===== http.Server =====

==== What is it? ====
`http.Server` is the configurable HTTP server type in Go’s `net/http` package.
It gives you more control than `http.ListenAndServe()` (timeouts, TLS, graceful shutdown, etc.).

==== What is it used for? ====
  * Run an HTTP server with production-ready settings (timeouts).
  * Support graceful shutdown.
  * Serve HTTPS (TLS).
  * Customize handler, error logger, max header size, etc.

==== Key fields (common) ====
  * `Addr`: address to listen on (e.g. `":8080"`)
  * `Handler`: your router/handler (e.g. `mux`)
  * `ReadHeaderTimeout`: limit time to read request headers
  * `ReadTimeout`: total time to read request (headers + body)
  * `WriteTimeout`: time allowed to write response
  * `IdleTimeout`: keep-alive idle time
  * `ErrorLog`: custom logger
  * `MaxHeaderBytes`: limit request header size

==== Example: server with timeouts ====
<code go>
package main

import (
    "context"
    "log"
    "net/http"
    "os"
    "os/signal"
    "syscall"
    "time"
)

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
        w.WriteHeader(http.StatusOK)
        w.Write([]byte("ok"))
    })

    srv := &http.Server{
        Addr:              ":8080",
        Handler:           mux,
        ReadHeaderTimeout: 5 * time.Second,
        ReadTimeout:       10 * time.Second,
        WriteTimeout:      10 * time.Second,
        IdleTimeout:       60 * time.Second,
    }

    // Start server in background goroutine
    go func() {
        log.Println("listening on", srv.Addr)
        if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
            log.Fatal(err)
        }
    }()

    // Graceful shutdown on SIGINT/SIGTERM
    stop := make(chan os.Signal, 1)
    signal.Notify(stop, os.Interrupt, syscall.SIGTERM)
    <-stop

    ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
    defer cancel()

    log.Println("shutting down...")
    _ = srv.Shutdown(ctx)
}
</code>

==== Notes / pitfalls ====
  * `ListenAndServe()` blocks; use a goroutine if you also need to handle shutdown signals.
  * Always set timeouts in production to reduce slowloris-style attacks.
  * Use `Shutdown(ctx)` for graceful shutdown; use `Close()` for immediate close.

==== Related ====
  * [[go:stdlib:http_server|HTTP server]]
  * [[go:stdlib:http_server_listenandserve|http.ListenAndServe]]
  * [[go:concurrency:context|context.Context]]

==== Hard words (English) ====
  * **configurable** /kənˈfɪɡjərəbəl/: cấu hình được
  * **timeout** /ˈtaɪmaʊt/: hết thời gian chờ
  * **graceful shutdown** /ˈɡreɪsfəl ˈʃʌtdaʊn/: tắt êm (xử lý xong rồi tắt)
  * **TLS** /ˌtiː el ˈes/: bảo mật truyền tải (HTTPS)
  * **keep-alive** /ˌkiːp əˈlaɪv/: giữ kết nối
  * **slowloris** /ˈsloʊˌlɔːrɪs/: kiểu tấn công giữ kết nối chậm
  * **signal** /ˈsɪɡnəl/: tín hiệu hệ điều hành