Server-Side Development with Hapi.js — 400 Series Errors

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.

Conflict

We can return a 409 response ith @hapi/boom with the Boom.conflict method by writing:

const Hapi = require('@hapi/hapi');  
const Boom = require('@hapi/boom');  
const init = async () => {  
  const server = new Hapi.Server({  
    port: 3000,  
    host: '0.0.0.0'  
  });  
  server.route({  
    method: 'GET',  
    path: '/',  
    handler(request, h) {        
      throw Boom.conflict('conflict');  
    }  
  });  
  await server.start();  
  console.log('Server running at:', server.info.uri);  
};  
process.on('unhandledRejection', (err) => {  
  console.log(err);  
  process.exit(1);  
});  
init();

Then when we go to the / route, we get:

{"statusCode":409,"error":"Conflict","message":"conflict"}

as the response.

Resource Gone Error

We can return the resource gone error by writing:

const Hapi = require('@hapi/hapi');  
const Boom = require('@hapi/boom');  
const init = async () => {  
  const server = new Hapi.Server({  
    port: 3000,  
    host: '0.0.0.0'  
  });  
  server.route({  
    method: 'GET',  
    path: '/',  
    handler(request, h) {        
      throw Boom.resourceGone('gone');  
    }  
  });  
  await server.start();  
  console.log('Server running at:', server.info.uri);  
};  
process.on('unhandledRejection', (err) => {  
  console.log(err);  
  process.exit(1);  
});  
init();

We call Boom.resourceGone to create the error object. The argument we pass in is the message.

Then we get:

{"statusCode":410,"error":"Gone","message":"gone"}

as the response when we go to / .

Length Required

We call the Boom.lengthRequired method to return a 411 response.

For example, we can write:

const Hapi = require('@hapi/hapi');  
const Boom = require('@hapi/boom');  
const init = async () => {  
  const server = new Hapi.Server({  
    port: 3000,  
    host: '0.0.0.0'  
  });  
  server.route({  
    method: 'GET',  
    path: '/',  
    handler(request, h) {        
      throw Boom.lengthRequired('length required');  
    }  
  });  
  await server.start();  
  console.log('Server running at:', server.info.uri);  
};  
process.on('unhandledRejection', (err) => {  
  console.log(err);  
  process.exit(1);  
});  
init();

We pass in the message as the argument.

Then we get:

{"statusCode":411,"error":"Length Required","message":"length required"}

as the response.

Precondition Failed Error

We can call Boom.preconditionFailed to returns a 412 response.

For instance, we can write:

const Hapi = require('@hapi/hapi');  
const Boom = require('@hapi/boom');  
const init = async () => {  
  const server = new Hapi.Server({  
    port: 3000,  
    host: '0.0.0.0'  
  });  
  server.route({  
    method: 'GET',  
    path: '/',  
    handler(request, h) {        
      throw Boom.preconditionFailed('precondition failed');  
    }  
  });  
  await server.start();  
  console.log('Server running at:', server.info.uri);  
};  
process.on('unhandledRejection', (err) => {  
  console.log(err);  
  process.exit(1);  
});  
init();

to pass in a message.

Entity Too Large

To return a 413 entity too large response, we call Boom.entityTooLarge .

For instance, we can write:

const Hapi = require('@hapi/hapi');  
const Boom = require('@hapi/boom');  
const init = async () => {  
  const server = new Hapi.Server({  
    port: 3000,  
    host: '0.0.0.0'  
  });  
  server.route({  
    method: 'GET',  
    path: '/',  
    handler(request, h) {        
      throw Boom.entityTooLarge('too big');  
    }  
  });  
  await server.start();  
  console.log('Server running at:', server.info.uri);  
};  
process.on('unhandledRejection', (err) => {  
  console.log(err);  
  process.exit(1);  
});  
init();

to throw the error.

And we get:

{"statusCode":413,"error":"Request Entity Too Large","message":"too big"}

as the response.

Unsupported Media Type

We can call Boom.unsupportedMediaType to throw a 415 unsupported media type error:

const Hapi = require('@hapi/hapi');  
const Boom = require('@hapi/boom');  
const init = async () => {  
  const server = new Hapi.Server({  
    port: 3000,  
    host: '0.0.0.0'  
  });  
  server.route({  
    method: 'GET',  
    path: '/',  
    handler(request, h) {        
      throw Boom.unsupportedMediaType('that media is not supported');  
    }  
  });  
  await server.start();  
  console.log('Server running at:', server.info.uri);  
};  
process.on('unhandledRejection', (err) => {  
  console.log(err);  
  process.exit(1);  
});  
init();

Then we get:

{"statusCode":415,"error":"Unsupported Media Type","message":"that media is not supported"}

as the response.

Conclusion

We can return kinds of error responses with Hapi Boom.