sqlite3-helper

sqlite3-helper

A promise based wrapper library for the work with sqlite3. It's intended for simple server-apps for nodejs and offer some new functions and a migration-system.

How to install

Like always

npm i sqlite3-helper

How to use

In every file you want access to a sqlite3 database simply require the library and use it right away in any async-function (or as a promise).

anyServerFile.js

const DB = require('sqlite3-helper');

(async () => {
  let row = await DB().queryFirstRow('SELECT * FROM users WHERE id=?', userId);
  console.log(row.firstName, row.lastName, row.email);
})()

To setup your database, create a sql-file named 001-init.sql in a migrations-directory in the root-directory of your program.

~/migrations/001-init.sql

-- Up
CREATE TABLE `users` (
  id INTEGER PRIMARY KEY, 
  firstName TEXT NOT NULL, 
  lastName TEXT NOT NULL, 
  email TEXT NOT NULL
);

-- Down
DROP TABLE IF EXISTS `users`;

And that's it!

Node version < 10

If you work with a node version < 10 (having no support for async function * async generator functions) use sqlite3-helper/no-generators instead:

const DB = require('sqlite3-helper/no-generators');

// ...

One global instance

A normal, simple application is mostly working with only one database. To make the class managment more easy, this library does the access-control for you - mainly as a singleton. (But you can create a new instance to access other databases.)

The database loads lazy. Only when it's used for the first time, the database is read from the file, the migration is started and the journal-mode WAL is set. The default directory of the database is './data/sqlite3.db'.

If you want to change the default-values, you can do this by calling the library once in the beginning of your server-code and thus setting it up:

index.js

const DB = require('sqlite3-helper');

// The first call creates the global instance with your settings
DB({
  path: './data/sqlite3.db', // this is the default
  memory: false, // create a db only in memory
  readonly: false, // read only
  fileMustExist: false, // throw error if database not exists
  WAL: true, // automatically enable 'PRAGMA journal_mode = WAL'
  migrate: {  // disable completely by setting `migrate: false`
    force: false, // set to 'last' to automatically reapply the last migration-file
    table: 'migration', // name of the database table that is used to keep track
    migrationsPath: './migrations' // path of the migration-files
  }
})

After that you can use the library without parameter:

anotherAPIFile.js

const DB = require('sqlite3-helper');

// a second call directly returns the global instance
(async ()=>{
  let row = await DB().queryFirstRow('SELECT * FROM users WHERE id=?', userId);
  console.log(row.firstName, row.lastName, row.email);
})()

New Functions

This class implements shorthand methods for sqlite3.

(async ()=>{
  // shorthand for db.prepare('SELECT * FROM users').all(); 
  let allUsers = await DB().query('SELECT * FROM users');
  // result: [{id: 1, firstName: 'a', lastName: 'b', email: '[e-mail]'},{},...]
  // result for no result: []

  // shorthand for db.prepare('SELECT * FROM users WHERE id=?').get(userId); 
  let row = await DB().queryFirstRow('SELECT * FROM users WHERE id=?', userId);
  // result: {id: 1, firstName: 'a', lastName: 'b', email: '[e-mail]'}
  // result for no result: undefined

  // shorthand for db.prepare('SELECT * FROM users WHERE id=?').get(999) || {}; 
  let {id, firstname} = await DB().queryFirstRowObject('SELECT * FROM users WHERE id=?', userId);
  // result: id = 1; firstName = 'a'
  // result for no result: id = undefined; firstName = undefined

  // shorthand for db.prepare('SELECT * FROM users WHERE id=?').pluck(true).get(userId); 
  let email = await DB().queryFirstCell('SELECT email FROM users WHERE id=?', userId);
  // result: '[e-mail]'
  // result for no result: undefined

  // shorthand for db.prepare('SELECT * FROM users').all().map(e => e.email); 
  let emails = await DB().queryColumn('email', 'SELECT email FROM users');
  // result: ['[e-mail]', '[e-mail]', ...]
  // result for no result: []

  // shorthand for db.prepare('SELECT * FROM users').all().reduce((o, e) => {o[e.lastName] = e.email; return o;}, {});
  let emailsByLastName = await DB().queryKeyAndColumn('lastName', 'email', 'SELECT lastName, name FROM users');
  // result: {b: '[e-mail]', c: '[e-mail]', ...}
  // result for no result: {}
})()

Insert, Update and Replace

There are shorthands for update, insert and replace. They are intended to make programming of CRUD-Rest-API-functions easier. With a blacklist or a whitelist it's even possible to send a request's query (or body) directly into the database.

Update

// const numberOfChangedRows = DB().update(table, data, where, whitelist = undefined)

// simple use with a object as where and no whitelist
await DB().update('users', {
  lastName: 'Mustermann',
  firstName: 'Max'
}, {
  email: '[e-mail]'
})

// data from a request and a array as a where and only editing of lastName and firstName is allowed
await DB().update('users', req.body, ['email = ?', req.body.email], ['lastName', 'firstName'])


// update with blacklist (id and email is not allowed; only valid columns of the table are allowed) and where is a shorthand for ['id = ?', req.body.id]
await DB().updateWithBlackList('users', req.body, req.body.id, ['id', 'email'])

Insert and replace

// const lastInsertID = DB().insert(table, datas, whitelist = undefined)
// const lastInsertID = DB().replace(table, datas, whitelist = undefined)

// simple use with an object and no whitelist
await DB().insert('users', {
  lastName: 'Mustermann',
  firstName: 'Max',
  email: '[e-mail]'
})

// inserting two users
await DB().insert('users', [{
  lastName: 'Mustermann',
  firstName: 'Max',
  email: '[e-mail]'
}, {
  lastName: 'Mustermann2',
  firstName: 'Max2',
  email: '[e-mail]'
}])

// data from a request and only lastName and firstName are set
await DB().replace('users', req.body, ['lastName', 'firstName'])


// replace with blacklist (id and email is not allowed; only valid columns of the table are allowed)
await DB().replaceWithBlackList('users', req.body, ['id', 'email']) // or insertWithBlackList

Try and catch

If you want to put invalid values into the database, the functions will throw an error. So don't forget to surround the functions with a try-catch. Here is an example for an express-server:

const { Router } = require('express')
const bodyParser = require('body-parser')
const DB = require('sqlite3-helper')

router.patch('/user/:id', bodyParser.json(), async function (req, res, next) {
  try {
    if (!req.params.id) {
      res.status(400).json({error: 'missing id'})
      return
    }
    await DB().updateWithBlackList(
      'users',
      req.body,
      req.params.id,
      ['id']
    )

    res.statusCode(200)
  } catch (e) {
    console.error(e)
    res.status(503).json({error: e.message})
  }
})

Migrations

The migration in this library mimics the migration system of the excellent sqlite by Kriasoft.

To use this feature you have to create a migrations-directory in your root. Inside you create sql-files that are seperated in a up- and a down-part:

migrations/001-initial-schema.sql

-- Up
CREATE TABLE Category (id INTEGER PRIMARY KEY, name TEXT);
CREATE TABLE Post (id INTEGER PRIMARY KEY, categoryId INTEGER, title TEXT,
  CONSTRAINT Post_fk_categoryId FOREIGN KEY (categoryId)
    REFERENCES Category (id) ON UPDATE CASCADE ON DELETE CASCADE);
INSERT INTO Category (id, name) VALUES (1, 'Business');
INSERT INTO Category (id, name) VALUES (2, 'Technology');

-- Down
DROP TABLE Category
DROP TABLE Post;

migrations/002-missing-index.sql

-- Up
CREATE INDEX Post_ix_categoryId ON Post (categoryId);

-- Down
DROP INDEX Post_ix_categoryId;

The files need to be numbered. They are automatically executed before the first use of the database.

NOTE: For the development environment, while working on the database schema, you may want to set force: 'last' (default false) that will force the migration API to rollback and re-apply the latest migration over again each time when Node.js app launches. See "Global Instance".

License

MIT