rethinkdbdash

rethinkdbdash

An experimental (yet stable) Node.js driver for RethinkDB with promises and a connection pool.

Note: To use yield as shown in the examples, you have to start node unstable (>= 0.11) with the --harmony flag.

Quick start

---

• Example with promises but without generators:

var r = require('rethinkdbdash')();
r.table("foo").get("bar").run().then(function(result) {
    console.log(JSON.stringify(result, null, 2));
}).error(function(err) {
    console.log(err);
});

• Example with callback:

var r = require('rethinkdbdash')();
r.table("foo").get("bar").run(function(err, result) {
    if (err) {
        return console.log(err);
    }
    console.log(JSON.stringify(result, null, 2));
})

• Example wih koa:

var app = require('koa')();
var r = require('rethinkdbdash')();

app.use(function *(){
    var result = yield r.table("foo").get("bar").run();

    this.body = JSON.stringify(result);
});

app.listen(3000);

Note: You have to start node with the --harmony flag.

• Example with bluebird:

var Promise = require('bluebird');
var r = require('rethinkdbdash')();

var run = Promise.coroutine(function* () {
    var result

    try{
        result = yield r.table("foo").get("bar").run();
        console.log(JSON.stringify(result, null, 2));
    }
    catch(e) {
        console.log(e);
    }
})();

Note: You have to start node with the --harmony flag.

Install

---

npm install rethinkdbdash

The rethinkdbdash-unstable package is a relic from the past when the driver had a dependency on node-protobuf.

Documentation

---

While rethinkdbdash uses almost the same syntax as the official driver, there are still a few differences.

This section references all the differences. For all the other methods not mentionned here, please refer to the official driver's documentation.

The differences are:

Module name

Import rethinkdbdash:

var r = require('rethinkdbdash')(options);

options can be:

• {pool: false} -- if you do not want to use a connection pool.
• the options for the connection pool, which can be:

{
    min: <number>, // minimum number of connections in the pool, default 50
    max: <number>, // maximum number of connections in the pool, default 1000
    bufferSize: <number>, // minimum number of connections available in the pool, default 50
    timeoutError: <number>, // wait time before reconnecting in case of an error (in ms), default 1000
    timeoutGb: <number>, // how long the pool keep a connection that hasn't been used (in ms), default 60*60*1000
    maxExponent: <number>, // the maximum timeout before trying to reconnect is 2^maxExponent*timeoutError, default 6 (~60 seconds for the longest wait)
    silent: <boolean> // console.error errors (default false)
}

Promises

RethinkDB official driver support both syntaxes (promises and callback) since 1.13 (used to support only callback). Rethinkdbdash support both syntaxes (promises and callback) since 1.14 (used to support only promises).

Connection pool

Rethinkdbdash implements a connection pool and is created by default.

If you do not want to use a connection pool, iniitialize rethinkdbdash with {pool: false} like this:

var r = require('rethinkdbdash')({pool: false});

You can provide options for the connection pool with the following syntax:

var r = require('rethinkdbdash')({
    min: <number>, // minimum number of connections in the pool, default 50
    max: <number>, // maximum number of connections in the pool, default 1000
    bufferSize: <number>, // minimum number of connections available in the pool, default 50
    timeoutError: <number>, // wait time before reconnecting in case of an error (in ms), default 1000
    timeoutGb: <number>, // how long the pool keep a connection that hasn't been used (in ms), default 60*60*1000
    maxExponent: <number>, // the maximum timeout before trying to reconnect is 2^maxExponent*timeoutError, default 6 (~60 seconds for the longest wait)
    silent: <boolean> // console.error errors (default false)
});

try {
    var cursor = yield r.table("foo").run();
    var result = yield cursor.toArray(); // The connection used in the cursor will be released when all the data will be retrieved
}
catch(e) {
    console.log(e.message);
}

Get the number of connections

r.getPool().getLength();

Get the number of available connections

r.getPool().getAvailableLength();

Drain the pool

r.getPool().drain();

The pool can emits emits:

• draining: when drain is called
• queueing: when a query is added/removed from the queue (queries waiting for a connection), the size of the queue is provided
• size: when the number of connections changes, the number of connections is provided
• available-size: when the number of available connections changes, the number of available connections is provided

Note: If a query returns a cursor, the connection will not be released as long as the cursor hasn't fetched everything or has been closed.

Cursor

Rethinkdbdash automatically coerce cursor to arrays. If you need a raw cursor, you can call the run command with the option {cursor: true}.

var result = yield r.expr([1, 2, 3]).run()
console.log(JSON.stringify(result)) // print [1, 2, 3]

// Or with a cursor
var cursor = yield r.expr([1, 2, 3]).run({cursor: true})
var result = yield cursor.toArray();

console.log(JSON.stringify(result)) // print [1, 2, 3]

Errors

• Better backtraces

Long backtraces are split on multiple lines.
In case the driver cannot serialize the query, it provides a better location of the error.

• Arity errors

The server may return confusing error messages when the wrong number of arguments is provided (See issue 2463 to track progress). Rethinkdbdash tries to make up for it by catching errors before sending the query to the server if possible.

Miscellaneous

• Maximum nesting depth

The maximum nesting depth is your documents is by default 100 (instead of 20). You can also change this setting with:

r.setNestingLevel(<number>)

• Maximum array length

The maximum array length in your result is by default 100000. You can change this limit with the option arrayLimit in run, or set it per instance of r with:

r.setArrayLimit(<number>)

• Performance

The tree representation of the query is built step by step and stored which avoid recomputing it if the query is re-run.

The code was partially optimized for v8, and is written in pure JavaScript which avoids errors like issue #2839

• Connection

If you do not wish to use rethinkdbdash connection pool, you can implement yours. The connections created with rethinkdbdash emits a "release" event when they receive an error, an atom, or the end (or full) sequence.

A connection can also emit a "timeout" event if the underlying connection times out.

• undefined values in an object

Rethinkdbdash will ignore the keys/values where the value is undefined.

Run tests

---

Update test/config.js if your RethinkDB instance doesn't run on the default parameters.

Run

npm test

Tests are also being run on wercker:

• Builds: https://app.wercker.com/#applications/52dffe8ba4acb3ef16010ef8/tab
• Box:
  • Github: https://github.com/neumino/box-rethinkdbdash
  • Wercker builds: https://app.wercker.com/#applications/52dffc65a4acb3ef16010b60/tab