linkchecker/linkcheck/checker/httpurl.py
2019-04-18 19:59:52 +01:00

372 lines
14 KiB
Python

# -*- coding: iso-8859-1 -*-
# Copyright (C) 2000-2014 Bastian Kleineidam
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
"""
Handle http links.
"""
import requests
# The validity of SSL certs is ignored to be able
# the check the URL and recurse into it.
# The warning about invalid SSL certs is given to the
# user instead.
import warnings
warnings.simplefilter('ignore', requests.packages.urllib3.exceptions.InsecureRequestWarning)
try:
from cStringIO import StringIO
except ImportError:
# Python 3
from io import StringIO
from .. import (log, LOG_CHECK, strformat, mimeutil,
url as urlutil, LinkCheckerError, httputil)
from . import (internpaturl, proxysupport)
from ..HtmlParser import htmlsax
from ..htmlutil import linkparse
# import warnings
from .const import WARN_HTTP_EMPTY_CONTENT
from requests.sessions import REDIRECT_STATI
# assumed HTTP header encoding
HEADER_ENCODING = "iso-8859-1"
HTTP_SCHEMAS = ('http://', 'https://')
# helper alias
unicode_safe = strformat.unicode_safe
class HttpUrl (internpaturl.InternPatternUrl, proxysupport.ProxySupport):
"""
Url link with http scheme.
"""
def reset (self):
"""
Initialize HTTP specific variables.
"""
super(HttpUrl, self).reset()
# initialize check data
# server headers
self.headers = {}
self.auth = None
self.ssl_cipher = None
self.ssl_cert = None
def allows_robots (self, url):
"""
Fetch and parse the robots.txt of given url. Checks if LinkChecker
can get the requested resource content.
@param url: the url to be requested
@type url: string
@return: True if access is granted, otherwise False
@rtype: bool
"""
return not self.aggregate.config['robotstxt'] or self.aggregate.robots_txt.allows_url(self)
def content_allows_robots (self):
"""
Return False if the content of this URL forbids robots to
search for recursive links.
"""
if not self.is_html():
return True
# construct parser object
handler = linkparse.MetaRobotsFinder()
parser = htmlsax.parser(handler)
handler.parser = parser
if self.charset:
parser.encoding = self.charset
# parse
try:
parser.feed(self.get_content())
parser.flush()
except linkparse.StopParse as msg:
log.debug(LOG_CHECK, "Stopped parsing: %s", msg)
pass
# break cyclic dependencies
handler.parser = None
parser.handler = None
return handler.follow
def add_size_info (self):
"""Get size of URL content from HTTP header."""
if self.headers and "Content-Length" in self.headers and \
"Transfer-Encoding" not in self.headers:
# Note that content-encoding causes size differences since
# the content data is always decoded.
try:
self.size = int(self.getheader("Content-Length"))
except (ValueError, OverflowError):
pass
else:
self.size = -1
def check_connection (self):
"""
Check a URL with HTTP protocol.
Here is an excerpt from RFC 1945 with common response codes:
The first digit of the Status-Code defines the class of response. The
last two digits do not have any categorization role. There are 5
values for the first digit:
- 1xx: Informational - Not used, but reserved for future use
- 2xx: Success - The action was successfully received,
understood, and accepted.
- 3xx: Redirection - Further action must be taken in order to
complete the request
- 4xx: Client Error - The request contains bad syntax or cannot
be fulfilled
- 5xx: Server Error - The server failed to fulfill an apparently
valid request
"""
self.session = self.aggregate.get_request_session()
# set the proxy, so a 407 status after this is an error
self.set_proxy(self.aggregate.config["proxy"].get(self.scheme))
self.construct_auth()
# check robots.txt
if not self.allows_robots(self.url):
self.add_info(_("Access denied by robots.txt, checked only syntax."))
self.set_result(_("syntax OK"))
self.do_check_content = False
return
# check the http connection
request = self.build_request()
self.send_request(request)
self._add_response_info()
self.follow_redirections(request)
self.check_response()
if self.allows_simple_recursion():
self.parse_header_links()
def build_request(self):
"""Build a prepared request object."""
clientheaders = {}
if (self.parent_url and
self.parent_url.lower().startswith(HTTP_SCHEMAS)):
clientheaders["Referer"] = self.parent_url
kwargs = dict(
method='GET',
url=self.url,
headers=clientheaders,
)
if self.auth:
kwargs['auth'] = self.auth
log.debug(LOG_CHECK, "Prepare request with %s", kwargs)
request = requests.Request(**kwargs)
return self.session.prepare_request(request)
def send_request(self, request):
"""Send request and store response in self.url_connection."""
# throttle the number of requests to each host
self.aggregate.wait_for_host(self.urlparts[1])
kwargs = self.get_request_kwargs()
kwargs["allow_redirects"] = False
self._send_request(request, **kwargs)
def _send_request(self, request, **kwargs):
"""Send GET request."""
log.debug(LOG_CHECK, "Send request %s with %s", request, kwargs)
log.debug(LOG_CHECK, "Request headers %s", request.headers)
self.url_connection = self.session.send(request, **kwargs)
self.headers = self.url_connection.headers
self._add_ssl_info()
def _add_response_info(self):
"""Set info from established HTTP(S) connection."""
self.charset = httputil.get_charset(self.headers)
self.set_content_type()
self.add_size_info()
def _get_ssl_sock(self):
"""Get raw SSL socket."""
assert self.scheme == u"https", self
raw_connection = self.url_connection.raw._connection
if not raw_connection:
# this happens with newer requests versions:
# https://github.com/linkchecker/linkchecker/issues/76
return None
if raw_connection.sock is None:
# sometimes the socket is not yet connected
# see https://github.com/kennethreitz/requests/issues/1966
raw_connection.connect()
return raw_connection.sock
def _add_ssl_info(self):
"""Add SSL cipher info."""
if self.scheme == u'https':
sock = self._get_ssl_sock()
if not sock:
log.debug(LOG_CHECK, "cannot extract SSL certificate from connection")
self.ssl_cert = None
elif hasattr(sock, 'cipher'):
self.ssl_cert = sock.getpeercert()
else:
# using pyopenssl
cert = sock.connection.get_peer_certificate()
self.ssl_cert = httputil.x509_to_dict(cert)
log.debug(LOG_CHECK, "Got SSL certificate %s", self.ssl_cert)
else:
self.ssl_cert = None
def construct_auth (self):
"""Construct HTTP Basic authentication credentials if there
is user/password information available. Does not overwrite if
credentials have already been constructed."""
if self.auth:
return
_user, _password = self.get_user_password()
if _user is not None and _password is not None:
self.auth = (_user, _password)
def set_content_type (self):
"""Return content MIME type or empty string."""
self.content_type = httputil.get_content_type(self.headers)
def is_redirect(self):
"""Check if current response is a redirect."""
return ('location' in self.headers and
self.url_connection.status_code in REDIRECT_STATI)
def get_request_kwargs(self):
"""Construct keyword parameters for Session.request() and
Session.resolve_redirects()."""
kwargs = dict(stream=True, timeout=self.aggregate.config["timeout"])
if self.proxy:
kwargs["proxies"] = {self.proxytype: self.proxy}
if self.scheme == u"https" and self.aggregate.config["sslverify"]:
kwargs['verify'] = self.aggregate.config["sslverify"]
else:
kwargs['verify'] = False
return kwargs
def get_redirects(self, request):
"""Return iterator of redirects for given request."""
kwargs = self.get_request_kwargs()
return self.session.resolve_redirects(self.url_connection,
request, **kwargs)
def follow_redirections(self, request):
"""Follow all redirections of http response."""
log.debug(LOG_CHECK, "follow all redirections")
if self.is_redirect():
# run connection plugins for old connection
self.aggregate.plugin_manager.run_connection_plugins(self)
response = None
for response in self.get_redirects(request):
newurl = response.url
log.debug(LOG_CHECK, "Redirected to %r", newurl)
self.aliases.append(newurl)
# XXX on redirect errors this is not printed
self.add_info(_("Redirected to `%(url)s'.") % {'url': newurl})
# Reset extern and recalculate
self.extern = None
self.set_extern(newurl)
self.urlparts = strformat.url_unicode_split(newurl)
self.build_url_parts()
self.url_connection = response
self.headers = response.headers
self.url = urlutil.urlunsplit(self.urlparts)
self.scheme = self.urlparts[0].lower()
self._add_ssl_info()
self._add_response_info()
if self.is_redirect():
# run connection plugins for old connection
self.aggregate.plugin_manager.run_connection_plugins(self)
def getheader (self, name, default=None):
"""Get decoded header value.
@return: decoded header value or default of not found
@rtype: unicode or type of default
"""
value = self.headers.get(name)
if value is None:
return default
return unicode_safe(value, encoding=HEADER_ENCODING)
def check_response (self):
"""Check final result and log it."""
if self.url_connection.status_code >= 400:
self.set_result(u"%d %s" % (self.url_connection.status_code, self.url_connection.reason),
valid=False)
else:
if self.url_connection.status_code == 204:
# no content
self.add_warning(self.url_connection.reason,
tag=WARN_HTTP_EMPTY_CONTENT)
if self.url_connection.status_code >= 200:
self.set_result(u"%r %s" % (self.url_connection.status_code, self.url_connection.reason))
else:
self.set_result(_("OK"))
def read_content(self):
"""Return data and data size for this URL.
Can be overridden in subclasses."""
maxbytes = self.aggregate.config["maxfilesizedownload"]
buf = StringIO()
for data in self.url_connection.iter_content(chunk_size=self.ReadChunkBytes):
if buf.tell() + len(data) > maxbytes:
raise LinkCheckerError(_("File size too large"))
buf.write(data)
return buf.getvalue()
def parse_header_links(self):
"""Parse URLs in HTTP headers Link:."""
for linktype, linkinfo in self.url_connection.links.items():
url = linkinfo["url"]
name = u"Link: header %s" % linktype
self.add_url(url, name=name)
if 'Refresh' in self.headers:
from ..htmlutil.linkparse import refresh_re
value = self.headers['Refresh'].strip()
mo = refresh_re.match(value)
if mo:
url = unicode_safe(mo.group("url"))
name = u"Refresh: header"
self.add_url(url, name=name)
if 'Content-Location' in self.headers:
url = self.headers['Content-Location'].strip()
name = u"Content-Location: header"
self.add_url(url, name=name)
def is_parseable (self):
"""
Check if content is parseable for recursion.
@return: True if content is parseable
@rtype: bool
"""
if not self.valid:
return False
# some content types must be validated with the page content
if self.content_type in ("application/xml", "text/xml"):
rtype = mimeutil.guess_mimetype_read(self.get_content)
if rtype is not None:
# XXX side effect
self.content_type = rtype
if self.content_type not in self.ContentMimetypes:
log.debug(LOG_CHECK, "URL with content type %r is not parseable", self.content_type)
return False
return True
def get_robots_txt_url (self):
"""
Get the according robots.txt URL for this URL.
@return: robots.txt URL
@rtype: string
"""
return "%s://%s/robots.txt" % tuple(self.urlparts[0:2])