#!/usr/bin/env python
# -*- encoding: utf-8 -*-

'''
@Author  :   y
@License :   (C) Copyright 2013-2019, HJIMI
@Contact :   bj-yez-magzine@163.com
@File    :   check_web_stat.py
@Time    :   2019-06-24 16:58
@Desc    :
'''

import sys

import socket
import ssl
from urllib.parse import urlparse
import re
import logging

from optparse import OptionParser # 命令行工具模块


logging.basicConfig()

def check(url):
    """检测一个地址是否可以正常访问.正常返回true,否则返回false"""    
    host = ""
    scheme = "http"
    port = 80

    r = urlparse(url)
    if (r.scheme != ""):
        scheme = r.scheme
    dest = r.netloc.split(":")
    if(len(dest) == 2):
        port = int(dest[1])
    else:
        if(scheme == 'http'):
            port = 80
        elif(scheme == 'https'):
            port = 443
    host = dest[0]

    resource = r.path

    return check_webserver(host, resource, scheme, port)

def check_webserver(host, resource, schema = "http", port = 80):
    #创建一个 TCP socket
    s = None
    if (schema == "http"):
        s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
    elif (schema == "https"):    
        s = ssl.wrap_socket(socket.socket()) 

    if not resource.startswith('/'):
        resource = '/' + resource
    request_string = "GET %s HTTP/1.1\r\nHost:%s\r\n\r\n" % (resource, host)
    
    logging.debug("Attempting to connect to %s on port %s" % (host, port))

    try:
        # s.settimeout(1000)
        s.connect((host, port))
        logging.debug("Connected to %s on port %s" % (host, port))
        s.send(str.encode(request_string))
        #获取前100个字节
        rsp = s.recv(100)
        logging.debug('Received 100 bytes of HTTP response')
        logging.debug('%s' % rsp)
    except socket.error as e:
        logging.debug("Connection to %s on port %s failed: %s" % (host, port, e))
        return False
    finally:
        #关闭socket连接
        logging.debug("Closing the connection")
        s.close()

    lines = rsp.splitlines() #将一个段落的字符串以行为单位分割成一个列表

    # logging.debug('First line of HTTP response: %s' % lines[0])

    try:
        version, status, message = re.split(r'\s+', bytes.decode(lines[0]), 2)
        logging.debug('Version: %s, Status: %s, Message: %s' % (version, status, message))
    except ValueError:
        logging.debug('Failed to split status line')
        return False

    if status in ['200', '301']:
        logging.debug('Success - status was %s' % status)
        return True
    else:
        logging.debug('Status was %s' % status)
        return False


if __name__=='__main__':
    parser = OptionParser()   #构造optionparser的对象

    #往optionparser对象中增加option ：parser.add_option()
    parser.add_option("-d", "--host", dest="host", default='localhost', help="HOST for webserver", metavar="HOST")
    parser.add_option("-r", "--resource", dest="resource", default='index.html', help="RESOURCE to check", metavar="RESOURCE")
    parser.add_option("-s", "--schema", dest="schema", default='http', help="SCHEMA for request", metavar="SCHEMA")
    parser.add_option("-p", "--port", dest="port", type="int", default=80, help="PORT for webserver", metavar="PORT")

    (options, args) = parser.parse_args()  #调用optionparser的解析函数,在options中使用解析到的options，在args中使用其他的位置参数args

    # logging.debug('options: %s, args: %s' % (options, args))
    # result = check_webserver(options.host, options.resource, options.schema, options.port)
    result = check(args[0])

    logging.debug('check_webserver returned %s' % result)

    sys.exit(not result)