Connection


Connection()

Parameters
  • base «Mongoose» a mongoose instance

Inherits:
  • «NodeJS EventEmitter http://nodejs.org/api/events.html#events_class_events_eventemitter»

Connection constructor

For practical reasons, a Connection equals a Db.


Connection.prototype.close()

Parameters
  • [force] «Boolean» optional

  • [callback] «Function» optional

Returns:
  • «Promise»

Closes the connection


Connection.prototype.collection()

Parameters
  • name «String» of the collection

  • [options] «Object» optional collection options

Returns:
  • «Collection» collection instance

Retrieves a collection, creating it if not cached.

Not typically needed by applications. Just talk to your collection through your model.


Connection.prototype.collections

Type:
  • «property»

A hash of the collections associated with this connection


Connection.prototype.config

Type:
  • «property»

A hash of the global options that are associated with this connection


Connection.prototype.createCollection()

Parameters
  • collection «string» The collection to create

  • [options] «Object» see MongoDB driver docs

  • [callback] «Function»
Returns:
  • «Promise»

Helper for createCollection(). Will explicitly create the given collection with specified options. Used to create capped collections and views from mongoose.

Options are passed down without modification to the MongoDB driver's createCollection() function


Connection.prototype.db

Type:
  • «property»

The mongodb.Db instance, set when the connection is opened


Connection.prototype.deleteModel()

Parameters
  • name «String|RegExp» if string, the name of the model to remove. If regexp, removes all models whose name matches the regexp.

Returns:
  • «Connection» this

Removes the model named name from this connection, if it exists. You can use this function to clean up any models you created in your tests to prevent OverwriteModelErrors.

Example:

conn.model('User', new Schema({ name: String }));
console.log(conn.model('User')); // Model object
conn.deleteModel('User');
console.log(conn.model('User')); // undefined

// Usually useful in a Mocha `afterEach()` hook
afterEach(function() {
  conn.deleteModel(/.+/); // Delete every model
});

Connection.prototype.dropCollection()

Parameters
  • collection «string» The collection to delete

  • [callback] «Function»
Returns:
  • «Promise»

Helper for dropCollection(). Will delete the given collection, including all documents and indexes.


Connection.prototype.dropDatabase()

Parameters
  • [callback] «Function»
Returns:
  • «Promise»

Helper for dropDatabase(). Deletes the given database, including all collections, documents, and indexes.

Example:

const conn = mongoose.createConnection('mongodb://localhost:27017/mydb');
// Deletes the entire 'mydb' database
await conn.dropDatabase();

Connection.prototype.get()

Parameters
  • key «String»

Gets the value of the option key. Equivalent to conn.options[key]

Example:

conn.get('test'); // returns the 'test' value

Connection.prototype.host

Type:
  • «property»

The host name portion of the URI. If multiple hosts, such as a replica set, this will contain the first host name in the URI

Example

mongoose.createConnection('mongodb://localhost:27017/mydb').host; // "localhost"

Connection.prototype.model()

Parameters
  • name «String|Function» the model name or class extending Model

  • [schema] «Schema» a schema. necessary when defining a model

  • [collection] «String» name of mongodb collection (optional) if not given it will be induced from model name

Returns:
  • «Model» The compiled model

Defines or retrieves a model.

var mongoose = require('mongoose');
var db = mongoose.createConnection(..);
db.model('Venue', new Schema(..));
var Ticket = db.model('Ticket', new Schema(..));
var Venue = db.model('Venue');

When no collection argument is passed, Mongoose produces a collection name by passing the model name to the utils.toCollectionName method. This method pluralizes the name. If you don't like this behavior, either pass a collection name or set your schemas collection name option.

Example:

var schema = new Schema({ name: String }, { collection: 'actor' });

// or

schema.set('collection', 'actor');

// or

var collectionName = 'actor'
var M = conn.model('Actor', schema, collectionName)

Connection.prototype.modelNames()

Returns:
  • «Array»

Returns an array of model names created on this connection.


Connection.prototype.name

Type:
  • «property»

The name of the database this connection points to.

Example

mongoose.createConnection('mongodb://localhost:27017/mydb').name; // "mydb"

Connection.prototype.openUri()

Parameters
  • uri «String» The URI to connect with.

  • [options] «Object» Passed on to http://mongodb.github.io/node-mongodb-native/2.2/api/MongoClient.html#connect

    • [options.bufferCommands=true] «Boolean» Mongoose specific option. Set to false to disable buffering on all models associated with this connection.

    • [options.dbName] «String» The name of the database we want to use. If not provided, use database name from connection string.

    • [options.user] «String» username for authentication, equivalent to options.auth.user. Maintained for backwards compatibility.

    • [options.pass] «String» password for authentication, equivalent to options.auth.password. Maintained for backwards compatibility.

    • [options.autoIndex=true] «Boolean» Mongoose-specific option. Set to false to disable automatic index creation for all models associated with this connection.

    • [options.useNewUrlParser=false] «Boolean» False by default. Set to true to opt in to the MongoDB driver's new URL parser logic.

    • [options.useUnifiedTopology=false] «Boolean» False by default. Set to true to opt in to the MongoDB driver's replica set and sharded cluster monitoring engine.

    • [options.useFindAndModify=true] «Boolean» True by default. Set to false to make findOneAndUpdate() and findOneAndRemove() use native findOneAndUpdate() rather than findAndModify().

    • [options.reconnectTries=30] «Number» If you're connected to a single server or mongos proxy (as opposed to a replica set), the MongoDB driver will try to reconnect every reconnectInterval milliseconds for reconnectTries times, and give up afterward. When the driver gives up, the mongoose connection emits a reconnectFailed event. This option does nothing for replica set connections.

    • [options.reconnectInterval=1000] «Number» See reconnectTries option above.

    • [options.poolSize=5] «Number» The maximum number of sockets the MongoDB driver will keep open for this connection. By default, poolSize is 5. Keep in mind that, as of MongoDB 3.4, MongoDB only allows one operation per socket at a time, so you may want to increase this if you find you have a few slow queries that are blocking faster queries from proceeding. See Slow Trains in MongoDB and Node.js.

    • [options.bufferMaxEntries] «Number» The MongoDB driver also has its own buffering mechanism that kicks in when the driver is disconnected. Set this option to 0 and set bufferCommands to false on your schemas if you want your database operations to fail immediately when the driver is not connected, as opposed to waiting for reconnection.

    • [options.connectTimeoutMS=30000] «Number» How long the MongoDB driver will wait before killing a socket due to inactivity during initial connection. Defaults to 30000. This option is passed transparently to Node.js' socket#setTimeout() function.

    • [options.socketTimeoutMS=30000] «Number» How long the MongoDB driver will wait before killing a socket due to inactivity after initial connection. A socket may be inactive because of either no activity or a long-running operation. This is set to 30000 by default, you should set this to 2-3x your longest running operation if you expect some of your database operations to run longer than 20 seconds. This option is passed to Node.js socket#setTimeout() function after the MongoDB driver successfully completes.

    • [options.family=0] «Number» Passed transparently to Node.js' dns.lookup() function. May be either 0,4, or6.4means use IPv4 only,6means use IPv6 only,0` means try both.

  • [callback] «Function»

Opens the connection with a URI using MongoClient.connect().


Connection.prototype.pass

Type:
  • «property»

The password specified in the URI

Example

mongoose.createConnection('mongodb://val:psw@localhost:27017/mydb').pass; // "psw"

Connection.prototype.plugin()

Parameters
  • fn «Function» plugin callback

  • [opts] «Object» optional options

Returns:
  • «Connection» this

Declares a plugin executed on all schemas you pass to conn.model()

Equivalent to calling .plugin(fn) on each schema you create.

Example:

const db = mongoose.createConnection('mongodb://localhost:27017/mydb');
db.plugin(() => console.log('Applied'));
db.plugins.length; // 1

db.model('Test', new Schema({})); // Prints "Applied"

Connection.prototype.plugins

Type:
  • «property»

The plugins that will be applied to all models created on this connection.

Example:

const db = mongoose.createConnection('mongodb://localhost:27017/mydb');
db.plugin(() => console.log('Applied'));
db.plugins.length; // 1

db.model('Test', new Schema({})); // Prints "Applied"

Connection.prototype.port

Type:
  • «property»

The port portion of the URI. If multiple hosts, such as a replica set, this will contain the port from the first host name in the URI.

Example

mongoose.createConnection('mongodb://localhost:27017/mydb').port; // 27017

Connection.prototype.readyState

Type:
  • «property»

Connection ready state

  • 0 = disconnected
  • 1 = connected
  • 2 = connecting
  • 3 = disconnecting

Each state change emits its associated event name.

Example

conn.on('connected', callback);
conn.on('disconnected', callback);

Connection.prototype.set()

Parameters
  • key «String»
  • val «Any»

Sets the value of the option key. Equivalent to conn.options[key] = val

Supported options include

Example:

conn.set('test', 'foo');
conn.get('test'); // 'foo'
conn.options.test; // 'foo'

Connection.prototype.startSession()

Parameters
  • [options] «Object» see the mongodb driver options

    • [options.causalConsistency=true] «Boolean» set to false to disable causal consistency

  • [callback] «Function»
Returns:
  • «Promise<ClientSession>» promise that resolves to a MongoDB driver ClientSession

Requires MongoDB >= 3.6.0. Starts a MongoDB session for benefits like causal consistency, retryable writes, and transactions.

Example:

const session = await conn.startSession();
let doc = await Person.findOne({ name: 'Ned Stark' }, null, { session });
await doc.remove();
// `doc` will always be null, even if reading from a replica set
// secondary. Without causal consistency, it is possible to
// get a doc back from the below query if the query reads from a
// secondary that is experiencing replication lag.
doc = await Person.findOne({ name: 'Ned Stark' }, null, { session, readPreference: 'secondary' });

Connection.prototype.useDb()

Parameters
  • name «String» The database name

  • [options] «Object»
    • [options.useCache=false] «Boolean» If true, cache results so calling useDb() multiple times with the same name only creates 1 connection object.

Returns:
  • «Connection» New Connection Object

Switches to a different database using the same connection pool.

Returns a new connection object, with the new db.


Connection.prototype.user

Type:
  • «property»

The username specified in the URI

Example

mongoose.createConnection('mongodb://val:psw@localhost:27017/mydb').user; // "val"