70 lines
3.3 KiB
Python
70 lines
3.3 KiB
Python
from types import SimpleNamespace
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from django.core.files.base import ContentFile
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from django.core.files.storage import default_storage
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from django.db import models, IntegrityError
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from django.db.models import Model
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from authentication.models import ToolshedUser
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def hash_upload(instance, filename):
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return f"{instance.hash[:2]}/{instance.hash[2:4]}/{instance.hash[4:6]}/{instance.hash[6:]}"
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class FileManager(models.Manager):
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def get_or_create(self, **kwargs):
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if 'data' in kwargs and type(kwargs['data']) == str:
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import base64
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from hashlib import sha256
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content = base64.b64decode(kwargs['data'], validate=True)
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kwargs.pop('data')
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content_hash = sha256(content).hexdigest()
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kwargs['file'] = ContentFile(content, content_hash)
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kwargs['hash'] = content_hash
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else:
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raise ValueError('data must be a base64 encoded string or file and hash must be provided')
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try:
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return self.get(hash=kwargs['hash']), False
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except self.model.DoesNotExist:
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return self.create(**kwargs), True
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def create(self, **kwargs):
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if 'data' in kwargs and type(kwargs['data']) == str:
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import base64
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from hashlib import sha256
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content = base64.b64decode(kwargs['data'], validate=True)
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kwargs.pop('data')
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content_hash = sha256(content).hexdigest()
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kwargs['file'] = ContentFile(content, content_hash)
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kwargs['hash'] = content_hash
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elif 'file' in kwargs and 'hash' in kwargs and type(kwargs['file']) == ContentFile:
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pass
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else:
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raise ValueError('data must be a base64 encoded string or file and hash must be provided')
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if not self.filter(hash=kwargs['hash']).exists():
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# The upload path is derived entirely from the hash (hash_upload, above), and hash
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# is DB-unique - so if no File row owns this hash yet, anything already sitting at
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# its computed path is necessarily a stale orphan (e.g. left behind by a bug in
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# cleanup code that deleted a File row without removing its stored bytes, or a
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# crashed upload). Clear it before saving instead of letting Django's storage layer
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# invent an alternate filename to avoid the "collision" - a suffixed name would
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# silently break every part of the app that derives this file's URL purely from its
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# hash (media serving, thumbnail generation, item/avatar attachment), and no future
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# caller could ever discover it again.
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expected_path = hash_upload(SimpleNamespace(hash=kwargs['hash']), '')
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if default_storage.exists(expected_path):
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default_storage.delete(expected_path)
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return super().create(**kwargs)
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else:
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raise IntegrityError('File with this hash already exists')
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class File(Model):
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file = models.FileField(upload_to=hash_upload, null=False, blank=False, unique=True)
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mime_type = models.CharField(max_length=255, null=False, blank=False)
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hash = models.CharField(max_length=64, null=False, blank=False, unique=True)
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created_at = models.DateTimeField(auto_now_add=True)
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updated_at = models.DateTimeField(auto_now=True)
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objects = FileManager()
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