Re: [Configobj-develop] ConfigObj drops quotes sometimes

[Michael F. <fuz...@vo...>]

Jeffrey Barish wrote:
> On Friday 16 January 2009 04:07:43 Michael Foord wrote:
>   
>> Jeffrey Barish wrote:
>>     
>>> On Monday 12 January 2009 08:16:57 Michael Foord wrote:
>>>       
>>>> Jeffrey Barish wrote:
>>>>         
>>>>> I write the repr of a tuple to my configuration file on exit.  Usually,
>>>>> I find "<tuple>" in my configuration file afterward, but occasionally
>>>>> the quotation marks are missing.  I have not been able to detect a
>>>>> pattern. Any suggestions?
>>>>>           
>>>> Is it actually causing any problems?
>>>>         
>>> Or worse: If the value in the configuration file is
>>>
>>> ('a', ['b', 'c'])
>>>
>>> then I get a ParseError (at line 8) when I try to read it.  That error I
>>> cannot fix.
>>>
>>> BTW, I am using version 4.5.3.
>>>       
>> Did you have any luck reproducing this?
>>
>> Michael
>>     
>
> I finally figured out what was going on here, but I am still unclear about one 
> point.  In my configuration file, I have a line like
>
> atuple = "('a', ['b', 'c'])"
>
> I created a validator for the purpose of converting that string to a tuple.  
> The problem arises when I call the write method because a tuple gets written 
> back to the configuration file rather than a repr of a tuple.  I suspect that 
> configobj is working the way it is supposed to work, but what I wanted was to 
> be handed a tuple yet still have the write method write the repr of the 
> tuple.  Currently, I have turned off the conversion in the validator and 
> instead perform the conversion in my program.  I am not happy that I must 
> have eval's scattered throughout my code to perform the conversion previously 
> performed centrally in the validator.  I'm wondering whether there is a way 
> to restore the conversion provided in the validator but still have the write 
> method write the value in its original form.
>
> FWIW, here's a test program configtest.py:
>
> import configobj, validate, os
>
> CONFIGRC = os.path.join(os.getcwd(), 'configrc')
>
> class Configurator(configobj.ConfigObj):
>     def __init__(self):
>         configobj.ConfigObj.__init__(self, CONFIGRC, 
> configspec=CONFIGRC+'.spec')
>         val = validate.Validator({'check_tuple': self._tuple_validator})
>         res = self.validate(val, preserve_errors=True)
>
>     def _tuple_validator(self, val, default=None):
>         return eval(val)
>         #return val
>
> if __name__ == '__main__':
>     config = Configurator()
>     config.write()
>
> configrc:
>
> atuple = "('One', ['Two'])"
>
> configrc.spec:
>
> atuple = check_tuple()
>
>   

You could try unrepr mode which should allow you to read and write 
tuples without the need for validation functions - the syntax is 
slightly different from normal ConfigObj files though as it uses Python 
syntax for strings, lists, tuples and dicts.

If ConfigObj writes tuples out in a way that it can't read back in then 
I can understand how that is frustrating - although ConfigObj is not 
really intended to be *able* to do that, particularly tuples with nested 
lists. You could easily use ConfigObj.walk to transform tuple values 
back into *correct* strings before calling write.

Michael

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