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query

query is a directive executor who decodes/encodes a field from/to URL querystring parameters, i.e. http.Request.URL.Query().

Signature​

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

Decoding​

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

Usage​

type ListUsersInput struct {
	IsMember bool  `in:"query=is_member"`
	AgeRange []int `in:"query=age_range[],age_range"`
}
Request (URL query)ListUsersInput
GET /users?is_member=1&age_range[]=3&age_range[]=5
{
    IsMember: true,
    AgeRange: []int{3, 5},
}
GET /users?age_range=3&age_range=5
{
    IsMember: false,
    AgeRange: []int{3, 5},
}
GET /users?is_member=true
{
    IsMember: true,
    AgeRange: []int{},
}

Runable Example​

package main

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

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

type ListUsersInput struct {
	IsMember bool  `in:"query=is_member"`
	AgeRange []int `in:"query=age_range[],age_range"`
}

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

func main() {
	router := chi.NewRouter()
	router.With(
		httpin.NewInput(ListUsersInput{}),
	).Get("/users", ListUsers)

	r, _ := http.NewRequest("GET", "/users?is_member=1&age_range=18&age_range=60", nil)

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

Output:

input: &main.ListUsersInput{IsMember:true, AgeRange:[]int{18, 60}}

Encoding​

query will encode the field to the first key, i.e. KEY1, results in ?KEY1=VALUE.

Runable Example​

package main

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

	"github.com/ggicci/httpin"
)

type ListUsersInput struct {
	IsMember bool  `in:"query=is_member"`
	AgeRange []int `in:"query=age_range[],age_range"`
}

func main() {
	input := &ListUsersInput{
		IsMember: true,
		AgeRange: []int{18, 60},
	}
	r, _ := httpin.NewRequest("GET", "/users", input)
	data, _ := httputil.DumpRequest(r, false)
	fmt.Printf("%s\n", data)
}

Output:

GET /users?age_range%5B%5D=18&age_range%5B%5D=60&is_member=true HTTP/1.1