Validating

Moleculer has a built-in validator module. It uses the fastest-validator library.

Built-in validator

It’s enabled by default, so you should just define params property in action definition which contains validation schema for the incoming ctx.params.

Example

const { ServiceBroker } = require("moleculer");

const broker = new ServiceBroker({
    validation: true // Default is true
});

broker.createService({
    name: "say",
    actions: {
        hello: {
            // Validator schema for params
            params: {
                name: { type: "string", min: 2 }
            },
            handler(ctx) {
                return "Hello " + ctx.params.name;
            }
        }
    }
});

broker.call("say.hello").then(console.log)
    .catch(err => console.error(err.message));
// -> throw ValidationError: "The 'name' field is required!"

broker.call("say.hello", { name: 123 }).then(console.log)
    .catch(err => console.error(err.message));
// -> throw ValidationError: "The 'name' field must be a string!"

broker.call("say.hello", { name: "Walter" }).then(console.log)
    .catch(err => console.error(err.message));
// -> "Hello Walter"

Play it on Runkit

Example validation schema

{
    id: { type: "number", positive: true, integer: true },
    name: { type: "string", min: 3, max: 255 },
    status: "boolean" // short-hand def
}

Documentation

Find more information about validation schema in the documentation of the library

Custom validator

Custom validator can be created. You should implement compile and validate methods of BaseValidator.

Create a Joi validator

const BaseValidator = require("moleculer").Validator;
const { ValidationError } = require("moleculer").Errors;

class JoiValidator extends BaseValidator {
    constructor() {
        super();
        this.validator = require("joi");
    }

    compile(schema) {
        return (params) => this.validate(params, schema);
    }

    validate(params, schema) {
        const res = this.validator.validate(params, schema);
        if (res.error)
            throw new ValidationError(res.error.message, null, res.error.details);

        return true;
    }
}

module.exports = JoiValidator;

Use custom Joi validator

const { ServiceBroker } = require("moleculer");
const Joi = require("joi");
const JoiValidator = require("./joi.validator");

const broker = new ServiceBroker({
    logger: true,
    validation: true,
    validator: new JoiValidator()
});

// --- SERVICE ---
broker.createService({
    name: "greeter",
    actions: {
        hello: {
            params: Joi.object().keys({
                name: Joi.string().min(4).max(30).required()
            }),
            handler(ctx) {
                return `Hello ${ctx.params.name}`;
            }
        }
    }
});

// --- TEST ---
broker.start()
    .then(() => broker.call("greeter.hello").then(res => broker.logger.info(res)))
    .catch(err => broker.logger.error(err.message, err.data))

    .then(() => broker.call("greeter.hello", { name: 100 }).then(res => broker.logger.info(res)))
    .catch(err => broker.logger.error(err.message, err.data))

    .then(() => broker.call("greeter.hello", { name: "Joe" }).then(res => broker.logger.info(res)))
    .catch(err => broker.logger.error(err.message, err.data))

    .then(() => broker.call("greeter.hello", { name: "John" }).then(res => broker.logger.info(res)))
    .catch(err => broker.logger.error(err.message, err.data));

Find more validators

Check the modules page and find more validators.