dosage/dosagelib/util.py
2022-05-28 17:52:42 +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) 2015-2020 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 = {
'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 ;) .
""" % {'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