extensions-website/files/admin.py

import logging

from django.conf import settings
from django.contrib import admin
from django.template.loader import render_to_string
from django.urls import reverse
from django.utils.safestring import mark_safe
import background_task.admin
import background_task.models

from .models import File, FileValidation
import files.signals

logger = logging.getLogger(__name__)


def schedule_scan(self, request, queryset):
    """Scan selected files."""
    for instance in queryset:
        files.signals.schedule_scan(instance)


def make_thumbnails(self, request, queryset):
    """Make thumbnails for selected files."""
    for instance in queryset.filter(type__in=(File.TYPES.IMAGE, File.TYPES.VIDEO)):
        files.tasks.make_thumbnails.task_function(file_id=instance.pk)


class FileValidationInlineAdmin(admin.StackedInline):
    model = FileValidation
    readonly_fields = ('date_created', 'date_modified', 'is_ok', 'results')
    extra = 0

    def _nope(self, request, obj):
        return False

    has_add_permission = _nope
    has_change_permission = _nope
    has_delete_permission = _nope


@admin.register(File)
class FileAdmin(admin.ModelAdmin):
    class Media:
        css = {'all': ('files/admin/file.css',)}

    def thumbnails(self, obj):
        if not obj or not (obj.is_image or obj.is_video):
            return ''
        try:
            context = {'file': obj, 'MEDIA_URL': settings.MEDIA_URL}
            return render_to_string('files/admin/thumbnails.html', context)
        except Exception:
            # Make sure any exception happening here is always logged
            # (e.g. admin eats exceptions in ModelAdmin properties, making it hard to debug)
            logger.exception('Failed to render thumbnails')
            raise

    def get_form(self, request, obj=None, **kwargs):
        """Override metadata help text depending on file type."""
        if obj and (obj.is_image or obj.is_video):
            help_text = 'Additional information about the file, e.g. existing thumbnails.'
            kwargs.update({'help_texts': {'metadata': help_text}})
        return super().get_form(request, obj, **kwargs)

    view_on_site = False
    save_on_top = True

    list_filter = (
        'validation__is_ok',
        'type',
        'status',
        'date_status_changed',
        'date_approved',
        ('extension', admin.EmptyFieldListFilter),
    )
    list_display = (
        'original_name',
        'extension_link',
        'user',
        'date_created',
        'type',
        'status',
        'is_ok',
    )

    list_select_related = ('version__extension', 'user')

    readonly_fields = (
        'id',
        'date_created',
        'date_modified',
        'date_approved',
        'date_status_changed',
        'size_bytes',
        'thumbnails',
        'thumbnail',
        'type',
        'user',
        'original_hash',
        'original_name',
        'hash',
        'content_type',
    )
    search_fields = (
        '^version__extension__slug',
        '^version__extension__name',
        'extensions__slug',
        'extensions__name',
        'original_name',
        'hash',
        'source',
    )

    fieldsets = (
        (
            None,
            {
                'fields': (
                    'id',
                    ('source', 'thumbnails', 'thumbnail'),
                    ('type', 'content_type', 'original_name'),
                    'status',
                )
            },
        ),
        (
            'Dates',
            {
                'fields': (
                    'date_created',
                    'date_modified',
                    'date_status_changed',
                    'date_approved',
                )
            },
        ),
        (
            'Details',
            {
                'fields': (
                    ('hash', 'original_hash'),
                    'metadata',
                    'size_bytes',
                    'user',
                ),
            },
        ),
    )

    inlines = [FileValidationInlineAdmin]
    actions = [schedule_scan, make_thumbnails]

    def extension_link(self, obj):
        return (
            mark_safe(
                '<a href="{}" target="_blank">{}</a>'.format(
                    reverse('admin:extensions_extension_change', args=(obj.extension_id,)),
                    obj.extension,
                )
            )
            if obj.extension_id
            else '-'
        )

    extension_link.short_description = 'Extension'

    def is_ok(self, obj):
        return obj.validation.is_ok if hasattr(obj, 'validation') else None

    is_ok.boolean = True


try:
    admin.site.unregister(background_task.models.Task)
    admin.site.unregister(background_task.models.CompletedTask)
except admin.site.NotRegistered:
    pass


class TaskMixin:
    """Modify a few properties of background tasks displayed in admin."""

    def no_errors(self, obj):
        """Replace background_task's "has_error".

        Make Django's red/green boolean icons less confusing
        in the context of "there's an error during task run".
        """
        return not bool(obj.last_error)

    no_errors.boolean = True


@admin.register(background_task.models.Task)
@admin.register(background_task.models.CompletedTask)
class TaskAdmin(background_task.admin.TaskAdmin, TaskMixin):
    date_hierarchy = 'run_at'
    list_display = [
        'run_at',
        'task_name',
        'task_params',
        'attempts',
        'no_errors',
        'locked_by',
        'locked_by_pid_running',
    ]
    list_filter = (
        'task_name',
        'run_at',
        'failed_at',
        'locked_at',
        'attempts',
        'creator_content_type',
    )
    search_fields = ['task_name', 'task_params', 'last_error', 'verbose_name']