How to use TLS Conn.Read to read a large size of data - go

Question

I'm trying with tls.Conn i.e, conn.Read from golang crypto/tls to read a large size of data. However when all the data is read out, then the program will never stop. Why? My simplified code is as follow:
// server
func main() {
log.SetFlags(log.Lshortfile)
cer, err := tls.LoadX509KeyPair("server.pem", "server.key")
if err != nil {
log.Println(err)
return
}
config := &tls.Config{Certificates: []tls.Certificate{cer}}
ln, err := tls.Listen("tcp", ":2000", config)
if err != nil {
log.Println(err)
return
}
defer ln.Close()
for {
conn, err := ln.Accept()
if err != nil {
log.Println(err)
continue
}
go handleConnection(conn)
}
}
func handleConnection(conn net.Conn) {
defer conn.Close()
buf := make([]byte, 0)
tmp := make([]byte, 1000)
totalSize := 0
for {
n, err := conn.Read(tmp) //after read all the data, server stucked here
totalSize += n
if err != nil {
if err != io.EOF {
log.Printf("prover: conn: read: %s", err)
}
break
}
buf = append(buf, tmp[:n]...)
}
n, err := conn.Write([]byte("finished"))
if err != nil {
log.Println(n, err)
return
}
}
The logic of the client:
// client
func main() {
log.SetFlags(log.Lshortfile)
conf := &tls.Config{
InsecureSkipVerify: true,
}
conn, err := tls.Dial("tcp", "127.0.0.1:2000", conf)
if err != nil {
log.Println(err)
return
}
defer conn.Close()
writeData := make([]byte, 4096)
n, err := conn.Write(writeData)
if err != nil {
log.Println(n, err)
return
}
fmt.Println("finish writing")
buf := make([]byte, 4096)
n, err = conn.Read(buf)
if err != nil {
log.Println(n, err)
}
fmt.Print("finish reading")
}
How can I read a large size of data in the server and after the data is completely read out, then the server will send a response to the client. I tried with net.Conn (TCPConn), this logic works. WHy?