Introduction

mserv-pgentity is mserv extension that simplifies creating CRUD like actions for postgres-backed data entities. The middleware assumes that mserv-validate is present and the postgres client is pg-promise.

Installation

$ npm i --save mserv-pgentity

Usage

var entity  = require('mserv-pgentity'),
	service = require('mserv')(),

service.extend('enitity', entity, {
	postgres: 'postgres://localhost/mydatabase'
})

service.ext.entity('todo', {
	table: 'todos',
	scope: 'userId',
	keys: {id:'uuid'}
	model: {
		userId: Joi.string().guid(),
		id:     Joi.string().guid(),
		seq:    Joi.number(),
		title:  Joi.string(),
		done:   Joi.boolean(),
	},
	create: true,
	read:   true,
	update: true,
	delete: true
})


service.invoke('todo.fetch.all', {ownerId:'12345678-1234-1234-1234-123456789012'})

Options

The extension accepts only one option:

• postgres: URI to the postgres database. If the context middleware is installed the postgres property will be added to the context.

Entities

When creating entities there are more options:

• name : prefix for the action names that are created.
• table : postgres table name with schema prefix if needed.
• scope : multi-tenant support throw scoping.
• keys : object with key names and their types.
• model : object with column names (camel-cased) and their Joi model.
• create : if true the <name>.create action will be created. Can also be a generator function, which acts as middleware around the create action. The generator function should have the following signature: function*(array[Object], next) and yield next(array) where array is the possibly modified array of objects that was initially passed in.
• read : if true the <name>.find.by<Key> actions will be created for each key. Can also be a generator function, which acts as middleware around the read action. See create for more details.
• update : if true the <name>.update action will be created. Can also be a generator function, which acts as middleware around the update action. See create for more details.
• delete : if true the <name>.delete action will be created. Can also be a generator function, which acts as middleware around the delete action. See create for more details.
• merge : if true the <name>.merge action will be created. Can also be a generator function, which acts as middleware around the merge action. Merge attempts perform update and will insert if the update failed. See create for more details.

Actions

The following actions are generated for you when using mserv-pgentity. Note that all functions support both a single and batch modes.

• <name>.create : In single mode the argument should be an object that satisfies model. The result will be the created object or an exception will be thrown. In batch mode, the argument should be an object with a batch key whose value is an array of objects satisfying model. Returns an array of objects. Objects that could not be created will return {error$} with some details.

• <name>.fetch.by<Key> : There will be one such action for each specified key. The argument would be an object with the <key> field that is either a single value or an array of values (single or batch). The result is either null, a single object or an array of objects.

• <name>.fetch : Takes no arguments (or a scope argument) and returns all of the records.

• <name>.update : In single mode the argument should be an object that satisfies model. The result will be the updated object or an exception will be thrown. In batch mode, the argument should be an object with a batch key whose value is an array of objects satisfying model. Returns an array of objects. Objects that could not be created will return {error$} with some details.

• <name>.delete.by<Key> : There will be one such action for each specified key. The argument would be an object with the <key> field that is either a single value or an array of values (single or batch). The result is always the number of deleted records.

• <name>.delete.all<Key> : Only if scoped, Takes no arguments and deletes all of the records within the scope. The result is the number of deleted records.

Scoping

Scoping was introduced to facilitate multi-tenancy. When scoped, all actions will require a key whose name is what was specified in the scope. For example if scope: 'tenantId' then all actions will require a tenantId. If the scope key is not present then a missingScope exception is thrown.