Resizing image proxy

On the fly resizer and proxy for your images written in pure GO

Requires MongoDB replicaSet and S3 compatible storage

WIP

Structure

Project currently consists of two applications: backoffice and resizing proxy. Backoffice is an API that is used for uploading images, configuring their settings, removing them. UI for the backend API is TODO. Proxy has only one endpoint {host}:{port}/v1/images/{imageId}/{transformations}.{extension}. In transformations you can specify desired transformations separated by underscore _ and extension is just one of allowed extension (png, jpg - for now). Example:

localhost:3333/v1/images/5ffacaab456cb200a1ad1dd0/cl20_h300_q80.png

that will crop image from the left by 20%, limit height by 300px and reduce quality from the original to 80% and return image encoded as PNG

Available transformation segments

h\d{1,5} - height (if width not provided - proportion will be preserved)
w\d{1,5} - width (if height not provided - proportion will be preserved)
w\d{1,5}_h\d{1,5} - width and height (proportion will be changed)
s\d{1,3} - scale down by percent (if scaleUp is disabled - cannot be larger than 100)
fh - flip horizontally
fv - flip vertically
bw - black & white (TODO)
o\d{1,2} - opacity in percent (TODO)
r90 - rotate 90 degrees
r180 - rotate 90 degrees
r270 - rotate 90 degrees
cl\d{1,2} - crop left by percent
cr\d{1,2} - crop right by percent
ct\d{1,2} - crop top by percent
cb\d{1,2} - crop bottom by percent
c\d{1,2} - crop all sides by percent

Caching

All resized images are stored in a storage (S3 only for now). It happens asyncronously, after resized image is returned to the client. Additional Redis cache is TODO. On the next request with similar transformation requirements resized image will be fetched from the storage.

Discrete steps

To prevent DDoS attacks you can specify discrete steps for all transformations. So, for example, a client will not be able to actually get images different by one pixel in height. Instead a closest possible result will be returned. E.g. if you set DISCRETE_SIZE_STEP env var to 50, and your original image has height of 230px than proxy will return only heights: 230px, 180px, 130px, 80px and 30px, fetching nearest possible height to the requested one.

Backoffice

Has 3 routes at the moment

GET {host}:{port}/api/v1/images/{id} get an image by ID
POST {host}:{port}/api/v1/images - create an image (upload)
GET {host}:{port}/api/v1/images - get images with pagination and filter
DELETE {host}:{port}/api/v1/images/{id} - delete an image and all sliced copies from the registry and storage

TODO

Swagger for backoffice
Support webp
Decide on crop/rotation/flipping order
Warmup worker
Fully dockerize
UI for backoffice
More transformations (rotation, opacity)
Transformation on image create
Watermark on image create
Auto crop
Redis caching
MySQL as alternative DB
Azure and Google cloud as alternative storage

Running

First start minio and mongodb

make data

Then build and lauch proxy and the backoffice

make local/build
make local/run/proxy
make local/run/backoffice

denismitr / resizer