Stuck on reading

[markx]

When I tried to use this client to connect to some mud servers, I found that sometimes it doesn't print all the text. After some digging, I found that the program got stuck on conn.Read when it's fed with a big buffer.

After more digging, I found out that the c.r.Buffered() returns more than 0, so it get stuck at c.ReadByte() in the next iteration. https://github.com/ziutek/telnet/blob/master/conn.go#L306

Also, I'm not sure if it's related, but usually it gets stuck in the middle on a line.

I'm not familiar with telnet or your client enough to solve this. Could you take a look?

Below is a snippet that can show the problem. You can run it multiple times to see how the problem is like.

func main() {
    conn, err := telnet.Dial("tcp", "bat.org:23")
    if err != nil {
        log.Fatal(err)
    }

    for {
        data := make([]byte, 512) // if I change the buffer size to 1, it doesn't hang
        n, err := conn.Read(data)
        if n > 0 {
            fmt.Print(string(data))
        }

        if err != nil {
            log.Fatal(err)
        }
    }
}

[markx]

I found the problem!

The Read call hangs when the servers send messages that end with a command, but ReadByte will try to read another byte.

I submitted a PR #16 , which has some API behavior changes... There could be other solutions, but let me know how you think about my changes.

[ziutek]

I've fixed this issue before read you PR.

It seems that tryReadByte works like intended.

The bug was in use ReadByte in Read instead of raw tryReadByte.

[ziutek]

After this fix, the Read can still hang after read real byte. I fixed this case. I added bat.org example. Fill free to improve it if you want. Try the last commit.

[markx]

Yeah thanks. This is a better fix.