// Copyright 2018 The etcd Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Package httputil provides HTTP utility functions.
package httputil

import (
	"io"
	"net"
	"net/http"
)

// GracefulClose drains http.Response.Body until it hits EOF
// and closes it. This prevents TCP/TLS connections from closing,
// therefore available for reuse.
// Borrowed from golang/net/context/ctxhttp/cancelreq.go.
func GracefulClose(resp *http.Response) {
	io.Copy(io.Discard, resp.Body)
	resp.Body.Close()
}

// GetHostname returns the hostname from request Host field.
// It returns empty string, if Host field contains invalid
// value (e.g. "localhost:::" with too many colons).
func GetHostname(req *http.Request) string {
	if req == nil {
		return ""
	}
	h, _, err := net.SplitHostPort(req.Host)
	if err != nil {
		return req.Host
	}
	return h
}