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Python Crawler

发表于: 2014-08-01   作者:cywhoyi   来源:转载   浏览:
摘要: __author__ = 'chenyang' #!/usr/bin/env python """Web Crawler/Spider This module implements a web crawler. This is very _basic_ only and needs to be extended to do anything use
__author__ = 'chenyang'

#!/usr/bin/env python

"""Web Crawler/Spider

This module implements a web crawler. This is very _basic_ only
and needs to be extended to do anything usefull with the
traversed pages.
"""

import re
import sys
import time
import math
import urllib2
import urlparse
import optparse
from cgi import escape
from traceback import format_exc
from Queue import Queue, Empty as QueueEmpty

from BeautifulSoup import BeautifulSoup


__version__ = "0.2"
__copyright__ = "CopyRight (C) 2008-2011 by James Mills"
__license__ = "MIT"
__author__ = "James Mills"
__author_email__ = "James Mills, James dot Mills st dotred dot com dot au"

USAGE = "%prog [options] <url>"
VERSION = "%prog v" + __version__

AGENT = "%s/%s" % (__name__, __version__)


class Crawler(object):
    def __init__(self, root, depth, locked=True):
        self.root = root
        self.depth = depth
        self.locked = locked
        self.host = urlparse.urlparse(root)[1]
        self.urls = []
        self.links = 0
        self.followed = 0

    def crawl(self):
        page = Fetcher(self.root)
        page.fetch()
        q = Queue()
        for url in page.urls:
            q.put(url)
        followed = [self.root]

        n = 0

        while True:
            try:
                url = q.get()
            except QueueEmpty:
                break

            n += 1

            if url not in followed:
                try:
                    host = urlparse.urlparse(url)[1]
                    if self.locked and re.match(".*%s" % self.host, host):
                        followed.append(url)
                        self.followed += 1
                        page = Fetcher(url)
                        page.fetch()
                        for i, url in enumerate(page):
                            if url not in self.urls:
                                self.links += 1
                                q.put(url)
                                self.urls.append(url)
                        if n > self.depth and self.depth > 0:
                            break
                except Exception, e:
                    print "ERROR: Can't process url '%s' (%s)" % (url, e)
                    print format_exc()


class Fetcher(object):
    def __init__(self, url):
        self.url = url
        self.urls = []

    def __getitem__(self, x):
        return self.urls[x]

    def _addHeaders(self, request):
        request.add_header("User-Agent", AGENT)

    def open(self):
        url = self.url
        try:
            request = urllib2.Request(url)
            handle = urllib2.build_opener()
        except IOError:
            return None
        return (request, handle)

    def fetch(self):
        request, handle = self.open()
        self._addHeaders(request)
        if handle:
            try:
                content = unicode(handle.open(request).read(), "utf-8",
                                  errors="replace")
                soup = BeautifulSoup(content)
                #######BeautifulSoup提供a标签#
                tags = soup('a')
            except urllib2.HTTPError, error:
                if error.code == 404:
                    print >> sys.stderr, "ERROR: %s -> %s" % (error, error.url)
                else:
                    print >> sys.stderr, "ERROR: %s" % error
                tags = []
            except urllib2.URLError, error:
                print >> sys.stderr, "ERROR: %s" % error
                tags = []
            for tag in tags:
                href = tag.get("href")
                if href is not None:
                    url = urlparse.urljoin(self.url, escape(href))
                    if url not in self:
                        self.urls.append(url)


def getLinks(url):
    page = Fetcher(url)
    page.fetch()
    for i, url in enumerate(page):
        print "%d. %s" % (i, url)


def parse_options():
    """parse_options() -> opts, args

    Parse any command-line options given returning both
    the parsed options and arguments.
    """

    parser = optparse.OptionParser(usage=USAGE, version=VERSION)

    parser.add_option("-q", "--quiet",
                      action="store_true", default=False, dest="quiet",
                      help="Enable quiet mode")

    parser.add_option("-l", "--links",
                      action="store_true", default=False, dest="links",
                      help="Get links for specified url only")

    parser.add_option("-d", "--depth",
                      action="store", type="int", default=30, dest="depth",
                      help="Maximum depth to traverse")

    opts, args = parser.parse_args()

    if len(args) < 1:
        parser.print_help()
        raise SystemExit, 1

    return opts, args


def main():
    opts, args = parse_options()

    url = args[0]

    if opts.links:
        getLinks(url)
        raise SystemExit, 0

    depth = opts.depth

    sTime = time.time()

    print "Crawling %s (Max Depth: %d)" % (url, depth)
    crawler = Crawler(url, depth)
    crawler.crawl()
    print "\n".join(crawler.urls)

    eTime = time.time()
    tTime = eTime - sTime

    print "Found:    %d" % crawler.links
    print "Followed: %d" % crawler.followed
    print "Stats:    (%d/s after %0.2fs)" % (
        int(math.ceil(float(crawler.links) / tTime)), tTime)


if __name__ == "__main__":
    main()

 

Python BeautifulSoup 简单笔记                                     

http://rsj217.diandian.com/post/2012-11-01/40041235132

 

TK   calculation

 

import Tkinter as tk

calc = tk.Tk()
calc.title("CrappyCalc")

buttons = [
'7',  '8',  '9',  '*',  'C',
'4',  '5',  '6',  '/',  'Neg',
'1',  '2',  '3',  '-',  '$',
'0',  '.',  '=',  '+',  '@' ]

# set up GUI
row = 1
col = 0
for i in buttons:
    button_style = 'raised'
    action = lambda x = i: click_event(x)
    tk.Button(calc, text = i, width = 4, height = 3, relief = button_style, command = action) \
		.grid(row = row, column = col, sticky = 'nesw', )
    col += 1
    if col > 4:
        col = 0
        row += 1

display = tk.Entry(calc, width = 40, bg = "white")
display.grid(row = 0, column = 0, columnspan = 5)

def click_event(key):

	# = -> calculate results
    if key == '=':
        # safeguard against integer division
        if '/' in display.get() and '.' not in display.get():
            display.insert(tk.END, ".0")
			
        # attempt to evaluate results
        try:
            result = eval(display.get())
            display.insert(tk.END, " = " + str(result))
        except:
            display.insert(tk.END, "   Error, use only valid chars")
			
	# C -> clear display		
    elif key == 'C':
        display.delete(0, tk.END)
		
		
	# $ -> clear display		
    elif key == '$':
        display.delete(0, tk.END)
        display.insert(tk.END, "$$$$C.$R.$E.$A.$M.$$$$")
		

	# @ -> clear display		
    elif key == '@':
        display.delete(0, tk.END)
        display.insert(tk.END, "wwwwwwwwwwwwwwwwebsite")		

		
	# neg -> negate term
    elif key == 'neg':
        if '=' in display.get():
            display.delete(0, tk.END)
        try:
            if display.get()[0] == '-':
                display.delete(0)
            else:
                display.insert(0, '-')
        except IndexError:
            pass

	# clear display and start new input		
    else:
        if '=' in display.get():
            display.delete(0, tk.END)
        display.insert(tk.END, key)

# RUNTIME
calc.mainloop()

 

Python Crawler

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