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annotate core/image_uploader.py @ 718:bf5340705d0c

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Completed view to delete user photos. Still need to modify the admin to delete not just the model instance but the S3 bucket keys.
author Brian Neal <bgneal@gmail.com>
date Wed, 18 Sep 2013 21:34:05 -0500
parents e888d627928f
children 775e7f74096a
rev   line source
bgneal@700 1 """This module contains a function to upload an image file to a S3Bucket.
bgneal@696 2
bgneal@700 3 The image can be resized and a thumbnail can be generated and uploaded as well.
bgneal@696 4
bgneal@696 5 """
bgneal@696 6 import logging
bgneal@696 7 from io import BytesIO
bgneal@696 8 import os.path
bgneal@700 9 import tempfile
bgneal@696 10 import uuid
bgneal@696 11
bgneal@696 12 from PIL import Image
bgneal@696 13
bgneal@700 14 from core.functions import temp_open
bgneal@700 15
bgneal@696 16
bgneal@696 17 logger = logging.getLogger(__name__)
bgneal@696 18
bgneal@696 19
bgneal@700 20 def upload(fp, bucket, metadata=None, new_size=None, thumb_size=None):
bgneal@700 21 """Upload an image file to a given S3Bucket.
bgneal@696 22
bgneal@700 23 The image can optionally be resized and a thumbnail can be generated and
bgneal@700 24 uploaded as well.
bgneal@696 25
bgneal@700 26 Parameters:
bgneal@700 27 fp - The image file to process. This is expected to be an instance of
bgneal@700 28 Django's UploadedFile class. The file must have a name attribute and
bgneal@700 29 we expect the name to have an extension. This is extension is
bgneal@700 30 used for the uploaded image and thumbnail names.
bgneal@700 31 bucket - A core.s3.S3Bucket instance to upload to.
bgneal@700 32 metadata - If not None, must be a dictionary of metadata to apply to the
bgneal@700 33 uploaded file and thumbnail.
bgneal@700 34 new_size - If not None, the image will be resized to the dimensions
bgneal@700 35 specified by new_size, which must be a (width, height) tuple.
bgneal@700 36 thumb_size - If not None, a thumbnail image will be created with the
bgneal@700 37 dimensions specified by thumb_size, which must be a (width,
bgneal@700 38 height) tuple. The thumbnail will use the same metadata, if
bgneal@700 39 present, as the image. The thumbnail filename will be the
bgneal@700 40 same basename as the image with a 't' appended. The
bgneal@700 41 extension will be the same as the original image.
bgneal@700 42
bgneal@700 43 A tuple is returned: (image_url, thumb_url) where thumb_url will be None if
bgneal@700 44 a thumbnail was not requested.
bgneal@696 45 """
bgneal@696 46
bgneal@700 47 logger.info('Processing image file: {}'.format(fp.name))
bgneal@700 48
bgneal@700 49 # Trying to use PIL (or Pillow) on a Django UploadedFile is often
bgneal@700 50 # problematic because the file is often an in-memory file if it is under
bgneal@700 51 # a certain size. This complicates matters and many of the operations we try
bgneal@700 52 # to perform on it fail if this is the case. To get around these issues,
bgneal@700 53 # we make a copy of the file on the file system and operate on the copy.
bgneal@700 54 # First generate a unique name and temporary file path.
bgneal@696 55 unique_key = uuid.uuid4().hex
bgneal@700 56 ext = os.path.splitext(fp.name)[1]
bgneal@700 57 temp_name = os.path.join(tempfile.gettempdir(), unique_key + ext)
bgneal@696 58
bgneal@700 59 # Write the UploadedFile to a temporary file on disk
bgneal@700 60 with temp_open(temp_name, 'wb') as temp_file:
bgneal@700 61 for chunk in fp.chunks():
bgneal@700 62 temp_file.write(chunk)
bgneal@700 63 temp_file.close()
bgneal@696 64
bgneal@700 65 # Resize image if necessary
bgneal@700 66 if new_size:
bgneal@700 67 image = Image.open(temp_name)
bgneal@700 68 if image.size > new_size:
bgneal@700 69 logger.debug('Resizing from {} to {}'.format(image.size, new_size))
bgneal@700 70 image.thumbnail(new_size, Image.ANTIALIAS)
bgneal@700 71 image.save(temp_name)
bgneal@696 72
bgneal@700 73 # Create thumbnail if necessary
bgneal@700 74 thumb = None
bgneal@700 75 if thumb_size:
bgneal@700 76 logger.debug('Creating thumbnail {}'.format(thumb_size))
bgneal@700 77 image = Image.open(temp_name)
bgneal@700 78 image.thumbnail(thumb_size, Image.ANTIALIAS)
bgneal@700 79 thumb = BytesIO()
bgneal@700 80 image.save(thumb, format=image.format)
bgneal@696 81
bgneal@700 82 # Upload images to S3
bgneal@700 83 file_key = unique_key + ext
bgneal@700 84 logging.debug('Uploading image')
bgneal@700 85 image_url = bucket.upload_from_filename(file_key, temp_name, metadata)
bgneal@696 86
bgneal@700 87 thumb_url = None
bgneal@700 88 if thumb:
bgneal@700 89 logging.debug('Uploading thumbnail')
bgneal@700 90 thumb_key = '{}t{}'.format(unique_key, ext)
bgneal@700 91 thumb_url = bucket.upload_from_string(thumb_key,
bgneal@700 92 thumb.getvalue(),
bgneal@700 93 metadata)
bgneal@696 94
bgneal@700 95 logger.info('Completed processing image file: {}'.format(fp.name))
bgneal@696 96
bgneal@700 97 return (image_url, thumb_url)