Patch Field

Introduced in v0.12.0.

import "github.com/ggicci/httpin/patch"

patch.Field is a generic struct:

type Field[T any] struct {
	Value T
	Valid bool
}

It takes in a type parameter as the type of the actual value it holds, and wraps in a Valid field as a sentinel, which is used to tell "the field is missing" from "the field is empty".

Use patch.Field[T] as the type of a field.

JSON Payload Request

import "github.com/ggicci/httpin/patch"

type AccountPatchPayload struct {
	Username patch.Field[string]
	Gender   patch.Field[string]
	Age      patch.Field[int]
}

func PatchAccount(rw http.ResponseWriter, r *http.Request) {
	var payload AccountPatchPayload
	json.NewDecoder(r.Body).Decode(&payload)

	if !payload.Username.Valid {
		// field "Username" is missing (not found or null)
	}
}

caution

In this package, and in a JSON object, a field is defined as a missing field when:

• if the name/key of the field is not found in the JSON object
• or the name/key of the field is present but its value is null, null is interpreted as having no value

For example, in the following two JSON objects, field Name is missing:

{ "Age": 18 }
{ "Name": null, "Age": 18 }

Form Request

import "github.com/ggicci/httpin/patch"

type AccountPatchForm struct {
	Username patch.Field[string] `in:"form=username"`
	Gender   patch.Field[string] `in:"form=gender"`
	Age      patch.Field[int]    `in:"form=age"`
}

func PatchAccount(rw http.ResponseWriter, r *http.Request) {
    payload := r.Context().Value(httpin.Input).(*AccountPatchForm)

	if !payload.Username.Valid {
		// field "Username" is missing (not found or null)
	}
}

caution

In this package, in a querystring, form or multipart-form request, a field is defined as a missing field when:

• the name/key of the field doesn't appear in the request

For example, in the following request, gender field is empty but not missing (i.e. Gender.Valid == true), while age field is missing (i.e. Age.Valid == false):

GET /tasks?username=ggicci&gender=