hapi-api-version

Lead Maintainer: Tim Costa

An API versioning plugin for hapi v17 onwards.

Features / Goals

• Supports versioning via accept and custom header (default api-version) as described on troyhunt.com
• 100% test coverage
• Easy to use and flexible
• Follows the hapi coding conventions
• Allows to follow the DRY principle

Requirements

Runs with Node >=8 and hapi >=17 which is tested with Travis CI.

Installation

npm install --save hapi-api-version

Usage

Register it with the server:

'use strict';

const Hapi = require('hapi');

const init = async function () {
    try {
        const server = new Hapi.server({ port: 3000 });
        await server.register({
            plugin: require('hapi-api-version'),
            options: {
                validVersions: [1, 2],
                defaultVersion: 2,
                vendorName: 'mysuperapi'
            }
        })
        await server.start();
        console.log('Server running at:', server.info.uri);
    }   
    catch (err) {
        console.error(err);
        process.exit(1);
    }
}
init();

Time to add some routes...

There are typically two common use cases which this plugin is designed to address.

Unversioned routes

This is the type of routes which never change regardless of the api version. The route definition and the handler stay the same.

server.route({
    method: 'GET',
    path:'/loginStatus',
    handler: function (request, h) {

        const loggedIn = ...;

        return {
          loggedIn: loggedIn
        };
    }
});

Versioned routes

This is the type of routes which actually change.

Handler only

In simple cases where just the handler differs you could use this approach.

const usersVersion1 = [{
    name: 'Peter Miller'
}];

const usersVersion2 = [{
    firtname: 'Peter',
    lastname: 'Miller'
}];

server.route({
    method: 'GET',
    path: '/users',
    handler: function (request, h) {

        const version = request.pre.apiVersion;

        if (version === 1) {
            return usersVersion1;
        }

        return usersVersion2;
    }
});

Different route definitions per version

Sometimes it is required to change not just the handler but also the route definition itself.

const usersVersion1 = [{
    name: 'Peter Miller'
}];

const usersVersion2 = [{
    firtname: 'Peter',
    lastname: 'Miller'
}];

server.route({
    method: 'GET',
    path: '/v1/users',
    handler: function (request, h) {

        return usersVersion1;
    },
    config: {
        response: {
            schema: Joi.array().items(
                Joi.object({
                    name: Joi.string().required()
                })
            )
        }
    }
});

server.route({
    method: 'GET',
    path: '/v2/users',
    handler: function (request, h) {

        return usersVersion2;
    },
    config: {
        response: {
            schema: Joi.array().items(
                Joi.object({
                    firtname: Joi.string().required(),
                    lastname: Joi.string().required()
                })
            )
        }
    }

});

Note the different schemas for response validation here.

The user still sends a request to /users and the plugin rewrites it internally to either /v1/users or /v2/users based on the requested version.

Example

A complete working example with routes can be found in the example folder.

Documentation

hapi-api-version works internally with rewriting urls. The process is very simple:

1. Check if an accept header OR a custom header (default api-version) is present and extract the version
2. If a version was extracted check if it is valid, otherwise respond with a status code 400
3. If no version was extracted (e.g. no headers sent) use the default version
4. Check if a versioned route (like /v2/users) exists -> if so rewrite the url from /users to /v2/users, otherwise do nothing

Options

The options for the plugin are validated on plugin registration.

• validVersions (required) is an array of integer values. Specifies all valid api versions you support. Anything else will be considered invalid and the plugin responds with a status code 400.
• defaultVersion (required) is an integer that is included in validVersions. Defines which version to use if no headers are sent.
• vendorName (required) is a string. Defines the vendor name used in the accept header.
• versionHeader (optional) is a string. Defines the name of the custom header to use. Per default this is api-version.
• passiveMode (optional) is a boolean. Allows to bypass when no headers are supplied. Useful when you serve other content like documentation and reduces overhead on processing those.
• basePath (optional) is a string. In case we have a base path different from / (example: /api/). Per default this is /.

Getting the requested API version in the handler

You can get the API version requested by the user (or maybe the default version if nothing was requested) in the handler. It is stored in request.pre.apiVersion.

Headers

The headers must have a specific format to be correctly recognized and processed by the plugin.

Accept header

Accept: application/vnd.mysuperapi.v2+json

Here mysuperapi is what was specified in options as vendorName. If the vendor name does not match, the default version will be used instead.

Custom header

api-version: 2

Here api-version is the default name of the custom header. It can be specified in the options via versionHeader.

Running the tests

lab is used for all tests. Make sure you install it globally before running the tests:

npm install -g lab

Now just execute the tests:

npm test

To see the coverage report in html just execute:

npm run test-coverage

After this the html report can be found in coverage/coverage.html.

License

Apache-2.0