Loopback with Node.JS and MongoDB

Pablo Ezequiel

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Feb 23, 2017 · 4 min read

This post is a continuation of “Mean Stack App Sample — The backend (I)”, with the api from the previous post I will make some test with Loopbak 3.x

Get in context — the previous post

That is the main picture of the api from the previous post:

Where the app.js is

Loopback version

Loopback is similar to swagger, a very nice tool to describe an API REST, and It also have a design tool and in my humble opinion is easier o better than swagger in combination to Node.js … It is just a simple and personal opinion..

There is two interesting post that I will follow:

And

Let´s start

I will use a new dir

$ npm install -g strongloop

Let´s create the app with the Loopback cli

$ slc loopback todo

From an empty dir, loopack built the followings dirs:

Let´s create the model (cat and cats)

$ slc loopback:model

The result:

Let´s start the app:

And when we browse

http://0.0.0.0:3000/explorer

we can see the browser api explorer

Let insert one or two cats:

cat 1: “Ramoncito”

I get the error because we don´t have the datasource attached:

“Cannot call cat.replaceOrCreate(). The replaceOrCreate method has not been setup. The PersistedModel has not been correctly attached to a DataSource!”,

The mongo db connector to looback 3.x that I am using is

$ npm install loopback-connector-mongodb — save

we will edit the server/datasources.json file

With:

Next:

Un get cats and an emty response, that it is good: we don´t have db errors!

Let´s insert a Cat with the POST:

OK! we haev a good response:

Let´s do the get again:

http://0.0.0.0:3000/api/cats

From Robomongo:

I made a mistake with “cat” and “cats” api … I would have to reuse my existing API… with in this example I made a mistake… model “cat” instead “cats”

Entities: Singular or Plurals?

¿El nombre del Endpoint debería ser singular o plural? keep-it-simple: siempre plural: evita lidiar con plurales irregulares (person/people, goose/geese) y modernos frameworks generarán de esa manera: /tickets y /tickets/12. (1)

May be in the standalone sample I could revert “cats” by “cat”

Ok… I will end the post at this point with a successful backend node.js app built with loopback and that is able to connect to the mongo db database

References

• https://elbauldelprogramador.com/buenas-practicas-para-el-diseno-de-una-api-restful-pragmatica/#filtrado