Source code for shuup.front.templatetags.thumbnails

# -*- coding: utf-8 -*-
# This file is part of Shuup.
#
# Copyright (c) 2012-2017, Shoop Commerce Ltd. All rights reserved.
#
# This source code is licensed under the OSL-3.0 license found in the
# LICENSE file in the root directory of this source tree.
from __future__ import unicode_literals

import six
from django.conf import settings
from django_jinja import library
from easy_thumbnails.alias import aliases
from easy_thumbnails.exceptions import InvalidImageFormatError
from easy_thumbnails.files import get_thumbnailer
from easy_thumbnails.templatetags.thumbnail import RE_SIZE


[docs]def process_thumbnailer_options(kwargs):
    default_options = getattr(settings, "THUMBNAIL_DEFAULT_OPTIONS", {})
    options = {}
    options.update(default_options)
    options.update(kwargs)
    size = options.setdefault('size', (128, 128))
    if isinstance(size, six.text_type):
        m = RE_SIZE.match(size)
        if m:
            options["size"] = (int(m.group(1)), int(m.group(2)))
        else:
            raise ValueError("%r is not a valid size." % size)
    return options


@library.filter
[docs]def thumbnail(source, alias=None, generate=True, **kwargs):
    if not source:
        return None
    thumbnailer = get_thumbnailer(source)
    if not thumbnailer:
        return None

    if _is_svg(thumbnailer.file):
        return source.url if hasattr(source, 'url') else None

    if alias:
        options = aliases.get(alias, target=thumbnailer.alias_target)
        options.update(process_thumbnailer_options(kwargs))
    else:
        options = process_thumbnailer_options(kwargs)

    try:
        thumbnail = thumbnailer.get_thumbnail(options, generate=generate)
        return thumbnail.url
    except (IOError, InvalidImageFormatError):
        return None


def _is_svg(fileobj):
    """
    Detect if file object contains SVG data.

    >>> from io import BytesIO as B
    >>> assert _is_svg(B(b'<?xml><svg></svg>')) is True
    >>> assert _is_svg(B(b'something else')) is False
    >>> assert _is_svg(b'not a file') is None
    """
    try:
        return _is_svg_inner(fileobj)
    except (AttributeError, IOError):
        return None


def _is_svg_inner(fileobj):
    pos = fileobj.tell()
    try:
        fileobj.seek(0)
        content = fileobj.read(1024)
    finally:
        fileobj.seek(pos)
    return (b'<svg' in content and b'>' in content)


@library.filter
[docs]def thumbnailer(source):
    return get_thumbnailer(source)