rethinkdbdash
A Node.js driver for RethinkDB with promises and a connection pool.
This is the branch for Node 0.11.10
and 0.11.9
that provides the package rethinkdbdash-unstable
.
If you use a stable version of Node, please install rethinkdbdash
.
rethinkdbdash-unstable
depends on node-protobuf
which is written in C++ and use V8's API.
Lower or higher version of Node won't work.
Note: To use yield
as shown in the examples, you have to start node
with
the --harmony
flag.
Quick start
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);
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
- Build node 0.11.10 (checkout
v0.11.10-release
) from source.
Binaries won't work withnode-protobuf
-- some libraries are not properly linked. - Install the
libprotobuf
binary and development files (required to buildnode-protobuf
in the next step). - Install
rethinkdbdash-unstable
withnpm
.
npm install rethinkdbdash-unstable
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
}
Promises
Rethinkdbdash returns a bluebird promise when a method in the official driver takes a callback.
Example 1 with yield
:
try{
var cursor = yield r.table("foo").run();
var result = yield cursor.toArray();
//process(result);
}
else {
console.log(e.message);
}
Example 2 with yield
:
try{
var cursor = yield r.table("foo").run();
var row;
while(cursor.hasNext()) {
row = yield cursor.next();
//process(row);
}
}
else {
console.log(e.message);
}
Example with then
and error
:
r.table("foo").run().then(function(connection) {
//...
}).error(function(e) {
console.log(e.mssage)
})
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 that:
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
});
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();
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 does not extend Array
with methods and returns a cursor as long as your
result is a sequence.
var cursor = yield r.expr([1, 2, 3]).run()
console.log(JSON.stringify(cursor)) // does *not* print [1, 2, 3]
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 parse the query, it provides a better location of the error.
- Different handling for queries that cannot be parsed on the server.
In case an error occured because the server cannot parse the protobuf message, the
official driver emits an error
on the connection.
Rethinkdbdash emits an error and rejects all queries running on this connection and
close the connection. This is the only way now to avoid having some part of your
program hang forever.
Miscellaneous
- Maximum nesting depth
The maximum nesting depth is your documents is by default 100 (instead of 20). You can change this setting with
r.setNestingLevel(<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.
exprJSON
, internal method used by insert
, is more efficient in the worst case.
- 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.
Run tests
Update test/config.js
if your RethinkDB instance doesn't run on the default parameters.
Run
mocha --harmony-generators
Tests are also being run on wercker:
Roadmap
============
- Pre-serialize a query (not sure if possible though)