Is it possible create a moleculer service with many Validator instances? - moleculer

Question

I would like to have more than one Validator instance on my service to handle different languages. Is there any way to implement that?
Something like that:
{
en: new Validator({ messages: { ... }}),
de: new Validator({ messages: { ... }})
// ...
}

Answer 1

It is not available. You should create a custom multi-validators. Here is a quick example:
"use strict";
const _ = require("lodash");
const { ServiceBroker } = require("moleculer");
const BaseValidator = require("moleculer").Validators.Base;
const Validator = require("fastest-validator");
const DefaultMessages = require("fastest-validator/lib/messages");
const { ValidationError } = require("moleculer").Errors;
// --- I18N VALIDATOR CLASS ---
class I18NValidator extends BaseValidator {
constructor(messages) {
super();
0;
this.validators = {};
Object.keys(messages).forEach(lang => {
this.validators[lang] = new Validator();
this.validators[lang].messages = Object.assign({}, DefaultMessages, messages[lang]);
});
}
compile(schema) {
this.checks = {};
Object.keys(this.validators).forEach(lang => {
this.checks[lang] = this.validators[lang].compile(schema);
});
return this.checks;
}
middleware() {
return function I18NValidator(handler, action) {
// Wrap a param validator
if (action.params && typeof action.params === "object") {
const checks = this.compile(action.params);
return function validateContextParams(ctx) {
const check = checks[ctx.meta.lang] || checks["en"];
const res = check(ctx.params);
if (res === true)
return handler(ctx);
else
return Promise.reject(new ValidationError("Parameters validation error!", null, res));
};
}
return handler;
}.bind(this);
}
}
let broker = new ServiceBroker({
logger: true,
validation: true,
validator: new I18NValidator({
"en": {
"string": "The '{field}' field must be a string!"
},
"hu": {
"string": "A '{field}' mezőnek szövegnek kell lennie!"
}
})
});
// --- TEST BROKER ---
broker.createService({
name: "greeter",
actions: {
hello: {
params: {
name: { type: "string", min: 4 }
},
handler(ctx) {
return `Hello ${ctx.params.name}`;
}
}
}
});
broker.start()
// No meta lang
.then(() => broker.call("greeter.hello", { name: 100 }).then(res => broker.logger.info(res)))
.catch(err => broker.logger.error(err.message, err.data))
// "hu" lang
.then(() => broker.call("greeter.hello", { name: 100 }, { meta: { lang: "hu" }}).then(res => broker.logger.info(res)))
.catch(err => broker.logger.error(err.message, err.data))
// "en" lang
.then(() => broker.call("greeter.hello", { name: 100 }, { meta: { lang: "en" }}).then(res => broker.logger.info(res)))
.catch(err => broker.logger.error(err.message, err.data));
It reads the lang from the ctx.meta.lang but you can change it for your case.