Support epoch timestamp for date filter

[pirsquare]

Currently date filter won't work for epoch timestamp. In other libraries, epoch timestamp works.
https://liquidjs.com/playground.html

{% assign created_timestamp = "1645173284" -%}
{{ created_timestamp | date: "%d %b %Y" }}

Will render

18 Feb 2022

We can add a minor update to date filter to support epoch timestamp

try:
    dat = datetime.datetime.fromtimestamp(int(dat), datetime.timezone.utc)
except:
    pass

Full function update

@with_environment
@liquid_filter
@functools.lru_cache(maxsize=10)
def date(
    dat: Union[datetime.datetime, str], fmt: str, *, environment: Environment
) -> str:
    """Formats a datetime according the the given format string."""
    if is_undefined(dat):
        return ""

    if is_undefined(fmt):
        return str(dat)

    # try if it's epoch timestamp
    try:
        dat = datetime.datetime.fromtimestamp(int(dat), datetime.timezone.utc)
    except:
        pass

    if isinstance(dat, str):
        if dat in ("now", "today"):
            dat = datetime.datetime.now()
        else:
            dat = parser.parse(dat)

    if not isinstance(dat, (datetime.datetime, datetime.date)):
        raise FilterArgumentError(
            f"date expected datetime.datetime, found {type(dat).__name__}"
        )

    rv = dat.strftime(fmt)

    if environment.autoescape and isinstance(fmt, Markup):
        return Markup(rv)
    return 

[jg-rp]

Hi @pirsquare,

Thank you. The date filter in the reference implementation of Liquid supports timestamps too.

This will be fixed in the next release. Until then, you can register the new date implementation, or an implementation of your own, with an Environment like this.

import datetime
from typing import Union
from dateutil import parser

from liquid import Environment
from liquid import Markup
from liquid import is_undefined

from liquid.filter import liquid_filter
from liquid.filter import with_environment

from liquid.exceptions import FilterArgumentError


@with_environment
@liquid_filter
def date(
    dat: Union[datetime.datetime, str, int],
    fmt: str,
    *,
    environment: Environment,
) -> str:
    """Formats a datetime according the the given format string."""
    if is_undefined(dat):
        return ""

    if is_undefined(fmt):
        return str(dat)

    if isinstance(dat, str):
        if dat in ("now", "today"):
            dat = datetime.datetime.now()
        elif dat.isdigit():
            # The reference implementation does not support string
            # representations of negative integers either.
            dat = datetime.datetime.fromtimestamp(int(dat))
        else:
            try:
                dat = parser.parse(dat)
            except parser.ParserError:
                # Input is returned unchanged. This is consistent
                # with the reference implementation.
                return str(dat)
    elif isinstance(dat, int):
        try:
            dat = datetime.datetime.fromtimestamp(dat)
        except (OverflowError, OSError):
            # Testing on Windows shows that it can't handle some
            # negative integers.
            return str(dat)

    if not isinstance(dat, (datetime.datetime, datetime.date)):
        raise FilterArgumentError(
            f"date expected datetime.datetime, found {type(dat).__name__}"
        )

    rv = dat.strftime(fmt)

    if environment.autoescape and isinstance(fmt, Markup):
        return Markup(rv)
    return rv


# Example of replacing the built-in `date` filter
env = Environment()
env.add_filter("date", date)

t = env.from_string("{{ '1152098955' | date: '%m/%d/%Y' }}")
print(t.render())

[pirsquare]

Yes I actually did that, thankfully you had a section on it to replace existing filter. Great library and thank you for your work!

[jg-rp]

Fixed in version 1.4.3, now released.