JSON decoding benchmarks

main.go

package main

import (
	"encoding/json"
	"io/ioutil"
	"net/http"
)

func createMovieHandlerUnmarshal(w http.ResponseWriter, r *http.Request) {
	var input struct {
		Title   string   `json:"title"`
		Year    int32    `json:"year"`
		Runtime int32    `json:"runtime"`
		Genres  []string `json:"genres"`
	}

	body, err := ioutil.ReadAll(r.Body)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	err = json.Unmarshal(body, &input)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
}

func createMovieHandlerDecoder(w http.ResponseWriter, r *http.Request) {
	var input struct {
		Title   string   `json:"title"`
		Year    int32    `json:"year"`
		Runtime int32    `json:"runtime"`
		Genres  []string `json:"genres"`
	}

	err := json.NewDecoder(r.Body).Decode(&input)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
}

main_test.go

package main

import (
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
)

const body = `{"title":"Moana","year":2016,"runtime":107, "genres":["animation","adventure"]}`

func BenchmarkUnmarshal(b *testing.B) {
	w := httptest.NewRecorder()

	for n := 0; n < b.N; n++ {
		r, err := http.NewRequest(http.MethodPost, "", strings.NewReader(body))
		if err != nil {
			b.Fatal(err)
		}

		createMovieHandlerUnmarshal(w, r)
	}
}

func BenchmarkDecoder(b *testing.B) {
	w := httptest.NewRecorder()

	for n := 0; n < b.N; n++ {
		r, err := http.NewRequest(http.MethodPost, "", strings.NewReader(body))
		if err != nil {
			b.Fatal(err)
		}

		createMovieHandlerDecoder(w, r)
	}
}