如何爲這些DNS數據庫方法創建一個Python類？

我想寫一些代碼來區域傳輸DNS區域，然後解析記錄並將它們放入數據庫中。我從來沒有在python中使用過類，我認爲這可能和學習如何使用它們一樣好。不知道我在這裏做錯了什麼。這是在Python版本2.6上運行的。我可以得到一些指導嗎？在理解如何使用類時遇到困難。如何爲這些DNS數據庫方法創建一個Python類？

代碼：

import pymysql 
import time 
import dns.zone 
import dns.query 
from pprint import pprint 
from dns.exception import DNSException 
from dns.rdataclass import * 
from dns.rdatatype import * 


a_records = {} 
cname_records = {} 

... # excluding db connection credentials 

cur = conn.cursor() 

try: 
    zone = dns.zone.from_xfr(dns.query.xfr(ns, domain)) 
    print "zone xferred" 
except DNSException, e: 
    print e.__class__, e 


def main(): 
    compile_records() 

    for key, value in a_records.iteritems(): 
     sqlfoo.select_a(domain, key, value) 
    for key, value in cname_records.iteritems(): 
     sqlfoo.select_cname(domain, key, value) 

def compile_records(): 
    for (name, ttl, rdata) in zone.iterate_rdatas('A'): 
     a_records[name.to_text()] = rdata.to_text() 
    for (name, ttl, rdata) in zone.iterate_rdatas('CNAME'): 
     cname_records[name.to_text()] = rdata.to_text() 


class sqlfoo: 

    def __init__(self, domain, subdomain, ip, cname): 
     self.domain = domain 
     self.subdomain = subdomain 
     self.ip = ip 
     self.cname = cname 
     self.results = results 

    def select_a(self, domain, subdomain, ip): 
     build_select = """ 
         SELECT domain, subdomain, cname, ip 
         FROM zones 
         WHERE domain = %s 
         AND subdomain = %s 
         AND ip = %s; 
         """ 
     select_params = [ domain, subdomain, ip ] 
     cur.execute(build_select, select_params) 
     results = cur.fetchall() 
     if not any(results): # if the row isn't found, add it 
      print domain, subdomain, ip 
      self.insert_a(domain, subdomain, ip) 


    def select_cname(self, domain, subdomain, cname): 
     build_select = """ 
         SELECT domain, subdomain, cname, ip 
         FROM zones 
         WHERE domain = %s 
         AND subdomain = %s 
         AND cname = %s; 
         """ 
     select_params = [ domain, subdomain, cname ] 
     cur.execute(build_select, select_params) 
     results = cur.fetchall() 
     if not any(results): # if the row isn't found, add it 
      print domain, subdomain, cname 
      self.insert_cname(domain, subdomain, cname) 

    def insert_a(domain, subdomain, ip): 
     build_insert = """ 
         INSERT INTO zones 
         (Id, 
         domain, 
         record_type, 
         subdomain, 
         cname, 
         first_seen) 
         VALUES 
         (NULL, %s, `A`, %s, %s, %s); 
         """ 

     insert_params = [ domain, subdomain, ip, current_epoch ] 
     cur.execute(build_insert, insert_params) 

    def insert_cname(domain, subdomain, ip): 
     build_insert = """ 
         INSERT INTO zones 
         (Id, 
         domain, 
         record_type, 
         subdomain, 
         cname, 
         first_seen) 
         VALUES 
         (NULL, %s, `CNAME`, %s, %s, %s); 
         """ 

     insert_params = [ domain, subdomain, cname, current_epoch ] 
     cur.execute(build_insert, insert_params) 


main() 

cur.close() 
conn.close()

當我運行代碼，我得到下面的輸出。

(venv)[[email protected] ]$ python zone-etl.py 
    zone xferred 
    Traceback (most recent call last): 
     File "zone-etl.py", line 125, in <module> 
     main() 
     File "zone-etl.py", line 42, in main 
     sqlfoo.select_a(domain, key, value) 
    TypeError: unbound method select_a() must 
be called with sqlfoo instance as first argument (got str instance instead)

來源

2016-02-12 dobbs

您定義了什麼是sqlfoo _is_，現在您需要創建一個sqlfoo（「實例」），然後執行sqlfoo事物（「方法」）。這是面向對象編程的核心概念。谷歌，我會寫一個簡短的例子（如果有人不打我） – mhopeng

您需要創建一個類的實例來使用這些方法。下面是一個例子：

class Employee: 
    def __init__(self, name, salary): 
     self.name = name 
     self.salary = salary 

    def displayEmployee(self): 
     print "Name : ", self.name, ", Salary: ", self.salary 

emp = Employee("Aaron", 5000) 
emp.displayEmployee()

來源

2016-02-12 18:52:22 Jumayel

你必須使用它之前實例化類。

當你調用sqlfoo，你實際上應該這樣做：

sqlfoo_instance = sqlfoo(domain_value, subdomain_value, ip_value, cname_value) 

... 
for key, value in a_records.iteritems(): 
    sqlfoo.select_a(domain, key, value) 
for key, value in cname_records.iteritems(): 
    sqlfoo.select_cname(domain, key, value) 
...

在你的情況我建議你得到一點點熟悉面向對象編程第一，因爲你在做什麼，只有創建更多的樣板代碼來完成與使用過程式編程相同的功能。因此，你會收穫OOP的好處。

來源

2016-02-12 19:00:45

如何爲這些DNS數據庫方法創建一個Python類？

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