*merge-conditional (Edwin)

This is a small change, but really is nice.  Just about everything looks good
to me.  I only have one small style niggle, below.


> === modified file 'launchpadlib/_browser.py'
> --- launchpadlib/_browser.py	2008-12-05 21:38:50 +0000
> +++ launchpadlib/_browser.py	2009-01-21 21:38:08 +0000
> @@ -43,7 +43,8 @@
>  from launchpadlib.errors import HTTPError
>  from launchpadlib._oauth.oauth import (
>      OAuthRequest, OAuthSignatureMethod_PLAINTEXT)
> -from launchpadlib._utils import uri
> +from launchpadlib._utils import uri, json
> +from launchpadlib._utils.json import DatetimeJSONEncoder
>  
>  
>  OAUTH_REALM = 'https://api.launchpad.net'
> @@ -261,5 +262,5 @@
>              headers['If-Match'] = cached_etag
>  
>          self._request(
> -            url, simplejson.dumps(representation), 'PATCH',
> -            extra_headers=extra_headers)
> +            url, simplejson.dumps(representation, cls=DatetimeJSONEncoder),
> +            'PATCH', extra_headers=extra_headers)
> 
> === added file 'launchpadlib/_utils/json.py'
> --- launchpadlib/_utils/json.py	1970-01-01 00:00:00 +0000
> +++ launchpadlib/_utils/json.py	2009-01-21 21:38:08 +0000
> @@ -0,0 +1,35 @@
> +# Copyright 2009 Canonical Ltd.
> +
> +# This file is part of launchpadlib.
> +#
> +# launchpadlib is free software: you can redistribute it and/or modify
> +# it under the terms of the GNU Lesser General Public License as
> +# published by the Free Software Foundation, either version 3 of the
> +# License, or (at your option) any later version.
> +#
> +# launchpadlib is distributed in the hope that it will be useful, but
> +# WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +# Lesser General Public License for more details.
> +#
> +# You should have received a copy of the GNU Lesser General Public
> +# License along with launchpadlib.  If not, see
> +# <http://www.gnu.org/licenses/>.
> +
> +"""Classes for working with JSON."""
> +
> +__metaclass__ = type
> +__all__ = ['DatetimeJSONEncoder']
> +
> +import datetime
> +import simplejson
> +
> +class DatetimeJSONEncoder(simplejson.JSONEncoder):
> +    """A JSON encoder that understands datetime objects.
> +
> +    Datetime objects are formatted according to ISO 1601.
> +    """
> +    def default(self, obj):
> +        if isinstance(obj, datetime.datetime):
> +            return obj.isoformat()
> +        return simplejson.JSONEncoder.default(self, obj)
> 
> === modified file 'launchpadlib/docs/modifications.txt'
> --- launchpadlib/docs/modifications.txt	2009-01-12 13:25:47 +0000
> +++ launchpadlib/docs/modifications.txt	2009-01-21 21:38:08 +0000
> @@ -305,3 +305,26 @@
>      A conflicting display name
>  
>  
> +== Data types ==
> +
> +From the perspective of the launchpadlib user, date and date-time
> +fields always look like Python datetime objects.
> +
> +    >>> firefox = launchpad.projects['firefox']
> +    >>> milestone = firefox.all_milestones[0]
> +    >>> milestone.date_targeted
> +    datetime.datetime(2056, 10, 16,...)
> +
> +These fields can be changed and written back to the server, just like
> +objects of other types.
> +
> +    >>> from datetime import datetime
> +    >>> milestone.date_targeted = datetime(2009, 1, 1)
> +    >>> milestone.lp_save()
> +
> +A datetime object may also be used as an argument to a named operation.
> +
> +    >>> series = firefox.series[0]
> +    >>> series.newMilestone(
> +    ...     name="test", date_targeted = datetime(2009, 1, 1))

niggle: kwargs usually don't have surrounding spaces (that is,
"date_targeted=datetime(2009, 1, 1)").

> +    <milestone at ...>
> 
> === modified file 'launchpadlib/docs/people.txt'
> --- launchpadlib/docs/people.txt	2008-10-02 16:08:22 +0000
> +++ launchpadlib/docs/people.txt	2009-01-21 21:38:08 +0000
> @@ -198,7 +198,7 @@
>      >>> salgado.hide_email_addresses
>      False
>      >>> salgado.date_created
> -    u'2005-06-06T08:59:51.596025+00:00'
> +    datetime.datetime(2005, 6, 6, 8, 59, 51, 596025, ...)
>      >>> print salgado.time_zone
>      None
>      >>> salgado.is_valid
> @@ -299,7 +299,7 @@
>      >>> bassists.hide_email_addresses
>      False
>      >>> bassists.date_created
> -    u'...'
> +    datetime.datetime(...)
>      >>> print bassists.time_zone
>      None
>      >>> bassists.is_valid
> 
> === modified file 'launchpadlib/resource.py'
> --- launchpadlib/resource.py	2008-12-08 14:26:55 +0000
> +++ launchpadlib/resource.py	2009-01-21 21:38:08 +0000
> @@ -34,6 +34,7 @@
>  from urlparse import urlparse
>  
>  from launchpadlib._utils.uri import URI
> +from launchpadlib._utils.json import DatetimeJSONEncoder
>  from launchpadlib.errors import HTTPError
>  from wadllib.application import Resource as WadlResource
>  
> @@ -331,7 +332,7 @@
>          http_method = self.wadl_method.name
>          args = self._transform_resources_to_links(kwargs)
>          for key, value in args.items():
> -            args[key] = simplejson.dumps(value)
> +            args[key] = simplejson.dumps(value, cls=DatetimeJSONEncoder)
>          if http_method in ('get', 'head', 'delete'):
>              url = self.wadl_method.build_request_url(**args)
>              in_representation = ''
> 
>