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annotate core/image_uploader.py @ 821:71db8076dc3d

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Bandmap WIP: geocoding integrated with add form. Add form works. Before submitting the form, client side JS makes a geocode request to Google and populates hidden lat/lon fields with the result. Successfully created a model instance on the server side. Still need to update admin dashboard, admin approval, and give out badges for adding bands to the map. Once that is done, then work on displaying the map with filtering.
author Brian Neal <bgneal@gmail.com>
date Tue, 23 Sep 2014 20:40:31 -0500
parents df2799f725d8
children 234726f5a47a
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@738 47 filename = fp.name
bgneal@737 48 logger.info('Processing image file: %s', filename)
bgneal@700 49
bgneal@700 50 # Trying to use PIL (or Pillow) on a Django UploadedFile is often
bgneal@700 51 # problematic because the file is often an in-memory file if it is under
bgneal@700 52 # a certain size. This complicates matters and many of the operations we try
bgneal@700 53 # to perform on it fail if this is the case. To get around these issues,
bgneal@700 54 # we make a copy of the file on the file system and operate on the copy.
bgneal@700 55 # First generate a unique name and temporary file path.
bgneal@696 56 unique_key = uuid.uuid4().hex
bgneal@700 57 ext = os.path.splitext(fp.name)[1]
bgneal@700 58 temp_name = os.path.join(tempfile.gettempdir(), unique_key + ext)
bgneal@696 59
bgneal@700 60 # Write the UploadedFile to a temporary file on disk
bgneal@700 61 with temp_open(temp_name, 'wb') as temp_file:
bgneal@700 62 for chunk in fp.chunks():
bgneal@700 63 temp_file.write(chunk)
bgneal@700 64 temp_file.close()
bgneal@696 65
bgneal@700 66 # Resize image if necessary
bgneal@700 67 if new_size:
bgneal@700 68 image = Image.open(temp_name)
bgneal@700 69 if image.size > new_size:
bgneal@700 70 logger.debug('Resizing from {} to {}'.format(image.size, new_size))
bgneal@700 71 image.thumbnail(new_size, Image.ANTIALIAS)
bgneal@700 72 image.save(temp_name)
bgneal@696 73
bgneal@700 74 # Create thumbnail if necessary
bgneal@700 75 thumb = None
bgneal@700 76 if thumb_size:
bgneal@700 77 logger.debug('Creating thumbnail {}'.format(thumb_size))
bgneal@700 78 image = Image.open(temp_name)
bgneal@700 79 image.thumbnail(thumb_size, Image.ANTIALIAS)
bgneal@700 80 thumb = BytesIO()
bgneal@700 81 image.save(thumb, format=image.format)
bgneal@696 82
bgneal@700 83 # Upload images to S3
bgneal@700 84 file_key = unique_key + ext
bgneal@700 85 logging.debug('Uploading image')
bgneal@700 86 image_url = bucket.upload_from_filename(file_key, temp_name, metadata)
bgneal@696 87
bgneal@700 88 thumb_url = None
bgneal@700 89 if thumb:
bgneal@700 90 logging.debug('Uploading thumbnail')
bgneal@700 91 thumb_key = '{}t{}'.format(unique_key, ext)
bgneal@700 92 thumb_url = bucket.upload_from_string(thumb_key,
bgneal@700 93 thumb.getvalue(),
bgneal@700 94 metadata)
bgneal@696 95
bgneal@737 96 logger.info('Completed processing image file: %s', filename)
bgneal@696 97
bgneal@700 98 return (image_url, thumb_url)