/
wat_extract_links.py
541 lines (492 loc) · 22.4 KB
/
wat_extract_links.py
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import idna
import os
import re
import ujson as json
from urllib.parse import urljoin, urlparse
from pyspark.sql.types import StructType, StructField, StringType
from sparkcc import CCSparkJob
class ExtractLinksJob(CCSparkJob):
"""Extract links from WAT files and redirects from WARC files
and save them as pairs <from, to>"""
name = "ExtractLinks"
output_schema = StructType([
StructField("s", StringType(), True),
StructField("t", StringType(), True)
])
warc_parse_http_header = False
processing_robotstxt_warc = False
records_response = None
records_response_wat = None
records_response_warc = None
records_response_robotstxt = None
records_failed = None
records_non_html = None
records_response_redirect = None
link_count = None
http_redirect_pattern = re.compile(b'^HTTP\\s*/\\s*1\\.[01]\\s*30[12378]\\b')
http_redirect_location_pattern = re.compile(b'^Location:\\s*(\\S+)',
re.IGNORECASE)
http_link_pattern = re.compile(r'<([^>]*)>')
http_success_pattern = re.compile(b'^HTTP\\s*/\\s*1\\.[01]\\s*200\\b')
robotstxt_warc_path_pattern = re.compile(r'.*/robotstxt/')
robotstxt_sitemap_pattern = re.compile(b'^Sitemap:\\s*(\\S+)',
re.IGNORECASE)
url_abs_pattern = re.compile(r'^(?:https?:)?//')
# Meta properties usually offering links:
# <meta property="..." content="https://..." />
html_meta_property_links = {
'og:url', 'og:image', 'og:image:secure_url',
'og:video', 'og:video:url', 'og:video:secure_url',
'twitter:url', 'twitter:image:src'}
# Meta names usually offering links
html_meta_links = {
'twitter:image', 'thumbnail', 'application-url',
'msapplication-starturl', 'msapplication-TileImage', 'vb_meta_bburl'}
def add_arguments(self, parser):
parser.add_argument("--intermediate_output", type=str,
default=None,
help="Intermediate output to recover job from")
@staticmethod
def _url_join(base, link):
# TODO: efficiently join without reparsing base
# TODO: canonicalize
pass
def iterate_records(self, warc_uri, archive_iterator):
"""Iterate over all WARC records and process them"""
self.processing_robotstxt_warc \
= ExtractLinksJob.robotstxt_warc_path_pattern.match(warc_uri)
for record in archive_iterator:
for res in self.process_record(record):
yield res
self.records_processed.add(1)
def process_record(self, record):
link_count = 0
if self.is_wat_json_record(record):
try:
wat_record = json.loads(self.get_payload_stream(record).read())
except ValueError as e:
self.get_logger().error('Failed to load JSON: {}'.format(e))
self.records_failed.add(1)
return
warc_header = wat_record['Envelope']['WARC-Header-Metadata']
if warc_header['WARC-Type'] != 'response':
# WAT request or metadata records
return
self.records_response.add(1)
self.records_response_wat.add(1)
url = warc_header['WARC-Target-URI']
for link in self.get_links(url, wat_record):
link_count += 1
yield link
elif self.is_response_record(record):
self.records_response.add(1)
self.records_response_warc.add(1)
stream = self.get_payload_stream(record)
http_status_line = stream.readline()
if (self.processing_robotstxt_warc and ExtractLinksJob
.http_success_pattern.match(http_status_line)):
self.records_response_robotstxt.add(1)
for link in self.process_robotstxt(record, stream,
http_status_line):
link_count += 1
yield link
elif ExtractLinksJob.http_redirect_pattern.match(http_status_line):
self.records_response_redirect.add(1)
for link in self.process_redirect(record, stream,
http_status_line):
link_count += 1
yield link
else:
return
if link_count == 0:
# ensure that the URL itself is a node in the graph
# (every visited URL should be a node)
uri = self.get_warc_header(record, 'WARC-Target-URI')
for link in self.yield_link(uri, uri):
link_count += 1
yield link
self.link_count.add(link_count)
def process_redirect(self, record, stream, http_status_line):
"""Process redirects (HTTP status code 30[12378])
and yield redirect links"""
line = stream.readline()
while line:
m = ExtractLinksJob.http_redirect_location_pattern.match(line)
if m:
redir_to = m.group(1).strip()
try:
redir_to = redir_to.decode('utf-8')
except UnicodeError as e:
self.get_logger().warning(
'URL with unknown encoding: {} - {}'.format(
redir_to, e))
return
redir_from = self.get_warc_header(record, 'WARC-Target-URI')
for link in self.yield_link(redir_from, redir_to):
yield link
return
elif line == b'\r\n':
# end of HTTP header
return
line = stream.readline()
def process_robotstxt(self, record, stream, http_status_line):
# Robots.txt -> sitemap links are meaningful for host-level graphs,
# page-level graphs usually do not contain the robots.txt as a node
pass
def yield_redirect(self, src, target, http_status_line):
if src != target:
yield src, target
def yield_http_header_links(self, url, headers):
if 'Content-Location' in headers:
yield url, headers['Content-Location']
if 'Link' in headers:
for m in ExtractLinksJob.http_link_pattern.finditer(headers['Link']):
yield url, m.group(1)
def yield_links(self, src_url, base_url, links, url_attr, opt_attr=None):
# base_url = urlparse(base)
if not base_url:
base_url = src_url
has_links = False
for l in links:
link = None
if url_attr in l:
link = l[url_attr]
elif opt_attr in l and ExtractLinksJob.url_abs_pattern.match(l[opt_attr]):
link = l[opt_attr]
else:
continue
# lurl = _url_join(base_url, urlparse(link)).geturl()
try:
lurl = urljoin(base_url, link)
except ValueError:
continue
has_links = True
yield src_url, lurl
if not has_links:
# ensure that every page is a node in the graph
# even if it has not outgoing links
yield src_url, src_url
def yield_link(self, src, target):
yield src, target
def get_links(self, url, record):
try:
response_meta = record['Envelope']['Payload-Metadata']['HTTP-Response-Metadata']
if 'Headers' in response_meta:
# extract links from HTTP header
for l in self.yield_http_header_links(url, response_meta['Headers']):
yield l
if 'HTML-Metadata' not in response_meta:
self.records_non_html.add(1)
return
html_meta = response_meta['HTML-Metadata']
base = None
if 'Head' in html_meta:
head = html_meta['Head']
if 'Base' in head:
try:
base = urljoin(url, head['Base'])
except ValueError:
pass
if 'Link' in head:
# <link ...>
for l in self.yield_links(url, base, head['Link'], 'url'):
yield l
if 'Metas' in head:
for m in head['Metas']:
if (('property' in m and m['property']
in ExtractLinksJob.html_meta_property_links)
or ('name' in m and m['name']
in ExtractLinksJob.html_meta_links)
or ('content' in m
and ExtractLinksJob.url_abs_pattern.match(m['content']))):
for l in self.yield_links(url, base, [m], 'content'):
yield l
if 'Scripts' in head:
for l in self.yield_links(url, base, head['Scripts'], 'url'):
yield l
if 'Links' in html_meta:
for l in self.yield_links(url, base, html_meta['Links'],
'url', 'href'):
yield l
except KeyError as e:
self.get_logger().error("Failed to parse record for {}: {}".format(
url, e))
self.records_failed.add(1)
def init_accumulators(self, session):
super(ExtractLinksJob, self).init_accumulators(session)
sc = session.sparkContext
self.records_failed = sc.accumulator(0)
self.records_non_html = sc.accumulator(0)
self.records_response = sc.accumulator(0)
self.records_response_wat = sc.accumulator(0)
self.records_response_warc = sc.accumulator(0)
self.records_response_redirect = sc.accumulator(0)
self.records_response_robotstxt = sc.accumulator(0)
self.link_count = sc.accumulator(0)
def log_accumulators(self, session):
super(ExtractLinksJob, self).log_accumulators(session)
self.log_accumulator(session, self.records_response,
'response records = {}')
self.log_accumulator(session, self.records_failed,
'records failed to process = {}')
self.log_accumulator(session, self.records_non_html,
'records not HTML = {}')
self.log_accumulator(session, self.records_response_wat,
'response records WAT = {}')
self.log_accumulator(session, self.records_response_warc,
'response records WARC = {}')
self.log_accumulator(session, self.records_response_redirect,
'response records redirects = {}')
self.log_accumulator(session, self.records_response_robotstxt,
'response records robots.txt = {}')
self.log_accumulator(session, self.link_count,
'non-unique link pairs = {}')
def run_job(self, session):
output = None
if self.args.input != '':
input_data = session.sparkContext.textFile(
self.args.input,
minPartitions=self.args.num_input_partitions)
output = input_data.mapPartitionsWithIndex(self.process_warcs)
if not self.args.intermediate_output:
df = session.createDataFrame(output, schema=self.output_schema)
else:
if output is not None:
session.createDataFrame(output, schema=self.output_schema) \
.write \
.format(self.args.output_format) \
.option("compression", self.args.output_compression) \
.saveAsTable(self.args.intermediate_output)
self.log_accumulators(session.sparkContext)
warehouse_dir = session.conf.get('spark.sql.warehouse.dir',
'spark-warehouse')
intermediate_output = os.path.join(warehouse_dir,
self.args.intermediate_output)
df = session.read.parquet(intermediate_output)
df.dropDuplicates() \
.coalesce(self.args.num_output_partitions) \
.sortWithinPartitions('s', 't') \
.write \
.format(self.args.output_format) \
.option("compression", self.args.output_compression) \
.saveAsTable(self.args.output)
self.log_accumulators(session.sparkContext)
class ExtractHostLinksJob(ExtractLinksJob):
"""Extract links from WAT files, redirects from WARC files,
and sitemap links from robots.txt response records.
Extract the host names, reverse the names (example.com -> com.example)
and save the pairs <source_host, target_host>."""
name = "ExtrHostLinks"
output_schema = StructType([
StructField("s", StringType(), True),
StructField("t", StringType(), True)
])
num_input_partitions = 32
num_output_partitions = 16
# match global links
# - with URL scheme, more restrictive than specified in
# https://tools.ietf.org/html/rfc3986#section-3.1
# - or starting with //
# (all other "relative" links are within the same host)
global_link_pattern = re.compile(r'^(?:[a-z][a-z0-9]{1,5}:)?//',
re.IGNORECASE|re.ASCII)
# match IP addresses
# - including IPs with leading `www.' (stripped)
ip_pattern = re.compile(r'^(?:www\.)?\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\Z')
# valid host names, relaxed allowing underscore, allowing also IDNAs
# https://en.wikipedia.org/wiki/Hostname#Restrictions_on_valid_hostnames
host_part_pattern = re.compile(r'^[a-z0-9]([a-z0-9_-]{0,61}[a-z0-9])?\Z',
re.IGNORECASE|re.ASCII)
# simple pattern to match many but not all host names in URLs
url_parse_host_pattern = re.compile(r'^https?://([a-z0-9_.-]{2,253})(?:[/?#]|\Z)',
re.IGNORECASE|re.ASCII)
@staticmethod
def get_surt_host(url):
m = ExtractHostLinksJob.url_parse_host_pattern.match(url)
if m:
host = m.group(1)
else:
try:
host = urlparse(url).hostname
except Exception as e:
# self.get_logger().debug("Failed to parse URL {}: {}\n".format(url, e))
return None
if not host:
return None
host = host.strip().lower()
if len(host) < 1 or len(host) > 253:
return None
if ExtractHostLinksJob.ip_pattern.match(host):
return None
parts = host.split('.')
if parts[-1] == '':
# trailing dot is allowed, strip it
parts = parts[0:-1]
if len(parts) <= 1:
# do not accept single-word hosts, must be at least `domain.tld'
return None
if len(parts) > 2 and parts[0] == 'www':
# strip leading 'www' to reduce number of "duplicate" hosts,
# but leave at least 2 trailing parts (www.com is a valid domain)
parts = parts[1:]
for (i, part) in enumerate(parts):
if len(part) > 63:
return None
if not ExtractHostLinksJob.host_part_pattern.match(part):
try:
idn = idna.encode(part).decode('ascii')
except (idna.IDNAError, idna.core.InvalidCodepoint, UnicodeError, IndexError, Exception):
# self.get_logger().debug("Invalid host name: {}".format(url))
return None
# TODO: idna verifies the resulting string for length restrictions or invalid chars,
# maybe no further verification is required:
if ExtractHostLinksJob.host_part_pattern.match(idn):
parts[i] = idn
else:
# self.get_logger().debug("Invalid host name: {}".format(url))
return None
parts.reverse()
return '.'.join(parts)
def yield_links(self, src_url, base_url, links, url_attr, opt_attr=None,
src_host=None, base_host=None):
if not src_host:
src_host = ExtractHostLinksJob.get_surt_host(src_url)
if base_url and not base_host:
base_host = ExtractHostLinksJob.get_surt_host(base_url)
if base_host and not src_host:
src_host = base_host
if not src_host:
return
target_hosts = set()
inner_host_links = 0
for l in links:
if not l:
continue
if url_attr in l:
link = l[url_attr]
elif opt_attr in l and ExtractLinksJob.url_abs_pattern.match(l[opt_attr]):
link = l[opt_attr]
else:
continue
if self.global_link_pattern.match(link):
try:
thost = ExtractHostLinksJob.get_surt_host(link)
if not thost:
pass # no host, e.g., http:///abc/, file:///C:...
elif thost == src_host:
pass # global link to same host
else:
target_hosts.add(thost)
except ValueError:
pass
else:
inner_host_links += 1
for t in target_hosts:
yield src_host, t
if inner_host_links > 0 and base_url is not None:
if base_host and base_host != src_host:
# any internal link becomes an external link
yield src_host, base_host
def yield_link(self, src, target):
src_host = ExtractHostLinksJob.get_surt_host(src)
thost = ExtractHostLinksJob.get_surt_host(target)
if thost and src_host:
yield src_host, thost
def yield_http_header_links(self, url, headers, src_host=None):
links = []
if 'Content-Location' in headers:
links.append(headers['Content-Location'])
if 'Link' in headers:
for m in ExtractLinksJob.http_link_pattern.finditer(headers['Link']):
links.append(m.group(1))
if links:
if not src_host:
src_host = ExtractHostLinksJob.get_surt_host(url)
if not src_host:
return
for link in links:
host = ExtractHostLinksJob.get_surt_host(link)
if host is not None and src_host != host:
yield src_host, host
def get_links(self, url, record):
try:
response_meta = record['Envelope']['Payload-Metadata']['HTTP-Response-Metadata']
src_host = ExtractHostLinksJob.get_surt_host(url)
if src_host:
if 'Headers' in response_meta:
# extract links from HTTP header
for l in self.yield_http_header_links(url, response_meta['Headers'],
src_host=src_host):
yield l
if 'HTML-Metadata' not in response_meta:
self.records_non_html.add(1)
return
html_meta = response_meta['HTML-Metadata']
base = None
base_host = None
if 'Head' in html_meta:
head = html_meta['Head']
if 'Base' in head:
try:
base = urljoin(url, head['Base'])
base_host = ExtractHostLinksJob.get_surt_host(base)
except ValueError:
pass
if 'Link' in head:
# <link ...>
for l in self.yield_links(url, base, head['Link'], 'url',
src_host=src_host, base_host=base_host):
yield l
if 'Metas' in head:
for m in head['Metas']:
if (('property' in m and m['property']
in ExtractLinksJob.html_meta_property_links)
or ('name' in m and m['name']
in ExtractLinksJob.html_meta_links)
or ('content' in m
and ExtractLinksJob.url_abs_pattern.match(m['content']))):
for l in self.yield_links(url, base, [m], 'content',
src_host=src_host, base_host=base_host):
yield l
if 'Scripts' in head:
for l in self.yield_links(url, base, head['Scripts'], 'url',
src_host=src_host, base_host=base_host):
yield l
if 'Links' in html_meta:
for l in self.yield_links(url, base, html_meta['Links'],
'url', 'href',
src_host=src_host, base_host=base_host):
yield l
except KeyError as e:
self.get_logger().error("Failed to parse record for {}: {}".format(
url, e))
self.records_failed.add(1)
def process_robotstxt(self, record, stream, _http_status_line):
"""Process robots.txt and yield sitemap links"""
line = stream.readline()
while line:
if line == b'\r\n':
# end of HTTP header
break
line = stream.readline()
line = stream.readline()
while line:
m = ExtractLinksJob.robotstxt_sitemap_pattern.match(line)
if m:
sitemap = m.group(1).strip()
try:
sitemap = sitemap.decode('utf-8')
from_robotstxt = record.rec_headers.get_header('WARC-Target-URI')
src_host = ExtractHostLinksJob.get_surt_host(from_robotstxt)
thost = ExtractHostLinksJob.get_surt_host(sitemap)
if thost and src_host and src_host != thost:
yield src_host, thost
except UnicodeError as e:
self.get_logger().warning(
'URL with unknown encoding: {} - {}'.format(
sitemap, e))
line = stream.readline()
if __name__ == "__main__":
# job = ExtractLinksJob()
job = ExtractHostLinksJob()
job.run()