feat(standard-validator): Add standard schema validation

[muningis]

Group of different Schema Validation libraries authors has agreed on a standard schema, so other libraries, don't have even to care what validation library you're using, as typings and output must match spec.

[changeset-bot]

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Latest commit: 986c34f

The changes in this PR will be included in the next version bump.

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@hono/standard-validator	Minor

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[EdamAme-x]

great!!

[yusukebe]

Hi @muningis

This is awesome! The code below actually works!

import { Hono } from 'hono'
import { sValidator } from '@hono/standard-validator'
import { type } from 'arktype'
import * as v from 'valibot'
import { z } from 'zod'

const aSchema = type({
  agent: 'string',
})

const vSchema = v.object({
  slag: v.string(),
})

const zSchema = z.object({
  name: z.string(),
})

const app = new Hono()

app.get(
  '/:slag',
  sValidator('header', aSchema),
  sValidator('param', vSchema),
  sValidator('query', zSchema),
  (c) => {
    const headerValue = c.req.valid('header')
    const paramValue = c.req.valid('param')
    const queryValue = c.req.valid('query')
    return c.json({ headerValue, paramValue, queryValue })
  }
)

const res = await app.request('/foo?name=foo', {
  headers: {
    agent: 'foo',
  },
})

console.log(await res.json())

/**
{
  headerValue: {
    agent: "foo",
  },
  paramValue: {
    slag: "foo",
  },
  queryValue: {
    name: "foo",
  },
}
 */

I'll review this. First, can you add the CI like this: https://github.com/honojs/middleware/blob/main/.github/workflows/ci-hello.yml

[muningis]

Hy! Sure, will do it later today once I'm back from work.

[yusukebe]

Hey @fabian-hiller ! Can you review this?

[fabian-hiller]

Yes, I will review it later. Make sure to add Hono to the Standard Schema ecosystem list once this is merged. 😎

[fabian-hiller]

Once Standard Schema is accepted by the JS community, Hono could try to implement it natively to remove the adapter altogether.

[yusukebe]

LGTM!

[yusukebe]

Hey @fabian-hiller. This looks good to me. Can you approve this?

[fabian-hiller]

Rest LGTM

[fabian-hiller]

Should this be Hook<Schema, E, P, Target> instead? At least the Valibot validator middleware implementation is using the schema object and not its output. But maybe this is a bug in the Valibot validator middleware.

[muningis]

Valibot and Zod has different Hook implementation, this one is based on Zod.

[fabian-hiller]

@yusukebe should this be uniformed?

[yusukebe]

@yusukebe should this be uniformed?

It's better to unify the implementation. Following Zod Validator is good. The current implementation in this PR is okay, but we should change the implementation of the Valibot Validator.

[fabian-hiller]

This is probably not a problem in this implementation, but the Valibot validator middleware uses output instead of data for the output value. Could it be that the Valibot implementation should be updated?

[muningis]

Hm. Does valibot transform values if it fails to validate? Personally, I think, ideally, we should return whatever was passed, before transformations and defaults, in case of failed validation.

[fabian-hiller]

Yes, Valibot always provides an output that can contain transformations when using safeParse or safeParseAsync. I have no opinion on the implementation. I just noticed it.

[muningis]

Working with original data IMO has slightly more better handling if there’s something you need to do what’s not available/possible with schema and/or want to use it for observability. Would be nice to hear what @yusukebe has to say on this.

[yusukebe]

It's okay with @muningis's implementation for this Standard Validator. It's helpful to see the original data. Regarding the Validabot Validator, I think both updating and not are okay.

[muningis]

Would probably be good/nice to update Valibot Validator, but that would be ugly breaking change :/

[muningis]

Anything else we should do, or this is good to go?

[yusukebe]

This is good! Let's land it.

@muningis Thank you for the great work. Standardizing the schema libs for the validator will be a big thing for Hono and the TS/JS ecosystem!

@fabian-hiller Thank you for the review!

[Eghizio]

Does it work with OpenAPI like @hono/zod-openapi or is it planned to?

[muningis]

@Eghizio - @hono/zod-openapi depeneds on @asteasolutions/zod-to-openapi.

From my understanding, @asteasolutions/zod-to-openapi relies on internals of zod (which differs from Valibot, Arktype or Effect Schema). What they have in common, is output and typings of that. Since this supports zod, it should be fine with @hono/zod-openapi when using just zod.

[Eghizio]

Thanks @muningis 🙇
It would be amazing to have all of the standard schema compliant validators allow for generating Open API spec & Swagger out of the box in Hono ✨