prism

Python library to process images and store the results to Amazon S3. Originally developed to power Fondu.

Philosophy:

• Assume nothing about your data models
• Use the md5 hash of images as keys, avoiding duplicate images and sensitive filenames.

Usage

# Imports
from boto.s3.connection import S3Connection
import prism

# Construct an s3 connection client
s3_conn = S3Connection('YOUR_ACCESS_KEY_ID', 'YOUR_SECRET_ACCESS_KEY')

# Build a Prism connection object around the s3 connection
prism_conn = prism.Connection(s3_conn, 'img.example.com', 'http://img.example.com/')

# Build a processing spec
spec = {
    'key_prefix': u'users/',
    'format': u'JPEG',
    'derivative_specs': [
        {
            'filters': [prism.filters.ThumbnailFilter(60, 60)],
            'key_suffix': u'-small',
        },
    ],
}

# Get the Prism collection manager using this spec
user_image_manager = prism_conn.get_collection_manager(**spec)

# Now process images
image_url = u'http://3.bp.blogspot.com/_xs4Qi1Qk2Ck/TKH76M7UaaI/AAAAAAAADXc/56rKShHiK1M/s1600/hot-dog-mustard-small.jpg'
image_hash = user_image_manager.process_image_url(image_url)

# Save the image_hash to your db for later retrieval

# Get the S3 url for this just-saved image
url = user_image_manager.get_url(image_hash)

# A derivative with suffix 'small' was created too
url_small = u'{url}-small'.format(url=url)

Spec options

key_prefix

If present, all keys will be prefixed with this string. Useful for categorizing or foldering different groups of images within the same S3 bucket.

format

Output format of the images. Options are JPEG or PNG. Defaults to JPEG.

derivative_specs

A list of derivative images to create from the original. Each derivative spec has parameters as follows:

filters

A list of filters to run the original image through to produce the derivative. Works like a processing chain, and runs first to last.

key_suffix

A suffix to give each image created from this derivative spec. Used for retrieving this derivative image once you have the url for the original

blacklist

A list of unicode md5 hashes to blacklist. Useful for "banning" certain images, regardless of filename.