boards/models/attachment/viewers.py

from django.contrib.staticfiles import finders
from django.contrib.staticfiles.templatetags.staticfiles import static
from django.core.files.images import get_image_dimensions
from django.template.defaultfilters import filesizeformat

from boards import settings
from boards.utils import get_domain, cached_result, get_extension

FILE_STUB_IMAGE = 'images/file.png'
FILE_STUB_URL = 'url'
FILE_FILEFORMAT = 'images/fileformats/{}.png'


FILE_TYPES_VIDEO = (
    'video/webm',
    'video/mp4',
    'video/mpeg',
    'video/ogv',
)
FILE_TYPE_SVG = 'image/svg+xml'
FILE_TYPES_AUDIO = (
    'audio/ogg',
    'audio/mpeg',
    'audio/opus',
    'audio/x-flac',
    'audio/mpeg',
)
FILE_TYPES_IMAGE = (
    'image/jpeg',
    'image/jpg',
    'image/png',
    'image/bmp',
    'image/gif',
)

PLAIN_FILE_FORMATS = {
    'zip': 'archive',
    'tar': 'archive',
    'gz': 'archive',
    'mid' : 'midi',
}

URL_PROTOCOLS = {
    'magnet': 'magnet',
}

CSS_CLASS_IMAGE = 'image'
CSS_CLASS_THUMB = 'thumb'

ABSTRACT_VIEW = '<div class="image">'\
        '{}'\
        '<div class="image-metadata"><a href="{}" download >{}, {}</a>'\
        ' <a class="file-menu" href="#" data-type="{}" data-search-url="{}" data-filename="{}" data-id="{}">&#8942; </a></div>'\
        '</div>'
URL_VIEW = '<div class="image">' \
        '{}' \
        '<div class="image-metadata">{}</div>' \
        '</div>'
ABSTRACT_FORMAT_VIEW = '<a href="{}">'\
        '<img class="url-image" src="{}" width="{}" height="{}"/>'\
        '</a>'
VIDEO_FORMAT_VIEW = '<video width="200" height="150" controls src="{}"></video>'
AUDIO_FORMAT_VIEW = '<audio controls src="{}"></audio>'
IMAGE_FORMAT_VIEW = '<a class="{}" href="{full}">' \
        '<img class="post-image-preview"' \
        ' src="{}"' \
        ' alt="{}"' \
        ' width="{}"' \
        ' height="{}"' \
        ' data-width="{}"' \
        ' data-height="{}" />' \
        '</a>'
SVG_FORMAT_VIEW = '<a class="thumb" href="{}">'\
        '<img class="post-image-preview" width="200" height="150" src="{}" />'\
        '</a>'
URL_FORMAT_VIEW = '<a href="{}">' \
        '<img class="url-image" src="{}" width="{}" height="{}"/>' \
        '</a>'


def get_viewers():
    return AbstractViewer.__subclasses__()


def get_static_dimensions(filename):
    file_path = finders.find(filename)
    return get_image_dimensions(file_path)


# TODO Move this to utils
def file_exists(filename):
    return finders.find(filename) is not None


class AbstractViewer:
    def __init__(self, file, file_type, id, url):
        self.file = file
        self.file_type = file_type
        self.id = id
        self.url = url
        self.extension = get_extension(self.file.name).lower()

    @staticmethod
    def supports(file_type):
        return True

    def get_view(self):
        search_host = settings.get('External', 'ImageSearchHost')
        if search_host:
            if search_host.endswith('/'):
                search_host = search_host[:-1]
            search_url = search_host + self.file.url
        else:
            search_url = ''

        return ABSTRACT_VIEW.format(self.get_format_view(), self.file.url,
                self.file_type, filesizeformat(self.file.size),
                self.file_type, search_url, self.file.name, self.id)

    def get_format_view(self):
        image_name = PLAIN_FILE_FORMATS.get(self.extension, self.extension)
        file_name = FILE_FILEFORMAT.format(image_name)

        if file_exists(file_name):
            image = file_name
        else:
            image = FILE_STUB_IMAGE

        w, h = get_static_dimensions(image)

        return ABSTRACT_FORMAT_VIEW.format(self.file.url, static(image), w, h)


class VideoViewer(AbstractViewer):
    @staticmethod
    def supports(file_type):
        return file_type in FILE_TYPES_VIDEO

    def get_format_view(self):
        return VIDEO_FORMAT_VIEW.format(self.file.url)


class AudioViewer(AbstractViewer):
    @staticmethod
    def supports(file_type):
        return file_type in FILE_TYPES_AUDIO

    def get_format_view(self):
        return AUDIO_FORMAT_VIEW.format(self.file.url)


class SvgViewer(AbstractViewer):
    @staticmethod
    def supports(file_type):
        return file_type == FILE_TYPE_SVG

    def get_format_view(self):
        return SVG_FORMAT_VIEW.format(self.file.url, self.file.url)


class ImageViewer(AbstractViewer):
    @staticmethod
    def supports(file_type):
        return file_type in FILE_TYPES_IMAGE

    def get_format_view(self):
        metadata = '{}, {}'.format(self.file.name.split('.')[-1],
                                   filesizeformat(self.file.size))

        try:
            width, height = get_image_dimensions(self.file.path)
        except Exception:
            # If the image is a decompression bomb, treat it as just a regular
            # file
            return super().get_format_view()

        preview_path = self.file.path.replace('.', '.200x150.')
        try:
            pre_width, pre_height = get_image_dimensions(preview_path)
        except Exception:
            return super().get_format_view()

        split = self.file.url.rsplit('.', 1)
        w, h = 200, 150
        thumb_url = '%s.%sx%s.%s' % (split[0], w, h, split[1])

        return IMAGE_FORMAT_VIEW.format(CSS_CLASS_THUMB,
                thumb_url,
                self.id,
                str(pre_width),
                str(pre_height), str(width), str(height),
                full=self.file.url, image_meta=metadata)


class UrlViewer(AbstractViewer):
    @staticmethod
    def supports(file_type):
        return file_type is None

    def get_view(self):
        return URL_VIEW.format(self.get_format_view(), get_domain(self.url))

    def get_format_view(self):
        protocol = self.url.split(':')[0]

        domain = get_domain(self.url)

        if protocol in URL_PROTOCOLS:
            url_image_name = URL_PROTOCOLS.get(protocol)
        elif domain:
            url_image_name = self._find_image_for_domains(domain) or FILE_STUB_URL
        else:
            url_image_name = FILE_STUB_URL

        image_path = 'images/{}.png'.format(url_image_name)
        image = static(image_path)
        w, h = get_static_dimensions(image_path)

        return URL_FORMAT_VIEW.format(self.url, image, w, h)

    @cached_result()
    def _find_image_for_domains(self, domain):
        """
        Searches for the domain image for every domain level except top.
        E.g. for l3.example.co.uk it will search for l3.example.co.uk, then
        example.co.uk, then co.uk
        """
        levels = domain.split('.')
        while len(levels) > 1:
            domain = '.'.join(levels)

            filename = 'images/domains/{}.png'.format(domain)
            if file_exists(filename):
                return 'domains/' + domain
            else:
                del levels[0]