从文本文件读取查询参数

Question

I want to store the parameters for a mysql-connect in a textfile but do not know, what could be the most elegant way to store them in "query.txt" The readline() command seemed to be an option but somehow makes thing very inelegant. Can somebody suggest a smooth solution? thanks!

open("query.txt")
??? read parameters host, user, pass, db from query.txt ???
???sql = MySQLdb.connect (host = "%s", user = "%s", passwd = "%s", db = "s%"), host, user, pass, db)‬

This line causes me headache as well. I haven't figured out yet how to correctly make this query....

Answer 1

Yet another way: let's say you have a text file, params.txt , that contains Python-style dictionary literal that has your parameters. It might look like this:

# my cool SQL parameters
{ "user":   "lilu",
  "passwd": "multipass",
  "host":   "woo.foo.baz",
  "db":     "human-resources" }

You can use a safe and standard Python literals parser ast.literal_eval to convert the contents of this file into a dictionary object, which you can then pass on to your SQL connection function.

import ast

defaults = dict(host='default-host-name', user='default-user-name')

# "U" mode is used so that no matter what newline styles you have in the file,
# they all become \n in memory.
with open('params.txt', 'rU') as params_fo:
    params = dict(defaults)
    params.update(ast.literal_eval(params_fo.read()))
    sql = MySQLdb.connect(**params)

Answer 2

It will better and more confortable for you to use a serialization:

import cPickle

with open('pickler file.pic','w') as f:
    host, user, passw, db = 'bouloudou','bididi',198754,'the_db'
    cPickle.dump([host, user, passw, db],f)



with open('pickler file.pic','r') as f:
    host, user, passw, db = cPickle.load(f)

Answer 3

Assuming that "query.txt' contains :

hostname username password db  

you can do :

host, user, pass, db = open('query.txt').read().split()
sql = MySQLdb.connect (host = "%s", user = "%s", passwd = "%s", db = "s%"), host, user, pass, db)‬

Answer 4

You can use JSON if you want a text file that's both nicely-formatted and easy to read:

# Query parameters class
class QueryParams:
    def __init__(self, paramsDict):
        self.__dict__.update(paramsDict)

# Read text file
q = json.load(open('query.txt'), object_hook = lambda dc: QueryParams(dc))

# Use params
sql = MySQLdb.connect (host = "%s", user = "%s", passwd = "%s", db = "s%"), q.host, q.user, q.pass, q.db)‬

Answer 5

parameters.txt containing

MyHost, MyUsername, MyPassword, MyDb

In the script:

host, user, passw, db = open('parameters.txt').read().split()
sql = MySQLdb.connect (host , user, passw, db)