loopback-connector-mongodb

loopback-connector-mongodb

The official MongoDB connector for the LoopBack framework.

Please see the full documentation at loopback.io.

Installation

In your application root directory, enter this command to install the connector:

npm install loopback-connector-mongodb --save

This installs the module from npm and adds it as a dependency to the application's package.json file.

If you create a MongoDB data source using the data source generator as described below, you don't have to do this, since the generator will run npm install for you.

Creating a MongoDB data source

Use the Data source generator to add a MongoDB data source to your application.
The generator will prompt for the database server hostname, port, and other settings required to connect to a MongoDB database. It will also run the npm install command above for you.

The entry in the application's /server/datasources.json will look like this:

"mydb": {
  "host": "myserver",
  "port": 27017,
  "url":  "",
  "database": "test",
  "password": "mypassword",
  "name": "mydb",
  "user": "me",
  "connector": "mongodb"  
}

Edit datasources.json to add any other additional properties that you require.

Connection properties

Property	Type	Description
connector	String	Connector name, either “loopback-connector-mongodb” or “mongodb”.
database	String	Database name
host	String	Database host name
password	String	Password to connect to database
port	Number	Database TCP port
url	String	Connection URL of form mongodb://user:password@host/db. Overrides other connection settings (see below).
username	String	Username to connect to database

NOTE: In addition to these properties, you can use additional Single Server Connection parameters supported by node-mongodb-native.

Additional properties

• allowExtendedOperators: Set to true to enable using MongoDB operators such as $currentDate, $inc, $max, $min, $mul, $rename, $setOnInsert, $set, $unset, $addToSet, $pop, $pullAll, $pull, $pushAll, $push, and $bit. Default is false.
• enableGeoIndexing: Set to true to enable 2dsphere indexing for model properties of type GeoPoint. This allows for indexed near queries. Default is false.
• lazyConnect:
  • Default is false.
  • If set to true, the database instance will not be attached to the datasource and the connection is deferred.
  • It will try to establish the connection automatically once users hit the endpoint. If the mongodb server is offline, the app will start, however, the endpoints will not work.
• disableDefaultSort: Set to true to disable the default sorting behavior on id column, this will help performance using indexed columns available in mongodb.

Setting the url property in datasource.json

You can set the url property to a connection URL in datasources.json to override individual connection parameters such as host, user, and password.

Additionally, you can override the global url property in environment-specific data source configuration files, for example for production in datasources.production.json, and use the individual connection parameters host, user, password, and port. To do this, you must set url to false, null, or “” (empty string). If you set url to undefined or remove the url property altogether, the override will not work.

For example, for production, use datasources.production.json as follows (for example) to overide the url setting in `datasources.json:

"mydb": {
  "host": "myserver",
  "port": 27017,
  "url":  false,
  "database": "test",
  "password": "mypassword",
  "name": "mydb",
  "user": "me",
  "connector": "mongodb"  
}

For more information on setting data source configurations for different environments, see Environment-specific configuration.

Security Considerations

MongoDB Driver allows the $where operator to pass in JavaScript to execute on the Driver which can be used for NoSQL Injection. See MongoDB: Server-side JavaScript for more on this MongoDB feature.

To protect users against this potential vulnerability, LoopBack will automatically remove the $where and mapReduce operators from a query before it's passed to the MongoDB Driver. If you need to use these properties from within LoopBack programatically, you can disable the sanitization by passing in an options object with disableSanitization property set to true.

Example:

Post.find(
    {where: {$where: 'function() { /*JS function here*/}'}},
    {disableSanitization: true},
    (err, p) => {
        // code to handle results / error.
    }
);

Type mappings

See LoopBack types for details on LoopBack's data types.

LoopBack to MongoDB types

Type conversion is mainly handled by Mongodb. See 'node-mongodb-native' for details.

Customizing MongoDB configuration for tests/examples

By default, examples and tests from this module assume there is a MongoDB server instance running on localhost at port 27017.

To customize the settings, you can drop in a .loopbackrc file to the root directory of the project or the home folder.

Note: Tests and examples in this project configure the data source using the deprecated '.loopbackrc' file method, which is not suppored in general. For information on configuring the connector in a LoopBack application, please refer to loopback.io.

The .loopbackrc file is in JSON format, for example:

{
    "dev": {
        "mongodb": {
            "host": "127.0.0.1",
            "database": "test",
            "username": "youruser",
            "password": "yourpass",
            "port": 27017
        }
    },
    "test": {
        "mongodb": {
            "host": "127.0.0.1",
            "database": "test",
            "username": "youruser",
            "password": "yourpass",
            "port": 27017
        }
    }
}

Note: username/password is only required if the MongoDB server has authentication enabled.

Running tests

Own instance

If you have a local or remote MongoDB instance and would like to use that to run the test suite, use the following command:

• Linux

MONGODB_HOST=<HOST> MONGODB_PORT=<PORT> MONGODB_DATABASE=<DATABASE> CI=true npm test

• Windows

SET MONGODB_HOST=<HOST> SET MONGODB_PORT=<PORT> SET MONGODB_DATABASE=<DATABASE> SET CI=true npm test

Docker

If you do not have a local MongoDB instance, you can also run the test suite with very minimal requirements.

• Assuming you have Docker installed, run the following script which would spawn a MongoDB instance on your local:

source setup.sh <HOST> <PORT> <DATABASE>

where <HOST>, <PORT> and <DATABASE> are optional parameters. The default values are localhost, 27017 and testdb respectively.

• Run the test:

npm test

Leak detection

Tests run for 100 iterations by default, but can be increased by setting the env var ITERATIONS.

make leak-detection # run 100 iterations (default)

or

ITERATIONS=1000 make leak-detection # run 1000 iterations

Running benchmarks

Benchmarks must be run on a Unix-like operating system.

make benchmarks

The results will be output in ./benchmarks/results.md.

strictObjectIDCoercion flag

In version 1.17.0, the id of string type is being converted to ObjectID, when the string length is 12 or 24 and has the format of an ObjectID i.e /^[0-9a-fA-F]{24}$/. To avoid this issue, the strictObjectIDCoercion flag should be set to true in the model-definition file. It is also possible to enable this flag on a per method bases by passing it in as part of the options object.

model-definition.js

{
  "name": "myModelName",
  "base": "PersistedModel",
  "idInjection": false,
  "options": {
    "validateUpsert": true,
    "strictObjectIDCoercion": true
  },
...
}

boot-script.js

'use strict';
var util = require('util');

module.exports = function(app) {
  var db = app.dataSources.mongoDs;
  var myModelName = app.models.myModelName;

  db.automigrate(function(err) {
    if (err) throw err;
    console.log('Automigrate complete');

    myModelName.create([{
      id: '59460487e9532ae90c324b59',
      name: 'Bob',
    }, {
      id: '59460487e9532ae90c324b5a',
      name: 'Sam',
    }, {
      id: '420',
      name: 'Foo',
      age: 1,
    }, {
      id: '21',
      name: 'Bar',
    }], function(err, result) {
      if (err) throw err;
      console.log('\nCreated instances of myModelName: ' + util.inspect(result, 4));

      myModelName.find({where: {id: {inq: ['59460487e9532ae90c324b59',
        '59460487e9532ae90c324b5a']}}},
      function(err, result) {
        if (err) throw err;
        console.log('\nFound instance with inq: ' + util.inspect(result, 4));
      });
    });
  });
};

Per method basis

myModelName.find(
  {where: {id: {inq: ['59460487e9532ae90c324b59', '59460487e9532ae90c324b5a']}}},
  {strictObjectIDCoercion: true},
  function(err, result) {
    // ... 
  }
)

Release notes

• 1.1.7 - Do not return MongoDB-specific _id to client API, except if specifically specified in the model definition