websql

node-websql

The WebSQL Database API, implemented for Node using sqlite3.

Install

npm install websql

Usage

var openDatabase = require('websql');

Create a SQLite3 database called mydb.db:

var db = openDatabase('mydb.db', '1.0', 'description', 1);

Create an in-memory database:

var db = openDatabase(':memory:', '1.0', 'description', 1);

API

openDatabase(name, version, description, size [, callback])

The name is the name of the database. It's passed verbatim to sqlite3.

The version is the database version (currently ignored - see below).

The description and size attributes are ignored, but they are required for compatibility with the WebSQL API.

The callback just returns the same database object returned synchronously (migrations currently aren't supported - see below).

For more information how to use the WebSQL API, see the spec or various tutorials.

For more information on sqlite3, see the SQLite3 readme.

In the browser

You can also use this module in the browser (via Browserify/Webpack/etc.), in which case it will just use window.openDatabase, meaning you are subject to browser WebSQL support.

Goals

The WebSQL Database API is a deprecated standard, but in many cases it's useful to reuse legacy code designed for browsers that support WebSQL. Also, it allows you to quickly test WebSQL-based code in Node, which can be convenient.

The goal of this API is to exactly match the existing WebSQL API, as implemented in browsers. If there's any difference between browsers (e.g. rows[0] is supported in Chrome, whereas only rows.item(0) is supported in Safari), then the lowest-common denominator version is exported by this library.

This library has a robust test suite, and has been known to pass the PouchDB test suite as well.

Non-Goals

This library is not designed to:

• Invent new APIs, e.g. deleting databases, supporting BLOBs, encryption, etc.
• Support WebSQL in Firefox, IE, or other non-WebSQL browsers

In other words, the goal is not to carry the torch of WebSQL, but rather to bridge the gap from existing WebSQL-based code to Node.js.

Custom SQLite3 bindings

This library is designed to allow swappable SQLite3 implementations, beyond just node-sqlite3. To use a custom implementation, use this API:

var customOpenDatabase = require('websql/custom');
var openDatabase = customOpenDatabase(SQLiteDatabase);

This SQLiteDatabase implementation needs to be a constructor-style function with a constructor signature like so:

// takes a single argument: the database name
var db = new SQLiteDatabase('dbname');

Then it implements a single function, exec(), like so:

function exec(queries, readOnly, callback) {
  // queries: an array of SQL statements and queries, with a key "sql" and "args"
  // readOnly: whether or not these queries are in "read only" mode
  // callback: callback to be called with results (first arg is error, second arg is results)
}

Here is the full specification:

SQLiteDatabase(name (String))

Construct a new SQLiteDatbase object, with the given string name.

exec(queries (Array), readOnly (boolean), callback (function))

Execute the list of SQLQuerys. If we are in readOnly mode, then any non-SELECT queries need to throw an error without executing. This function calls the Node-style callback with an error as the first argument or the Array<SQLResult> as the second argument.

SQLQuery

A SQL query and bindings to execute. This can be a plain JavaScript object or a custom class, as long as it has the following members:

sql (String)

The SQL query to execute.

args (Array)

The arguments to bind the query.

E.g.:

{
  sql: 'INSERT INTO foo values (?, ?)',
  args: ['bar', 'baz']
}

SQLResult

A result returned by a SQL query. This can be a plain JavaScript object or a custom class, as long as it has the following members:

error

A JavaScript Error object, or undefined if the SQLQuery did not throw an error. If error is truthy, then it's assumed insertId, rowsAffected, and rows are falsy (they will be ignored anyway).

insertId (number)

An insertion ID representing the new row number, or undefined if nothing was inserted.

rowsAffected (number)

The number of rows affected by the query, or 0 if none.

rows (Array)

The rows returned by a SELECT query, or empty if none.

Each object is a mapping of keys (columns) to values (value fetched).

E.g.:

{
  insertId: undefined,
  rowsAffected: 0,
  rows: [
    {'foo': 'bar'},
    {'foo': 'baz'},
  ]
}

Or:

{
  error: new Error('whoopsie')
}

For an example implementation (and the one used by this module) see lib/sqlite/SQLiteDatabase.js.

TODOs

The versioning and migration APIs (i.e. changeVersion()) are not supported. Pull requests welcome!

Testing

First:

npm install

Main test suite:

npm test

Linter:

npm run lint

Test in debug mode (e.g. with the node-inspector):

npm run test-debug

Run the test suite against actual WebSQL in a browser:

npm run test-local

Run the actual-WebSQL test against PhantomJS:

npm run test-phantom