Thanks for the suggestion Massimo.
It looks like the GAE code is working properly, at least for inserting
the data (see below for details on how I tested this). The truncation
for displaying GAE datetime values was happening in the as_list()
function in the sql.py file [line 2346], and when I removed that step
from my code I could work with information in GAE's datastore with
micro-second precision.
However, it took more work to get fractional seconds working for
SQLite. Here is a description of the changes I made to the code in
sql.py.
Truncation of fractional seconds happens during both insertion and
reading from the database.
To fix insertion, I changed line 409 from this:
obj = obj.strftime('%Y-%m-%d %H:%M:%S')
to this:
if obj.microsecond > 0:
obj = obj.strftime('%Y-%m-%d %H:%M:%S') + '.' + str
(obj.microsecond).zfill(6)
else:
obj = obj.strftime('%Y-%m-%d %H:%M:%S')
To fix reading from the database, I added these lines after 2302:
ms = 0 # default
if (len(str(value)) > 19) and (str(value)[19] == '.'):
dec = str(value).rfind('.')
dec_end = len(str(value))
if 18 < dec < dec_end:
ms = int(int(str(value)[dec+1:dec_end]) * pow
(10,(7-dec_end+dec)) )
and I changed this line:
row[tablename][fieldname] = datetime.datetime(y, m, d,
h, mi, s)
to be this:
row[tablename][fieldname] = datetime.datetime(y, m, d,
h, mi, s, ms)
If I'm interpreting the sql.py code correctly, this issue probably
affects all of the other databases - I didn't change any of the
special-case code for datetime support for other types of databases,
or for the time data type. And I didn't change the IS_DATETIME()
function in validators.py either.
Note that these routines could be simplified when operating with
python2.6:
"New in version 2.6: time and datetime objects support a %f format
code which expands to the number of microseconds in the object, zero-
padded on the left to six places." (http://docs.python.org/library/
datetime.html)
For python2.5, it's possible to use the datetime's microsecond
attribute to get the information.
Dan
For future reference by GAE developers (including myself):
Using the GAE development console (http://localhost:8080/_ah/admin/
interactive), I could run a quick set of lines to get the actual
values stored in the GAE datastore, which indeed contain the full
precision of what I inserted. These are the lines that I used:
import datetime as datetime
from google.appengine.ext import db
class timetest(db.Model):
starttime = db.DateTimeProperty()
endtime = db.DateTimeProperty()
qry = db.Query(timetest)
rows = qry.fetch(limit=5)
for r in rows:
print r.starttime
which produced these results, including some fractional seconds:
1970-01-01 00:00:44.400000
1970-01-01 00:00:12.200000
On Jun 29, 6:55 pm, mdipierro <mdipie...@cs.depaul.edu> wrote:
> correction. not print statements on GAE but logging statetements.
>
> On Jun 29, 8:54 pm, mdipierro <mdipie...@cs.depaul.edu> wrote:
>
> > In gluon/contrib/gql.py web2py does this:
>
> > if field.type == 'datetime' and value != None and not
> > isinstance(value, datetime.datetime):
> > (y, m, d) = [int(x) for x in
> > str(value)[:10].strip().split('-')]
> > time_items = [int(x) for x in
> > str(value)[11:].strip().split(':')[:3]]
> > if len(time_items) == 3:
> > (h, mi, s) = time_items
> > else:
> > (h, mi, s) = time_items + [0]
> > row[tablename][fieldname] = datetime.datetime
> > (y,m,d,h,mi,s)
> > ....
> > else:
> > row[tablename][fieldname] = value
>
> > perhaps you can put some print statements and see what "value" vs what
> > it should be.
>
> > Massimo
>
> > On Jun 29, 8:36 pm, Dan <danbr...@gmail.com> wrote:
>
> > > Here is some sample code to produce the behavior I'm trying to
> > > describe. Note that in the controller, there are 2 lines commented out
> > > because they return an error ("TypeError: unsupported operand type(s)
> > > for -: 'str' and 'str'")
>
> > > db.define_table('timetest',
> > > db.Field('starttime','datetime',default=request.now),
> > > db.Field('endtime','datetime',default=request.now),
> > > )
>
> > > def timetest():
> > > form=FORM(TABLE(
> > > TR("Start time (Epoch Seconds UTC):",INPUT
> > > (_type="text",_name="start_time_es")),
> > > TR("End time (Epoch Seconds UTC):",INPUT
> > > (_type="text",_name="end_time_es")),
> > > TR("",INPUT(_type="submit",_value="Submit"))
> > > ))
>
> > > rowtoinsert = {}
> > > if form.accepts(request.vars):
> > > response.flash="form accepted input"
> > > startdatetime = datetime.datetime.utcfromtimestamp(float
> > > (form.vars.start_time_es))
> > > enddatetime = datetime.datetime.utcfromtimestamp(float
> > > (form.vars.end_time_es))
> > > # make the database insertion
> > > rowtoinsert={
> > > 'starttime':startdatetime,
> > > 'endtime':enddatetime,
> > > }
> > > idinserted = db.timetest.insert(**rowtoinsert)
> > > elif form.errors:
> > > response.flash="form is invalid"
>
> > > existing_rows = db(db.timetest.id>0).select().as_list()
> > > # for r in existing_rows:
> > > # r['time_difference'] = r['endtime'] - r['starttime']
>
> > > return dict(form=form,
> > > rowtoinsert=rowtoinsert,
> > > existing_rows=existing_rows)
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