Storable

Data store facilities

Import

_ <- fat.extra.Storable

file library, sdk library, enigma library, Error type, Text type, Void type and Method type are automatically imported with this import

Mixins

This library introduces two mixin types: Storable and EncryptedStorable

Storable

The Storable mixin provides methods for storing and retrieving objects in the filesystem using JSON serialization.

Prototype members

the load and save methods throw FileError on failure

load backfills declared type defaults for keys absent from the stored record (stored values take precedence), so that records survive data model evolution, e.g. fields added after the record was written

erase always targets self.id, ignoring any arguments

EncryptedStorable

Extends Storable with encryption capabilities for safer data storage. Requires an implementation of getEncryptionKey method.

Usage example

_ <- fat.extra.Storable

# Define a type that includes Storable (or EncryptedStorable)
User = (
  Storable  # Include the Storable mixin

  # EncryptedStorable                             # alternative implementation
  # getEncryptionKey = (): Text -> '3ncryp1ptM3'  # could get via KMS or config

  ## Argument slots
  name: Text
  email: Text

  # Setters return new immutable instance copy with updated field
  setName = (name: Text) -> self + User * { name }
  setEmail = (email: Text) -> self + User * { email }
)

# Create a new user instance
newUser = User('Jane Doe', 'jane.doe@example.com')

# Save the new user
newUser.save

# Update a user's information and save the changes
updatedUser = newUser
  .setName('Jane Smith')
  .setEmail('jane.smith@example.com')
updatedUser.save

# List all saved users
userIds = User.list

# Load a user from the filesystem
userId = userIds(0)  # ...or newUser.id
loadedUser = User.load(userId)

# Delete user's data from the filesystem
loadedUser.erase  # always targets the instance's own id

Storable in Web Build

When using fry built with Emscripten (for example, when using FatScript Playground), this prototype uses embedded commands $storableSet, $storableGet, $storableList, and $storableRemove, which are only defined in the web build. Therefore, instead of using the conventional file system for storage, there is special support for using the browser's localStorage object.

See also

• Extra package