dosage/dosagelib/util.py
Tobias Gruetzmacher e98a1601ca Remove workaround for libxml2 older 2.9.3 (2015)
This workaround was written in 2016 while that version was still found
on many systems. Addionally, this workaround needs to be enabled by the
developer, who might not even be aware that they need to enable it for a
specific module. We still throw a warning to the user if running with
such an old libxml version.
2020-09-29 21:16:48 +02:00

485 lines
14 KiB
Python

# SPDX-License-Identifier: MIT
# Copyright (C) 2004-2008 Tristan Seligmann and Jonathan Jacobs
# Copyright (C) 2012-2014 Bastian Kleineidam
# Copyright (C) 2015-2019 Tobias Gruetzmacher
import html
import os
import re
import subprocess
import sys
import time
import traceback
from functools import lru_cache
from urllib.parse import (parse_qs, quote as url_quote, unquote as url_unquote,
urlparse, urlunparse, urlsplit)
from urllib.robotparser import RobotFileParser
import lxml
from .output import out
from .configuration import UserAgent, App, SupportUrl
from . import AppName
# Maximum content size for HTML pages
MaxContentBytes = 1024 * 1024 * 3 # 3 MB
# The character set to encode non-ASCII characters in a URL. See also
# http://tools.ietf.org/html/rfc2396#section-2.1
# Note that the encoding is not really specified, but most browsers
# encode in UTF-8 when no encoding is specified by the HTTP headers,
# else they use the page encoding for followed link. See als
# http://code.google.com/p/browsersec/wiki/Part1#Unicode_in_URLs
UrlEncoding = "utf-8"
def get_system_uid():
"""Get a (probably) unique ID to identify a system.
Used to differentiate votes.
"""
try:
if os.name == 'nt':
return get_nt_system_uid()
if sys.platform == 'darwin':
return get_osx_system_uid()
except Exception:
return get_mac_uid()
else:
return get_mac_uid()
def get_nt_system_uid():
r"""Get the MachineGuid from
HKEY_LOCAL_MACHINE\Software\Microsoft\Cryptography\MachineGuid
"""
import winreg
lm = winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE)
try:
key = winreg.OpenKey(lm, r"Software\Microsoft\Cryptography")
try:
return winreg.QueryValueEx(key, "MachineGuid")[0]
finally:
key.Close()
finally:
lm.Close()
def get_osx_system_uid():
"""Get the OSX system ID.
$ system_profiler |grep "r (system)"
Serial Number (system): C24E1322XYZ
"""
res = backtick(["system_profile"]).splitlines()
for line in res:
if "r (system)" in line:
return line.split(':', 1)[1].strip()
raise ValueError("Could not find system number in %r" % res)
def get_mac_uid():
"""Get the MAC address of the system."""
import uuid
return "%d" % uuid.getnode()
def backtick(cmd, encoding='utf-8'):
"""Return decoded output from command."""
data = subprocess.Popen(cmd, stdout=subprocess.PIPE).communicate()[0]
return data.decode(encoding)
def unicode_safe(text, encoding=UrlEncoding, errors='ignore'):
"""Decode text to Unicode if not already done."""
if isinstance(text, str):
return text
return text.decode(encoding, errors)
def tagre(tag, attribute, value, quote='"', before="", after=""):
"""Return a regular expression matching the given HTML tag, attribute
and value. It matches the tag and attribute names case insensitive,
and skips arbitrary whitespace and leading HTML attributes. The "<>" at
the start and end of the HTML tag is also matched.
@param tag: the tag name
@ptype tag: string
@param attribute: the attribute name
@ptype attribute: string
@param value: the attribute value
@ptype value: string
@param quote: the attribute quote (default ")
@ptype quote: string
@param after: match after attribute value but before end
@ptype after: string
@return: the generated regular expression suitable for re.compile()
@rtype: string
"""
if before:
prefix = r"[^>]*%s[^>]*\s+" % before
else:
prefix = r"(?:[^>]*\s+)?"
attrs = dict(
tag=case_insensitive_re(tag),
attribute=case_insensitive_re(attribute),
value=value,
quote=quote,
prefix=prefix,
after=after,
)
return (r'<\s*%(tag)s\s+%(prefix)s' +
r'%(attribute)s\s*=\s*%(quote)s%(value)s%(quote)' +
r's[^>]*%(after)s[^>]*>') % attrs
def case_insensitive_re(name):
"""Reformat the given name to a case insensitive regular expression string
without using re.IGNORECASE. This way selective strings can be made case
insensitive.
@param name: the name to make case insensitive
@ptype name: string
@return: the case insensitive regex
@rtype: string
"""
return "".join("[%s%s]" % (c.lower(), c.upper()) for c in name)
def get_page(url, session, **kwargs):
"""Get text content of given URL."""
check_robotstxt(url, session)
# read page data
page = urlopen(url, session, max_content_bytes=MaxContentBytes, **kwargs)
out.debug(u"Got page content %r" % page.content, level=3)
return page
def makeSequence(item):
"""If item is already a list or tuple, return it.
Else return a tuple with item as single element."""
if isinstance(item, (list, tuple)):
return item
return (item,)
def prettyMatcherList(things):
"""Try to construct a nicely-formatted string for a list of matcher
objects. Those may be compiled regular expressions or strings..."""
norm = []
for x in makeSequence(things):
if hasattr(x, 'pattern'):
norm.append(x.pattern)
else:
norm.append(x)
return "('%s')" % "', '".join(norm)
def normaliseURL(url):
"""Normalising
- strips and leading or trailing whitespace,
- replaces HTML entities and character references,
- removes any leading empty segments to avoid breaking urllib2.
"""
url = unicode_safe(url).strip()
# XXX: brutal hack
url = html.unescape(url)
pu = list(urlparse(url))
segments = pu[2].split('/')
while segments and segments[0] in ('', '..'):
del segments[0]
pu[2] = '/' + '/'.join(segments)
# remove leading '&' from query
if pu[4].startswith('&'):
pu[4] = pu[4][1:]
# remove anchor
pu[5] = ""
return urlunparse(pu)
def get_roboturl(url):
"""Get robots.txt URL from given URL."""
pu = urlparse(url)
return urlunparse((pu[0], pu[1], "/robots.txt", "", "", ""))
def check_robotstxt(url, session):
"""Check if robots.txt allows our user agent for the given URL.
@raises: IOError if URL is not allowed
"""
roboturl = get_roboturl(url)
rp = get_robotstxt_parser(roboturl, session=session)
if not rp.can_fetch(UserAgent, str(url)):
raise IOError("%s is disallowed by %s" % (url, roboturl))
@lru_cache()
def get_robotstxt_parser(url, session=None):
"""Get a RobotFileParser for the given robots.txt URL."""
rp = RobotFileParser()
try:
req = urlopen(url, session, max_content_bytes=MaxContentBytes,
allow_errors=range(600))
except Exception:
# connect or timeout errors are treated as an absent robots.txt
rp.allow_all = True
else:
if req.status_code >= 400:
rp.allow_all = True
elif req.status_code == 200:
rp.parse(req.text.splitlines())
return rp
def urlopen(url, session, referrer=None, max_content_bytes=None,
allow_errors=(), **kwargs):
"""Open an URL and return the response object."""
out.debug(u'Open URL %s' % url)
if 'headers' not in kwargs:
kwargs['headers'] = {}
if referrer:
kwargs['headers']['Referer'] = referrer
out.debug(u'Sending headers %s' % kwargs['headers'], level=3)
out.debug(u'Sending cookies %s' % session.cookies)
if 'data' not in kwargs:
method = 'GET'
else:
method = 'POST'
out.debug(u'Sending POST data %s' % kwargs['data'], level=3)
req = session.request(method, url, **kwargs)
out.debug(u'Response cookies: %s' % req.cookies)
check_content_size(url, req.headers, max_content_bytes)
if req.status_code not in allow_errors:
req.raise_for_status()
return req
def check_content_size(url, headers, max_content_bytes):
"""Check that content length in URL response headers do not exceed the
given maximum bytes.
"""
if not max_content_bytes:
return
if 'content-length' in headers:
size = int(headers['content-length'])
if size > max_content_bytes:
raise IOError(
'URL content of %s with %d bytes exceeds %d bytes.' %
(url, size, max_content_bytes))
def splitpath(path):
"""Split a path in its components."""
c = []
head, tail = os.path.split(path)
while tail:
c.insert(0, tail)
head, tail = os.path.split(head)
return c
def getRelativePath(basepath, path):
"""Get a path that is relative to the given base path."""
basepath = splitpath(os.path.abspath(basepath))
path = splitpath(os.path.abspath(path))
afterCommon = False
for c in basepath:
if afterCommon or path[0] != c:
path.insert(0, os.path.pardir)
afterCommon = True
else:
del path[0]
return os.path.join(*path)
def getQueryParams(url):
"""Get URL query parameters."""
query = urlsplit(url).query
out.debug(u'Extracting query parameters from %r (%r)...' % (url, query))
return parse_qs(query)
def internal_error(out=sys.stderr, etype=None, evalue=None, tb=None):
"""Print internal error message (output defaults to stderr)."""
print(os.linesep, file=out)
print("""********** Oops, I did it again. *************
You have found an internal error in %(app)s. Please write a bug report
at %(url)s and include at least the information below:
Not disclosing some of the information below due to privacy reasons is ok.
I will try to help you nonetheless, but you have to give me something
I can work with ;) .
""" % dict(app=AppName, url=SupportUrl), file=out)
if etype is None:
etype = sys.exc_info()[0]
if evalue is None:
evalue = sys.exc_info()[1]
print(etype, evalue, file=out)
if tb is None:
tb = sys.exc_info()[2]
traceback.print_exception(etype, evalue, tb, None, out)
print_app_info(out=out)
print_proxy_info(out=out)
print_locale_info(out=out)
print(os.linesep,
"******** %s internal error, over and out ********" % AppName,
file=out)
def print_env_info(key, out=sys.stderr):
"""If given environment key is defined, print it out."""
value = os.getenv(key)
if value is not None:
print(key, "=", repr(value), file=out)
def print_proxy_info(out=sys.stderr):
"""Print proxy info."""
print_env_info("http_proxy", out=out)
def print_locale_info(out=sys.stderr):
"""Print locale info."""
for key in ("LANGUAGE", "LC_ALL", "LC_CTYPE", "LANG"):
print_env_info(key, out=out)
def print_app_info(out=sys.stderr):
"""Print system and application info (output defaults to stderr)."""
print("System info:", file=out)
print(App, file=out)
print("Python %(version)s on %(platform)s" %
{"version": sys.version, "platform": sys.platform}, file=out)
print("libxml2 version: %i.%i.%i" % lxml.etree.LIBXML_VERSION, file=out)
stime = strtime(time.time())
print("Local time:", stime, file=out)
print("sys.argv", sys.argv, file=out)
def strtime(t):
"""Return ISO 8601 formatted time."""
return (time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(t)) +
strtimezone())
def strtimezone():
"""Return timezone info, %z on some platforms, but not supported on all.
"""
if time.daylight:
zone = time.altzone
else:
zone = time.timezone
return "%+04d" % (-zone // 3600)
def rfc822date(indate):
"""Format date in rfc822 format."""
return time.strftime("%a, %d %b %Y %H:%M:%S GMT", time.gmtime(indate))
def unquote(text):
"""Replace all percent-encoded entities in text."""
while '%' in text:
newtext = url_unquote(text)
if newtext == text:
break
text = newtext
return text
def quote(text, safechars='/'):
"""Percent-encode given text."""
return url_quote(text, safechars)
def strsize(b):
"""Return human representation of bytes b. A negative number of bytes
raises a value error."""
if b < 0:
raise ValueError("Invalid negative byte number")
if b < 1024:
return "%dB" % b
if b < 1024 * 10:
return "%dKB" % (b // 1024)
if b < 1024 * 1024:
return "%.2fKB" % (float(b) / 1024)
if b < 1024 * 1024 * 10:
return "%.2fMB" % (float(b) / (1024 * 1024))
if b < 1024 * 1024 * 1024:
return "%.1fMB" % (float(b) / (1024 * 1024))
if b < 1024 * 1024 * 1024 * 10:
return "%.2fGB" % (float(b) / (1024 * 1024 * 1024))
return "%.1fGB" % (float(b) / (1024 * 1024 * 1024))
def getFilename(name):
"""Get a filename from given name without dangerous or incompatible
characters."""
# first replace all illegal chars
name = re.sub(r"[^0-9a-zA-Z_\-\.]", "_", name)
# then remove double dots and underscores
while ".." in name:
name = name.replace('..', '.')
while "__" in name:
name = name.replace('__', '_')
# remove a leading dot or minus
if name.startswith((".", "-")):
name = name[1:]
return name
def getExistingFile(name, max_suffix=1000):
"""Add filename suffix until file exists
@return: filename if file is found
@raise: ValueError if maximum suffix number is reached while searching
"""
num = 1
stem, ext = os.path.splitext(name)
filename = name
while not os.path.exists(filename):
suffix = "-%d" % num
filename = stem + suffix + ext
num += 1
if num >= max_suffix:
raise ValueError("No file %r found" % name)
return filename
def getNonexistingFile(name):
"""Add filename suffix until file not exists
@return: filename
"""
num = 1
stem, ext = os.path.splitext(name)
filename = name
while os.path.exists(filename):
suffix = "-%d" % num
filename = stem + suffix + ext
num += 1
return filename
def strlimit(s, length=72):
"""If the length of the string exceeds the given limit, it will be cut
off and three dots will be appended.
@param s: the string to limit
@type s: string
@param length: maximum length
@type length: non-negative integer
@return: limited string, at most length+3 characters long
"""
assert length >= 0, "length limit must be a non-negative integer"
if not s or len(s) <= length:
return s
if length == 0:
return ""
return "%s..." % s[:length]
def uniq(input):
"""Remove duplicates from a list while preserving the list order"""
output = []
for item in input:
if item not in output:
output.append(item)
return output