Image Thumbs

Easy-to-use library to create image thumbnails from images existing on some (cloud) object storage or from disk.

Currently implemented is a connection to Google Cloud Storage, but it can be easily extended to other providers.

Supported formats

PNG and JPEG are currently the only supported image formats.

How to use

Sizes

Configure what thumbnails you would like to have in a .yaml file:

thumbs:
  - name: standard      # This name will be added to the thumbnail with an underscore (_)
    # Optional; The default pattern is /{image_stem}_{thumb_name}
    # The original extension is always appended to the end, e.g., `.png`
    naming_pattern: "/{thumb_name}/{image_stem}"
    quality: 80         # PNG ignores this variable as it is always lossless
    size: [ 640, 480 ]  # Target size of the thumbnail. May not always be exact.
    mode: fit           # Available are: 'fit' and 'crop'

  - name: mini
    quality: 80
    size: [ 40, 40 ]
    mode: crop

Google credentials

This crate relies on object_store for the interaction with the storage backend. Currently, this crate only supports Google Cloud Storage and AWS S3.

To configure the Google Service Account, use one of the following environment variables as described in the object_store crate.

GOOGLE_SERVICE_ACCOUNT: location of service account file
GOOGLE_SERVICE_ACCOUNT_PATH: (alias) location of service account file
SERVICE_ACCOUNT: (alias) location of service account file
GOOGLE_SERVICE_ACCOUNT_KEY: JSON serialized service account key
GOOGLE_BUCKET: bucket name
GOOGLE_BUCKET_NAME: (alias) bucket name

Then use it in your code

use image_thumbs::GoogleCloudStorage;

#[tokio::main]
async fn main() {
    // Path to your thumbnail configuration yaml. You may specify the .yaml extension in the path, but you don't need to.
    let thumbs = image_thumbs::ImageThumbs::<GoogleCloudStorage>::new("examples/image_thumbs")
        .await
        .unwrap();
    thumbs
        .create_thumbs("penguin.jpg", "/thumbs", false)  // do not override existing images
        .await
        .unwrap();
    thumbs
        .create_thumbs("penguin.png", "/thumbs", true)  // do override existing images
        .await
        .unwrap();
}

For AWS S3 the following environment variables as described in the object_store crate:

AWS_BUCKET: required bucket name
AWS_ACCESS_KEY_ID: access_key_id
AWS_SECRET_ACCESS_KEY: secret_access_key
AWS_DEFAULT_REGION: region
AWS_ENDPOINT: endpoint
AWS_SESSION_TOKEN: token
AWS_ALLOW_HTTP: set to "true" to permit HTTP connections without TLS
AWS_REQUEST_PAYER: set to "true" to permit operations on requester-pays buckets.