"""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 unquote, urlparse, urlsplit, urlunparse from docutils import nodes from requests.exceptions import ConnectionError, HTTPError, SSLError, TooManyRedirects from sphinx.builders.dummy import DummyBuilder from sphinx.locale import __ from sphinx.transforms.post_transforms import SphinxPostTransform from sphinx.util import encode_uri, logging, requests from sphinx.util.console import ( # type: ignore[attr-defined] 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 Generator, Iterator from typing import Any, Callable from requests import Response from sphinx.application import Sphinx from sphinx.config import Config logger = logging.getLogger(__name__) uri_re = re.compile('([a-z]+:)?//') # matches to foo:// and // (a protocol relative URL) 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 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.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: self.app.statuscode = 1 def process_result(self, result: CheckResult) -> None: filename = self.env.doc2path(result.docname, False) linkstat = {'filename': 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 == 'broken': if self.app.quiet or self.app.warningiserror: 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) -> None: self.json_outfile.write(json.dumps(data)) self.json_outfile.write('\n') def write_entry(self, what: str, docname: str, filename: str, 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: builder = cast(CheckExternalLinksBuilder, self.app.builder) hyperlinks = builder.hyperlinks docname = self.env.docname # reference nodes for refnode in self.document.findall(nodes.reference): if 'refuri' in refnode: uri = refnode['refuri'] _add_uri(self.app, uri, refnode, hyperlinks, docname) # image nodes for imgnode in self.document.findall(nodes.image): uri = imgnode['candidates'].get('?') if uri and '://' in uri: _add_uri(self.app, uri, imgnode, hyperlinks, docname) # raw nodes for rawnode in self.document.findall(nodes.raw): uri = rawnode.get('source') if uri and '://' in uri: _add_uri(self.app, uri, rawnode, hyperlinks, docname) def _add_uri(app: Sphinx, uri: str, node: nodes.Element, hyperlinks: dict[str, Hyperlink], docname: str) -> None: if newuri := 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, app.env.doc2path(docname), lineno) class Hyperlink(NamedTuple): uri: str docname: str docpath: str 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]) -> Generator[CheckResult, None, None]: 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.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, dict]]: 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 # 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 (self.check_anchors and response.ok and anchor and not contains_anchor(response, anchor)): raise Exception(__(f'Anchor {anchor!r} not found')) # 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 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) # Unauthorised: the reference probably exists if status_code == 401: return 'working', '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)): 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) -> 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(unquote(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 chunk = chunk.decode() # manually try to decode it 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.""" for url, pattern in list(app.config.linkcheck_allowed_redirects.items()): try: app.config.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 app.config.linkcheck_allowed_redirects.pop(url) def setup(app: Sphinx) -> dict[str, Any]: app.add_builder(CheckExternalLinksBuilder) app.add_post_transform(HyperlinkCollector) app.add_config_value('linkcheck_ignore', [], False) app.add_config_value('linkcheck_exclude_documents', [], False) app.add_config_value('linkcheck_allowed_redirects', {}, False) app.add_config_value('linkcheck_auth', [], False) app.add_config_value('linkcheck_request_headers', {}, False) app.add_config_value('linkcheck_retries', 1, False) app.add_config_value('linkcheck_timeout', None, False, [int, float]) app.add_config_value('linkcheck_workers', 5, False) app.add_config_value('linkcheck_anchors', True, False) # Anchors starting with ! are ignored since they are # commonly used for dynamic pages app.add_config_value('linkcheck_anchors_ignore', ['^!'], False) app.add_config_value('linkcheck_anchors_ignore_for_url', (), False, (tuple, list)) app.add_config_value('linkcheck_rate_limit_timeout', 300.0, False) 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, }