moviewyrm/bookwyrm/models/fields.py
2021-11-28 08:50:29 -08:00

537 lines
18 KiB
Python

""" activitypub-aware django model fields """
from dataclasses import MISSING
import imghdr
import re
from uuid import uuid4
from urllib.parse import urljoin
import dateutil.parser
from dateutil.parser import ParserError
from django.contrib.postgres.fields import ArrayField as DjangoArrayField
from django.core.exceptions import ValidationError
from django.core.files.base import ContentFile
from django.db import models
from django.forms import ClearableFileInput, ImageField as DjangoImageField
from django.utils import timezone
from django.utils.translation import gettext_lazy as _
from django.utils.encoding import filepath_to_uri
from bookwyrm import activitypub
from bookwyrm.connectors import get_image
from bookwyrm.sanitize_html import InputHtmlParser
from bookwyrm.settings import MEDIA_FULL_URL
def validate_remote_id(value):
"""make sure the remote_id looks like a url"""
if not value or not re.match(r"^http.?:\/\/[^\s]+$", value):
raise ValidationError(
_("%(value)s is not a valid remote_id"),
params={"value": value},
)
def validate_localname(value):
"""make sure localnames look okay"""
if not re.match(r"^[A-Za-z\-_\.0-9]+$", value):
raise ValidationError(
_("%(value)s is not a valid username"),
params={"value": value},
)
def validate_username(value):
"""make sure usernames look okay"""
if not re.match(r"^[A-Za-z\-_\.0-9]+@[A-Za-z\-_\.0-9]+\.[a-z]{2,}$", value):
raise ValidationError(
_("%(value)s is not a valid username"),
params={"value": value},
)
class ActivitypubFieldMixin:
"""make a database field serializable"""
def __init__(
self,
*args,
activitypub_field=None,
activitypub_wrapper=None,
deduplication_field=False,
**kwargs,
):
self.deduplication_field = deduplication_field
if activitypub_wrapper:
self.activitypub_wrapper = activitypub_field
self.activitypub_field = activitypub_wrapper
else:
self.activitypub_field = activitypub_field
super().__init__(*args, **kwargs)
def set_field_from_activity(self, instance, data, overwrite=True):
"""helper function for assinging a value to the field. Returns if changed"""
try:
value = getattr(data, self.get_activitypub_field())
except AttributeError:
# masssively hack-y workaround for boosts
if self.get_activitypub_field() != "attributedTo":
raise
value = getattr(data, "actor")
formatted = self.field_from_activity(value)
if formatted is None or formatted is MISSING or formatted == {}:
return False
current_value = (
getattr(instance, self.name) if hasattr(instance, self.name) else None
)
# if we're not in overwrite mode, only continue updating the field if its unset
if current_value and not overwrite:
return False
# the field is unchanged
if current_value == formatted:
return False
setattr(instance, self.name, formatted)
return True
def set_activity_from_field(self, activity, instance):
"""update the json object"""
value = getattr(instance, self.name)
formatted = self.field_to_activity(value)
if formatted is None:
return
key = self.get_activitypub_field()
# TODO: surely there's a better way
if instance.__class__.__name__ == "Boost" and key == "attributedTo":
key = "actor"
if isinstance(activity.get(key), list):
activity[key] += formatted
else:
activity[key] = formatted
def field_to_activity(self, value):
"""formatter to convert a model value into activitypub"""
if hasattr(self, "activitypub_wrapper"):
return {self.activitypub_wrapper: value}
return value
def field_from_activity(self, value):
"""formatter to convert activitypub into a model value"""
if value and hasattr(self, "activitypub_wrapper"):
value = value.get(self.activitypub_wrapper)
return value
def get_activitypub_field(self):
"""model_field_name to activitypubFieldName"""
if self.activitypub_field:
return self.activitypub_field
name = self.name.split(".")[-1]
components = name.split("_")
return components[0] + "".join(x.title() for x in components[1:])
class ActivitypubRelatedFieldMixin(ActivitypubFieldMixin):
"""default (de)serialization for foreign key and one to one"""
def __init__(self, *args, load_remote=True, **kwargs):
self.load_remote = load_remote
super().__init__(*args, **kwargs)
def field_from_activity(self, value):
if not value:
return None
related_model = self.related_model
if hasattr(value, "id") and value.id:
if not self.load_remote:
# only look in the local database
return related_model.find_existing(value.serialize())
# this is an activitypub object, which we can deserialize
return value.to_model(model=related_model)
try:
# make sure the value looks like a remote id
validate_remote_id(value)
except ValidationError:
# we don't know what this is, ignore it
return None
# gets or creates the model field from the remote id
if not self.load_remote:
# only look in the local database
return related_model.find_existing_by_remote_id(value)
return activitypub.resolve_remote_id(value, model=related_model)
class RemoteIdField(ActivitypubFieldMixin, models.CharField):
"""a url that serves as a unique identifier"""
def __init__(self, *args, max_length=255, validators=None, **kwargs):
validators = validators or [validate_remote_id]
super().__init__(*args, max_length=max_length, validators=validators, **kwargs)
# for this field, the default is true. false everywhere else.
self.deduplication_field = kwargs.get("deduplication_field", True)
class UsernameField(ActivitypubFieldMixin, models.CharField):
"""activitypub-aware username field"""
def __init__(self, activitypub_field="preferredUsername", **kwargs):
self.activitypub_field = activitypub_field
# I don't totally know why pylint is mad at this, but it makes it work
super(ActivitypubFieldMixin, self).__init__( # pylint: disable=bad-super-call
_("username"),
max_length=150,
unique=True,
validators=[validate_username],
error_messages={
"unique": _("A user with that username already exists."),
},
)
def deconstruct(self):
"""implementation of models.Field deconstruct"""
name, path, args, kwargs = super().deconstruct()
del kwargs["verbose_name"]
del kwargs["max_length"]
del kwargs["unique"]
del kwargs["validators"]
del kwargs["error_messages"]
return name, path, args, kwargs
def field_to_activity(self, value):
return value.split("@")[0]
PrivacyLevels = models.TextChoices(
"Privacy", ["public", "unlisted", "followers", "direct"]
)
class PrivacyField(ActivitypubFieldMixin, models.CharField):
"""this maps to two differente activitypub fields"""
public = "https://www.w3.org/ns/activitystreams#Public"
def __init__(self, *args, **kwargs):
super().__init__(
*args, max_length=255, choices=PrivacyLevels.choices, default="public"
)
# pylint: disable=invalid-name
def set_field_from_activity(self, instance, data, overwrite=True):
if not overwrite:
return False
original = getattr(instance, self.name)
to = data.to
cc = data.cc
# we need to figure out who this is to get their followers link
for field in ["attributedTo", "owner", "actor"]:
if hasattr(data, field):
user_field = field
break
if not user_field:
raise ValidationError("No user field found for privacy", data)
user = activitypub.resolve_remote_id(getattr(data, user_field), model="User")
if to == [self.public]:
setattr(instance, self.name, "public")
elif to == [user.followers_url]:
setattr(instance, self.name, "followers")
elif cc == []:
setattr(instance, self.name, "direct")
elif self.public in cc:
setattr(instance, self.name, "unlisted")
else:
setattr(instance, self.name, "followers")
return original == getattr(instance, self.name)
def set_activity_from_field(self, activity, instance):
# explicitly to anyone mentioned (statuses only)
mentions = []
if hasattr(instance, "mention_users"):
mentions = [u.remote_id for u in instance.mention_users.all()]
# this is a link to the followers list
# pylint: disable=protected-access
followers = instance.user.followers_url
if instance.privacy == "public":
activity["to"] = [self.public]
activity["cc"] = [followers] + mentions
elif instance.privacy == "unlisted":
activity["to"] = [followers]
activity["cc"] = [self.public] + mentions
elif instance.privacy == "followers":
activity["to"] = [followers]
activity["cc"] = mentions
if instance.privacy == "direct":
activity["to"] = mentions
activity["cc"] = []
class ForeignKey(ActivitypubRelatedFieldMixin, models.ForeignKey):
"""activitypub-aware foreign key field"""
def field_to_activity(self, value):
if not value:
return None
return value.remote_id
class OneToOneField(ActivitypubRelatedFieldMixin, models.OneToOneField):
"""activitypub-aware foreign key field"""
def field_to_activity(self, value):
if not value:
return None
return value.to_activity()
class ManyToManyField(ActivitypubFieldMixin, models.ManyToManyField):
"""activitypub-aware many to many field"""
def __init__(self, *args, link_only=False, **kwargs):
self.link_only = link_only
super().__init__(*args, **kwargs)
def set_field_from_activity(self, instance, data, overwrite=True):
"""helper function for assigning a value to the field"""
if not overwrite and getattr(instance, self.name).exists():
return False
value = getattr(data, self.get_activitypub_field())
formatted = self.field_from_activity(value)
if formatted is None or formatted is MISSING:
return False
getattr(instance, self.name).set(formatted)
instance.save(broadcast=False)
return True
def field_to_activity(self, value):
if self.link_only:
return f"{value.instance.remote_id}/{self.name}"
return [i.remote_id for i in value.all()]
def field_from_activity(self, value):
if value is None or value is MISSING:
return None
if not isinstance(value, list):
# If this is a link, we currently aren't doing anything with it
return None
items = []
for remote_id in value:
try:
validate_remote_id(remote_id)
except ValidationError:
continue
items.append(
activitypub.resolve_remote_id(remote_id, model=self.related_model)
)
return items
class TagField(ManyToManyField):
"""special case of many to many that uses Tags"""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.activitypub_field = "tag"
def field_to_activity(self, value):
tags = []
for item in value.all():
activity_type = item.__class__.__name__
if activity_type == "User":
activity_type = "Mention"
tags.append(
activitypub.Link(
href=item.remote_id,
name=getattr(item, item.name_field),
type=activity_type,
)
)
return tags
def field_from_activity(self, value):
if not isinstance(value, list):
return None
items = []
for link_json in value:
link = activitypub.Link(**link_json)
tag_type = link.type if link.type != "Mention" else "Person"
if tag_type == "Book":
tag_type = "Edition"
if tag_type != self.related_model.activity_serializer.type:
# tags can contain multiple types
continue
items.append(
activitypub.resolve_remote_id(link.href, model=self.related_model)
)
return items
class ClearableFileInputWithWarning(ClearableFileInput):
"""max file size warning"""
template_name = "widgets/clearable_file_input_with_warning.html"
class CustomImageField(DjangoImageField):
"""overwrites image field for form"""
widget = ClearableFileInputWithWarning
class ImageField(ActivitypubFieldMixin, models.ImageField):
"""activitypub-aware image field"""
def __init__(self, *args, alt_field=None, **kwargs):
self.alt_field = alt_field
super().__init__(*args, **kwargs)
# pylint: disable=arguments-differ
def set_field_from_activity(self, instance, data, save=True, overwrite=True):
"""helper function for assinging a value to the field"""
value = getattr(data, self.get_activitypub_field())
formatted = self.field_from_activity(value)
if formatted is None or formatted is MISSING:
return False
if (
not overwrite
and hasattr(instance, self.name)
and getattr(instance, self.name)
):
return False
getattr(instance, self.name).save(*formatted, save=save)
return True
def set_activity_from_field(self, activity, instance):
value = getattr(instance, self.name)
if value is None:
return
alt_text = getattr(instance, self.alt_field)
formatted = self.field_to_activity(value, alt_text)
key = self.get_activitypub_field()
activity[key] = formatted
def field_to_activity(self, value, alt=None):
url = get_absolute_url(value)
if not url:
return None
return activitypub.Document(url=url, name=alt)
def field_from_activity(self, value):
image_slug = value
# when it's an inline image (User avatar/icon, Book cover), it's a json
# blob, but when it's an attached image, it's just a url
if hasattr(image_slug, "url"):
url = image_slug.url
elif isinstance(image_slug, str):
url = image_slug
else:
return None
try:
validate_remote_id(url)
except ValidationError:
return None
response = get_image(url)
if not response:
return None
image_content = ContentFile(response.content)
extension = imghdr.what(None, image_content.read()) or ""
image_name = f"{uuid4()}.{extension}"
return [image_name, image_content]
def formfield(self, **kwargs):
"""special case for forms"""
return super().formfield(
**{
"form_class": CustomImageField,
**kwargs,
}
)
def get_absolute_url(value):
"""returns an absolute URL for the image"""
name = getattr(value, "name")
if not name:
return None
url = filepath_to_uri(name)
if url is not None:
url = url.lstrip("/")
url = urljoin(MEDIA_FULL_URL, url)
return url
class DateTimeField(ActivitypubFieldMixin, models.DateTimeField):
"""activitypub-aware datetime field"""
def field_to_activity(self, value):
if not value:
return None
return value.isoformat()
def field_from_activity(self, value):
try:
date_value = dateutil.parser.parse(value)
try:
return timezone.make_aware(date_value)
except ValueError:
return date_value
except (ParserError, TypeError):
return None
class HtmlField(ActivitypubFieldMixin, models.TextField):
"""a text field for storing html"""
def field_from_activity(self, value):
if not value or value == MISSING:
return None
sanitizer = InputHtmlParser()
sanitizer.feed(value)
return sanitizer.get_output()
class ArrayField(ActivitypubFieldMixin, DjangoArrayField):
"""activitypub-aware array field"""
def field_to_activity(self, value):
return [str(i) for i in value]
class CharField(ActivitypubFieldMixin, models.CharField):
"""activitypub-aware char field"""
class TextField(ActivitypubFieldMixin, models.TextField):
"""activitypub-aware text field"""
class BooleanField(ActivitypubFieldMixin, models.BooleanField):
"""activitypub-aware boolean field"""
class IntegerField(ActivitypubFieldMixin, models.IntegerField):
"""activitypub-aware boolean field"""
class DecimalField(ActivitypubFieldMixin, models.DecimalField):
"""activitypub-aware boolean field"""
def field_to_activity(self, value):
if not value:
return None
return float(value)