scientific-programming-exer.../exam/ex01/receive.py

60 lines
1.8 KiB
Python

import logging
from url import construct_url
from proxy import get_data_with_proxy, NoMoreProxiesException
logger = logging.getLogger(__name__)
def _receive_links(title, connection):
url = construct_url(title)
result = get_data_with_proxy(url, connection)
# This is basically because we don't know the page ID.
for k, page_data in result["query"]["pages"].items():
cursor = connection.cursor()
if(not "links" in page_data):
destination_title = page_data["title"].replace(" ", "_")
# avoid 1-loops
if(destination_title == title):
pass
cursor.execute("INSERT INTO links(source, destination) VALUES(?, ?)", (title, destination_title))
yield destination_title
else:
for destination in page_data["links"]:
destination_title = destination["title"].replace(" ", "_")
cursor.execute("INSERT INTO links(source, destination) VALUES(?, ?)", (title, destination_title))
yield destination_title
connection.commit()
def receive_links(title, connection):
return list(_receive_links(title, connection))
def receive_link_graph(title, connection, depth):
if(depth < 0):
# end of recursion
return
cursor = connection.cursor()
cursor.execute("SELECT COUNT(source) FROM links WHERE source=?", (title,))
if(cursor.fetchone()[0] != 0):
# we fetched that title already
return
logger.info("fetching links for {}".format(title))
for link in _receive_links(title, connection):
try:
receive_link_graph(link, connection, depth - 1)
except NoMoreProxiesException as e:
logger.exception("All proxies are blocked")
# Wikipedia blocked all our proxies.
# Retry later, so we have to store our list that is still to fetch.
cursor = connection.cursor()
cursor.execute("INSERT INTO failed_to_fetch(title, depth) VALUES(?, ?)", (link, depth - 1))
connection.commit()