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.
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.
npm install rethinkdbdash
The rethinkdbdash-unstable
package is a relic from the past when the driver had a dependency on node-protobuf
.
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:
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
}
Rethinkdbdash uses promises and not callback. RethinkDB >= 1.13 handles both syntaxes.
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)
})
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
});
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.
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]
- 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.
- 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.
- 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
.
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: