[Freeipa-devel] [PATCH 0137] ipalib: Add DateTime parameter

[Jan Cholasta]

Hi,

On 10.1.2014 21:21, Nathaniel McCallum wrote:
> On Thu, 2014-01-09 at 16:30 +0100, Tomas Babej wrote:
>> Hi,
>>
>> Adds a parameter that represents a DateTime format using datetime.datetime
>> object from python's native datetime library.
>>
>> In the CLI, accepts one of the following formats:
>> Accepts subset of values defined by ISO 8601:
>> %Y-%m-%dT%H:%M:%S
>> %Y-%m-%dT%H:%M
>> '%Y%m%dT%H:%M:%S'
>> '%Y%m%dT%H:%M'
>>
>> Also accepts LDAP Generalized time in the following format:
>> '%Y%m%d%H%M%SZ'
>>
>> As a simplification, it does not deal with timezone info and ISO 8601
>> values with timezone info (+-hhmm) are rejected. Values are expected
>> to be in the UTC timezone.
>>
>> Values are saved to LDAP as LDAP Generalized time values in the format
>> '%Y%m%d%H%SZ' (no time fractions and UTC timezone is assumed). To avoid
>> confusion, in addition to subset of ISO 8601 values, the LDAP generalized
>> time in the format '%Y%m%d%H%M%SZ' is also accepted as an input (as this
>> is the
>> format user will see on the output).
>>
>> Part of: https://fedorahosted.org/freeipa/ticket/3306
>
> The date/time syntax formats are not compliant with ISO 8601. You stated
> they are expected to be in UTC timezone, but no 'Z' is expected in most
> of them. This is not only non-standard, but would prevent you from every
> supporting local time in the future.

+1, please require the trailing "Z".


I think generalized time format should be the preferred one, as it is 
stored in LDAP and thus returned by commands. Also, do we really need 
all of these other formats?


Few nitpicks about DateTime implementation:

   * you should call Param._convert_scalar from DateTime._convert_scalar
   * raise ConversionError instead of ValidationError and use 
get_param_name() for name
   * instead of "isinstance(value, str) or isinstance(value, unicode)" 
use "isinstance(value, basestring)"
   * don't use pythonisms in public error messages (""does not match any 
of accepted formats: %s" % self.accepted_formats")
   * public error messages should be translatable

It should look something like this (untested, from top of my head):

     type = datetime.datetime
     type_error = _('must be a date/time value')

     def _convert_scalar(self, value, index=None):
         if isinstance(value, basestring):
             for date_format in self.accepted_formats:
                 try:
                     time = datetime.datetime.strptime(value, date_format)
                     return time
                 except ValueError:
                     pass

             # If we get here, the strptime call did not succeed for any
             # the accepted formats, therefore raise error

             error = _("does not match any of accepted formats: %s") % 
(', '.join(self.accepted_formats))

             raise ConversionError(name=self.get_param_name(),
                                   index=index,
                                   error=error)

         return super(DateTime, self)._convert_scalar(value, index)


+    if isinstance(value, DateTime):
+        return str(value)

Return datetime object here please, or at least unicode in generalized 
time format (or whatever the preferred format is, see above).


+    elif isinstance(val, datetime.datetime):
+        return val.strftime("%Y%m%dT%H:%M:%S")

Again, please use the preferred format here please.


Honza

-- 
Jan Cholasta