"""The CheckExternalLinksBuilder class."""
from __future__ import annotations
import contextlib
import json
import re
import socket
import time
from html.parser import HTMLParser
from os import path
from queue import PriorityQueue, Queue
from threading import Thread
from typing import TYPE_CHECKING, NamedTuple, cast
from urllib.parse import quote, unquote, urlparse, urlsplit, urlunparse
from docutils import nodes
from requests.exceptions import ConnectionError, HTTPError, SSLError, TooManyRedirects
from requests.exceptions import Timeout as RequestTimeout
from sphinx.builders.dummy import DummyBuilder
from sphinx.locale import __
from sphinx.transforms.post_transforms import SphinxPostTransform
from sphinx.util import logging, requests
from sphinx.util._uri import encode_uri
from sphinx.util.console import darkgray, darkgreen, purple, red, turquoise
from sphinx.util.http_date import rfc1123_to_epoch
from sphinx.util.nodes import get_node_line
if TYPE_CHECKING:
from collections.abc import Callable, Iterator
from typing import Any
from requests import Response
from sphinx.application import Sphinx
from sphinx.config import Config
from sphinx.util._pathlib import _StrPath
from sphinx.util.typing import ExtensionMetadata
logger = logging.getLogger(__name__)
# matches to foo:// and // (a protocol relative URL)
uri_re = re.compile('([a-z]+:)?//')
DEFAULT_REQUEST_HEADERS = {
'Accept': 'text/html,application/xhtml+xml;q=0.9,*/*;q=0.8',
}
CHECK_IMMEDIATELY = 0
QUEUE_POLL_SECS = 1
DEFAULT_DELAY = 60.0
[docs]
class CheckExternalLinksBuilder(DummyBuilder):
"""
Checks for broken external links.
"""
name = 'linkcheck'
epilog = __('Look for any errors in the above output or in %(outdir)s/output.txt')
def init(self) -> None:
self.broken_hyperlinks = 0
self.timed_out_hyperlinks = 0
self.hyperlinks: dict[str, Hyperlink] = {}
# set a timeout for non-responding servers
socket.setdefaulttimeout(5.0)
def finish(self) -> None:
checker = HyperlinkAvailabilityChecker(self.config)
logger.info('')
output_text = path.join(self.outdir, 'output.txt')
output_json = path.join(self.outdir, 'output.json')
with (
open(output_text, 'w', encoding='utf-8') as self.txt_outfile,
open(output_json, 'w', encoding='utf-8') as self.json_outfile,
):
for result in checker.check(self.hyperlinks):
self.process_result(result)
if self.broken_hyperlinks or self.timed_out_hyperlinks:
self.app.statuscode = 1
def process_result(self, result: CheckResult) -> None:
filename = self.env.doc2path(result.docname, False)
linkstat: dict[str, str | int] = {
'filename': str(filename),
'lineno': result.lineno,
'status': result.status,
'code': result.code,
'uri': result.uri,
'info': result.message,
}
self.write_linkstat(linkstat)
if result.status == 'unchecked':
return
if result.status == 'working' and result.message == 'old':
return
if result.lineno:
logger.info('(%16s: line %4d) ', result.docname, result.lineno, nonl=True)
if result.status == 'ignored':
if result.message:
logger.info(darkgray('-ignored- ') + result.uri + ': ' + result.message)
else:
logger.info(darkgray('-ignored- ') + result.uri)
elif result.status == 'local':
logger.info(darkgray('-local- ') + result.uri)
self.write_entry(
'local', result.docname, filename, result.lineno, result.uri
)
elif result.status == 'working':
logger.info(darkgreen('ok ') + result.uri + result.message)
elif result.status == 'timeout':
if self.app.quiet:
logger.warning(
'timeout ' + result.uri + result.message,
location=(result.docname, result.lineno),
)
else:
logger.info(
red('timeout ') + result.uri + red(' - ' + result.message)
)
self.write_entry(
'timeout',
result.docname,
filename,
result.lineno,
result.uri + ': ' + result.message,
)
self.timed_out_hyperlinks += 1
elif result.status == 'broken':
if self.app.quiet:
logger.warning(
__('broken link: %s (%s)'),
result.uri,
result.message,
location=(result.docname, result.lineno),
)
else:
logger.info(
red('broken ') + result.uri + red(' - ' + result.message)
)
self.write_entry(
'broken',
result.docname,
filename,
result.lineno,
result.uri + ': ' + result.message,
)
self.broken_hyperlinks += 1
elif result.status == 'redirected':
try:
text, color = {
301: ('permanently', purple),
302: ('with Found', purple),
303: ('with See Other', purple),
307: ('temporarily', turquoise),
308: ('permanently', purple),
}[result.code]
except KeyError:
text, color = ('with unknown code', purple)
linkstat['text'] = text
if self.config.linkcheck_allowed_redirects:
logger.warning(
'redirect ' + result.uri + ' - ' + text + ' to ' + result.message,
location=(result.docname, result.lineno),
)
else:
logger.info(
color('redirect ')
+ result.uri
+ color(' - ' + text + ' to ' + result.message)
)
self.write_entry(
'redirected ' + text,
result.docname,
filename,
result.lineno,
result.uri + ' to ' + result.message,
)
else:
raise ValueError('Unknown status %s.' % result.status)
def write_linkstat(self, data: dict[str, str | int]) -> None:
self.json_outfile.write(json.dumps(data))
self.json_outfile.write('\n')
def write_entry(
self, what: str, docname: str, filename: _StrPath, line: int, uri: str
) -> None:
self.txt_outfile.write(f'{filename}:{line}: [{what}] {uri}\n')
class HyperlinkCollector(SphinxPostTransform):
builders = ('linkcheck',)
default_priority = 800
def run(self, **kwargs: Any) -> None:
for node in self.document.findall():
if uri := self.find_uri(node):
self._add_uri(uri, node)
def find_uri(self, node: nodes.Element) -> str | None:
"""Find a URI for a given node.
This call can be used to retrieve a URI from a provided node. If no
URI exists for a provided node, this call will return ``None``.
This method can be useful for extension developers who wish to
easily inject hyperlinks into a builder by only needing to override
this method.
:param node: A node class
:returns: URI of the node
"""
# reference nodes
if isinstance(node, nodes.reference):
if 'refuri' in node:
return node['refuri']
# image nodes
if isinstance(node, nodes.image):
uri = node['candidates'].get('?')
if uri and '://' in uri:
return uri
# raw nodes
if isinstance(node, nodes.raw):
uri = node.get('source')
if uri and '://' in uri:
return uri
return None
def _add_uri(self, uri: str, node: nodes.Element) -> None:
"""Registers a node's URI into a builder's collection of hyperlinks.
Provides the ability to register a URI value determined from a node
into the linkcheck's builder. URI's processed through this call can
be manipulated through a ``linkcheck-process-uri`` event before the
builder attempts to validate.
:param uri: URI to add
:param node: A node class where the URI was found
"""
builder = cast(CheckExternalLinksBuilder, self.app.builder)
hyperlinks = builder.hyperlinks
docname = self.env.docname
if newuri := self.app.emit_firstresult('linkcheck-process-uri', uri):
uri = newuri
try:
lineno = get_node_line(node)
except ValueError:
lineno = -1
if uri not in hyperlinks:
hyperlinks[uri] = Hyperlink(
uri, docname, self.env.doc2path(docname), lineno
)
class Hyperlink(NamedTuple):
uri: str
docname: str
docpath: _StrPath
lineno: int
class HyperlinkAvailabilityChecker:
def __init__(self, config: Config) -> None:
self.config = config
self.rate_limits: dict[str, RateLimit] = {}
self.rqueue: Queue[CheckResult] = Queue()
self.workers: list[Thread] = []
self.wqueue: PriorityQueue[CheckRequest] = PriorityQueue()
self.num_workers: int = config.linkcheck_workers
self.to_ignore: list[re.Pattern[str]] = list(
map(re.compile, self.config.linkcheck_ignore)
)
def check(self, hyperlinks: dict[str, Hyperlink]) -> Iterator[CheckResult]:
self.invoke_threads()
total_links = 0
for hyperlink in hyperlinks.values():
if self.is_ignored_uri(hyperlink.uri):
yield CheckResult(
hyperlink.uri, hyperlink.docname, hyperlink.lineno, 'ignored', '', 0
)
else:
self.wqueue.put(CheckRequest(CHECK_IMMEDIATELY, hyperlink), False)
total_links += 1
done = 0
while done < total_links:
yield self.rqueue.get()
done += 1
self.shutdown_threads()
def invoke_threads(self) -> None:
for _i in range(self.num_workers):
thread = HyperlinkAvailabilityCheckWorker(
self.config, self.rqueue, self.wqueue, self.rate_limits
)
thread.start()
self.workers.append(thread)
def shutdown_threads(self) -> None:
self.wqueue.join()
for _worker in self.workers:
self.wqueue.put(CheckRequest(CHECK_IMMEDIATELY, None), False)
def is_ignored_uri(self, uri: str) -> bool:
return any(pat.match(uri) for pat in self.to_ignore)
class CheckRequest(NamedTuple):
next_check: float
hyperlink: Hyperlink | None
class CheckResult(NamedTuple):
uri: str
docname: str
lineno: int
status: str
message: str
code: int
class HyperlinkAvailabilityCheckWorker(Thread):
"""A worker class for checking the availability of hyperlinks."""
def __init__(
self,
config: Config,
rqueue: Queue[CheckResult],
wqueue: Queue[CheckRequest],
rate_limits: dict[str, RateLimit],
) -> None:
self.rate_limits = rate_limits
self.rqueue = rqueue
self.wqueue = wqueue
self.anchors_ignore: list[re.Pattern[str]] = list(
map(re.compile, config.linkcheck_anchors_ignore)
)
self.anchors_ignore_for_url: list[re.Pattern[str]] = list(
map(re.compile, config.linkcheck_anchors_ignore_for_url)
)
self.documents_exclude: list[re.Pattern[str]] = list(
map(re.compile, config.linkcheck_exclude_documents)
)
self.auth = [
(re.compile(pattern), auth_info)
for pattern, auth_info in config.linkcheck_auth
]
self.timeout: int | float | None = config.linkcheck_timeout
self.request_headers: dict[str, dict[str, str]] = (
config.linkcheck_request_headers
)
self.check_anchors: bool = config.linkcheck_anchors
self.allowed_redirects: dict[re.Pattern[str], re.Pattern[str]]
self.allowed_redirects = config.linkcheck_allowed_redirects
self.retries: int = config.linkcheck_retries
self.rate_limit_timeout = config.linkcheck_rate_limit_timeout
self._allow_unauthorized = config.linkcheck_allow_unauthorized
if config.linkcheck_report_timeouts_as_broken:
self._timeout_status = 'broken'
else:
self._timeout_status = 'timeout'
self.user_agent = config.user_agent
self.tls_verify = config.tls_verify
self.tls_cacerts = config.tls_cacerts
self._session = requests._Session()
super().__init__(daemon=True)
def run(self) -> None:
while True:
next_check, hyperlink = self.wqueue.get()
if hyperlink is None:
# An empty hyperlink is a signal to shutdown the worker; cleanup resources here
self._session.close()
break
uri, docname, _docpath, lineno = hyperlink
if uri is None:
break
netloc = urlsplit(uri).netloc
with contextlib.suppress(KeyError):
# Refresh rate limit.
# When there are many links in the queue, workers are all stuck waiting
# for responses, but the builder keeps queuing. Links in the queue may
# have been queued before rate limits were discovered.
next_check = self.rate_limits[netloc].next_check
if next_check > time.time():
# Sleep before putting message back in the queue to avoid
# waking up other threads.
time.sleep(QUEUE_POLL_SECS)
self.wqueue.put(CheckRequest(next_check, hyperlink), False)
self.wqueue.task_done()
continue
status, info, code = self._check(docname, uri, hyperlink)
if status == 'rate-limited':
logger.info(
darkgray('-rate limited- ') + uri + darkgray(' | sleeping...')
)
else:
self.rqueue.put(CheckResult(uri, docname, lineno, status, info, code))
self.wqueue.task_done()
def _check(
self, docname: str, uri: str, hyperlink: Hyperlink
) -> tuple[str, str, int]:
# check for various conditions without bothering the network
for doc_matcher in self.documents_exclude:
if doc_matcher.match(docname):
info = (
f'{docname} matched {doc_matcher.pattern} from '
'linkcheck_exclude_documents'
)
return 'ignored', info, 0
if len(uri) == 0 or uri.startswith(('#', 'mailto:', 'tel:')):
return 'unchecked', '', 0
if not uri.startswith(('http:', 'https:')):
if uri_re.match(uri):
# Non-supported URI schemes (ex. ftp)
return 'unchecked', '', 0
src_dir = path.dirname(hyperlink.docpath)
if path.exists(path.join(src_dir, uri)):
return 'working', '', 0
return 'broken', '', 0
# need to actually check the URI
status, info, code = '', '', 0
for _ in range(self.retries):
status, info, code = self._check_uri(uri, hyperlink)
if status != 'broken':
break
return status, info, code
def _retrieval_methods(
self,
check_anchors: bool,
anchor: str,
) -> Iterator[tuple[Callable[..., Response], dict[str, bool]]]:
if not check_anchors or not anchor:
yield self._session.head, {'allow_redirects': True}
yield self._session.get, {'stream': True}
def _check_uri(self, uri: str, hyperlink: Hyperlink) -> tuple[str, str, int]:
req_url, delimiter, anchor = uri.partition('#')
if delimiter and anchor:
for rex in self.anchors_ignore:
if rex.match(anchor):
anchor = ''
break
else:
for rex in self.anchors_ignore_for_url:
if rex.match(req_url):
anchor = ''
break
anchor = unquote(anchor)
# handle non-ASCII URIs
try:
req_url.encode('ascii')
except UnicodeError:
req_url = encode_uri(req_url)
# Get auth info, if any
for pattern, auth_info in self.auth: # NoQA: B007 (false positive)
if pattern.match(uri):
break
else:
auth_info = None
# update request headers for the URL
headers = _get_request_headers(uri, self.request_headers)
# Linkcheck HTTP request logic:
#
# - Attempt HTTP HEAD before HTTP GET unless page content is required.
# - Follow server-issued HTTP redirects.
# - Respect server-issued HTTP 429 back-offs.
error_message = ''
status_code = -1
response_url = retry_after = ''
for retrieval_method, kwargs in self._retrieval_methods(
self.check_anchors, anchor
):
try:
with retrieval_method(
url=req_url,
auth=auth_info,
headers=headers,
timeout=self.timeout,
**kwargs,
_user_agent=self.user_agent,
_tls_info=(self.tls_verify, self.tls_cacerts),
) as response:
if anchor and self.check_anchors and response.ok:
try:
found = contains_anchor(response, anchor)
except UnicodeDecodeError:
return 'ignored', 'unable to decode response content', 0
if not found:
return (
'broken',
__("Anchor '%s' not found") % quote(anchor),
0,
)
# Copy data we need from the (closed) response
status_code = response.status_code
redirect_status_code = (
response.history[-1].status_code if response.history else None
) # NoQA: E501
retry_after = response.headers.get('Retry-After', '')
response_url = f'{response.url}'
response.raise_for_status()
del response
break
except RequestTimeout as err:
return self._timeout_status, str(err), 0
except SSLError as err:
# SSL failure; report that the link is broken.
return 'broken', str(err), 0
except (ConnectionError, TooManyRedirects) as err:
# Servers drop the connection on HEAD requests, causing
# ConnectionError.
error_message = str(err)
continue
except HTTPError as err:
error_message = str(err)
# Unauthorized: the client did not provide required credentials
if status_code == 401:
status = 'working' if self._allow_unauthorized else 'broken'
return status, 'unauthorized', 0
# Rate limiting; back-off if allowed, or report failure otherwise
if status_code == 429:
if next_check := self.limit_rate(response_url, retry_after):
self.wqueue.put(CheckRequest(next_check, hyperlink), False)
return 'rate-limited', '', 0
return 'broken', error_message, 0
# Don't claim success/failure during server-side outages
if status_code == 503:
return 'ignored', 'service unavailable', 0
# For most HTTP failures, continue attempting alternate retrieval methods
continue
except Exception as err:
# Unhandled exception (intermittent or permanent); report that
# the link is broken.
return 'broken', str(err), 0
else:
# All available retrieval methods have been exhausted; report
# that the link is broken.
return 'broken', error_message, 0
# Success; clear rate limits for the origin
netloc = urlsplit(req_url).netloc
self.rate_limits.pop(netloc, None)
if (
(response_url.rstrip('/') == req_url.rstrip('/'))
or _allowed_redirect(req_url, response_url, self.allowed_redirects)
): # fmt: skip
return 'working', '', 0
elif redirect_status_code is not None:
return 'redirected', response_url, redirect_status_code
else:
return 'redirected', response_url, 0
def limit_rate(self, response_url: str, retry_after: str | None) -> float | None:
delay = DEFAULT_DELAY
next_check = None
if retry_after:
try:
# Integer: time to wait before next attempt.
delay = float(retry_after)
except ValueError:
try:
# An HTTP-date: time of next attempt.
next_check = rfc1123_to_epoch(retry_after)
except (ValueError, TypeError):
# TypeError: Invalid date format.
# ValueError: Invalid date, e.g. Oct 52th.
pass
else:
delay = next_check - time.time()
else:
next_check = time.time() + delay
netloc = urlsplit(response_url).netloc
if next_check is None:
max_delay = self.rate_limit_timeout
try:
rate_limit = self.rate_limits[netloc]
except KeyError:
delay = DEFAULT_DELAY
else:
last_wait_time = rate_limit.delay
delay = 2.0 * last_wait_time
if delay > max_delay > last_wait_time:
delay = max_delay
if delay > max_delay:
return None
next_check = time.time() + delay
self.rate_limits[netloc] = RateLimit(delay, next_check)
return next_check
def _get_request_headers(
uri: str,
request_headers: dict[str, dict[str, str]],
) -> dict[str, str]:
url = urlsplit(uri)
candidates = (
f'{url.scheme}://{url.netloc}',
f'{url.scheme}://{url.netloc}/',
uri,
'*',
)
for u in candidates:
if u in request_headers:
return {**DEFAULT_REQUEST_HEADERS, **request_headers[u]}
return {}
def contains_anchor(response: Response, anchor: str) -> bool:
"""Determine if an anchor is contained within an HTTP response."""
parser = AnchorCheckParser(anchor)
# Read file in chunks. If we find a matching anchor, we break
# the loop early in hopes not to have to download the whole thing.
for chunk in response.iter_content(chunk_size=4096, decode_unicode=True):
if isinstance(chunk, bytes):
# requests failed to decode, manually try to decode it
chunk = chunk.decode()
parser.feed(chunk)
if parser.found:
break
parser.close()
return parser.found
class AnchorCheckParser(HTMLParser):
"""Specialised HTML parser that looks for a specific anchor."""
def __init__(self, search_anchor: str) -> None:
super().__init__()
self.search_anchor = search_anchor
self.found = False
def handle_starttag(self, tag: Any, attrs: Any) -> None:
for key, value in attrs:
if key in ('id', 'name') and value == self.search_anchor:
self.found = True
break
def _allowed_redirect(
url: str, new_url: str, allowed_redirects: dict[re.Pattern[str], re.Pattern[str]]
) -> bool:
return any(
from_url.match(url) and to_url.match(new_url)
for from_url, to_url in allowed_redirects.items()
)
class RateLimit(NamedTuple):
delay: float
next_check: float
def rewrite_github_anchor(app: Sphinx, uri: str) -> str | None:
"""Rewrite anchor name of the hyperlink to github.com
The hyperlink anchors in github.com are dynamically generated. This rewrites
them before checking and makes them comparable.
"""
parsed = urlparse(uri)
if parsed.hostname == 'github.com' and parsed.fragment:
prefixed = parsed.fragment.startswith('user-content-')
if not prefixed:
fragment = f'user-content-{parsed.fragment}'
return urlunparse(parsed._replace(fragment=fragment))
return None
def compile_linkcheck_allowed_redirects(app: Sphinx, config: Config) -> None:
"""Compile patterns in linkcheck_allowed_redirects to the regexp objects."""
linkcheck_allowed_redirects = app.config.linkcheck_allowed_redirects
for url, pattern in list(linkcheck_allowed_redirects.items()):
try:
linkcheck_allowed_redirects[re.compile(url)] = re.compile(pattern)
except re.error as exc:
logger.warning(
__('Failed to compile regex in linkcheck_allowed_redirects: %r %s'),
exc.pattern,
exc.msg,
)
finally:
# Remove the original regexp-string
linkcheck_allowed_redirects.pop(url)
def setup(app: Sphinx) -> ExtensionMetadata:
app.add_builder(CheckExternalLinksBuilder)
app.add_post_transform(HyperlinkCollector)
app.add_config_value('linkcheck_ignore', [], '')
app.add_config_value('linkcheck_exclude_documents', [], '')
app.add_config_value('linkcheck_allowed_redirects', {}, '')
app.add_config_value('linkcheck_auth', [], '')
app.add_config_value('linkcheck_request_headers', {}, '')
app.add_config_value('linkcheck_retries', 1, '')
app.add_config_value('linkcheck_timeout', 30, '', (int, float))
app.add_config_value('linkcheck_workers', 5, '')
app.add_config_value('linkcheck_anchors', True, '')
# Anchors starting with ! are ignored since they are
# commonly used for dynamic pages
app.add_config_value('linkcheck_anchors_ignore', ['^!'], '')
app.add_config_value('linkcheck_anchors_ignore_for_url', (), '', (tuple, list))
app.add_config_value('linkcheck_rate_limit_timeout', 300.0, '', (int, float))
app.add_config_value('linkcheck_allow_unauthorized', False, '')
app.add_config_value('linkcheck_report_timeouts_as_broken', False, '', bool)
app.add_event('linkcheck-process-uri')
app.connect('config-inited', compile_linkcheck_allowed_redirects, priority=800)
# FIXME: Disable URL rewrite handler for github.com temporarily.
# ref: https://github.com/sphinx-doc/sphinx/issues/9435
# app.connect('linkcheck-process-uri', rewrite_github_anchor)
return {
'version': 'builtin',
'parallel_read_safe': True,
'parallel_write_safe': True,
}
