// Copyright 2017 The Hugo 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 hugolib
import (
"bytes"
"fmt"
"html/template"
"io"
"path/filepath"
"runtime"
"strings"
jww "github.com/spf13/jwalterweatherman"
"github.com/spf13/hugo/helpers"
)
const (
alias = "{{ .Permalink }}"
aliasXHtml = "{{ .Permalink }}"
)
var defaultAliasTemplates *template.Template
func init() {
defaultAliasTemplates = template.New("")
template.Must(defaultAliasTemplates.New("alias").Parse(alias))
template.Must(defaultAliasTemplates.New("alias-xhtml").Parse(aliasXHtml))
}
type aliasHandler struct {
Templates *template.Template
log *jww.Notepad
allowRoot bool
}
func newAliasHandler(t *template.Template, l *jww.Notepad, allowRoot bool) aliasHandler {
return aliasHandler{t, l, allowRoot}
}
func (a aliasHandler) renderAlias(isXHTML bool, permalink string, page *Page) (io.Reader, error) {
t := "alias"
if isXHTML {
t = "alias-xhtml"
}
template := defaultAliasTemplates
if a.Templates != nil {
template = a.Templates
t = "alias.html"
}
data := struct {
Permalink string
Page *Page
}{
permalink,
page,
}
buffer := new(bytes.Buffer)
err := template.ExecuteTemplate(buffer, t, data)
if err != nil {
return nil, err
}
return buffer, nil
}
func (s *Site) writeDestAlias(path, permalink string, p *Page) (err error) {
return s.publishDestAlias(false, path, permalink, p)
}
func (s *Site) publishDestAlias(allowRoot bool, path, permalink string, p *Page) (err error) {
handler := newAliasHandler(s.Tmpl.Lookup("alias.html"), s.Log, allowRoot)
isXHTML := strings.HasSuffix(path, ".xhtml")
s.Log.DEBUG.Println("creating alias:", path, "redirecting to", permalink)
targetPath, err := handler.targetPathAlias(path)
if err != nil {
return err
}
aliasContent, err := handler.renderAlias(isXHTML, permalink, p)
if err != nil {
return err
}
return s.publish(targetPath, aliasContent)
}
func (a aliasHandler) targetPathAlias(src string) (string, error) {
originalAlias := src
if len(src) <= 0 {
return "", fmt.Errorf("Alias \"\" is an empty string")
}
alias := filepath.Clean(src)
components := strings.Split(alias, helpers.FilePathSeparator)
if !a.allowRoot && alias == helpers.FilePathSeparator {
return "", fmt.Errorf("Alias \"%s\" resolves to website root directory", originalAlias)
}
// Validate against directory traversal
if components[0] == ".." {
return "", fmt.Errorf("Alias \"%s\" traverses outside the website root directory", originalAlias)
}
// Handle Windows file and directory naming restrictions
// See "Naming Files, Paths, and Namespaces" on MSDN
// https://msdn.microsoft.com/en-us/library/aa365247%28v=VS.85%29.aspx?f=255&MSPPError=-2147217396
msgs := []string{}
reservedNames := []string{"CON", "PRN", "AUX", "NUL", "COM0", "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9", "LPT0", "LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9"}
if strings.ContainsAny(alias, ":*?\"<>|") {
msgs = append(msgs, fmt.Sprintf("Alias \"%s\" contains invalid characters on Windows: : * ? \" < > |", originalAlias))
}
for _, ch := range alias {
if ch < ' ' {
msgs = append(msgs, fmt.Sprintf("Alias \"%s\" contains ASCII control code (0x00 to 0x1F), invalid on Windows: : * ? \" < > |", originalAlias))
continue
}
}
for _, comp := range components {
if strings.HasSuffix(comp, " ") || strings.HasSuffix(comp, ".") {
msgs = append(msgs, fmt.Sprintf("Alias \"%s\" contains component with a trailing space or period, problematic on Windows", originalAlias))
}
for _, r := range reservedNames {
if comp == r {
msgs = append(msgs, fmt.Sprintf("Alias \"%s\" contains component with reserved name \"%s\" on Windows", originalAlias, r))
}
}
}
if len(msgs) > 0 {
if runtime.GOOS == "windows" {
for _, m := range msgs {
a.log.ERROR.Println(m)
}
return "", fmt.Errorf("Cannot create \"%s\": Windows filename restriction", originalAlias)
}
for _, m := range msgs {
a.log.WARN.Println(m)
}
}
// Add the final touch
alias = strings.TrimPrefix(alias, helpers.FilePathSeparator)
if strings.HasSuffix(alias, helpers.FilePathSeparator) {
alias = alias + "index.html"
} else if !strings.HasSuffix(alias, ".html") {
alias = alias + helpers.FilePathSeparator + "index.html"
}
if originalAlias != alias {
a.log.INFO.Printf("Alias \"%s\" translated to \"%s\"\n", originalAlias, alias)
}
return alias, nil
}