extensions-website/files/models.py

from pathlib import Path
from typing import Dict, Any
import logging

from django.contrib.auth import get_user_model
from django.db import models

from common.model_mixins import CreatedModifiedMixin, TrackChangesMixin
from files.utils import get_sha256, guess_mimetype_from_ext, get_thumbnail_upload_to
from constants.base import FILE_STATUS_CHOICES, FILE_TYPE_CHOICES
import utils

User = get_user_model()
log = logging.getLogger(__name__)


class FileManager(models.Manager):
    @property
    def listed(self):
        return self.filter(status=self.model.STATUSES.APPROVED)

    @property
    def unlisted(self):
        return self.exclude(status=self.model.STATUSES.APPROVED)


def file_upload_to(instance, filename):
    prefix = 'files/'
    if instance.is_image:
        prefix = 'images/'
    elif instance.is_video:
        prefix = 'videos/'

    _hash = instance.hash.split(':')[-1]
    extension = Path(filename).suffix
    path = Path(prefix, _hash[:2], _hash).with_suffix(extension)
    return path


def thumbnail_upload_to(instance, filename):
    return get_thumbnail_upload_to(instance.hash)


class File(CreatedModifiedMixin, TrackChangesMixin, models.Model):
    track_changes_to_fields = {'status', 'size_bytes', 'hash', 'thumbnail', 'metadata'}

    TYPES = FILE_TYPE_CHOICES
    STATUSES = FILE_STATUS_CHOICES

    date_approved = models.DateTimeField(null=True, blank=True, editable=False)
    date_status_changed = models.DateTimeField(null=True, blank=True, editable=False)

    source = models.FileField(null=False, blank=False, upload_to=file_upload_to)
    thumbnail = models.ImageField(
        upload_to=thumbnail_upload_to,
        null=True,
        blank=True,
        max_length=256,
        help_text='Thumbnail generated from uploaded image or video source file',
        editable=False,
    )
    content_type = models.CharField(max_length=256, null=True, blank=True)
    type = models.PositiveSmallIntegerField(
        choices=TYPES,
        null=True,
        blank=True,
        help_text=(
            'Indicates that this is an image, a video '
            'or a type of extension this file appears to match, '
            'as guessed from its contents.'
        ),
    )
    status = models.PositiveSmallIntegerField(choices=STATUSES, default=STATUSES.AWAITING_REVIEW)

    user = models.ForeignKey(
        User, related_name='files', null=False, blank=False, on_delete=models.CASCADE
    )
    size_bytes = models.PositiveBigIntegerField(default=0, editable=False)
    hash = models.CharField(max_length=255, null=False, blank=True, unique=True)
    original_name = models.CharField(max_length=255, blank=True, null=False)
    original_hash = models.CharField(
        max_length=255,
        null=False,
        blank=True,
        unique=True,
        help_text='The original hash of the file before we repackage it any way.',
    )

    metadata = models.JSONField(
        null=False,
        default=dict,
        blank=True,
        # TODO add link to the manifest file user manual page.
        help_text=('Meta information that was parsed from the `manifest file.'),
    )

    objects = FileManager()

    def __str__(self) -> str:
        return f'{self.original_name} ({self.get_status_display()})'

    @property
    def has_been_validated(self):
        try:
            self.validation
        except FileValidation.DoesNotExist:
            return False
        else:
            return True

    @classmethod
    def generate_hash(self, source):
        """Generate a hash for the File"""
        return f'sha256:{get_sha256(source)}'

    @property
    def file_path(self):
        return self.source.path if self.source else ''

    @property
    def filename(self):
        return self.source.name if self.source else ''

    def save(self, *args, **kwargs):
        """Set values that depend of the source file (size, original hash and name)."""
        if not self.size_bytes:
            self.size_bytes = self.source.size
        if not self.original_name:
            self.original_name = self.source.name

        if not self.content_type:
            self.content_type = guess_mimetype_from_ext(self.original_name)
        if self.content_type:
            if 'image' in self.content_type:
                self.type = self.TYPES.IMAGE
            if 'video' in self.content_type:
                self.type = self.TYPES.VIDEO

        if not self.original_hash or not self.hash:
            _hash = self.generate_hash(self.source)
            self.original_hash = _hash or self.original_hash
            self.hash = _hash or self.hash

        self.full_clean()
        return super().save(*args, **kwargs)

    @property
    def is_listed(self) -> bool:
        return self.status == self.STATUSES.APPROVED

    @property
    def is_image(self) -> bool:
        return self.type == self.TYPES.IMAGE

    @property
    def is_video(self) -> bool:
        return self.type == self.TYPES.VIDEO

    @property
    def suffix(self) -> str:
        path = Path(self.source.path)
        return ''.join(path.suffixes)

    @property
    def extension(self):
        return self.version.extension

    @property
    def parsed_extension_fields(self) -> Dict[str, Any]:
        """Return Extension-related data that was parsed from file's content."""
        data = self.metadata

        extension_id = data.get('id')
        name = data.get('name', self.original_name)
        return {
            'name': name,
            'slug': utils.slugify(extension_id),
            'extension_id': extension_id,
            'website': data.get('website'),
        }

    @property
    def parsed_version_fields(self) -> Dict[str, Any]:
        """Return Version-related data that was parsed from file's content."""
        # Currently, the content of the manifest file is the only
        # kind of file metadata that is supported.
        data = self.metadata
        return {
            'version': data.get('version'),
            'tagline': data.get('tagline'),
            'blender_version_min': data.get('blender_version_min'),
            'schema_version': data.get('schema_version'),
            'licenses': data.get('license'),
            'permissions': data.get('permissions'),
            'tags': data.get('tags'),
        }

    def get_submit_url(self) -> str:
        return self.extension.get_draft_url()

    def get_thumbnail_of_size(self, size_key: str) -> str:
        """Return absolute path portion of the URL of a thumbnail of this file.

        Fall back to the source file, if no thumbnail is stored.
        Log absence of the thumbnail file instead of exploding somewhere in the templates.
        """
        # We don't (yet?) have thumbnails for anything other than images and videos.
        assert self.is_image or self.is_video, f'File pk={self.pk} is neither image nor video'

        try:
            path = self.metadata['thumbnails'][size_key]['path']
            return self.thumbnail.storage.url(path)
        except (KeyError, TypeError):
            log.exception(f'File pk={self.pk} is missing thumbnail "{size_key}": {self.metadata}')
        return self.source.url

    @property
    def thumbnail_1080p_url(self) -> str:
        return self.get_thumbnail_of_size('1080p')

    @property
    def thumbnail_360p_url(self) -> str:
        return self.get_thumbnail_of_size('360p')


class FileValidation(CreatedModifiedMixin, TrackChangesMixin, models.Model):
    track_changes_to_fields = {'is_ok', 'results'}

    file = models.OneToOneField(File, related_name='validation', on_delete=models.CASCADE)
    is_ok = models.BooleanField(default=False)
    results = models.JSONField()