Reference
Connecting to MongoDB

Connecting to MongoDB

The core connection class is MongoClient. The casbah MongoClient class simply wraps the MongoClient Java class and provides a couple of scala helpers as well.

MongoClient is available in the global imports class:

import com.mongodb.casbah.Imports._

Simple connections

Below are some example connecting to MongoDB with Casbah:

// Connect to default - localhost, 27017
val mongoClient =  MongoClient()

// connect to "mongodb01" host, default port
val mongoClient =  MongoClient("mongodb01")

// connect to "mongodb02" host, port 42017
val mongoClient =  MongoClient("mongodb02", 42017)

MongoDB URI

As an alternative to providing host and port information, the mongodb URI format defines connections between applications and MongoDB. In Casbah the com.mongodb.casbah.MongoClientURI class handles string URI’s:

val uri = MongoClientURI("mongodb://localhost:27017/")
val mongoClient =  MongoClient(uri)

Note

URI style strings supports all the various connection scenarios, such as connecting to replicasets or using authentication and as such its often considered easier to use.

The following examples show both the long hand way of connecting purely in code and the URI style.

Connecting to ReplicaSets / mongos

The java driver automatically determines if it is speaking to a replicaset or a mongos and acts accordingly.

List of ServerAddress instances

val rs1 = new ServerAddress("localhost", 27017)
val rs2 = new ServerAddress("localhost", 27018)
val rs3 = new ServerAddress("localhost", 27019)
val mongoClient = MongoClient(List(rs1, rs2, rs3))

Note

The ServerAddress class isn’t wrapped by casbah - so you have to call new eg: new ServerAddress().

URI style connections

val uri = MongoClientURI("mongodb://localhost:27017,localhost:27018,localhost:27019/")
val mongoClient = MongoClient(uri)

Authentication

MongoDB currently provides two different authentication mechanisms. Challenge response and GSSAPI authentication (available in the subscriber edition). A commandline example of using GSSAPI authentication can be found in the examples.

MongoDBCredentials

// Automatically detect SCRAM-SHA-1 or Challenge Response protocol
val server = new ServerAddress("localhost", 27017)
val credentials = MongoCredential.createCredential(userName, source, password)
val mongoClient = MongoClient(server, List(credentials))

// SCRAM-SHA-1
val server = new ServerAddress("localhost", 27017)
val credentials = MongoCredential.createScramSha1Credential(userName, source, password)
val mongoClient = MongoClient(server, List(credentials))

// Challenge Response
val server = new ServerAddress("localhost", 27017)
val credentials = MongoCredential.createMongoCRCredential(userName, database, password)
val mongoClient = MongoClient(server, List(credentials))

// X.509 Protocol
val server = new ServerAddress("localhost", 27017)
val credentials = MongoCredential.createMongoX509Credential(userName)
val mongoClient = MongoClient(server, List(credentials))

// SASL PLAIN
val server = new ServerAddress("localhost", 27017)
val credentials = MongoCredential.createPlainCredential(userName, source, password)
val mongoClient = MongoClient(server, List(credentials))

// GSSAPI
val server = new ServerAddress("localhost", 27017)
val credentials = MongoCredential.createGSSAPICredential(userName)
val mongoClient = MongoClient(server, List(credentials))

Note

GSSAPI requires the kerberos to be configured correctly in java. Either via flags when running scala:

-Djava.security.krb5.realm=EXAMPLE.COM
-Djava.security.krb5.kdc=kdc.example.com -Djavax.security.auth.useSubjectCredsOnly=false

or in scala:

System.setProperty("java.security.krb5.realm", "EXAMPLE.COM")
System.setProperty("java.security.krb5.kdc", "kdc.example.com")
System.setProperty("javax.security.auth.useSubjectCredsOnly", "false")

To change Service Name (SPN) with kerberos set the mechanism property on the credential eg:

val credential = MongoCredential.createGSSAPICredential(userName)
credential.withMechanismProperty(key, value)

URI style connections

// SCRAM-SHA-1
val uri = MongoClientURI("mongodb://username:pwd@localhost/?authMechanism=SCRAM-SHA-1")
val mongoClient =  MongoClient(uri)

// GSSAPI
val uri = MongoClientURI("mongodb://username%40domain@kdc.example.com/?authMechanism=MONGODB-GSSAPI")
val mongoClient =  MongoClient(uri)

SSL connections

By default ssl is off for mongodb, but you can configure mongodb to enable ssl. Subscribers to the enterprise edition of mongodb have ssl support baked in.

MongoClientOptions

val options = MongoClientOptions(socketFactory=SSLSocketFactory.getDefault())
val client = MongoClient(serverName, options)

URI style connections

val uri = MongoClientURI("mongodb://localhost:27017/?ssl=true")
val mongoClient = MongoClient(uri)

Note

Ensure your keystore is configured correctly to validate ssl certificates

Connection Options

There are extra configuration options for connections, which cover setting the default write concern and read preferences to configuring socket timeouts.

For the more connection options see the mongodb connection reference.

Databases and Collections

To query mongodb you need a collection to query against. Collecions are simple to get from a connection, first get the database the collection is in, then get the collection:

val mongoClient = MongoClient()
val db = mongoClient("databaseName")
val collection = db("collectionName")

On this page