Files
zulip/tools/documentation_crawler/documentation_crawler/spiders/common/spiders.py
Tim Abbott 10e9c3bb84 documentation_crawler: Add exclude list.
This works around the issue that Google calendar returns errors on
HTTP HEAD requests.
2017-04-06 15:26:27 -07:00

115 lines
4.3 KiB
Python

#!/usr/bin/env python
from __future__ import print_function
import logging
import re
import scrapy
from scrapy import Request
from scrapy.linkextractors import IGNORED_EXTENSIONS
from scrapy.linkextractors.lxmlhtml import LxmlLinkExtractor
from scrapy.utils.url import url_has_any_extension
from typing import Any, Generator, List, Optional, Tuple
EXCLUDED_URLS = [
# Google calendar returns 404s on HEAD requests unconditionally
'https://calendar.google.com/calendar/embed?src=ktiduof4eoh47lmgcl2qunnc0o@group.calendar.google.com',
# Returns 409 errors to HEAD requests frequently
'https://medium.freecodecamp.com',
]
class BaseDocumentationSpider(scrapy.Spider):
name = None # type: Optional[str]
# Exclude domain address.
deny_domains = [] # type: List[str]
start_urls = [] # type: List[str]
deny = [] # type: List[str]
file_extensions = ['.' + ext for ext in IGNORED_EXTENSIONS] # type: List[str]
tags = ('a', 'area', 'img')
attrs = ('href', 'src')
def __init__(self, *args, **kwargs):
# type: (*Any, **Any) -> None
super(BaseDocumentationSpider, self).__init__(*args, **kwargs)
self.has_error = False
def _set_error_state(self):
# type: () -> None
self.has_error = True
def _has_extension(self, url):
# type: (str) -> bool
return url_has_any_extension(url, self.file_extensions)
def _is_external_url(self, url):
# type: (str) -> bool
return url.startswith('http') or self._has_extension(url)
def check_existing(self, response):
# type: (Any) -> None
self.log(response)
def check_permalink(self, response):
# type: (Any) -> None
self.log(response)
xpath_template = "//*[@id='{permalink}' or @name='{permalink}']"
m = re.match(r".+\#(?P<permalink>.*)$", response.request.url) # Get anchor value.
if not m:
return
permalink = m.group('permalink')
# Check permalink existing on response page.
if not response.selector.xpath(xpath_template.format(permalink=permalink)):
self._set_error_state()
raise Exception(
"Permalink #{} is not found on page {}".format(permalink, response.request.url))
def parse(self, response):
# type: (Any) -> Generator[Request, None, None]
self.log(response)
for link in LxmlLinkExtractor(deny_domains=self.deny_domains, deny_extensions=['doc'],
tags=self.tags, attrs=self.attrs, deny=self.deny,
canonicalize=False).extract_links(response):
callback = self.parse # type: Any
dont_filter = False
method = 'GET'
if self._is_external_url(link.url):
callback = self.check_existing
method = 'HEAD'
elif '#' in link.url:
dont_filter = True
callback = self.check_permalink
yield Request(link.url, method=method, callback=callback, dont_filter=dont_filter,
errback=self.error_callback)
def retry_request_with_get(self, request):
# type: (Request) -> Generator[Request, None, None]
request.method = 'GET'
request.dont_filter = True
yield request
def exclude_error(self, url):
if url in EXCLUDED_URLS:
return True
return False
def error_callback(self, failure):
# type: (Any) -> Optional[Generator[Any, None, None]]
if hasattr(failure.value, 'response') and failure.value.response:
response = failure.value.response
if self.exclude_error(response.url):
return None
if response.status == 404:
self._set_error_state()
raise Exception('Page not found: {}'.format(response))
if response.status == 405 and response.request.method == 'HEAD':
# Method 'HEAD' not allowed, repeat request with 'GET'
return self.retry_request_with_get(response.request)
self.log("Error! Please check link: {}".format(response), logging.ERROR)
elif isinstance(failure.type, IOError):
self._set_error_state()
else:
raise Exception(failure.value)
return None