Backend-js NPM

backend-js

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Backend-js is a layer built above expressjs and socket.io to enable behaviours framework for nodejs applications.

Installation

npm install backend-js

Usage

backend

var backend = require('backend-js');
var App = backend.app(__dirname + '/behaviours', {
    path: '/api/v1',
    parser: 'json',
    port: 8383,
    origins: '*'
});

var App = app(path, options)

parameter	type	description
path	string	path of behaviours directory.
options	object	app configurations object.
options.path	string	prefix path appended to the beginning of routes.
options.parser	string	if json, text, raw or urlencoded is used, the body of the request will be parse accordingly also the body of the response will be serialized accordingly.
options.parserOptions	object	options for parser.
options.port	number	port of server.
options.origins	string	comma separated domains allowed to send ajax requests to this server or *""** to allow any.
options.static	object	options object to define static served files.
options.static.route	string	virtual path/route for static served files.
options.static.path	string	relative path of the directory of static served files.

return	type	description
App	function	function conventionally denotes the Express application.

model

var backend = require('backend-js');
var model = backend.model();
var User = model({
  name: 'User'
}, {
  username: String,
  password: String
});

var ModelEntity = model(options, attributes, plugins)

parameter	type	description
options	string \| object	either model name for lazy loading or object for model configuration.
options.name	string	model name.
options.features	object	object contains special functionalities of the model. It is passed to data access layer.
options.query	array	array of QueryExpression repressing the query to be executed by default.
attributes	object	object describes the model schema. it contains key-value pairs where the key is a model attribute/field name and the value is the data type of this attribute/field. Data types are native javascript data types String, Number and Date. Data type could be javascript array of single object annotation [{}] or just an object annotation {} containing other key-value pairs expressing nested model schema.
plugins	array	array of mongoose plugins to define additional functionalities to the model.

return	type	description
ModelEntity	function	model constructor function prototyped as ModelEntity.

query

var QueryExpression = backend.QueryExpression;
var ComparisonOperators = {
    EQUAL: '=',
    NE: '$ne'
};
var LogicalOperators = {
    AND: '$and',
    OR: '$or',
    NOT: '$not'
};
backend.setComparisonOperators(ComparisonOperators);
backend.setLogicalOperators(LogicalOperators);
var query = [new QueryExpression({
    fieldName: 'username',
    comparisonOperator: ComparisonOperators.EQUAL,
    fieldValue: 'name'
}),new QueryExpression({    
    fieldName: 'password',
    comparisonOperator: ComparisonOperators.EQUAL,
    fieldValue: 'pass',
    logicalOperator: LogicalOperators.AND,
    contextualLevel: 0
})]

setComparisonOperators(operators)

setLogicalOperators(operators)

parameter	type	description
operators	object	object contains key-value pairs where the key is a unique id for an operator and the value is a corresponding database engine operator. It is passed to data access layer.

var expression = new QueryExpression(options)

parameter	type	description
options	object	object describes a condition in a where clause of a query.
options.fieldName	string	attribute/field name of the model to be part of the condition.
options.comparisonOperator	string	a value represents comparison operation to be manipulated by database engine.
options.fieldValue	any	the value to be compared to the attribute/field of the model.
options.logicalOperator	string	a value represents logical operation to be manipulated by database to combine multiple conditions.
options.contextualLevel	number	starts with 0 represents the depth of the logical operation in the conditions tree. It is used to indicate brackets.

return	type	description
expression	object	object represents a condition expression combined with other expressions to represent a query. It is adapted by data access layer..

entity

var ModelEntity = backend.ModelEntity;
var entity = new ModelEntity({});
var model = entity.getObjectConstructor();
var schema = entity.getObjectAttributes();
var features = entity.getObjectFeatures();
var query = entity.getObjectQuery();

var entity = new ModelEntity(features)

parameter	type	description
features	object	object contains special functionalities of the model. It is passed to data access layer.

return	type	description
entity	object	object contains all specifications and meta data of the model.
entity.getObjectConstructor	function	function returns the model constructor depending on the data access layer.
entity.getObjectAttributes	function	function returns the model schema key-value pairs.
entity.getObjectFeatures	function	function returns the model features.
entity.getObjectQuery	function	function returns the model query an array of QueryExpression to be executed by default.

behaviour (API / functional code unit)

var getUsers = behaviour({
  name: 'GetUsers',
  version: '1',
  path: '/users',
  method: 'GET'
}, function(init) {
  return function() {
    var self = init.apply(this, arguments).self();
    self.begin('Query', function(key, businessController, operation) {
        operation
          .entity(new User())
          .append(true)
          .apply();
      });
  };
});

var Behavior = behaviour(option, constructor);

parameter	type	description
options	object	api configuration (name, version, path, method, parameters, returns)
constructor	function	logic function works by registering on methods to do functions regardless its orders, like (database processor query, insert, delete or update), data mapping to map returns of data to specific format or server error handling

data access

you should define your own data access layer like following

var backend = require('backend-js');

var ModelController = function () {
    self.removeObjects = function (queryExprs, entity, callback) {
        // do remove
    };
    self.addObjects = function (objsAttributes, entity, callback) {
        // do add new
    };
    self.getObjects = function (queryExprs, entity, callback) {
        // do select
    };
    self.save = function (callback, oldSession) {
        // do select
    };
};

ModelController.defineEntity = function (name, attributes) {
    // define entity
    return entity;
};

ModelController.prototype.constructor = ModelController;

backend.setModelController(new ModelController());