Loopback Reference

Getting Started

To get started with a JSON API with loopback run:

hub clone tiy-tn-fee-2016-spring/base-api <project-name>
cd <project-name>
npm install
git remote remove origin

This will pull in the base API configured for local development and deployment to heroku. It also includes basic support for Login and an end-user model. The git remote remove origin removes the link to the shared repository so we can have our own version just for this project.

Remember to switch to the develop branch!

Generating Models

Next, we will want to generate some models. The command to generate new models is:

slc loopback:model

This will start a wizard with a few steps:

1. Model Name: This is the name of the model. It should be all lowercase with - between words
2. Data Source: Where to save the data to. Loopback allows multiple datasources, but we'll just use the one called db. This will be a memory store in development and will use a full database on Heroku.
3. Base Class: This sets up what to extend behavior from. Here we'll use PersistedModel to make sure our model has full CRUD (Create, Read, Update, Delete) support
4. Expose via REST API: This says if our model is available over the API. Pick Y for yes
5. Custom plural form: This is useful for words where we need a special plural form (ex. "goose" vs "geese"), leave this blank unless we need it
6. Common model or server only: This allows the model to be used from client side Javascript served by Loopback. That doesn't matter in our case, but pick common.
7. Properties: This sets up the attributes for our model (not the relationships)
   • Name: Name of the new attribute. It should be all lowercase with - between words
   • Property Type: What data type to store the data in, (we usually use just string, number, or boolean)
   • Required: Should we be able to save this with an empty version of this field?
   • Default Value: Leave this blank unless we know we want something different

Generating Relationships

Once we have our models defined, we can define our relationships using:

slc loopback:relation

The relation wizard is a bit harder to follow:

1. Model From: What model do we want to add the relationship to?
2. Relation Type: Should this be a HasMany or BelongsTo relationship?
3. Model To: What model should we relate to?
4. Property Name: (Usually this is default), if your client side is already created, you may need to modify this to match the existing properties
5. Custom Foreign Key: This changes the way the data is stored in the database (you likely won't need to change this)
6. Require a Through Model: Leave this as no