httptest413.go

package main

import (
	"crypto/tls"
	"fmt"
	"golang.org/x/net/http2"
	"io"
	"io/ioutil"
	"log"
	"time"
	"net/http"
	"net/http/httptest"
	"strings"
)

type ChunkyReader struct {
	R io.Reader // underlying reader
	N int64     // max bytes to read at a time
}

func (l *ChunkyReader) Read(p []byte) (n int, err error) {
	if int64(len(p)) > l.N {
		p = p[0:l.N]
	}
	n, err = l.R.Read(p)
	//l.N -= int64(n)
	return
}

func main() {

	ts := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		r.Body.Close()
		w.WriteHeader(http.StatusRequestEntityTooLarge)
		log.Printf("Http: %s", r.Proto)
		fmt.Fprintln(w, "abc")
	}))
	http2.ConfigureServer(ts.Config, &http2.Server{})
	ts.TLS = ts.Config.TLSConfig
	ts.StartTLS()
	defer ts.Close()

	tr := &http.Transport{TLSClientConfig: &tls.Config{
		InsecureSkipVerify: true,
	}}
	http2.ConfigureTransport(tr)
	client := &http.Client{
		Transport: tr,
	}

	// if its too small the script will work.
	raw := strings.Repeat("A", 65537)
	log.Printf("len(data)=%v\n", len(raw))
	sr := &ChunkyReader{strings.NewReader(raw), 128}
	req, err := http.NewRequest("POST", ts.URL, sr)
	if err != nil {
		log.Fatal(err)
	}

	for i := 0; i < 50; i++ { // racy?
		log.Printf("client.Do next\n")
		res, err := client.Do(req)
		log.Printf("client.Do done\n")
		if err != nil || res.StatusCode != 413 {
			scode := 0
			if res != nil {
				scode = res.StatusCode
			}
			log.Fatalf("Expected Status Code 413, Got status code: %d, error: %v", scode, err)
		}
		n, err := io.Copy(ioutil.Discard, res.Body)
		log.Printf("done Reading the server response's body n=(%v) err=%v\nres.headers: %v\n", n, err, res.Header)
		_ = res.Body.Close()
		time.Sleep(1 * time.Millisecond)
	}
}