Slixfeed/slixfeed/crawl.py

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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
TODO
1.1) Do not compose messages.
1.2) Return URLs, nothing else other (e.g. processed messages).
1.3) Correction of URLs is aceptable.
"""
from aiohttp import ClientError, ClientSession, ClientTimeout
from feedparser import parse
from lxml import html
import slixfeed.config as config
from slixfeed.fetch import download_feed
from slixfeed.url import complete_url, join_url, trim_url
from urllib.parse import urlsplit, urlunsplit
# TODO Use boolean as a flag to determine whether a single URL was found
# async def probe_page(
# callback, url, document, num=None, db_file=None):
# result = None
# try:
# # tree = etree.fromstring(res[0]) # etree is for xml
# tree = html.fromstring(document)
# except:
# result = (
# "> {}\nFailed to parse URL as feed."
# ).format(url)
# if not result:
# print("RSS Auto-Discovery Engaged")
# result = await feed_mode_auto_discovery(url, tree)
# if not result:
# print("RSS Scan Mode Engaged")
# result = await feed_mode_scan(url, tree)
# if not result:
# print("RSS Arbitrary Mode Engaged")
# result = await feed_mode_request(url, tree)
# if not result:
# result = (
# "> {}\nNo news feeds were found for URL."
# ).format(url)
# # elif msg:
# else:
# if isinstance(result, str):
# return result
# elif isinstance(result, list):
# url = result[0]
# if db_file:
# # print("if db_file", db_file)
# return await callback(db_file, url)
# elif num:
# return await callback(url, num)
# else:
# return await callback(url)
async def probe_page(url, document):
"""
Parameters
----------
url : str
URL.
document : TYPE
DESCRIPTION.
Returns
-------
result : list or str
Single URL as list or selection of URLs as str.
"""
result = None
try:
# tree = etree.fromstring(res[0]) # etree is for xml
tree = html.fromstring(document)
except:
result = (
"> {}\nFailed to parse URL as feed."
).format(url)
if not result:
print("RSS Auto-Discovery Engaged")
result = await feed_mode_auto_discovery(url, tree)
if not result:
print("RSS Scan Mode Engaged")
result = await feed_mode_scan(url, tree)
if not result:
print("RSS Arbitrary Mode Engaged")
result = await feed_mode_request(url, tree)
if not result:
result = (
"> {}\nNo news feeds were found for URL."
).format(url)
return result
# TODO Improve scan by gradual decreasing of path
async def feed_mode_request(url, tree):
"""
Lookup for feeds by pathname using HTTP Requests.
Parameters
----------
db_file : str
Path to database file.
url : str
URL.
tree : TYPE
DESCRIPTION.
Returns
-------
msg : str
Message with URLs.
"""
feeds = {}
parted_url = urlsplit(url)
paths = config.get_list("lists.yaml")
paths = paths["pathnames"]
for path in paths:
address = urlunsplit([
parted_url.scheme,
parted_url.netloc,
path,
None,
None
])
res = await download_feed(address)
if res[1] == 200:
# print(parse(res[0])["feed"]["title"])
# feeds[address] = parse(res[0])["feed"]["title"]
try:
title = parse(res[0])["feed"]["title"]
except:
title = '*** No Title ***'
feeds[address] = title
# Check whether URL has path (i.e. not root)
# Check parted_url.path to avoid error in case root wasn't given
# TODO Make more tests
if parted_url.path and parted_url.path.split('/')[1]:
paths.extend(
[".atom", ".feed", ".rdf", ".rss"]
) if '.rss' not in paths else -1
# if paths.index('.rss'):
# paths.extend([".atom", ".feed", ".rdf", ".rss"])
address = urlunsplit([
parted_url.scheme,
parted_url.netloc,
parted_url.path.split('/')[1] + path,
None,
None
])
res = await download_feed(address)
if res[1] == 200:
try:
feeds[address] = parse(res[0])
# print(feeds)
except:
continue
if len(feeds) > 1:
counter = 0
msg = (
"RSS URL discovery has found {} feeds:\n\n```\n"
).format(len(feeds))
feed_mark = 0
for feed in feeds:
try:
feed_name = feeds[feed]["feed"]["title"]
except:
feed_name = urlsplit(feed).netloc
feed_addr = feed
# AttributeError: 'str' object has no attribute 'entries'
try:
feed_amnt = len(feeds[feed].entries)
except:
continue
if feed_amnt:
# NOTE Because there could be many false positives
# which are revealed in second phase of scan, we
# could end with a single feed, which would be
# listed instead of fetched, so feed_mark is
# utilized in order to make fetch possible.
feed_mark = [feed_addr]
counter += 1
msg += (
"Title: {}\n"
"Link : {}\n"
"Items: {}\n"
"\n"
).format(feed_name, feed_addr, feed_amnt)
if counter > 1:
msg += (
"```\nThe above feeds were extracted from\n{}"
).format(url)
elif feed_mark:
return feed_mark
else:
msg = (
"No feeds were found for {}"
).format(url)
return msg
elif feeds:
return feeds
async def feed_mode_scan(url, tree):
"""
Scan page for potential feeds by pathname.
Parameters
----------
db_file : str
Path to database file.
url : str
URL.
tree : TYPE
DESCRIPTION.
Returns
-------
msg : str
Message with URLs.
"""
feeds = {}
# paths = []
# TODO Test
paths = config.get_list("lists.yaml")
paths = paths["pathnames"]
for path in paths:
# xpath_query = "//*[@*[contains(.,'{}')]]".format(path)
# xpath_query = "//a[contains(@href,'{}')]".format(path)
num = 5
xpath_query = "(//a[contains(@href,'{}')])[position()<={}]".format(path, num)
addresses = tree.xpath(xpath_query)
xpath_query = "(//a[contains(@href,'{}')])[position()>last()-{}]".format(path, num)
addresses += tree.xpath(xpath_query)
parted_url = urlsplit(url)
# NOTE Should number of addresses be limited or
# perhaps be N from the start and N from the end
for address in addresses:
# print(address.xpath('@href')[0])
# print(addresses)
address = address.xpath('@href')[0]
if "/" not in address:
protocol = parted_url.scheme
hostname = parted_url.netloc
pathname = address
address = urlunsplit([
protocol,
hostname,
pathname,
None,
None
])
if address.startswith('/'):
protocol = parted_url.scheme
hostname = parted_url.netloc
pathname = address
address = urlunsplit([
protocol,
hostname,
pathname,
None,
None
])
res = await download_feed(address)
if res[1] == 200:
try:
feeds[address] = parse(res[0])
# print(feeds[address])
# breakpoint()
# print(feeds)
except:
continue
if len(feeds) > 1:
# print(feeds)
# breakpoint()
counter = 0
msg = (
"RSS URL scan has found {} feeds:\n\n```\n"
).format(len(feeds))
feed_mark = 0
for feed in feeds:
# try:
# res = await download_feed(feed)
# except:
# continue
try:
feed_name = feeds[feed]["feed"]["title"]
except:
feed_name = urlsplit(feed).netloc
feed_addr = feed
feed_amnt = len(feeds[feed].entries)
if feed_amnt:
# NOTE Because there could be many false positives
# which are revealed in second phase of scan, we
# could end with a single feed, which would be
# listed instead of fetched, so feed_mark is
# utilized in order to make fetch possible.
feed_mark = [feed_addr]
counter += 1
msg += (
"Title : {}\n"
"Link : {}\n"
"Count : {}\n"
"\n"
).format(feed_name, feed_addr, feed_amnt)
if counter > 1:
msg += (
"```\nThe above feeds were extracted from\n{}"
).format(url)
elif feed_mark:
return feed_mark
else:
msg = (
"No feeds were found for {}"
).format(url)
return msg
elif feeds:
return feeds
async def feed_mode_auto_discovery(url, tree):
"""
Lookup for feeds using RSS autodiscovery technique.
See: https://www.rssboard.org/rss-autodiscovery
Parameters
----------
db_file : str
Path to database file.
url : str
URL.
tree : TYPE
DESCRIPTION.
Returns
-------
msg : str
Message with URLs.
"""
xpath_query = (
'//link[(@rel="alternate") and '
'(@type="application/atom+xml" or '
'@type="application/rdf+xml" or '
'@type="application/rss+xml")]'
)
# xpath_query = """//link[(@rel="alternate") and (@type="application/atom+xml" or @type="application/rdf+xml" or @type="application/rss+xml")]/@href"""
# xpath_query = "//link[@rel='alternate' and @type='application/atom+xml' or @rel='alternate' and @type='application/rss+xml' or @rel='alternate' and @type='application/rdf+xml']/@href"
feeds = tree.xpath(xpath_query)
if len(feeds) > 1:
msg = (
"RSS Auto-Discovery has found {} feeds:\n\n```\n"
).format(len(feeds))
for feed in feeds:
# # The following code works;
# # The following code will catch
# # only valid resources (i.e. not 404);
# # The following code requires more bandwidth.
# res = await download_feed(feed)
# if res[0]:
# disco = parse(res[0])
# title = disco["feed"]["title"]
# msg += "{} \n {} \n\n".format(title, feed)
feed_name = feed.xpath('@title')[0]
feed_addr = join_url(url, feed.xpath('@href')[0])
# if feed_addr.startswith("/"):
# feed_addr = url + feed_addr
msg += "{}\n{}\n\n".format(feed_name, feed_addr)
msg += (
"```\nThe above feeds were extracted from\n{}"
).format(url)
return msg
elif feeds:
feed_addr = join_url(url, feeds[0].xpath('@href')[0])
return [feed_addr]