fix: add timeout to proxy connection reading and writing

[Sniper91]

fast http client may hang forever when reading from proxy connection.
code to reproduce the bug:

proxy server

package main

import (
	"log"
	"net/http"
	"time"
)

func main() {
	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		log.Printf("Received request %s %s %s\n", r.Method, r.Host, r.RemoteAddr)
		if r.Method == http.MethodConnect {
			time.Sleep(1 * time.Hour) // proxy server may hang a long time for some reason
		}
	})
	log.Fatal(http.ListenAndServe(":8181", handler))
}

fast http client hangs and ignores the timeout because proxy server doesn't response

package main

import (
	"fmt"
	"os"
	"time"

	"github.com/valyala/fasthttp"
	"github.com/valyala/fasthttp/fasthttpproxy"
)

func main() {
	client := fasthttp.Client{
		ReadTimeout:  5 * time.Second,
		WriteTimeout: 5 * time.Second,
		Dial:         fasthttpproxy.FasthttpHTTPDialerTimeout("127.0.0.1:8181", 5*time.Second),
	}
	req := fasthttp.AcquireRequest()
	req.SetRequestURI("https://localhost:8080/")
	req.Header.SetMethod(fasthttp.MethodGet)
	resp := fasthttp.AcquireResponse()
	err := client.Do(req, resp)
	fasthttp.ReleaseRequest(req)
	if err == nil {
		fmt.Printf("DEBUG Response: %s\n", resp.Body())
	} else {
		fmt.Fprintf(os.Stderr, "ERR Connection error: %v\n", err)
	}
	fasthttp.ReleaseResponse(resp)
}

http client from standard library behaves normally

package main

import (
	"fmt"
	"io"
	"net/http"
	"net/url"
	"os"
	"time"
)

func main() {
	uu, _ := url.Parse("http://localhost:8181")
	client := &http.Client{
		Timeout: 5 * time.Second,
		Transport: &http.Transport{
			Proxy: http.ProxyURL(uu),
		},
	}
	resp, err := client.Get("https://localhost:8080/")
	if err != nil {
		fmt.Println(err)
	}
	io.Copy(os.Stdout, resp.Body)
	resp.Body.Close()
}

The implementation refers code from https://github.com/golang/go/blob/fe9b3c339978f37aad53875d9e6d2df35a1996ad/src/net/http/transport.go#L1725

[erikdubbelboer]

Why not just set a deadline on the connection? https://pkg.go.dev/net#Conn.SetDeadline

[Sniper91]

Why not just set a deadline on the connection? https://pkg.go.dev/net#Conn.SetDeadline

The connection will be read or write after function return. Calling net#Conn.SetDeadline here may cause unexpected os.ErrDeadlineExceeded error.

[erikdubbelboer]

You can call conn.SetDeadline(time.Time{}) before returning from the function to remove the deadline again.

[Sniper91]

You can call conn.SetDeadline(time.Time{}) before returning from the function to remove the deadline again.

Oh, It's more concise. I've already reimplemented this PR.

[erikdubbelboer]

Thanks!