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header

header is a directive executor who decodes/encodes a field from/to HTTP headers, i.e. http.Request.Header.

Signature​

Name: "header"
Args: KEY1 [,KEY2 [,KEY3, ...]]

Decoding​

header will examine values of the keys one by one (KEY1 -> KEY2 -> ...) from the HTTP headers, the first non-empty value will be used to set the corresponding field of the input struct.

caution

The keys will be normalized, see CanonicalHeaderKey, e.g. the header key of Content-Type and content-type are the same, which works like case-insensitive.

Usage​

type TokenInput struct {
	Token string `in:"header=x-api-token,Authorization"`
}
Request (Header)TokenInput
GET /users HTTP/1.1

Host: foo.example
X-API-Token: abc
{ Token: "abc" }
GET /users HTTP/1.1

Host: foo.example
x-api-token: abc
{ Token: "abc" }
GET /users HTTP/1.1

Host: foo.example
Authorization: good
{ Token: "good" }
GET /users HTTP/1.1

Host: foo.example
X-Api-Token: apple
Authorization: banana
{ Token: "apple" }

// Check order: X-Api-Token -> Authorization

Runable Example​

package main

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

	"github.com/ggicci/httpin"
	"github.com/go-chi/chi/v5"
)

type UpdateAccountInput struct {
	AccessToken   string `in:"header=x-myapp-access-token"`
	ClientVersion int    `in:"header=x-myapp-client-version"`
}

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

func main() {
	router := chi.NewRouter()
	router.With(
		httpin.NewInput(UpdateAccountInput{}),
	).Patch("/me", UpdateAccount)

	r, _ := http.NewRequest("PATCH", "/me", nil)
	r.Header.Set("x-myapp-access-token", "rainbow")
	r.Header.Set("X-Myapp-Client-Version", "284")
	r.Body = io.NopCloser(nil)

	rw := httptest.NewRecorder()
	router.ServeHTTP(rw, r)
}

Output:

input: &main.UpdateAccountInput{AccessToken:"rainbow", ClientVersion:284}

Encoding​

header will encode the field value to the HTTP headers, the first key will be used, i.e. KEY1, results in http.Request.Header.Set(KEY1, VALUE).

Runable Example​

package main

import (
	"fmt"
	"net/http/httputil"

	"github.com/ggicci/httpin"
)

type UpdateAccountInput struct {
	AccessToken   string `in:"header=x-myapp-access-token"`
	ClientVersion int    `in:"header=x-myapp-client-version"`
}

func main() {
	payload := &UpdateAccountInput{
		AccessToken:   "rainbow",
		ClientVersion: 813,
	}
	r, _ := httpin.NewRequest("PATCH", "/me", payload)
	data, _ := httputil.DumpRequest(r, true)
	fmt.Printf("%s\n", data)
}

Output:

PATCH /me HTTP/1.1
X-Myapp-Access-Token: rainbow
X-Myapp-Client-Version: 813