ArchiveBox/archivebox/extractors/title.py
2020-12-11 16:03:50 -05:00

130 lines
3.8 KiB
Python

__package__ = 'archivebox.extractors'
import re
from html.parser import HTMLParser
from pathlib import Path
from typing import Optional
from ..index.schema import Link, ArchiveResult, ArchiveOutput, ArchiveError
from ..util import (
enforce_types,
is_static_file,
download_url,
htmldecode,
)
from ..config import (
TIMEOUT,
CHECK_SSL_VALIDITY,
SAVE_TITLE,
CURL_BINARY,
CURL_ARGS,
CURL_VERSION,
CURL_USER_AGENT,
)
from ..logging_util import TimedProgress
HTML_TITLE_REGEX = re.compile(
r'<title.*?>' # start matching text after <title> tag
r'(.[^<>]+)', # get everything up to these symbols
re.IGNORECASE | re.MULTILINE | re.DOTALL | re.UNICODE,
)
class TitleParser(HTMLParser):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.title_tag = ""
self.title_og = ""
self.inside_title_tag = False
@property
def title(self):
return self.title_tag or self.title_og or None
def handle_starttag(self, tag, attrs):
if tag.lower() == "title" and not self.title_tag:
self.inside_title_tag = True
elif tag.lower() == "meta" and not self.title_og:
attrs = dict(attrs)
if attrs.get("property") == "og:title" and attrs.get("content"):
self.title_og = attrs.get("content")
def handle_data(self, data):
if self.inside_title_tag and data:
self.title_tag += data.strip()
def handle_endtag(self, tag):
if tag.lower() == "title":
self.inside_title_tag = False
@enforce_types
def should_save_title(link: Link, out_dir: Optional[str]=None) -> bool:
# if link already has valid title, skip it
if link.title and not link.title.lower().startswith('http'):
return False
if is_static_file(link.url):
return False
return SAVE_TITLE
def extract_title_with_regex(html):
match = re.search(HTML_TITLE_REGEX, html)
output = htmldecode(match.group(1).strip()) if match else None
return output
@enforce_types
def save_title(link: Link, out_dir: Optional[Path]=None, timeout: int=TIMEOUT) -> ArchiveResult:
"""try to guess the page's title from its content"""
from core.models import Snapshot
output: ArchiveOutput = None
cmd = [
CURL_BINARY,
*CURL_ARGS,
'--max-time', str(timeout),
*(['--user-agent', '{}'.format(CURL_USER_AGENT)] if CURL_USER_AGENT else []),
*([] if CHECK_SSL_VALIDITY else ['--insecure']),
link.url,
]
status = 'succeeded'
timer = TimedProgress(timeout, prefix=' ')
try:
html = download_url(link.url, timeout=timeout)
try:
# try using relatively strict html parser first
parser = TitleParser()
parser.feed(html)
output = parser.title
if output is None:
raise
except Exception:
# fallback to regex that can handle broken/malformed html
output = extract_title_with_regex(html)
# if title is better than the one in the db, update db with new title
if isinstance(output, str) and output:
if not link.title or len(output) >= len(link.title):
Snapshot.objects.filter(url=link.url,
timestamp=link.timestamp)\
.update(title=output)
else:
raise ArchiveError('Unable to detect page title')
except Exception as err:
status = 'failed'
output = err
finally:
timer.end()
return ArchiveResult(
cmd=cmd,
pwd=str(out_dir),
cmd_version=CURL_VERSION,
output=output,
status=status,
**timer.stats,
)