d-pac.plugins-spec

d-pac.plugins-spec v0.4

This module formally defines the plugins specification for d-pac. It uses json-schema to describe the mandatory plugin declaration and the data it accepts.

Plugin manifest

A d-pac plugin must declare an object in its package.json which adheres to schemas/pluginmanifest.json To verify your plugin fullfils all requirements:

var spec = require('d-pac.plugins-spec');
var pkg = require('./package.json'); // retrieve your plugin's package manifest

var result = spec.validatePluginmanifest(pkg);
console.log(result.isValid);

Plugin API

A d-pac plugin must expose a method conform to its type declaration in the manifest. ATM a single type is accepted: select.

Example:

module.exports.select = function select(selectionpayload){
    //do your stuff
};

This method should accept exactly one parameter which adheres to schemas/selectionpayload.json A plugin is allowed to override the payload schema in case it requires/ignores any of the fields.

References:

• schemas/assessment.json
• schemas/comparison.json
• schemas/representation.json
• schemas/selectionpayload.json

Module API

Schemas

This module exposes a mapping of schema declarations to schema names as schemas:

var spec = require('d-pac.plugins-spec');
console.log(Object.keys(spec.schemas));

#output
[ 'pluginmanifest',
  'assessment',
  'comparison',
  'representation',
  'selectionpayload' ]

Default Validators

It also exposes validators for each of the schemas:

console.log(Object.keys(spec));

#output
[ 'validatePluginmanifest',
  'validateAssessment',
  'validateComparison',
  'validateRepresentation',
  'validateSelectionpayload',
  'schemas',
  'createValidator',
  'VERSION' ]

Usage:

validate<SchemaType>(data) : Object

var result = spec.validateComparison(comparison);

The result is an object with isValid: Boolean and in case the data's not valid an errors array with all errors.

Custom Validators

You can create validators of your own, either based on one of the d-pac schemas, or completely new.

//new schema
var validator = subject.createValidator( {
	"$schema": "http://json-schema.org/draft-04/schema#",
	"title": "Test createValidator",
	"type": "object",
	"properties": {
	  "foo": {
	    "type": "number",
	    "required": true
	  }
	}
} );
console.log(validator( { foo: "foo" } ).isValid); //outputs: false
console.log(validator( { foo: 9 } ).isValid); //outputs: true

//based on existing
var validator = subject.createValidator( "selectionpayload", {
	"selectionpayload": {
	  "properties": {
	    "assessment": {
	      "required": true
	    }
	  }
	},
	"comparison": {
	  "properties": {
	    "updatedAt": {
	      "required": true
	    }
	  }
	}
} );

The above example creates a validator based on schemas/selectionpayload.json by passing the "selectionpayload" as a first argument. You can override the rules of the original schema, by passing extra rules as objects mapped to the schema names. E.g. the assessment property of selectionpayload is made mandatory in the above example.

Since the selectionpayload schema references several other schemas, you can override these too. E.g. all comparison objects passed to selectionpayload.comparisons are required to have a updatedAt property.

The structure of the overriding object must be exactly the same as that of the base schema, i.e. make sure you adhere to it strictly.

Plugin declaration retrieval from package manifests

You can use getPlugins to retrieve plugin declarations from package manifests:

var plugins = subject.getPlugins({
  "d-pac": [
    {
      "name": "test",
      "description": "test",
      "type": "select"
    }
  ],
  dependencies: {
    'd-pac.plugins-spec': '^0.4.0'
  }
});

To allow backwards compatibility to plugins that do not declare a dependency on this module, pass an options object with allowIndependents:true:

var plugins = subject.getPlugins({
  "d-pac": [
    {
      "name": "test",
      "description": "test",
      "type": "select"
    }
  ]
}, {
  allowIndependents: true
);