Connector

The table below lists functions a custom Read Model's connector should implement.

Function Name	Description
connect	Initializes a connection to storage.
disconnect	Closes the storage connection.
drop	Removes the Read Model's data from storage.
dispose	Dispose of this connector's unmanaged resources.

connect

Initializes a connection to storage. An implementation should return a store object.

Arguments

Argument Name	Description
readModelName	A read model for which to establish a connection.

Example

const connect = async (readModelName) => {
  fs.writeFileSync(`${prefix}${readModelName}.lock`, 'true', { flag: 'wx' })
  readModels.add(readModelName)
  const store = {
    get() {
      return JSON.parse(String(fs.readFileSync(`${prefix}${readModelName}`)))
    },
    set(value) {
      fs.writeFileSync(`${prefix}${readModelName}`, JSON.stringify(value))
    },
  }
  return store
}

disconnect

Closes the storage connection.

Arguments

Argument Name	Description
store	A store object.
readModelName	The read model to disconnect.

Example

const disconnect = async (store, readModelName) => {
  safeUnlinkSync(`${prefix}${readModelName}.lock`)
  readModels.delete(readModelName)
}

drop

Removes the Read Model's data from storage.

Arguments

Argument Name	Description
store	A store object.
readModelName	A Read Model whose data to remove.

Example

const drop = async (store, readModelName) => {
  safeUnlinkSync(`${prefix}${readModelName}.lock`)
  safeUnlinkSync(`${prefix}${readModelName}`)
}

dispose

Dispose of all unmanaged resources provided by this connector.

Example

const dispose = async () => {
  for (const readModelName of readModels) {
    safeUnlinkSync(`${prefix}${readModelName}.lock`)
  }
  readModels.clear()
}