python实现下载源码[整理]

class system():
    def initLog(self):
        global LOG_FILE
        import logging
        logger = logging.getLogger()
        hdlr = logging.FileHandler(LOG_FILE)
        formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
        hdlr.setFormatter(formatter)
        logger.addHandler(hdlr)
        logger.setLevel(logging.NOTSET)
        return logger

    def download(self,url,localfile=None,block_size=1024):
        logging = self.initLog()
        if localfile == None:
            localfile = os.path.join(os.getcwd(),os.path.basename(url))
        elif os.path.isdir(localfile):
            localfile = os.path.join(localfile,os.path.basename(url))
        elif os.path.isfile(localfile):
            os.remove(localfile)
        try:
            file_handle = open(localfile,'wb')
        except:
            errors = '%s is illegal!' % localfile
            logging.error(errors)
            return 0
        try:
            data = urllib2.urlopen(url)
        except:
            errors = 'download %s error!' % os.path.basename(localfile)
            logging.error(errors)
            return 0
        logging.info("Downloading %s ..." % os.path.basename(localfile))
        len_all = int(data.info().getheader('Content-Length'))
        d = data.read(block_size)
        file_handle.write(d)
        if (len_all < block_size):
            logging.info("Download 100.0%")
        else:
            len_done=block_size
            logging.info("%6.2f%s"%(float(len_done) * 100 / len_all,'%'))
        while (len(d) >= block_size ):
            d = data.read(block_size)
            file_handle.write(d)
            len_done=len_done+len(d)
            logging.info("\b\b\b\b\b\b\b%6.2f%s" % (float(len_done) * 100 / len_all,'%'))
        logging.info("\n")
        file_handle.close()
        return localfile

    def test2(self,tgz_name):
        logging = self.initLog()
        logging.info("starting ....\n")
        if not self.download('http://%s/%s' % (HTTP_SERVER,tgz_name)):
            return [0,"DOWN"]
        else:
            return [1,"OK"]