Server-Side Development with Hapi.js — Caching and Cookie

Hapi.js is a small Node framework for developing back end web apps.

In this article, we’ll look at how to create back end apps with Hapi.js.

Caching

We can control caching by setting some properties in our routes.

For example, we can write:

const Hapi = require('@hapi/hapi');

const init = async () => {

  const server = Hapi.server({
    port: 3000,
    host: '0.0.0.0'
  });

  server.route({
    path: '/{ttl?}',
    method: 'GET',
    handler(request, h) {
      const response = h.response({
        hello: 'world'
      });
      if (request.params.ttl) {
        response.ttl(request.params.ttl);
      }
      return response;
    },
    options: {
      cache: {
        expiresIn: 30 * 1000,
        privacy: 'private'
      }
    }
  });

  await server.start();
  console.log('Server running on %s', server.info.uri);
};

process.on('unhandledRejection', (err) => {
  console.log(err);
  process.exit(1);
});

init();

We call the route with server.route .

Then we call response.ttl to set the duration of the caching of the response.

We also set the options.cache.expiresIn property to set when the cache expires.

And privacy set whether the cache is private.

Last-Modified Header

We can also set the Last-Modified header added automatically to the response.

For instance, we can write:

const Hapi = require('@hapi/hapi');
const init = async () => {
  const server = Hapi.server({
    port: 3000,
    host: '0.0.0.0'
  });
  server.route({
    path: '/{ttl?}',
    method: 'GET',
    handler(request, h) {
      return h.response({ hello: 'world' })
        .header('Last-Modified', lastModified.toUTCString());
    },
    options: {
      cache: {
        expiresIn: 30 * 1000,
        privacy: 'private'
      }
    }
  });
  await server.start();
  console.log('Server running on %s', server.info.uri);
};

process.on('unhandledRejection', (err) => {
  console.log(err);
  process.exit(1);
});
init();

We call header with the Last-Modified key and the and the value

Cookies

We can add a cookie by calling the h.state method.

For instance, we can write:

const Hapi = require('@hapi/hapi');
const init = async () => {
  const server = Hapi.server({
    port: 3000,
    host: '0.0.0.0'
  });

  server.route({
    path: '/',
    method: 'GET',
    async handler (request, h) {
      h.state('data', { firstVisit: false });
      return h.response('Hello');
    },
  });
  await server.start();
  console.log('Server running on %s', server.info.uri);
};

process.on('unhandledRejection', (err) => {
  console.log(err);
  process.exit(1);
});
init();

We call h.state with the key and value.

Also, we can write:

const Hapi = require('@hapi/hapi');
const init = async () => {
  const server = Hapi.server({
    port: 3000,
    host: '0.0.0.0'
  });

  server.route({
    path: '/',
    method: 'GET',
    async handler (request, h) {
      return h.response('Hello').state('data', { firstVisit: false });
    },
  });
  await server.start();
  console.log('Server running on %s', server.info.uri);
};

process.on('unhandledRejection', (err) => {
  console.log(err);
  process.exit(1);
});
init();

to do the same thing.

We can override the options by writing:

const Hapi = require('@hapi/hapi');
const init = async () => {
  const server = Hapi.server({
    port: 3000,
    host: '0.0.0.0'
  });

  server.route({
    path: '/',
    method: 'GET',
    async handler (request, h) {
      return h.response('Hello').state('data', 'test', { encoding: 'none' });
    },
  });
  await server.start();
  console.log('Server running on %s', server.info.uri);
};

process.on('unhandledRejection', (err) => {
  console.log(err);
  process.exit(1);
});
init();

We set the encoding option by calling the state method with a 3rd argument.

Conclusion

We can add caching and set cookies in our web app with Hapi.