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annotate user_photos/forms.py @ 887:9a15f7c27526

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Actually save model object upon change. This commit was tested on the comments model. Additional logging added. Added check for Markdown image references. Added TODOs after observing behavior on comments.
author Brian Neal <bgneal@gmail.com>
date Tue, 03 Feb 2015 21:09:44 -0600
parents b6e98717690b
children 51a2051588f5
rev   line source
bgneal@695 1 """Forms for the user_photos application."""
bgneal@700 2 import datetime
bgneal@749 3 import hashlib
bgneal@700 4
bgneal@695 5 from django import forms
bgneal@697 6 from django.conf import settings
bgneal@695 7
bgneal@700 8 from core.s3 import S3Bucket
bgneal@700 9 from core.image_uploader import upload
bgneal@701 10 from core.services import get_redis_connection
bgneal@696 11 from user_photos.models import Photo
bgneal@696 12
bgneal@695 13
bgneal@701 14 def rate_limit(key, limit, seconds):
bgneal@701 15 """Use Redis to do a rate limit check. Returns True if the limit is violated
bgneal@701 16 and False otherwise.
bgneal@701 17
bgneal@701 18 key - the key to check in Redis
bgneal@701 19 limit - the rate limit maximum value
bgneal@701 20 seconds - the rate limit period in seconds
bgneal@701 21
bgneal@701 22 """
bgneal@701 23 conn = get_redis_connection()
bgneal@701 24 val = conn.incr(key)
bgneal@701 25 if val == 1:
bgneal@701 26 conn.expire(key, seconds)
bgneal@701 27 return val > limit
bgneal@701 28
bgneal@701 29
bgneal@695 30 class UploadForm(forms.Form):
bgneal@695 31 image_file = forms.ImageField()
bgneal@696 32
bgneal@696 33 def __init__(self, *args, **kwargs):
bgneal@696 34 self.user = kwargs.pop('user')
bgneal@696 35 super(UploadForm, self).__init__(*args, **kwargs)
bgneal@696 36
bgneal@701 37 def clean(self):
bgneal@701 38 cleaned_data = super(UploadForm, self).clean()
bgneal@701 39
bgneal@701 40 # rate limit uploads
bgneal@701 41 key = 'user_photos:counts:' + self.user.username
bgneal@701 42 limit = settings.USER_PHOTOS_RATE_LIMIT
bgneal@701 43 if rate_limit(key, *limit):
bgneal@701 44 raise forms.ValidationError("You've exceeded your upload quota. "
bgneal@701 45 "Please try again later.")
bgneal@701 46
bgneal@701 47 return cleaned_data
bgneal@701 48
bgneal@696 49 def save(self):
bgneal@696 50 """Processes the image and creates a new Photo object, which is saved to
bgneal@696 51 the database. The new Photo instance is returned.
bgneal@696 52
bgneal@749 53 Note that we do de-duplication. A signature is computed for the photo.
bgneal@749 54 If the user has already uploaded a file with the same signature, that
bgneal@749 55 photo object is returned instead.
bgneal@749 56
bgneal@696 57 This function should only be called if is_valid() returns True.
bgneal@696 58
bgneal@696 59 """
bgneal@749 60 # Check for duplicate uploads from this user
bgneal@749 61 signature = self._signature()
bgneal@749 62 try:
bgneal@749 63 return Photo.objects.get(user=self.user, signature=signature)
bgneal@749 64 except Photo.DoesNotExist:
bgneal@749 65 pass
bgneal@749 66
bgneal@749 67 # This must not be a duplicate, proceed with upload to S3
bgneal@700 68 bucket = S3Bucket(access_key=settings.USER_PHOTOS_ACCESS_KEY,
bgneal@700 69 secret_key=settings.USER_PHOTOS_SECRET_KEY,
bgneal@700 70 base_url=settings.USER_PHOTOS_BASE_URL,
bgneal@700 71 bucket_name=settings.USER_PHOTOS_BUCKET)
bgneal@700 72
bgneal@700 73 now = datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S')
bgneal@700 74 metadata = {'user': self.user.username, 'date': now}
bgneal@700 75
bgneal@700 76 url, thumb_url = upload(fp=self.cleaned_data['image_file'],
bgneal@700 77 bucket=bucket,
bgneal@700 78 metadata=metadata,
bgneal@700 79 new_size=settings.USER_PHOTOS_MAX_SIZE,
bgneal@700 80 thumb_size=settings.USER_PHOTOS_THUMB_SIZE)
bgneal@700 81
bgneal@749 82 photo = Photo(user=self.user, url=url, thumb_url=thumb_url,
bgneal@749 83 signature=signature)
bgneal@696 84 photo.save()
bgneal@696 85 return photo
bgneal@749 86
bgneal@749 87 def _signature(self):
bgneal@749 88 """Calculates and returns a signature for the image file as a hex digest
bgneal@749 89 string.
bgneal@749 90
bgneal@749 91 This function should only be called if is_valid() is True.
bgneal@749 92
bgneal@749 93 """
bgneal@749 94 fp = self.cleaned_data['image_file']
bgneal@749 95 md5 = hashlib.md5()
bgneal@749 96 for chunk in fp.chunks():
bgneal@749 97 md5.update(chunk)
bgneal@749 98 return md5.hexdigest()