Python爬取国外天气预报网站的方法

FetchLocation.py如下：

#encoding=utf-8
import sys
import httplib
import urllib2
import time
from threading import Thread
import threading
from Queue import Queue
from time import sleep
import re
import copy
from xml.dom import minidom
import HTMLParser
import datetime
q = Queue()
locks = [threading.RLock() for i in range(2)]
ThreadNumber = 20
locations = {}
conds = {}
def FindCountryBreadCrumbs(page):
lines = page.splitlines()
count = 0
start = -1
opened = False
for line in lines:
if line.find("<ul id=\"country-breadcrumbs\">") != -1:
start = count
opened = True
if opened and line.find("</ul>") != -1:
end = count
opened = False
count = count + 1
return "\n".join(lines[start: (end + 1)])
def GetText(nodelist):
rc = []
for node in nodelist:
if node.nodeType == node.TEXT_NODE:
rc.append(HTMLParser.HTMLParser().unescape(node.data))
return ''.join(rc)
def FindCondition(page):
pat = "<span class=\"cond\">(.*?)</span>"
cds = re.findall(pat, page)
cds = [HTMLParser.HTMLParser().unescape(cd).encode("utf-8") for cd in cds]
return cds
def ExtractInfo(url):
try:
page = urllib2.urlopen(url).read()
except Exception, e:
return []
text = FindCountryBreadCrumbs(page)
text = HTMLParser.HTMLParser().unescape(text)
dom = minidom.parseString(text.encode("utf-8"))
locs = []
lis = dom.getElementsByTagName("li")
for li in lis:
adr_list = li.getElementsByTagName("a")
if adr_list:
locs.append(GetText(adr_list[0].childNodes).encode("utf-8"))
strs = li.getElementsByTagName("strong")
if strs:
locs.append(GetText(strs[0].childNodes).encode("utf-8"))
cds = FindCondition(page)
return locs, cds
def AddMap(lst, m):
for x in lst:
if m.get(x) == None:
m[x] = 1
def working():
while True:
urls = q.get()
#print len(urls)
m = {}
m2 = {}
count = 0
for url in urls:
count = count + 1
#print "%d/%d" % (count, len(urls))
locs, cds = ExtractInfo(url)
AddMap(locs, m)
AddMap(cds, m2)
locks[1].acquire()
AddMap(m.keys(), locations)
AddMap(m2.keys(), conds)
locks[1].release()
q.task_done()
def main():
if len(sys.argv) < 2:
exit()
loc_path = sys.argv[1]
fp = open(loc_path, "r")
urls = [line.strip() for line in fp]
fp.close()
#urls = urls[0:1000]
blocks = len(urls) / ThreadNumber + 1
for start in range(0, len(urls), blocks):
end = start + blocks
if end > len(urls):
end = len(urls)
q.put(urls[start:end])
for i in range(ThreadNumber):
t = Thread(target=working)
t.setDaemon(True)
t.start()
q.join()
fp = open("location_name.fr", "w")
fp.write("\n".join(locations.keys()))
fp.close()
fp = open("conditions.fr", "w")
fp.write("\n".join(conds.keys()))
fp.close()
if __name__ == '__main__':
main()

希望本文所述对大家的python程序设计有所帮助。

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