Implement RFC7807

[Uzlopak]

Prerequisites

• [X] I have written a descriptive issue title
• [X] I have searched existing issues to ensure the feature has not already been requested

🚀 Feature Proposal

We could implement a toRFC7807-method, which creates RFC7807-compatible JSON Response to FastifyError and use it in fastify 4 by default.

So we could create a new Error like this

  const NewError = createError('CODE', 'hey %s, I like your %s %s')
  const err = new NewError('alice', 'attitude', 'see you')

and then the resulting JSON would be:

{
    type: "FastifyError",
    title: "FastifyError", 
    status: 500, // <-- statusCode
    detail: 'hey alice, I like your attitude', // <-- message 
    instance: '', // <-- here could be the route
    code: 'CODE',
    details: { }, // here could be the ajv error codes.
}

Motivation

No response

Example

No response

[mcollina]

This would be interesting. It might be too late for Fastify v4 but would you like to assemble a PR anyway?

[Uzlopak]

Is fastify-error the right place? Or should it be done in a different place?

[mcollina]

It should be done both here and in Fastify

[Uzlopak]

Reopening for #119

[mcollina]

How about we ads a new factory for RFC7807 errors?

[jsumners]

How about we ads a new factory for RFC7807 errors?

Seems like a good solution.