decoder

Introduced in v0.10.0.

decoder is a SPECIAL directive executor who overrides the decoder used to decode the value of the corresponding field.

Definition

Name: "decoder"
Args: DECODER_NAME

When there's a decoder directive defined for a field, the specified named decoder will be used rather than the default one which is auto-selected by the type of the field.

Usage

func decodeDate(value string) (interface{}, error) {
    return time.Parse("2006-01-02", value)
}

func init() {
    // Before using the decoder, you need to register it.
    httpin.RegisterNamedDecoder("date", httpin.ValueTypeDecoderFunc(decodeDate))
}

type ListUsersInput struct {
    Gender string `in:"form=gender"`
    // By default, the decoder is auto-selected by the field type, which is of `time.Time`.
    // When decoder directive is set, the specified named decoder "date" will be used instead.
    Birthday time.Time `in:"form=birthday;decoder=date"`
}

Run Example

package main

import (
    "fmt"
    "net/http"
    "net/http/httptest"
    "time"

    "github.com/ggicci/httpin"
    "github.com/justinas/alice"
)

func init() {
    httpin.RegisterNamedDecoder("date", httpin.ValueTypeDecoderFunc(decodeDate))
}

func decodeDate(value string) (interface{}, error) {
    return time.Parse("2006-01-02", value)
}

type ListUsersInput struct {
    Gender string `in:"form=gender"`
    // By default, the decoder is auto-selected by the field type, which is of `time.Time`.
    // When decoder directive is set, the specified named decoder "date" will be used instead.
    Birthday time.Time `in:"form=birthday;decoder=date"`
}

func ListUsers(rw http.ResponseWriter, r *http.Request) {
    input := r.Context().Value(httpin.Input).(*ListUsersInput)
    fmt.Printf("input: %#v\n", input)
}

func main() {
    mux := http.NewServeMux()
    mux.Handle("/users", alice.New(
        httpin.NewInput(ListUsersInput{}),
    ).ThenFunc(ListUsers))

    r, _ := http.NewRequest("GET", "/users?gender=male&birthday=1991-11-10", nil)
    rw := httptest.NewRecorder()
    mux.ServeHTTP(rw, r)
}