# -*- coding: utf-8 -*-
"""No Proxy
===============
The :mod:`darc.proxy.null` module contains the auxiliary functions
around managing and processing normal websites with no proxy.
"""
import gzip
import io
import json
import os
from typing import TYPE_CHECKING
import bs4
import requests
from darc._compat import RobotFileParser
from darc.const import CHECK, PATH_MISC, get_lock
from darc.db import save_requests
from darc.link import parse_link
from darc.logging import logger
from darc.parse import _check, get_content_type, urljoin
from darc.requests import request_session
from darc.save import save_link
if TYPE_CHECKING:
from typing import List, Optional
import darc.link as darc_link # Link
PATH = os.path.join(PATH_MISC, 'invalid.txt')
LOCK = get_lock()
[docs]def save_invalid(link: 'darc_link.Link') -> None:
"""Save link with invalid scheme.
The function will save link with invalid scheme to the file
as defined in :data:`~darc.proxy.null.PATH`.
Args:
link: Link object representing the link with invalid scheme.
"""
with LOCK: # type: ignore[union-attr]
with open(PATH, 'a') as file:
print(json.dumps({
'src': backref.url if (backref := link.url_backref) is not None else None, # pylint: disable=used-before-assignment
'url': link.url,
}), file=file)
[docs]def save_robots(link: 'darc_link.Link', text: str) -> str:
"""Save ``robots.txt``.
Args:
link: Link object of ``robots.txt``.
text: Content of ``robots.txt``.
Returns:
Saved path to ``robots.txt``, i.e.
``<root>/<proxy>/<scheme>/<hostname>/robots.txt``.
See Also:
* :func:`darc.save.sanitise`
"""
path = os.path.join(link.base, 'robots.txt')
root = os.path.split(path)[0]
os.makedirs(root, exist_ok=True)
with open(path, 'w') as file:
print(f'# {link.url}', file=file)
file.write(text)
return path
[docs]def save_sitemap(link: 'darc_link.Link', text: str) -> str:
"""Save sitemap.
Args:
link: Link object of sitemap.
text: Content of sitemap.
Returns:
Saved path to sitemap, i.e.
``<root>/<proxy>/<scheme>/<hostname>/sitemap_<hash>.xml``.
See Also:
* :func:`darc.save.sanitise`
"""
# <proxy>/<scheme>/<host>/sitemap_<hash>.xml
path = os.path.join(link.base, f'sitemap_{link.name}.xml')
root = os.path.split(path)[0]
os.makedirs(root, exist_ok=True)
with open(path, 'w') as file:
print(f'<!-- {link.url} -->', file=file)
file.write(text)
save_link(link)
return path
[docs]def have_robots(link: 'darc_link.Link') -> 'Optional[str]':
"""Check if ``robots.txt`` already exists.
Args:
link: Link object to check if ``robots.txt`` already exists.
Returns:
* If ``robots.txt`` exists, return the path to ``robots.txt``,
i.e. ``<root>/<proxy>/<scheme>/<hostname>/robots.txt``.
* If not, return :data:`None`.
"""
# <proxy>/<scheme>/<host>/robots.txt
path = os.path.join(link.base, 'robots.txt')
return path if os.path.isfile(path) else None
[docs]def have_sitemap(link: 'darc_link.Link') -> 'Optional[str]':
"""Check if sitemap already exists.
Args:
link: Link object to check if sitemap already exists.
Returns:
* If sitemap exists, return the path to the sitemap,
i.e. ``<root>/<proxy>/<scheme>/<hostname>/sitemap_<hash>.xml``.
* If not, return :data:`None`.
"""
# <proxy>/<scheme>/<host>/sitemap_<hash>.xml
path = os.path.join(link.base, f'sitemap_{link.name}.xml')
return path if os.path.isfile(path) else None
[docs]def read_robots(link: 'darc_link.Link', text: str, host: 'Optional[str]' = None) -> 'List[darc_link.Link]':
"""Read ``robots.txt`` to fetch link to sitemaps.
Args:
link: Original link to ``robots.txt``.
text: Content of ``robots.txt``.
host: Hostname of the URL to ``robots.txt``,
the value may not be same as in ``link``.
Returns:
List of link to sitemaps.
Note:
If the link to sitemap is not specified in
``robots.txt`` [*]_, the fallback link
``/sitemap.xml`` will be used.
.. [*] https://www.sitemaps.org/protocol.html#submit_robots
"""
rp = RobotFileParser()
with io.StringIO(text) as file:
rp.parse(file)
sitemaps = rp.site_maps()
if sitemaps is None:
return [parse_link(urljoin(link.url, '/sitemap.xml'), backref=link)]
return [parse_link(urljoin(link.url, sitemap), host=host, backref=link) for sitemap in sitemaps]
[docs]def get_sitemap(link: 'darc_link.Link', text: str, host: 'Optional[str]' = None) -> 'List[darc_link.Link]':
"""Fetch link to other sitemaps from a sitemap.
Args:
link: Original link to the sitemap.
text: Content of the sitemap.
host: Hostname of the URL to the sitemap,
the value may not be same as in ``link``.
Returns:
List of link to sitemaps.
Note:
As specified in the sitemap protocol,
it may contain links to other sitemaps. [*]_
.. [*] https://www.sitemaps.org/protocol.html#index
"""
sitemaps = []
soup = bs4.BeautifulSoup(text, 'html5lib')
# https://www.sitemaps.org/protocol.html#index
for loc in soup.select('sitemapindex > sitemap > loc'):
sitemaps.append(urljoin(link.url, loc.text))
return [parse_link(sitemap, host=host, backref=link) for sitemap in sitemaps]
[docs]def read_sitemap(link: 'darc_link.Link', text: str, check: bool = CHECK) -> 'List[darc_link.Link]':
"""Read sitemap.
Args:
link: Original link to the sitemap.
text: Content of the sitemap.
check: If perform checks on extracted links,
default to :data:`~darc.const.CHECK`.
Returns:
List of links extracted.
See Also:
* :func:`darc.parse._check`
* :func:`darc.parse._check_ng`
"""
soup = bs4.BeautifulSoup(text, 'html5lib')
# https://www.sitemaps.org/protocol.html
temp_list = [parse_link(urljoin(link.url, loc.text), host=link.host, backref=link)
for loc in soup.select('urlset > url > loc')]
# check content / proxy type
if check:
return _check(temp_list)
return temp_list
[docs]def fetch_sitemap(link: 'darc_link.Link', force: bool = False) -> None:
"""Fetch sitemap.
The function will first fetch the ``robots.txt``, then
fetch the sitemaps accordingly.
Args:
link: Link object to fetch for its sitemaps.
force: Force refetch its sitemaps.
Returns:
Contents of ``robots.txt`` and sitemaps.
See Also:
* :func:`darc.proxy.null.read_robots`
* :func:`darc.proxy.null.read_sitemap`
* :func:`darc.parse.get_sitemap`
"""
if force:
logger.warning('[ROBOTS] Force refetch %s', link.url)
robots_path = None if force else have_robots(link)
if robots_path is not None:
logger.warning('[ROBOTS] Cached %s', link.url)
with open(robots_path) as file:
robots_text = file.read()
else:
robots_link = parse_link(urljoin(link.url, '/robots.txt'), backref=link)
logger.info('[ROBOTS] Checking %s', robots_link.url)
with request_session(robots_link) as session:
try:
response = session.get(robots_link.url)
except requests.RequestException:
logger.pexc(message=f'[ROBOTS] Failed on {robots_link.url}')
return
if response.ok:
ct_type = get_content_type(response)
if ct_type not in ['text/text', 'text/plain']:
logger.error('[ROBOTS] Unresolved content type on %s (%s)', robots_link.url, ct_type)
robots_text = ''
else:
robots_text = response.text
save_robots(robots_link, robots_text)
logger.info('[ROBOTS] Checked %s', robots_link.url)
else:
logger.error('[ROBOTS] Failed on %s [%d]', robots_link.url, response.status_code)
robots_text = ''
if force:
logger.warning('[SITEMAP] Force refetch %s', link.url)
sitemaps = read_robots(link, robots_text, host=link.host)
for sitemap_link in sitemaps:
sitemap_path = None if force else have_sitemap(sitemap_link)
if sitemap_path is not None:
logger.warning('[SITEMAP] Cached %s', sitemap_link.url)
with open(sitemap_path) as file:
sitemap_text = file.read()
else:
logger.info('[SITEMAP] Fetching %s', sitemap_link.url)
with request_session(sitemap_link) as session:
try:
response = session.get(sitemap_link.url)
except requests.RequestException:
logger.pexc(message=f'[SITEMAP] Failed on {sitemap_link.url}')
continue
if not response.ok:
logger.error('[SITEMAP] Failed on %s [%d]', sitemap_link.url, response.status_code)
continue
# check content type
ct_type = get_content_type(response)
if ct_type == 'application/gzip':
try:
sitemap_text = gzip.decompress(response.content).decode()
except UnicodeDecodeError:
sitemap_text = response.text
elif ct_type in ['text/xml', 'text/html']:
sitemap_text = response.text
save_sitemap(sitemap_link, sitemap_text)
else:
logger.error('[SITEMAP] Unresolved content type on %s (%s)', sitemap_link.url, ct_type)
continue
logger.info('[SITEMAP] Fetched %s', sitemap_link.url)
# get more sitemaps
sitemaps.extend(get_sitemap(sitemap_link, sitemap_text, host=link.host))
# add link to queue
save_requests(read_sitemap(link, sitemap_text))
