Efficient way to handle error cases in REST Apis - node.js

Question

I am writing a REST API in node.js. I expect at max 5 parameters to arrive in my GET Request. If there are unidentified parameters I wish to send 400 Bad Request.
Currently I am handling it in the following way:
server.route({
method: "GET",
path : "/test",
handler : function (request, reply) {
if (request.query.a || request.query.b || request.query.c || request.query.d || request.query.e)
{
// do some processing
}
else {
reply("No valid parameters").code(400);
}
}
});
Right now this does not handle the case if there are some valid and some invalid cases. I can solve that by using more if conditions. But I was just wondering if there is a standard or more efficient method which is used by developers

Answer 1

Hapi has built-in validation support. You can use Joi to validate the query:
var Joi = require('joi');
...
server.route({
method: 'GET',
path: '/test',
config: {
validate: {
query: {
a: Joi.string(),
b: Joi.string(),
c: Joi.string(),
d: Joi.string(),
e: Joi.string()
}
}
},
handler: function (request, reply) {
return reply('ok');
}
});
If you send a request to /test?g=foo, then you get the following response:
{ statusCode: 400,
error: 'Bad Request',
message: '"g" is not allowed',
validation: { source: 'query', keys: [ 'g' ] } }

Answer 2

You can manually do this, but you are better off using a REST framework like mongoose or loopback (strongloop) to do the validation and error handling and other boilerplate code like model binding.

Answer 3

Perhaps you should consider the use of a framework, like Express, to use a middleware which is simply code you can reuse in different routes.
A simple pseudo/example looks like this
var app = express();
// a middleware with no mount path; gets executed for every request to the app
app.use(function (req, res, next) {
if (req.query.a && req.query.b) {
return next()
}
else {
return res.status(400).send('Not OK');
}
});
// a route and its handler function (middleware system) which handles GET requests to /user/:id
app.get('/user/:id', function (req, res, next) {
return res.send('OK');
});
// a different route, same middleware
app.get('/customer/:id', function (req, res, next) {
return res.send('OK');
});