@furystack/repository

repository

Repository implementation for FuryStack. With a repository, you can implement entity-level business logic in an easy and structured way. You can authorize, manipulate and observe CRUD operations.

Setting up a repository

You can set up a repository in the following way

class MyModel {
  public id!: number
  public value!: string
}

const myInjector = new Injector()
myInjector
  .setupStores(stores => stores.addStore(new InMemoryStore({ model: MyModel, primaryKey: 'id' })))
  .setupRepository(repo =>
    repo.createDataSet(MyModel, {
      onEntityAdded: ({ injector, entity }) => {
        injector.logger.verbose({ message: `An entity added with value '${entity.value}'` })
      },
      authorizeUpdate: async () => ({
        isAllowed: false,
        message: 'This is a read only dataset. No update is allowed. :(',
      }),
      /** custom repository options */
    }),
  )

In the following example we've created a physical InMemory store for the model MyModel, and we've configured a Repository with a DataSet. It will log to a logger when an entity has been added and it won't allow us to update entities.

Working with the DataSet

A DataSet is similar to a physical store, but it can have custom event callbacks and authorization logic. You can retrieve the dataset in a following way:

const dataSet = myInjector.getDataSetFor(MyModel)
dataSet.add(myInjector, { id: 1, value: 'foo' }) // <-- this will log to a logger
dataSet.update(myInjector, 1, { id: 1, value: 'bar' }) // <--- this one will be rejected

Events

Events are great for logging / monitoring DataSet changes or distribute changes to clients. They are simple optional callbacks - if they are defined, they will be called on a specific event. These events are onEntityAdded, onEntityUpdated and onEntityRemoved

Authorizing operations

Authorizers are similar callbacks but they have to return a promise with an AuthorizationResult object - you can allow or deny CRUD operations or add additional filters to collections with these Authorize callbacks. These areauthorizeAdd, authorizeUpdate, authorizeUpdateEntity (this needs an additional reload of entity but can compare with the original one), authorizeRemove, authroizeRemoveEntity (also needs reloading), authorizeGet,authorizeGetEntity (also needs reloading),

Modifiers and additional filters

There are some callbacks that modifies an entity before persisting (like modifyOnAdd or modifyOnUpdate). For example, you can fill createdByUser or lastModifiedByUser fields with these. There is an additional property called addFilter, you can use that to add a pre-filter condition before a filter expression will be evaluated in the data store - ensuring e.g. that the user can retrieve only suff from the physical store that she has enough permission.

Getting the Context

All methods above has an injector instance on the call parameter - you can use that injector to get service instances from the right caller context. It means that you can use e.g.: HttpUserContext to getting the current user.