urls.go

/*
   Copyright 2014 CoreOS, Inc.

   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 types

import (
	"errors"
	"fmt"
	"net"
	"net/url"
	"sort"
	"strings"
)

type URLs []url.URL

func (us URLs) String() string {
	return strings.Join(us.StringSlice(), ",")
}

func (us *URLs) Sort() {
	sort.Sort(us)
}
func (us URLs) Len() int           { return len(us) }
func (us URLs) Less(i, j int) bool { return us[i].String() < us[j].String() }
func (us URLs) Swap(i, j int)      { us[i], us[j] = us[j], us[i] }

func (us URLs) StringSlice() []string {
	out := make([]string, len(us))
	for i := range us {
		out[i] = us[i].String()
	}

	return out
}

func NewURLs(strs []string) (URLs, error) {
	all := make([]url.URL, len(strs))
	if len(all) == 0 {
		return nil, errors.New("no valid URLs given")
	}
	for i, in := range strs {
		in = strings.TrimSpace(in)
		u, err := url.Parse(in)
		if err != nil {
			return nil, err
		}
		if u.Scheme != "http" && u.Scheme != "https" {
			return nil, fmt.Errorf("URL scheme must be http or https: %s", in)
		}
		if _, _, err := net.SplitHostPort(u.Host); err != nil {
			return nil, fmt.Errorf(`URL address does not have the form "host:port": %s`, in)
		}
		if u.Path != "" {
			return nil, fmt.Errorf("URL must not contain a path: %s", in)
		}
		all[i] = *u
	}
	us := URLs(all)
	us.Sort()

	return us, nil
}