Storium

Storium is an abstraction layer that works on top of (and with) Knex.

I built this as a more intermediate level abstraction that extends the capabilities of Knex, groups some common functionality (stantization, validation, restrictions) for convenience, but stands back and doesn't try to dictate how your data structures should look or behave like a full ORM might do.

With this, you can think less about the low-level database/query problems, and more about your app-level storage problems (i.e., not how things are stored, but what gets stored and how should your app behave). You are in control of the how by defining your own query functions, validations, sanitizations, and schemas.

Install

npm install storium

Usage

Init

To initialze storium I like wrapping it in my own "adapter" module which helps act as a singleton reference from the rest of my application (I do the same with knex as well). Then I only need to worry about configuration and initialization in one central location that's predictable to reference.

See: https://knexjs.org/guide/#configuration-options

knex.js

const knex = require('knex')({
  client: 'pg',
  connection: {
    host : '127.0.0.1',
    port : 5432,
    user : 'your_database_user',
    password : 'your_database_password',
    database : 'myapp_test'
  }
})

module.exports = knex

All that's needed to configure storium is to pass your configured knex instance reference into it.

storium.js

const knex = require('./knex.js')
const storium = require('storium')(knex)

module.exports = storium

Store

With a configured instance of storium you can now use it to create new stores by providing its database table name, a schema, and any custom query functions you've created that you'd like to append to the store.

The basic way to create a new store is to use the storium.store() function like this:

example_store.js

const storium = require('./storium.js')

const example_schema = storium.schema({
  // ...see example schema below
})

const custom_func_1 = () => {}
const custom_func_2 = () => {}
const custom_func_3 = () => {}

const example_store = storium.store('examples', example_schema, {
  custom_func_1,
  custom_func_2,
  custom_func_3
})

module.exports = example_store

The signature for the store() function is as follows:

storium.store(table_name, schema_dfn, optional_custom_functions)

• table_name is the literal string name of the database table for this store
• schema_dfn is an object containing the schema definition (see below)
• optional_custom_functions is an object containing custom query functions

I'll explain custom query functions below, but out of the box, a store will have the following query functions:

• find()
• find_all()
• find_one()
• find_by_id()
• find_by_id_in()
• create()
• update()
• destroy()
• destroy_all()

...as well as other helper functions and properties:

• knex
• name
• schema
• selectables
• mutables
• sanitize()
• validate()
• mutable()
• prep()

Schema

A schema is a way to define what properties can be seen, what properties can be modified, custom transformations to "sanitize" input data, which properties are required, as well as various validations and types.

Each property in the schema must correspond exactly to the underlying database table columns being referenced when the store is initialized. Use square brackets if your table names cannot be defined as JS names (e.g., ['my-custom-column-name']).

const my_custom_validation = value => {
  return value === 'something custom'
}

const example_schema = storium.schema({
  id: Number,
  user_id: {
    type: Number,
    required: true
  },
  name: {
    type: String,
    mutable: true
  },
  url: {
    type: String,
    mutable: true,
    required: true,
    sanitize: value => String(value).trim(),
    validate: (value, test) => {
      test(value, 'not_empty', 'url must have a non-empty value')
      test(value, my_custom_validation, 'url must be a valid')
    }
  },
  is_admin: Boolean,
  created_at: Date,
  updated_at: Date
})

In this example, some properties are given a simple basic JS type. By default, a property will be treated as valid only if the input type matches the basic JS type defined in the schema.

More customizations can be made by assigning a custom object to a property schema, in which you can define various other settings such as custom sanitize() logic, custom validate() logic, if a property is "mutable" (that is, marking it as a field that a user can modify), a basic JS type, if the property is a required field, and whether it is selectable (e.g., perhaps on a user store you want to explicitly say that the password field should not be selectable as it is only used during authentication).

The test() function that is passed into the validate() function provides a basic way to validate a value. It is not a requirement, but provides some convenience. It's signature is test(value, validation, error) where value is the value being tested, validation can be either a function which returns true if the value is valid, or a string referencing one of the built-in validation methods ('is_url', 'is_email', 'is_numeric', or 'not_empty'). And finally error is either a string message to be thrown when not valid, or a function which will be called back when not valid and handled however you want to handle it.

Custom Queries

If the basic set of query functions is not sufficient, you can easily append additional custom query functions too. Each function takes the core storium properties listed above and should return a new function which takes your custom input.

const find_by_username_or_email = ({ knex, selectables, name }) => async ({ email, username }) => {
  return knex.first(selectables)
    .from(name)
    .where({ username: String(username) })
    .orWhere({ email: String(email) })
}

const find_by_user_id = ({ knex, selectables, name }) => async user_id => {
  return knex.select(selectables)
    .from(name)
    .where({ user_id })
}

const update_last_login = ({ knex, update }) => async id => {
  return update(id, {
    login_at: knex.fn.now()
  }, { force: true })
}

// Override the default `create()` function, but call default as result.
const transformed_create = ({ knex, selectables, name, create }) => async input => {
  // ...do something custom here (e.g., maybe transform the input or check some data first?)
  const transformed_input = my_transformer(input)

  // Pass intermediate result to default create() function (not necessary, but one use-case example):
  return create(transformed_input)
}

const example_store = storium.store('examples', example_schema, {
  find_by_username_or_email,
  find_by_user_id,
  update_last_login,
  create: transformed_create // overrides default create
})

Use

From elsewhere in your app, you can use your new store modules to interface with your database without being concerned about the details of how that works. Storium (and Knex) will have encapsulated all storage concerns providing a higher level interface for usage within your app.

Assuming some sort of ExpressJS app, a given resource's control functions might look something like this:

example_controller.js

const example_store = require('./example_store.js')

// POST /examples
const create_example = async (req, res, next) => {
  const example = await example_store.create(req.body)

  res.json({
    message: 'Example created',
    example
  })
}

// GET /examples
const get_all_examples = async (req, res, next) => {
  const examples = await example_store.find_all()

  res.json({
    message: 'Examples found',
    examples
  })
}

// GET /users/:user_id/examples
//
// This is an example of using a custom-defined query function (same kind of
// interface as defaults).
const get_user_examples = async (req, res, next) => {
  const user_id = Number(req.params.user_id)
  const examples = await example_store.find_by_user_id(user_id)

  res.json({
    message: 'User examples found',
    examples
  })
}

// GET /examples/:example_id
const get_example = async (req, res, next) => {
  const example_id = Number(req.params.example_id)
  const example = await example_store.find_by_id(example_id)

  res.json({
    message: 'Example found',
    example
  })
}

// PATCH /examples/:example_id
const modify_example = async (req, res, next) => {
  const example_id = Number(req.params.example_id)
  const example = await example_store.update(example_id, req.body)

  res.json({
    message: 'Example updated',
    example
  })
}

// DELETE /examples/:example_id
const remove_example = async (req, res, next) => {
  const example_id = Number(req.params.example_id)
  const num_removed = await example_store.destroy(example_id)

  res.json({
    message: 'Example updated',
    num_removed
  })
}

module.exports = {
  create_example,
  get_all_examples,
  get_example,
  modify_example,
  remove_example
}

License

MIT