Micro Toolkit API Generators

The Micro toolkit API generators will allow you to generate express handlers to connect to the micro toolkit services using a set of code conventions.

The generator is based on the concept of models that are described using metadata. Every model have a microservice associated to, this service should have required operations available.

Following the api example we have 2 models:

• task: representing a todo task item, that is associated with a user;
• user: representing the user, that can have a list of task associated to;

The metadata files that describe the models, present on each version, should have the following format:

Property	Description
properties	A whitelist of properties associated with the model, only this properties are returned by the api serialization.
relations	A collection of relations associated with the model.
actions	A list of actions available on the model (list, get, create, remove, update).

var taskMetadata = {
  properties: [ "id", "userId", "active" ],
  relations: [
    {
      name: "user",
      type: "resource"
    }
  ],
  actions: ["list", "get", "create", "update", "remove", "count"]
}

The list of actions will be translated into the following actions:

• list: GET /v1/tasks
• get: GET /v1/tasks/:id
• create: POST /v1/tasks
• update: PUT /v1/tasks/:id
• remove: DELETE /v1/tasks/:id
• count: GET /v1/tasks/count

The relations will result on the following endpoints depending on the type:

• resource: GET /v1/users/:id
• collection: GET /v1/users/:id/tasks

Install

$ npm install micro-toolkit-api-generators --save

Usage

The metadata should be dictionary where each key identifies the version identifier and the value should be a dictionary with the models description.

// metadata from api-example project
var metadata = {
  v1: {
    task: {
      properties: [ "id", "userId", "active" ],
      relations: [
        {
          name: "user",
          type: "resource"
        }
      ],
      actions: ["list", "get", "create", "update", "remove", "count"]
    },
    user: {
      properties: [ "id", "name" ],
      relations: [
        {
          "name": "tasks",
          "type": "collection"
        }
      ],
      "actions": ["get"]
    }
  }
};

Expose the api routes

The following snipets will allow you to add the api generator routes into a express application. To configure logger plugins check the project instructions.

var express = require('express');
var apiRouter = require('../../index');

var config = {
  runtimeConfig: { baseUrl: 'http://localhost:8081' },
  // metadata from api-example project
  metadata: metadata
};
var app = express();
var router = apiRouter(config);
app.use(router);
app.listen(8081);

Forwarding claims to service

The api generators allow to forward request claims into the microservice using the microservice header property on call. The api generator will use req.user to whitelist the claims selected. To use this feature the application just need to use a middleware to set req.user and define the whitelisted properties using the following configuration.

var express = require('express');
var apiRouter = require('../../index');

var config = {
  runtimeConfig: {
    baseUrl: 'http://localhost:8081',
    claims: 'userId,tenantId'
  },
  // metadata from api-example project
  metadata: metadata
};
var app = express();
var router = apiRouter(config);
// emulate auth middlware
app.use(function(req, res, next){
  var claims = { userId: '1', tenantId: '2' };
  req.user = claims;
  next();
});
app.use(router);
app.listen(8081);

Excluding some parameters from query string

By default the api generators will forward to the service all query string parameters except token and access_token. To override this configuration and have control over it the application can specificly set wich parameters to filter.

var config = {
  runtimeConfig: {
    baseUrl: 'http://localhost:8081',
    excludeQueryString: 'token,somethingElse'
  },
  // metadata from api-example project
  metadata: metadata
};

Support non standard actions

The default supported actions are list, get, create, remove, update, but the toolkit also support non standard action over a resource.

See following metadata example:

// metadata from api-example project
var metadata = {
  v1: {
    user: {
      properties: [ "id", "name", "active" ],
      relations: [
        {
          name: "tasks",
          type: "collection"
        }
      ],
      actions: [
        "get",
        { name: "active", httpVerb: "PUT", verb: "activate" },
        { name: "active", httpVerb: "DELETE", verb: "deactivate" }
      ]
    }

  }
};

The previous metadata will generate the following routes:

• PUT /v1/users/:id/active - that will call verb activate on the service, this operation should return the user model serialization
• DELETE /v1/users/:id/active - that will call verb deactivate on the service, this operation will not return any response body from the api

NOTE

At the moment the only support http verbs are: PUT, POST, DELETE. The PUT, POST verbs should return the model serialization.

Support subresource models

If we have a model that is dependent on a parent model, we can configure it in the model. This configuration will make the api routes being dependent on the parent resource routes.

As an example we can have the following model configuration (metadata from api-example project):

{
  "parent": "user",
  "properties": [ "id", "name", "userId"],
  "actions": ["list", "get", "create", "update", "remove"],
  "relations": [
    {
      "name": "user",
      "type": "resource"
    }
  ]
}

This will generate the following routes:

MICRO.API.METADATA::INFO - Loaded API Models...
MICRO.API.METADATA::INFO - Loading API routes...
MICRO.API.METADATA::TRACE - Mount route GET     /v1/users/:userId/roles
MICRO.API.METADATA::TRACE - Mount route GET     /v1/users/:userId/roles/:id
MICRO.API.METADATA::TRACE - Mount route POST    /v1/users/:userId/roles
MICRO.API.METADATA::TRACE - Mount route PUT     /v1/users/:userId/roles/:id
MICRO.API.METADATA::TRACE - Mount route DELETE  /v1/users/:userId/roles/:id
...
MICRO.API.METADATA::INFO - Loaded API routes...
MICRO.API::INFO - Server running on port 8081

The parameters userId and id(on resource endpoints only) will be sent to service on payload.

Support path prefix

If we have a model that needs to have a prefix path we may configure it using path key. This configuration will make the api routes prefixed with the path.

As an example we can have the following model configuration (metadata from api-example project):

{
  "properties": [ "name", "userId" ],
  "relations": [{ "name": "user", "type": "resource" }],
  "actions": ["list"],
  "path": {
    "prefix": "admin/"
  }
}

This will generate the following routes:

MICRO.API.METADATA::INFO - Loaded API Models...
MICRO.API.METADATA::INFO - Loading API routes...
MICRO.API.METADATA::TRACE - Mount route GET 	/v1/admin/claims

Overriding default paths

The path property allow you to override the default path configuration. The default path configuration is to transform the model name in a pluralized string, in certain cases we may need something different we can use path property.

As an example we can have the following model configuration (metadata api-example project):

{
  "path": "me",
  "currentUserKey": "userId",
  "properties": ["id", "name", "active"],
  "relations": [{ "name": "alerts", "type": "collection" }],
  "actions": ["get"]
}

This will generate a route GET /me instead of GET /mes.

Support current user endpoints

If we have a model that doesn't needs an identifier to be requested such as me, we can define what is the property present in request user object that should be sent in the payload.

As an example we can have the following model configuration (metadata api-example project):

{
  "path": "me",
  "currentUserKey": "userId",
  "properties": ["id", "name", "active"],
  "relations": [{ "name": "alerts", "type": "collection" }],
  "actions": ["get"]
}

This will generate a route GET /me where the property userId will be sent in the payload. The value for the userId property will be retrieved from current user object req.user.

The following model contains a alert relation and the userId property will also be sent in the relation payload.

Embeds support

This feature will allow to embed relations in the resource payload using a single call from the consumer. The relations can be a collection or single resource depending on the model definition. The relation name will be set as a property in the model payload.

The embeds will use the batch operation from embedable model using the following payload contract for request and response:

• one-to-one relations will send the following payload:

// Batch request payload example to embed users in a task model
{ id: ['pjanuario'] }

// Response:
[
  {
    id: 'pjanuario',
    data: {
      id: "pjanuario",
      name: "Pedro",
      active: true,
      roleId: "1",
      _links: {
        self: "/users/pjanuario",
        tasks: "/users/pjanuario/tasks",
        userAssignments: "/users/pjanuario/userassignments",
        role: "/users/pjanuario/roles/1"
      }
    }
  }
]

• one-to-many relations will send the following payload:

// Batch request payload example to embed tasks in a user model
{ userId: ['pjanuario'] }

// Response:
[
  {
    userId: 'pjanuario',
    data: [{
      id: "1",
      active: true,
      userId: "pjanuario",
      _links: {
        self: "/tasks/1",
        user: "/users/pjanuario"
      }
    }]
  }
]

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

Bump versioning

We use grunt bump package to control package versioning.

Bump Patch version

$ grunt bump

Bump Minor version

$ grunt bump:minor

Bump Major version

$ grunt bump:major

Running Specs

$ npm test

Coverage Report

We aim for 100% coverage and we hope it keeps that way! :) We use pre-commit and pre-push hooks and CI to accomplish this, so don't mess with our build! :P

Check the report after running npm test.

$ open ./coverage/lcov-report/index.html