querystring with property of type number fails

[AmosSzust]

querystring with property of type number fails

[metcoder95]

You can validate its format but nothing else unless manually coerced

[mcollina]

We might think of enabling coerceTypes by default in v5.

[Eomm]

We coerce the type already:
https://github.com/fastify/ajv-compiler?tab=readme-ov-file#ajv-configuration

https://runkit.com/embed/4gzt2onngmx9

Could you add a Minimal, Reproducible Example?

Without it, we are unable to help you.

[metcoder95]

You can solve this by either enabling coerceTypes on ajv or parse the req.query property and parse the type before doing the validation using the preValidation hook.

Fastify uses find-my-way as a router, and find-my-way uses fast-querystring which mimics the behaviour of node:querystring in a more performant way, and by default a query string number will always be parsed as string.

[AmosSzust]

and by default a query string number will always be parsed as string.

After struggling with it, I realized that. I thought I did something wrong with fastify. So there is no real meaning for validating query string params as they are always string.

[gurgunday]

Why are these tests passing?

'use strict'

const { test } = require('tap')
const Fastify = require('..')

test('querystring', t => {
  t.plan(4)

  const fastify = Fastify()

  fastify.get('/:id', {
    schema: {
      querystring: {
        type: 'object',
        properties: {
          a: { type: 'number' }
        }
      }
    }
  }, function (req, reply) {
    t.equal(req.query.a, 42)
    reply.code(200).send()
  })

  fastify.inject({
    method: 'GET',
    url: '/12?a=42'
  }, (err, res) => {
    t.error(err)
    t.equal(res.statusCode, 200)
    t.equal(res.payload, '')
  })
})

test('params', t => {
  t.plan(4)

  const fastify = Fastify()

  fastify.get('/:a', {
    schema: {
      params: {
        type: 'object',
        properties: {
          a: { type: 'integer' }
        }
      }
    }
  }, function (req, reply) {
    t.equal(req.params.a, 42)
    reply.code(200).send()
  })

  fastify.inject({
    method: 'GET',
    url: '/42'
  }, (err, res) => {
    t.error(err)
    t.equal(res.statusCode, 200)
    t.equal(res.payload, '')
  })
})

[AmosSzust]

Silly me, I initialize fastify like this

  ajv: {
    customOptions: {
      coerceTypes: false,
    },
  },

and I don't event remember why I did that, I copied this from another project I did and forgot about it. Thanks.