shrine.cr

Shrine is a toolkit for file attachments in Crystal applications. Heavily inspired by Shrine for Ruby.

Documentation

https://jetrockets.github.io/shrine.cr

Installation

Add the dependency to your shard.yml:

dependencies:
  shrine:
    github: jetrockets/shrine.cr

Run shards install

Usage

require "shrine"

Shrine.cr is under heavy development!

First of all you should configure Shrine.

Shrine.configure do |config|
  config.storages["cache"] = Storage::FileSystem.new("uploads", prefix: "cache")
  config.storages["store"] = Storage::FileSystem.new("uploads")
end

Now you can use Shrine directly to upload your files.

Shrine.upload(file, "store")

Shrine.upload method supports additional argument just like Shrine.rb. For example we want our file to have a custom filename.

Shrine.upload(file, "store", metadata: { "filename" => "foo.bar" })

Custom uploaders

To implement custom uploader class just inherit it from Shrine. You can override Shrine methods to implement custom logic. Here is an example how to create a custom file location.

class FileImport::AssetUploader < Shrine
  def generate_location(io : IO | UploadedFile, metadata, context, **options)
    name = super(io, metadata, **options)

    File.join("imports", context[:model].id.to_s, name)
  end
end

FileImport::AssetUploader.upload(file, "store", context: { model: YOUR_ORM_MODEL } })

S3 storage

Creating a Client

client = Awscr::S3::Client.new("region", "key", "secret")

For S3 compatible services, like DigitalOcean Spaces or Minio, you'll need to set a custom endpoint:

client = Awscr::S3::Client.new("nyc3", "key", "secret", endpoint: "https://nyc3.digitaloceanspaces.com")

Create a S3 storage

The storage is initialized by providing your bucket and client:

storage = Shrine::Storage::S3.new(bucket: "bucket_name", client: client, prefix: "prefix")

Sometimes you'll want to add additional upload options to all S3 uploads. You can do that by passing the :upload_options option:

storage = Shrine::Storage::S3.new(bucket: "bucket_name", client: client, upload_options: { "x-amz-acl"=> "public-read" })

You can tell S3 storage to make uploads public:

storage = Shrine::Storage::S3.new(bucket: "bucket_name", client: client, public: true)

ORM usage example

Currently ORM adapters are not implmented.

Lucky (Avram)

🎬 Watch the LuckyCast showing how to use Shrine for user profile images

Granite

class FileImport < Granite::Base
  connection pg
  table file_imports

  column id : Int64, primary: true
  column asset_data : Shrine::UploadedFile, converter: Granite::Converters::Json(Shrine::UploadedFile, JSON::Any)

  after_save do
    if @asset_changed && @asset_data
      @asset_data = FileImport::AssetUploader.store(@asset_data.not_nil!, move: true, context: { model: self })
      @asset_changed = false

      save!
    end
  end

  def asset=(upload : Amber::Router::File)
    @asset_data = FileImport::AssetUploader.cache(upload.file, metadata: { filename: upload.filename })
    @asset_changed = true
  end
end

Jennifer

class FileImport < Jennifer::Model::Base
  @asset_changed : Bool | Nil

  with_timestamps

  mapping(
    id: Primary32,
    asset_data: JSON::Any?,
    created_at: Time?,
    updated_at: Time?
  )

  after_save :move_to_store

  def asset=(upload : Amber::Router::File)
    self.asset_data = JSON.parse(FileImport::AssetUploader.cache(upload.file, metadata: { filename: upload.filename }).to_json)
    asset_changed! if asset_data
  end

  def asset
    Shrine::UploadedFile.from_json(asset_data.not_nil!.to_json) if asset_data
  end

  def asset_changed?
    @asset_changed || false
  end

  private def asset_changed!
    @asset_changed = true
  end

  private def move_to_store
    if asset_changed?
      self.asset_data = JSON.parse(FileImport::AssetUploader.store(asset.not_nil!, move: true, context: { model: self }).to_json)
      @asset_changed = false
      save!
    end
  end
end

Plugins

Shrine.cr has a plugins interface similar to Shrine.rb. You can extend functionality of uploaders inherited from Shrine and also extend UploadedFile class.

Determine MIME Type

The DetermineMimeType plugin is used to get mime type of uploaded file in several ways.


require "shrine/plugins/determine_mime_type"

class Uploader < Shrine
  load_plugin(
    Shrine::Plugins::DetermineMimeType,
    analyzer: Shrine::Plugins::DetermineMimeType::Tools::File
  )

  finalize_plugins!
end

Analyzers

The following analyzers are accepted:

| Name | Description | | --- | --- | | File| (Default). Uses the file utility to determine the MIME type from file contents. It is installed by default on most operating systems. | | Mime | Uses the MIME.from_filename method to determine the MIME type from file.| | ContentType | Retrieves the value of the #content_type attribute of the IO object. Note that this value normally comes from the "Content-Type" request header, so it's not guaranteed to hold the actual MIME type of the file. |

Add Metadata

The AddMetadata plugin provides a convenient method for extracting and adding custom metadata values.

require "base64"
require "shrine/plugins/add_metadata"

class Uploader < Shrine
  load_plugin(Shrine::Plugins::AddMetadata)

  add_metadata :signature, -> {
    Base64.encode(io.gets_to_end)
  }

  finalize_plugins!
end

The above will add "signature" to the metadata hash.

image.metadata["signature"]

Multiple values

You can also extract multiple metadata values at once.

class Uploader < Shrine
  load_plugin(Shrine::Plugins::AddMetadata)

  add_metadata :multiple_values, -> {
    text = io.gets_to_end

    Shrine::UploadedFile::MetadataType{
      "custom_1" => text,
      "custom_2" => text * 2
    }
  }

  finalize_plugins!
end

image.metadata["custom_1"]
image.metadata["custom_2"]

Store Dimensions

The StoreDimensions plugin extracts dimensions of uploaded images and stores them into the metadata. Additional dependency https://github.com/jetrockets/fastimage.cr needed for this plugin.


require "fastimage"
require "shrine/plugins/store_dimensions"

class Uploader < Shrine
  load_plugin(Shrine::Plugins::StoreDimensions,
    analyzer: Shrine::Plugins::StoreDimensions::Tools::FastImage)

  finalize_plugins!
end

image.metadata["width"]
image.metadata["height"]