"""The CheckExternalLinksBuilder class."""
import json
import re
import socket
import time
from copy import deepcopy
from datetime import datetime, timezone
from email.utils import parsedate_to_datetime
from html.parser import HTMLParser
from os import path
from queue import PriorityQueue, Queue
from threading import Thread
from typing import Any, Dict, Generator, List, NamedTuple, Optional, Tuple, Union, cast
from urllib.parse import unquote, urlparse, urlunparse
from docutils import nodes
from requests import Response
from requests.exceptions import ConnectionError, HTTPError, TooManyRedirects
from sphinx.application import Sphinx
from sphinx.builders.dummy import DummyBuilder
from sphinx.config import Config
from sphinx.environment import BuildEnvironment
from sphinx.locale import __
from sphinx.transforms.post_transforms import SphinxPostTransform
from sphinx.util import encode_uri, logging, requests
from sphinx.util.console import darkgray, darkgreen, purple, red, turquoise # type: ignore
from sphinx.util.nodes import get_node_line
logger = logging.getLogger(__name__)
uri_re = re.compile('([a-z]+:)?//') # matches to foo:// and // (a protocol relative URL)
class Hyperlink(NamedTuple):
uri: str
docname: str
lineno: Optional[int]
class CheckRequest(NamedTuple):
next_check: float
hyperlink: Optional[Hyperlink]
class CheckResult(NamedTuple):
uri: str
docname: str
lineno: int
status: str
message: str
code: int
class RateLimit(NamedTuple):
delay: float
next_check: float
# Tuple is old styled CheckRequest
CheckRequestType = Union[CheckRequest, Tuple[float, str, str, int]]
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 AnchorCheckParser(HTMLParser):
"""Specialized 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 check_anchor(response: requests.requests.Response, anchor: str) -> bool:
"""Reads HTML data from a response object `response` searching for `anchor`.
Returns True if anchor was found, False otherwise.
"""
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
chunk = chunk.decode() # manually try to decode it
parser.feed(chunk)
if parser.found:
break
parser.close()
return parser.found
[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.hyperlinks: Dict[str, Hyperlink] = {}
# set a timeout for non-responding servers
socket.setdefaulttimeout(5.0)
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_entry(self, what: str, docname: str, filename: str, line: int,
uri: str) -> None:
self.txt_outfile.write("%s:%s: [%s] %s\n" % (filename, line, what, uri))
def write_linkstat(self, data: dict) -> None:
self.json_outfile.write(json.dumps(data))
self.json_outfile.write('\n')
def finish(self) -> None:
checker = HyperlinkAvailabilityChecker(self.env, 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
class HyperlinkAvailabilityChecker:
def __init__(self, env: BuildEnvironment, config: Config) -> None:
self.config = config
self.env = env
self.rate_limits: Dict[str, RateLimit] = {}
self.rqueue: Queue = Queue()
self.workers: List[Thread] = []
self.wqueue: PriorityQueue[CheckRequest] = PriorityQueue()
self.to_ignore = [re.compile(x) for x in self.config.linkcheck_ignore]
def invoke_threads(self) -> None:
for _i in range(self.config.linkcheck_workers):
thread = HyperlinkAvailabilityCheckWorker(self.env, 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 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 is_ignored_uri(self, uri: str) -> bool:
return any(pat.match(uri) for pat in self.to_ignore)
class HyperlinkAvailabilityCheckWorker(Thread):
"""A worker class for checking the availability of hyperlinks."""
def __init__(self, env: BuildEnvironment, config: Config, rqueue: Queue,
wqueue: Queue, rate_limits: Dict[str, RateLimit]) -> None:
self.config = config
self.env = env
self.rate_limits = rate_limits
self.rqueue = rqueue
self.wqueue = wqueue
self.anchors_ignore = [re.compile(x)
for x in self.config.linkcheck_anchors_ignore]
self.documents_exclude = [re.compile(doc)
for doc in self.config.linkcheck_exclude_documents]
self.auth = [(re.compile(pattern), auth_info) for pattern, auth_info
in self.config.linkcheck_auth]
super().__init__(daemon=True)
def run(self) -> None:
kwargs = {}
if self.config.linkcheck_timeout:
kwargs['timeout'] = self.config.linkcheck_timeout
def get_request_headers() -> Dict[str, str]:
url = urlparse(uri)
candidates = ["%s://%s" % (url.scheme, url.netloc),
"%s://%s/" % (url.scheme, url.netloc),
uri,
"*"]
for u in candidates:
if u in self.config.linkcheck_request_headers:
headers = deepcopy(DEFAULT_REQUEST_HEADERS)
headers.update(self.config.linkcheck_request_headers[u])
return headers
return {}
def check_uri() -> Tuple[str, str, int]:
# split off anchor
if '#' in uri:
req_url, anchor = uri.split('#', 1)
for rex in self.anchors_ignore:
if rex.match(anchor):
anchor = None
break
else:
req_url = uri
anchor = None
# 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
kwargs['headers'] = get_request_headers()
try:
if anchor and self.config.linkcheck_anchors:
# Read the whole document and see if #anchor exists
response = requests.get(req_url, stream=True, config=self.config,
auth=auth_info, **kwargs)
response.raise_for_status()
found = check_anchor(response, unquote(anchor))
if not found:
raise Exception(__("Anchor '%s' not found") % anchor)
else:
try:
# try a HEAD request first, which should be easier on
# the server and the network
response = requests.head(req_url, allow_redirects=True,
config=self.config, auth=auth_info,
**kwargs)
response.raise_for_status()
# Servers drop the connection on HEAD requests, causing
# ConnectionError.
except (ConnectionError, HTTPError, TooManyRedirects) as err:
if isinstance(err, HTTPError) and err.response.status_code == 429:
raise
# retry with GET request if that fails, some servers
# don't like HEAD requests.
response = requests.get(req_url, stream=True,
config=self.config,
auth=auth_info, **kwargs)
response.raise_for_status()
except HTTPError as err:
if err.response.status_code == 401:
# We'll take "Unauthorized" as working.
return 'working', ' - unauthorized', 0
elif err.response.status_code == 429:
next_check = self.limit_rate(err.response)
if next_check is not None:
self.wqueue.put(CheckRequest(next_check, hyperlink), False)
return 'rate-limited', '', 0
return 'broken', str(err), 0
elif err.response.status_code == 503:
# We'll take "Service Unavailable" as ignored.
return 'ignored', str(err), 0
else:
return 'broken', str(err), 0
except Exception as err:
return 'broken', str(err), 0
else:
netloc = urlparse(req_url).netloc
try:
del self.rate_limits[netloc]
except KeyError:
pass
if response.url.rstrip('/') == req_url.rstrip('/'):
return 'working', '', 0
else:
new_url = response.url
if anchor:
new_url += '#' + anchor
if allowed_redirect(req_url, new_url):
return 'working', '', 0
elif response.history:
# history contains any redirects, get last
code = response.history[-1].status_code
return 'redirected', new_url, code
else:
return 'redirected', new_url, 0
def allowed_redirect(url: str, new_url: str) -> bool:
for from_url, to_url in self.config.linkcheck_allowed_redirects.items():
if from_url.match(url) and to_url.match(new_url):
return True
return False
def check(docname: str) -> 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
elif not uri.startswith(('http:', 'https:')):
if uri_re.match(uri):
# non supported URI schemes (ex. ftp)
return 'unchecked', '', 0
else:
srcdir = path.dirname(self.env.doc2path(docname))
if path.exists(path.join(srcdir, uri)):
return 'working', '', 0
else:
return 'broken', '', 0
# need to actually check the URI
for _ in range(self.config.linkcheck_retries):
status, info, code = check_uri()
if status != "broken":
break
return (status, info, code)
while True:
check_request = self.wqueue.get()
try:
next_check, hyperlink = check_request
if hyperlink is None:
break
uri, docname, lineno = hyperlink
except ValueError:
# old styled check_request (will be deprecated in Sphinx-5.0)
next_check, uri, docname, lineno = check_request
if uri is None:
break
netloc = urlparse(uri).netloc
try:
# 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
except KeyError:
pass
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 = check(docname)
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 limit_rate(self, response: Response) -> Optional[float]:
next_check = None
retry_after = response.headers.get("Retry-After")
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.
until = parsedate_to_datetime(retry_after)
except (TypeError, ValueError):
# TypeError: Invalid date format.
# ValueError: Invalid date, e.g. Oct 52th.
pass
else:
next_check = datetime.timestamp(until)
delay = (until - datetime.now(timezone.utc)).total_seconds()
else:
next_check = time.time() + delay
netloc = urlparse(response.url).netloc
if next_check is None:
max_delay = self.config.linkcheck_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 and last_wait_time < max_delay:
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
class HyperlinkCollector(SphinxPostTransform):
builders = ('linkcheck',)
default_priority = 800
def run(self, **kwargs: Any) -> None:
builder = cast(CheckExternalLinksBuilder, self.app.builder)
hyperlinks = builder.hyperlinks
def add_uri(uri: str, node: nodes.Element) -> None:
newuri = self.app.emit_firstresult('linkcheck-process-uri', uri)
if newuri:
uri = newuri
lineno = get_node_line(node)
uri_info = Hyperlink(uri, self.env.docname, lineno)
if uri not in hyperlinks:
hyperlinks[uri] = uri_info
# reference nodes
for refnode in self.document.findall(nodes.reference):
if 'refuri' not in refnode:
continue
uri = refnode['refuri']
add_uri(uri, refnode)
# image nodes
for imgnode in self.document.findall(nodes.image):
uri = imgnode['candidates'].get('?')
if uri and '://' in uri:
add_uri(uri, imgnode)
# raw nodes
for rawnode in self.document.findall(nodes.raw):
uri = rawnode.get('source')
if uri and '://' in uri:
add_uri(uri, rawnode)
def rewrite_github_anchor(app: Sphinx, uri: str) -> Optional[str]:
"""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])
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_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,
}
