# Services

Services are a set of reusable functions. They are particularly useful to respect the DRY (don’t repeat yourself) programming concept and to simplify controllers logic. Just like all the other parts of the Strapi backend, services can be customized.

# Implementation

A new service can be implemented:

To manually create a service, export a factory function that returns the service implementation (i.e. an object with methods). This factory function receives the strapi instance:

/**
 * @param {{ strapi: import('@strapi/strapi').Strapi }} opts
 */
module.exports = ({ strapi }) => {
  return {
    archiveArticles(ids) {
      // do some logic here
    },
  };
};

🤓 Entity Service API

To get started creating your own services, see Strapi's built-in functions in the Entity Service API documentation.

Example of an email service

The goal of a service is to store reusable functions. An email service could be useful to send emails from different functions in our codebase:

// path: ./src/api/email/services/email.js

const nodemailer = require('nodemailer'); // Requires nodemailer to be installed (npm install nodemailer)

// Create reusable transporter object using SMTP transport.
const transporter = nodemailer.createTransport({
  service: 'Gmail',
  auth: {
    user: 'user@gmail.com',
    pass: 'password',
  },
});

module.exports = {
  send: (from, to, subject, text) => {
    // Setup e-mail data.
    const options = {
      from,
      to,
      subject,
      text,
    };

    // Return a promise of the function that sends the email.
    return transporter.sendMail(options);
  },
};

The service is now available through the strapi.services global variable. It can be used in another part of the codebase, like in the following controller:

// path: ./src/api/user/controllers/user.js

module.exports = {
  // GET /hello
  signup: async ctx => {
    // Store the new user in database.
    const user = await User.create(ctx.query);

    // Send an email to validate his subscriptions.
    strapi.service('api::email.send')('welcome@mysite.com', user.email, 'Welcome', '...');


    // Send response to the server.
    ctx.send({
      ok: true,
    });
  },
};

✏️ NOTE

When a new content-type is created, Strapi builds a generic service with placeholder code, ready to be customized.

# Usage

Once a service is created, it's accessible from controllers or from other services:

// access an API service
strapi.service('api::apiName.serviceName');
// access a plugin service
strapi.service('plugin::pluginName.serviceName');

💡 TIP

To list all the available services, run yarn strapi services:list.

← Models →