Reading array from config file in python

Question

I have a problem. My program is using config file to set options, and one of those options is a tuple. Here's what i mean:

[common]
logfile=log.txt
db_host=localhost
db_user=root
db_pass=password
folder[1]=/home/scorpil
folder[2]=/media/sda5/
folder[3]=/media/sdb5/

etc... Can i parse this into tuple with ConfigParser module in Python? Is there some easy way to do this?

Alex · Accepted Answer · 2012-07-02 15:26:09Z

14

if you can change config format like this:

folder = /home/scorpil
         /media/sda5/
         /media/sdb5/

then in python:

config.get("common", "folder").split("\n")

answered Jul 2, 2012 at 15:26

Alex

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Comments

John Percival Hackworth · Accepted Answer · 2016-08-24 23:01:48Z

6

Your config could be:

[common]
logfile=log.txt
db_host=localhost
db_user=root
db_pass=password
folder = ("/home/scorpil", "/media/sda5/", "/media/sdb5/")

Assuming that you have config in a file named foo.cfg, you can do the following:

import ConfigParser
cp = ConfigParser.ConfigParser()
cp.read("foo.cfg")
folder = eval(cp.get("common", "folder"), {}, {})

print folder
print type(folder)

which should produce:

('/home/scorpil', '/media/sda5/', '/media/sdb5/')
<type 'tuple'>

-- EDIT -- I've since changed my mind about this, and would take the position today that using eval in this context is a bad idea. Even with a restricted environment, if the configuration file is under user control it may be a very bad idea. Today I'd probably recommend doing something interesting with split to avoid malicious code execution.

edited Aug 24, 2016 at 23:01

answered Nov 4, 2010 at 13:50

John Percival Hackworth

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2 Comments

John Percival Hackworth Over a year ago

I would agree that in general eval() is not good. In the case where you control the input, and restrict the execution environment it is an acceptable solution.

John Percival Hackworth Over a year ago

Evil no, gobsmackingly dangerous yes. The key to safer use of eval() is to ensure that you have specified the global and local parameters to eval(). See docs.python.org/2/library/functions.html#eval for more details.

Tai · Accepted Answer · 2017-12-19 16:43:23Z

4

Create configuration:

folders = ['/home/scorpil', '/media/sda5/', '/media/sdb5/']
config.set('common', 'folders', json.dumps(folders))

Load configuration:

tuple(json.loads(config.get('common', 'folders')))

answered Dec 19, 2017 at 16:43

Tai

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Comments

Rod · Accepted Answer · 2010-11-04 13:35:40Z

3

You can get the items list and use a list comprehension to create a list of all the items which name starts with a defined prefix, in your case folder

folders = tuple([ item[1] for item in configparser.items() if item[0].startswith("folder")])

answered Nov 4, 2010 at 13:35

Rod

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3 Comments

Terrel Shumway Over a year ago

This solution assumes that the entries in the file are in the proper order.

Rod Over a year ago

@Terrel Shumway is does but you could always sort the items beforehand.

Terrel Shumway Over a year ago

sorting beforehand won't help: folder[10] < folder[2]

Niel de Wet · Accepted Answer · 2010-11-04 13:35:35Z

1

I don't know ConfigParser, but you can easily read it into a list (perhaps using .append()) and then do myTuple = tuple(myList)

answered Nov 4, 2010 at 13:35

Niel de Wet

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Comments

Terrel Shumway · Accepted Answer · 2010-11-04 19:53:39Z

1

#!/usr/bin/env python
sample = """
[common]
logfile=log.txt
db_host=localhost
db_user=root
db_pass=password
folder[1]=/home/scorpil
folder[2]=/media/sda5/
folder[3]=/media/sdb5/
"""
from cStringIO import StringIO
import ConfigParser
import re
FOLDER_MATCH = re.compile(r"folder\[(\d+)\]$").match

def read_list(items,pmatch=FOLDER_MATCH):
    if not hasattr(pmatch,"__call__"):
        pmatch = re.compile(pmatch).match
    folder_list = []
    for k,v in items:
        m = pmatch(k)
        if m:
            folder_list.append((int(m.group(1)),v))
    return tuple( kv[1] for kv in sorted(folder_list) )


if __name__ == '__main__':
    cp = ConfigParser.SafeConfigParser()
    cp.readfp(StringIO(sample),"sample")

    print read_list(cp.items("common"))

edited Nov 4, 2010 at 19:53

answered Nov 4, 2010 at 14:51

Terrel Shumway

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Comments

woodz · Accepted Answer · 2021-02-13 23:11:34Z

You could stick to json completely

tst.json

{
  "common": {
    "logfile":"log.txt",
    "db_host":"localhost",
    "db_user":"root",
    "db_pass":"password",
    "folder": [
      "/home/scorpil",
      "/media/sda5/",
      "/media/sdb5/"
    ]
  }
}

then work with it

$ python3

>>> import json
>>> with open("tst.json", "r", encoding="utf8") as file_object:
...   job = json.load(file_object)
... 
>>> job
{'common': {'db_pass': 'password', 'logfile': 
'log.txt', 'db_user': 'root', 'folder': 
['/home/scorpil', '/media/sda5/', '/media/sdb5/'], 
'db_host': 'localhost'}}

>>> print (job["common"]["folder"][0])
/home/scorpil
>>> print (job["common"]["folder"][1])
/media/sda5/
print (job["common"]["folder"][2])
/media/sdb5/

>>> folder_tuple = tuple(job["common"]["folder"])
>>> folder_tuple
('/home/scorpil', '/media/sda5/', '/media/sdb5/')

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