179 lines
7.5 KiB
Python
179 lines
7.5 KiB
Python
"""
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This file is intended to perform read/writes against an SQL database such as PostgreSQL, Redshift, Mysql, MsSQL ...
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LICENSE (MIT)
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Copyright 2016-2020, The Phi Technology LLC
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Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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"""
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import psycopg2 as pg
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import mysql.connector as my
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import sys
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if sys.version_info[0] > 2 :
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from transport.common import Reader, Writer #, factory
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else:
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from common import Reader,Writer
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import json
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# from threading import Lock
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import pandas as pd
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import numpy as np
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class SQLRW :
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PROVIDERS = {"postgresql":"5432","redshift":"5432","mysql":"3306","mariadb":"3306"}
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DRIVERS = {"postgresql":pg,"redshift":pg,"mysql":my,"mariadb":my}
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def __init__(self,**_args):
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_info = {}
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_info['dbname'] = _args['db']
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self.table = _args['table']
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self.fields = _args['fields'] if 'fields' in _args else []
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if 'host' in _args :
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_info['host'] = 'localhost' if 'host' not in _args else _args['host']
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_info['port'] = SQLWriter.PROVIDERS[_args['provider']] if 'port' not in _args else _args['port']
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if 'username' in _args or 'user' in _args:
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key = 'username' if 'username' in _args else 'user'
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_info['user'] = _args[key]
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_info['password'] = _args['password']
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#
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# We need to load the drivers here to see what we are dealing with ...
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_handler = SQLWriter.DRIVERS[_args['provider']]
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self.conn = _handler.connect(**_info)
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def isready(self):
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_sql = "SELECT * FROM :table LIMIT 1".replace(":table",self.table)
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try:
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return pd.read_sql(_sql,self.conn).columns.tolist()
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except Exception as e:
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pass
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return False
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def apply(self,_sql):
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"""
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This function applies a command and/or a query against the current relational data-store
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:param _sql insert/select statement
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@TODO: Store procedure calls
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"""
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cursor = self.conn.cursor()
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try:
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if "select" in _sql.lower() :
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cursor.close()
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return pd.read_sql(_sql,self.conn)
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else:
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# Executing a command i.e no expected return values ...
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cursor.execute(_sql)
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self.conn.commit()
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finally:
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cursor.close()
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def close(self):
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try:
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self.connect.close()
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except Exception as error :
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print (error)
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pass
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class SQLReader(SQLRW,Reader) :
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def __init__(self,**_args):
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super().__init__(**_args)
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def read(self,**_args):
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if 'sql' in _args :
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_sql = (_args['sql'])
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else:
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_sql = "SELECT :fields FROM "+self.table
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if 'filter' in _args :
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_sql = _sql +" WHERE "+_args['filter']
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_fields = '*' if not self.fields else ",".join(self.fields)
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_sql = _sql.replace(":fields",_fields)
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if 'limit' in _args :
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_sql = _sql + " LIMIT "+str(_args['limit'])
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return self.apply(_sql)
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class SQLWriter(SQLRW,Writer):
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def __init__(self,**_args) :
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super().__init__(**_args)
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#
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# In the advent that data typing is difficult to determine we can inspect and perform a default case
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# This slows down the process but improves reliability of the data
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# NOTE: Proper data type should be set on the target system if their source is unclear.
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self._inspect = False if 'inspect' not in _args else _args['inspect']
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self._cast = False if 'cast' not in _args else _args['cast']
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def init(self,fields):
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if not fields :
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try:
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self.fields = pd.read_sql("SELECT * FROM :table LIMIT 1".replace(":table",self.table),self.conn).columns.tolist()
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finally:
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pass
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else:
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self.fields = fields;
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def make(self,fields):
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self.fields = fields
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sql = " ".join(["CREATE TABLE",self.table," (", ",".join(fields),")"])
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cursor = self.conn.cursor()
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try:
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cursor.execute(sql)
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except Exception as e :
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pass
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finally:
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cursor.close()
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def write(self,info):
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"""
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:param info writes a list of data to a given set of fields
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"""
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# inspect = False if 'inspect' not in _args else _args['inspect']
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# cast = False if 'cast' not in _args else _args['cast']
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if not self.fields :
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_fields = info.keys() if type(info) == dict else info[0].keys()
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_fields = list (_fields)
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self.init(_fields)
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if type(info) != list :
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info = [info]
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cursor = self.conn.cursor()
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try:
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_sql = "INSERT INTO :table (:fields) values (:values)".replace(":table",self.table) #.replace(":table",self.table).replace(":fields",_fields)
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if self._inspect :
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for _row in info :
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fields = list(_row.keys())
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if self._cast == False :
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values = ",".join(_row.values())
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else:
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values = "'"+"','".join([str(value) for value in _row.values()])+"'"
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# values = [ "".join(["'",str(_row[key]),"'"]) if np.nan(_row[key]).isnumeric() else str(_row[key]) for key in _row]
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# print (values)
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query = _sql.replace(":fields",",".join(fields)).replace(":values",values)
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cursor.execute(query)
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pass
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else:
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_fields = ",".join(self.fields)
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_sql = _sql.replace(":fields",_fields)
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_sql = _sql.replace(":values",",".join(["%("+name+")s" for name in self.fields]))
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# for row in info :
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# values = ["'".join(["",value,""]) if not str(value).isnumeric() else value for value in row.values()]
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cursor.executemany(_sql,info)
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self.conn.commit()
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except Exception as e:
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print (e)
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finally:
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cursor.close()
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pass
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def close(self):
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try:
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self.conn.close()
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finally:
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pass
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# _args = {"db":"sample","table":"foo","provider":"postgresql"}
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# # # w = SQLWriter(**_args)
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# # # w.write({"name":"kalara.io","email":"ceo@kalara.io","age":10})
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# r = SQLReader(**_args)
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# print (r.read(filter='age > 0',limit = 20)) |