python - 此代码正在运行，但现在我从 __getattribute__ 中的计数器收到递归错误
问题描述
我需要帮助使我的 Query 对象没有递归错误。为了检查正确数量的函数已被链调用，我添加了一个计数器来获取导致递归错误的属性。当我只有几个功能时没有发生这种情况，但现在一直在发生，我需要修复
改变功能。使用自我、对象等。我使用的是 python 3.5，这段代码在较小的时候可以工作，但后来出现了错误
import mysql.connector as sql
class Database:
def __init__(self):
# Attributes
host = "127.0.0.1"
database = "database"
user = "root"
password = None
self.connection = sql.connect(
host = host,
database = database,
user = user,
password = password
)
self.cursor = self.connection.cursor()
class Query(object):
"""
Object initialisers and attributes
----------------------------------
"""
def __init__(self, table):
super().__init__()
self.query = None
self._table = table
self._count = 0
self._countRequired = 1
self._return = False
self._leadMethods = ["select", "update", "insert", "join"]
self._selectorMethods = ["where"]
self._returnTypes = ["fetchAll", "get", "first", "chunk", "last", "row"]
self._specialCases = ["count", "len", "desc", "asc", "orderBy"]
def __call__(self):
if self._count >= self._countRequired:
self._execute()
else:
raise NotImplementedError("Check amount of methods for SQL statement first")
def __getattr__(self, attr, *args):
# Updatable
return "Attributes not found!"
def __getattribute__(*args):
args[0]._count += 1
return object.__getattribute__(*args)
"""
Private methods and static methods
----------------------------------
"""
@staticmethod
def count(self, columns):
chain = ""
if columns:
if type(columns) == type([]):
for i in range(0, len(columns)):
if i == len(columns):
chain += "COUNT(" + column + ") as count_" + column
break
chain += "COUNT(" + column + ") as count_" + column + ", "
elif type(columns) == type(""):
chain = "COUNT(" + columns + ") as count_" + columns
return chain
@staticmethod
def len(self, columns):
chain = ""
if columns:
if type(columns) == type([]):
for i in range(0, len(columns)):
if i == len(columns):
chain += "LEN(" + column + ") as len_" + column
break
chain += "LEN(" + column + ") as len_" + column + ", "
elif type(columns) == type(""):
chain = "LEN(" + columns + ") as len_" + columns
return chain
def _execute(self):
query = self.query
try:
self.cursor.execute(query)
if self._return == True:
return self.cursor.fetchall()
return True
except Exception as e:
return (False, e)
self.connection.commit()
"""
Public methods
--------------
"""
def select(self, columns=None, args=None):
values = None
if args:
specialCases = []
for arg in args:
for case in self._specialCases[:2]:
if arg == case:
specialCases += args
values = []
for case in specialCases:
try:
case = "" + case
x = getattr(self, case)(self, columns)
values += [x]
except Exception as e:
print("Special case doesn't exist.")
selector = ""
if columns == []:
for i in range(0, len(columns)):
if i == len(columns):
selector += columns[i]
break
selector += columns[i] + ","
elif columns:
selector = columns
else:
selector = "*"
if self.query == None:
sql = "SELECT " + selector + " FROM " + self._table
self.query = sql
self._countRequired += 2
self._return = True
return self
def update(self, columns=None, values=None):
statement = "UPDATE " + self._table + " SET "
if len(columns) != len(values):
raise Exception("Not equal amount of columns and values")
temp = ""
if type(columns) == type([]) and type(values) == type([]):
for i in range(0, len(columns)):
if i == len(columns):
temp += columns[i] + " = " + values[i]
break
elif type(columns) == type("") and type(values) == type(""):
temp += str(columns) + " = " + str(values)
statement += temp
self._query = statement
self._countRequired += 1
return self
def insert(self, columns=None, values=None):
statment = "INSERT INTO " + self._table + " "
temp = "("
if type(columns) == type([]) and type(values) == type([]):
for i in range(0, len(columns)):
if i == len(columns):
temp += str(columns[i]) + ") VALUES ("
break
temp += str(columns[i]) + ", "
for i in range(0, len(values)):
if values[i] == None:
values[i] = "NULL"
if i == len(VALUES):
temp += str(values[i]) + ")"
break
temp += str(values[i]) + ", "
return self
def join (self, table, compareOne, operator, compareTwo, type="INNER"):
statement = "{} JOIN {} ON {} {} {} ".format(str(type), str(table), str(compareOne), str(operator), str(compareTwo))
self._query += statement
return self
def where(self, column=None, value=None, operator=None):
statement = " WHERE "
if not operator:
operator = "="
if column and value:
temp = ""
if type(column) == type([]) and type(value) == type([]):
for i in range(0, len(column)):
if i == len(column):
temp += "{} {} {} ".format(column[i], operator, value[i])
break
temp += "{} {} {},".format(column[i], operator, value[i])
elif type(column) == type([]):
for i in range(0, len(column)):
if i == len(column):
temp += "{} {} {} ".format(column[i], operator, value)
break
temp += "{} {} {},".format(column[i], operator, value)
elif type(value) == type([]):
for i in range(0, len(value)):
if i == len(value):
temp += "{} {} {} ".format(column, operator, value[i])
break
temp += "{} {} {},".format(column, operator, value[i])
else:
temp = "{} {} {} ".format(column, operator, value)
statement += temp
self.query += statement
return self
def fetchAll(self):
return self
def get(self):
return self
def first(self):
self.query += "LIMIT 1"
return self
def last(self):
self.query += "DESC LIMIT 1"
return self
def row(self, n):
self.query += "AND id = " + str(n)
return self
def chunk(self, n, start=0):
sql = "AND id BETWEEN " + str(start) + " AND " + str(n)
self.query += sql
return self
"""
Extra Functions
"""
def orderBy(self, type):
if type in possible:
self._query += "ORDER BY " + str(type)
else:
raise Exception("Invalid orderBy value. Should be ASC or DESC")
return self
def override(self, password, sql):
if password == "password":
self._query = SQL
return self
应该可以输入：
q = Query('table').select().where('name', 'test').get()()
并返回结果
"SELECT * FROM table WHERE name=test;"
解决方案
修复 了我创建了一个函数数组，不包括 count 属性，这意味着我只计算它是否是流利界面可接受的方法
def __getattribute__(self, name):
methods = ["select", "update", "insert", "join", "where", "get", "row", "last", "first", "fetchAll", "chunk", "override", "orderBy"]
if name in methods:
self._count += 1
return object.__getattribute__(self, name)
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