vikunja-api/docs/concepts.md

Achitectural concepts

Vikunja was built with a maximum flexibility in mind while developing. To achive this, I built a set of easy-to-use functions and respective web handlers, all represented through interfaces.

CRUDable

This interface defines methods to Create/Read/ReadAll/Update/Delete something. In order to use the common web handler, the struct mus implement this and the rights interface.

Each of these methods is called on an instance of a struct like so:

func (l *List) ReadOne() (err error) {
	*l, err = GetListByID(l.ID)
	return
}

In that case, it takes the ID saved in the struct instance, gets the full list object and fills the original object with it. (See parambinder to understand where that ID is coming from).

All functions should behave like this, if they create or update something, they should return the created/updated struct instance. The only exception is ReadAll() which returns an interface. Usually this is an array, because, well you cannot make an array of a set type (If you know a way to do this, don't hesitate to drop me a message).