Python封装阻止函数调用？ [英] Python wrapper preventing function call?

问题描述

我写了一堆帮助函数来包装常用的函数，如插入和选择。下面包含的只是其中一个封装...我似乎不明白为什么它不工作。

I've written a bunch of helper functions to wrap common functions such as insert and select. Included below is just one of those wrappers... which I can't seem to figure out why it isn't working.

我怀疑这是与包装器：

from collections import Mapping
import sqlite3

def counter(func):
    def wrapper(*args, **kwargs):
        wrapper.count = wrapper.count + 1
    wrapper.count = 0
    return wrapper

@counter
def insert(val, cursor, table="reuters_word_list", logfile="queries.log"):
    if val:
        if isinstance(val, (basestring, Mapping)):
            val='\"'+val+'\"'
        query = ("insert into %s values (?);" % 'tablename', val)
        if logfile:
            to_logfile(query + '\n', logfile)
        cursor.execute(query)

if __name__ == '__main__':
    connection = sqlite3.connect('andthensome.db')
    cursor = connection.cursor()
    cursor.execute("create table wordlist (word text);")
    insert("foo", cursor)
    connection.commit()
    cursor.execute("select * from wordlist;")
    print cursor.fetchall()
    cursor.close()

推荐答案

>调用 func。

Your counter decorator never actually calls func.

尝试

def counter(func):
    def wrapper(*args, **kwargs):
        wrapper.count += 1
        return func(*args, **kwargs)       # <- this line is important!!
    wrapper.count = 0
    return wrapper

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