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comparison user_photos/forms.py @ 749:b6e98717690b

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For #59, add user photo de-duplication for uploads.
author Brian Neal <bgneal@gmail.com>
date Mon, 30 Dec 2013 15:05:43 -0600
parents 094492e66eb9
children 51a2051588f5
comparison
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748:e5869846d0dc 749:b6e98717690b
1 """Forms for the user_photos application.""" 1 """Forms for the user_photos application."""
2 import datetime 2 import datetime
3 import hashlib
3 4
4 from django import forms 5 from django import forms
5 from django.conf import settings 6 from django.conf import settings
6 7
7 from core.s3 import S3Bucket 8 from core.s3 import S3Bucket
47 48
48 def save(self): 49 def save(self):
49 """Processes the image and creates a new Photo object, which is saved to 50 """Processes the image and creates a new Photo object, which is saved to
50 the database. The new Photo instance is returned. 51 the database. The new Photo instance is returned.
51 52
53 Note that we do de-duplication. A signature is computed for the photo.
54 If the user has already uploaded a file with the same signature, that
55 photo object is returned instead.
56
52 This function should only be called if is_valid() returns True. 57 This function should only be called if is_valid() returns True.
53 58
54 """ 59 """
60 # Check for duplicate uploads from this user
61 signature = self._signature()
62 try:
63 return Photo.objects.get(user=self.user, signature=signature)
64 except Photo.DoesNotExist:
65 pass
66
67 # This must not be a duplicate, proceed with upload to S3
55 bucket = S3Bucket(access_key=settings.USER_PHOTOS_ACCESS_KEY, 68 bucket = S3Bucket(access_key=settings.USER_PHOTOS_ACCESS_KEY,
56 secret_key=settings.USER_PHOTOS_SECRET_KEY, 69 secret_key=settings.USER_PHOTOS_SECRET_KEY,
57 base_url=settings.USER_PHOTOS_BASE_URL, 70 base_url=settings.USER_PHOTOS_BASE_URL,
58 bucket_name=settings.USER_PHOTOS_BUCKET) 71 bucket_name=settings.USER_PHOTOS_BUCKET)
59 72
64 bucket=bucket, 77 bucket=bucket,
65 metadata=metadata, 78 metadata=metadata,
66 new_size=settings.USER_PHOTOS_MAX_SIZE, 79 new_size=settings.USER_PHOTOS_MAX_SIZE,
67 thumb_size=settings.USER_PHOTOS_THUMB_SIZE) 80 thumb_size=settings.USER_PHOTOS_THUMB_SIZE)
68 81
69 photo = Photo(user=self.user, url=url, thumb_url=thumb_url) 82 photo = Photo(user=self.user, url=url, thumb_url=thumb_url,
83 signature=signature)
70 photo.save() 84 photo.save()
71 return photo 85 return photo
86
87 def _signature(self):
88 """Calculates and returns a signature for the image file as a hex digest
89 string.
90
91 This function should only be called if is_valid() is True.
92
93 """
94 fp = self.cleaned_data['image_file']
95 md5 = hashlib.md5()
96 for chunk in fp.chunks():
97 md5.update(chunk)
98 return md5.hexdigest()