bytes
    downloaded = None
    expected = None

    def __init__(self, downloaded, expected):
        self.downloaded = downloaded
        self.expected = expected


class Trouble(Exception):
    """Trouble helper exception

    This is an exception to be handled with
    FileDownloader.trouble
    """

class YoutubeDLHandler(compat_urllib_request.HTTPHandler):
    """Handler for HTTP requests and responses.

    This class, when installed with an OpenerDirector, automatically adds
    the standard headers to every HTTP request and handles gzipped and
    deflated responses from web servers. If compression is to be avoided in
    a particular request, the original request in the program code only has
    to include the HTTP header "Youtubedl-No-Compression", which will be
    removed before making the real request.

    Part of this code was copied from:

    http://techknack.net/python-urllib2-handlers/

    Andrew Rowls, the author of that code, agreed to release it to the
    public domain.
    """

    @staticmethod
    def deflate(data):
        try:
            return zlib.decompress(data, -zlib.MAX_WBITS)
        except zlib.error:
            return zlib.decompress(data)

    @staticmethod
    def addinfourl_wrapper(stream, headers, url, code):
        if hasattr(compat_urllib_request.addinfourl, 'getcode'):
            return compat_urllib_request.addinfourl(stream, headers, url, code)
        ret = compat_urllib_request.addinfourl(stream, headers, url)
        ret.code = code
        return ret

    def http_request(self, req):
        for h in std_headers:
            if h in req.headers:
                del req.headers[h]
            req.add_header(h, std_headers[h])
        if 'Youtubedl-no-compression' in req.headers:
            if 'Accept-encoding' in req.headers:
                del req.headers['Accept-encoding']
            del req.headers['Youtubedl-no-compression']
        return req

    def http_response(self, req, resp):
        old_resp = resp
        # gzip
        if resp.headers.get('Content-encoding', '') == 'gzip':
            gz = gzip.GzipFile(fileobj=io.BytesIO(resp.read()), mode='r')
            resp = self.addinfourl_wrapper(gz, old_resp.headers, old_resp.url, old_resp.code)
            resp.msg = old_resp.msg
        # deflate
        if resp.headers.get('Content-encoding', '') == 'deflate':
            gz = io.BytesIO(self.deflate(resp.read()))
            resp = self.addinfourl_wrapper(gz, old_resp.headers, old_resp.url, old_resp.code)
            resp.msg = old_resp.msg
        return resp