urlutil.go

/*
Copyright 2016 The Kubernetes Authors All rights reserved.

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.
*/

package urlutil

import (
	"net"
	"net/url"
	"path"
	"path/filepath"
)

// URLJoin joins a base URL to one or more path components.
//
// It's like filepath.Join for URLs. If the baseURL is pathish, this will still
// perform a join.
//
// If the URL is unparsable, this returns an error.
func URLJoin(baseURL string, paths ...string) (string, error) {
	u, err := url.Parse(baseURL)
	if err != nil {
		return "", err
	}
	// We want path instead of filepath because path always uses /.
	all := []string{u.Path}
	all = append(all, paths...)
	u.Path = path.Join(all...)
	return u.String(), nil
}

// Equal normalizes two URLs and then compares for equality.
func Equal(a, b string) bool {
	au, err := url.Parse(a)
	if err != nil {
		a = filepath.Clean(a)
		b = filepath.Clean(b)
		// If urls are paths, return true only if they are an exact match
		return a == b
	}
	bu, err := url.Parse(b)
	if err != nil {
		return false
	}

	for _, u := range []*url.URL{au, bu} {
		if u.Path == "" {
			u.Path = "/"
		}
		u.Path = filepath.Clean(u.Path)
	}
	return au.String() == bu.String()
}

// ExtractHostname returns hostname from URL
func ExtractHostname(addr string) (string, error) {
	u, err := url.Parse(addr)
	if err != nil {
		return "", err
	}

	host, _, err := net.SplitHostPort(u.Host)
	if err != nil {
		return "", err
	}
	return host, nil
}