bgneal@700: """This module contains a function to upload an image file to a S3Bucket.
bgneal@696: 
bgneal@700: The image can be resized and a thumbnail can be generated and uploaded as well.
bgneal@696: 
bgneal@696: """
bgneal@696: import logging
bgneal@696: from io import BytesIO
bgneal@696: import os.path
bgneal@700: import tempfile
bgneal@696: import uuid
bgneal@696: 
bgneal@696: from PIL import Image
bgneal@696: 
bgneal@700: from core.functions import temp_open
bgneal@700: 
bgneal@696: 
bgneal@696: logger = logging.getLogger(__name__)
bgneal@696: 
bgneal@696: 
bgneal@700: def upload(fp, bucket, metadata=None, new_size=None, thumb_size=None):
bgneal@700:     """Upload an image file to a given S3Bucket.
bgneal@696: 
bgneal@700:     The image can optionally be resized and a thumbnail can be generated and
bgneal@700:     uploaded as well.
bgneal@696: 
bgneal@700:     Parameters:
bgneal@700:         fp - The image file to process. This is expected to be an instance of
bgneal@700:              Django's UploadedFile class. The file must have a name attribute and
bgneal@700:              we expect the name to have an extension. This is extension is
bgneal@700:              used for the uploaded image and thumbnail names.
bgneal@700:         bucket - A core.s3.S3Bucket instance to upload to.
bgneal@700:         metadata - If not None, must be a dictionary of metadata to apply to the
bgneal@700:                    uploaded file and thumbnail.
bgneal@700:         new_size - If not None, the image will be resized to the dimensions
bgneal@700:                    specified by new_size, which must be a (width, height) tuple.
bgneal@700:         thumb_size - If not None, a thumbnail image will be created with the
bgneal@700:                      dimensions specified by thumb_size, which must be a (width,
bgneal@700:                      height) tuple. The thumbnail will use the same metadata, if
bgneal@700:                      present, as the image. The thumbnail filename will be the
bgneal@700:                      same basename as the image with a 't' appended. The
bgneal@700:                      extension will be the same as the original image.
bgneal@700: 
bgneal@700:     A tuple is returned: (image_url, thumb_url) where thumb_url will be None if
bgneal@700:     a thumbnail was not requested.
bgneal@696:     """
bgneal@696: 
bgneal@737:     filename = fp.name.encode('utf-8')
bgneal@737:     logger.info('Processing image file: %s', filename)
bgneal@700: 
bgneal@700:     # Trying to use PIL (or Pillow) on a Django UploadedFile is often
bgneal@700:     # problematic because the file is often an in-memory file if it is under
bgneal@700:     # a certain size. This complicates matters and many of the operations we try
bgneal@700:     # to perform on it fail if this is the case. To get around these issues,
bgneal@700:     # we make a copy of the file on the file system and operate on the copy.
bgneal@700:     # First generate a unique name and temporary file path.
bgneal@696:     unique_key = uuid.uuid4().hex
bgneal@700:     ext = os.path.splitext(fp.name)[1]
bgneal@700:     temp_name = os.path.join(tempfile.gettempdir(), unique_key + ext)
bgneal@696: 
bgneal@700:     # Write the UploadedFile to a temporary file on disk
bgneal@700:     with temp_open(temp_name, 'wb') as temp_file:
bgneal@700:         for chunk in fp.chunks():
bgneal@700:             temp_file.write(chunk)
bgneal@700:         temp_file.close()
bgneal@696: 
bgneal@700:         # Resize image if necessary
bgneal@700:         if new_size:
bgneal@700:             image = Image.open(temp_name)
bgneal@700:             if image.size > new_size:
bgneal@700:                 logger.debug('Resizing from {} to {}'.format(image.size, new_size))
bgneal@700:                 image.thumbnail(new_size, Image.ANTIALIAS)
bgneal@700:                 image.save(temp_name)
bgneal@696: 
bgneal@700:         # Create thumbnail if necessary
bgneal@700:         thumb = None
bgneal@700:         if thumb_size:
bgneal@700:             logger.debug('Creating thumbnail {}'.format(thumb_size))
bgneal@700:             image = Image.open(temp_name)
bgneal@700:             image.thumbnail(thumb_size, Image.ANTIALIAS)
bgneal@700:             thumb = BytesIO()
bgneal@700:             image.save(thumb, format=image.format)
bgneal@696: 
bgneal@700:         # Upload images to S3
bgneal@700:         file_key = unique_key + ext
bgneal@700:         logging.debug('Uploading image')
bgneal@700:         image_url = bucket.upload_from_filename(file_key, temp_name, metadata)
bgneal@696: 
bgneal@700:     thumb_url = None
bgneal@700:     if thumb:
bgneal@700:         logging.debug('Uploading thumbnail')
bgneal@700:         thumb_key = '{}t{}'.format(unique_key, ext)
bgneal@700:         thumb_url = bucket.upload_from_string(thumb_key,
bgneal@700:                                               thumb.getvalue(),
bgneal@700:                                               metadata)
bgneal@696: 
bgneal@737:     logger.info('Completed processing image file: %s', filename)
bgneal@696: 
bgneal@700:     return (image_url, thumb_url)