moleculer-db

Moleculer service to store entities in database.

Features

• default CRUD actions
• cached actions
• pagination support
• pluggable adapter (NeDB is the default memory adapter for testing & prototyping)
• official adapters for MongoDB, PostgreSQL, SQLite, MySQL, MSSQL.
• fields filtering
• populating
• encode/decode IDs
• entity lifecycle events for notifications

Install

$ npm install moleculer-db --save

Usage

"use strict";

const { ServiceBroker } = require("moleculer");
const DbService = require("moleculer-db");

const broker = new ServiceBroker();

// Create a DB service for `user` entities
broker.createService({
    name: "users",
    mixins: [DbService],

    settings: {
        fields: ["_id", "username", "name"]
    },

    afterConnected() {
        // Seed the DB with ˙this.create`
    }
});

broker.start()

// Create a new user
.then(() => broker.call("users.create", {
    username: "john",
    name: "John Doe",
    status: 1
}))

// Get all users
.then(() => broker.call("users.find").then(console.log));

// List users with pagination
.then(() => broker.call("users.list", { page: 2, pageSize: 10 }).then(console.log));

// Get a user
.then(() => broker.call("users.get", { id: 2 }).then(console.log));

// Update a user
.then(() => broker.call("users.update", { id: 2, name: "Jane Doe" }).then(console.log));

// Delete a user
.then(() => broker.call("users.remove", { id: 2 }).then(console.log));

Settings

Property	Type	Default	Description
idField	String	required	Name of ID field.
fields	Array.<String>	null	Field filtering list. It must be an Array. If the value is null or undefined doesn't filter the fields of entities.
excludeFields	Array.<String>	null	Exclude fields from list. It must be an Array.
populates	Array	null	Schema for population. Read more.
pageSize	Number	required	Default page size in list action.
maxPageSize	Number	required	Maximum page size in list action.
maxLimit	Number	required	Maximum value of limit in find action. Default: -1 (no limit)
entityValidator	Object, function	null	Validator schema or a function to validate the incoming entity in create & 'insert' actions.

Note: idField does not work with Sequelize adapter as you can freely set your own ID while creating the model.

Actions

find

Find entities by query.

Parameters

Property	Type	Default	Description
populate	String, Array.<String>	required	Populated fields.
fields	String, Array.<String>	required	Fields filter.
limit	Number	-	Max count of rows.
offset	Number	-	Count of skipped rows.
sort	String	-	Sorted fields.
search	String	-	Search text.
searchFields	String, Array.<String>	required	Fields for searching.
query	Object	-	Query object. Passes to adapter.

Results

Type: Array.<Object>

List of found entities.

count

Get count of entities by query.

Parameters

Property	Type	Default	Description
search	String	-	Search text.
searchFields	String, Array.<String>	required	Fields list for searching.
query	Object	-	Query object. Passes to adapter.

Results

Type: Number

Count of found entities.

list

List entities by filters and pagination results.

Parameters

Property	Type	Default	Description
populate	String, Array.<String>	required	Populated fields.
fields	String, Array.<String>	required	Fields filter.
page	Number	-	Page number.
pageSize	Number	-	Size of a page.
sort	String	-	Sorted fields.
search	String	-	Search text.
searchFields	String, Array.<String>	required	Fields for searching.
query	Object	-	Query object. Passes to adapter.

Results

Type: Object

List of found entities and count with pagination info.

create

Create a new entity.

Parameters

Property	Type	Default	Description
params	Object	required	Entity to save.

Results

Type: Object

Saved entity.

insert

Create many new entities.

Parameters

Property	Type	Default	Description
entity	Object	-	Entity to save.
entities	Array.<Object>	-	Entities to save.

Results

Type: Object, Array.<Object>

Saved entity(ies).

get

Get entity by ID.

Parameters

Property	Type	Default	Description
id	any, Array.<any>	required	ID(s) of entity.
populate	String, Array.<String>	required	Field list for populate.
fields	String, Array.<String>	required	Fields filter.
mapping	Boolean	-	Convert the returned Array to Object where the key is the value of id.

Results

Type: Object, Array.<Object>

Found entity(ies).

update

Update an entity by ID.

After update, clear the cache & call lifecycle events.

Parameters

Property	Type	Default	Description
id	any	required	ID of entity.

Results

Type: Object

Updated entity.

remove

Remove an entity by ID.

Parameters

Property	Type	Default	Description
id	any	required	ID of entity.

Results

Type: Number

Count of removed entities.

Methods

sanitizeParams

Sanitize context parameters at find action.

Parameters

Property	Type	Default	Description
ctx	Context	required
params	Object	required

Results

Type: Object

getById

Get entity(ies) by ID(s).

Parameters

Property	Type	Default	Description
id	any, Array.<any>	required	ID or IDs.
decoding	Boolean	-	Need to decode IDs.

Results

Type: Object, Array.<Object>

Found entity(ies).

entityChanged

Clear the cache & call entity lifecycle events

Parameters

Property	Type	Default	Description
type	String	required
json	Object, Array.<Object>, Number	required
ctx	Context	required

Results

Type: Promise

clearCache

Clear cached entities

Parameters

Property	Type	Default	Description
No input parameters.

Results

Type: Promise

transformDocuments

Transform the fetched documents

Parameters

Property	Type	Default	Description
ctx	Context	required
params	Object	required
docs	Array, Object	required

Results

Type: Array, Object

validateEntity

Validate an entity by validator.

Parameters

Property	Type	Default	Description
entity	Object	required

Results

Type: Promise

encodeID

Encode ID of entity.

Parameters

Property	Type	Default	Description
id	any	required

Results

Type: any

decodeID

Decode ID of entity.

Parameters

Property	Type	Default	Description
id	any	required

Results

Type: any

_find

Find entities by query.

Parameters

Property	Type	Default	Description
ctx	Context	required	Context instance.
params	Object	-	Parameters.

Results

Type: Array.<Object>

List of found entities.

_count

Get count of entities by query.

Parameters

Property	Type	Default	Description
ctx	Context	required	Context instance.
params	Object	-	Parameters.

Results

Type: Number

Count of found entities.

_list

List entities by filters and pagination results.

Parameters

Property	Type	Default	Description
ctx	Context	required	Context instance.
params	Object	-	Parameters.

Results

Type: Object

List of found entities and count.

_create

Create a new entity.

Parameters

Property	Type	Default	Description
ctx	Context	required	Context instance.
params	Object	-	Parameters.

Results

Type: Object

Saved entity.

_insert

Create many new entities.

Parameters

Property	Type	Default	Description
ctx	Context	required	Context instance.
params	Object	-	Parameters.

Results

Type: Object, Array.<Object>

Saved entity(ies).

_get

Get entity by ID.

Parameters

Property	Type	Default	Description
ctx	Context	required	Context instance.
params	Object	-	Parameters.

Results

Type: Object, Array.<Object>

Found entity(ies).

_update

Update an entity by ID.

After update, clear the cache & call lifecycle events.

Parameters

Property	Type	Default	Description
ctx	Context	required	Context instance.
params	Object	-	Parameters.

Results

Type: Object

Updated entity.

_remove

Remove an entity by ID.

Parameters

Property	Type	Default	Description
ctx	Context	required	Context instance.
params	Object	-	Parameters.

Populating

The service supports to populate fields from other services. E.g.: if you have an author field in post entity, you can populate it with users service by ID of author. If the field is an Array of IDs, it will populate all entities via only one request.

Example of populate schema

broker.createService({
    name: "posts",
    mixins: [DbService],
    settings: {
        populates: {
            // Shorthand populate rule. Resolve the `voters` values with `users.get` action.
            "voters": "users.get",

            // Define the params of action call. It will receive only with username & full name of author.
            "author": {
                action: "users.get",
                params: {
                    fields: "username fullName"
                }
            },

            // Custom populator handler function
            "rate"(ids, docs, rule, ctx) {
                return Promise.resolve(...);
            }
        }
    }
});

// List posts with populated authors
broker.call("posts.find", { populate: ["author"]}).then(console.log);

The populate parameter is available in find, list and get actions.

Lifecycle entity events

There are 3 lifecycle entity events which are called when entities are manipulated.

broker.createService({
    name: "posts",
    mixins: [DbService],
    settings: {},

    afterConnected() {
        this.logger.info("Connected successfully");
    },

    entityCreated(json, ctx) {
        this.logger.info("New entity created!");
    },

    entityUpdated(json, ctx) {
        // You can also access to Context
        this.logger.info(`Entity updated by '${ctx.meta.user.name}' user!`);
    },

    entityRemoved(json, ctx) {
        this.logger.info("Entity removed", json);
    },    
});

Please note! If you manipulate multiple entities (updateMany, removeMany), the json parameter will be a Number instead of entities!

Extend with custom actions

Naturally you can extend this service with your custom actions.

const DbService = require("moleculer-db");

module.exports = {
    name: "posts",
    mixins: [DbService],

    settings: {
        fields: ["_id", "title", "content", "votes"]
    },

    actions: {
        // Increment `votes` field by post ID
        vote(ctx) {
            return this.adapter.updateById(ctx.params.id, { $inc: { votes: 1 } });
        },

        // List posts of an author
        byAuthors(ctx) {
            return this.find({
                query: {
                    author: ctx.params.authorID
                },
                limit: ctx.params.limit || 10,
                sort: "-createdAt"
            });
        }
    }
}

Remove default actions

According to moleculer documentation you can disable an action when override it with false

const DbService = require("moleculer-db");

module.exports = {
    name: "posts",
    mixins: [DbService],

    actions: {
        // Disable find default action
        find: false
    }
}

Test

$ npm test

In development with watching

$ npm run ci

License

The project is available under the MIT license.

Contact

Copyright (c) 2016-2024 MoleculerJS