ref: 02eaddc2fbe92c26e67d9f82dd9aabecbbf2106c
dir: /hugolib/permalinks.go/
// Copyright 2015 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 (
"errors"
"fmt"
"path"
"path/filepath"
"regexp"
"strconv"
"strings"
"github.com/gohugoio/hugo/helpers"
)
// pathPattern represents a string which builds up a URL from attributes
type pathPattern string
// pageToPermaAttribute is the type of a function which, given a page and a tag
// can return a string to go in that position in the page (or an error)
type pageToPermaAttribute func(*Page, string) (string, error)
// PermalinkOverrides maps a section name to a PathPattern
type PermalinkOverrides map[string]pathPattern
// knownPermalinkAttributes maps :tags in a permalink specification to a
// function which, given a page and the tag, returns the resulting string
// to be used to replace that tag.
var knownPermalinkAttributes map[string]pageToPermaAttribute
var attributeRegexp = regexp.MustCompile(`:\w+`)
// validate determines if a PathPattern is well-formed
func (pp pathPattern) validate() bool {
fragments := strings.Split(string(pp[1:]), "/")
var bail = false
for i := range fragments {
if bail {
return false
}
if len(fragments[i]) == 0 {
bail = true
continue
}
matches := attributeRegexp.FindAllStringSubmatch(fragments[i], -1)
if matches == nil {
continue
}
for _, match := range matches {
k := strings.ToLower(match[0][1:])
if _, ok := knownPermalinkAttributes[k]; !ok {
return false
}
}
}
return true
}
type permalinkExpandError struct {
pattern pathPattern
section string
err error
}
func (pee *permalinkExpandError) Error() string {
return fmt.Sprintf("error expanding %q section %q: %s", string(pee.pattern), pee.section, pee.err)
}
var (
errPermalinkIllFormed = errors.New("permalink ill-formed")
errPermalinkAttributeUnknown = errors.New("permalink attribute not recognised")
)
// Expand on a PathPattern takes a Page and returns the fully expanded Permalink
// or an error explaining the failure.
func (pp pathPattern) Expand(p *Page) (string, error) {
if !pp.validate() {
return "", &permalinkExpandError{pattern: pp, section: "<all>", err: errPermalinkIllFormed}
}
sections := strings.Split(string(pp), "/")
for i, field := range sections {
if len(field) == 0 {
continue
}
matches := attributeRegexp.FindAllStringSubmatch(field, -1)
if matches == nil {
continue
}
newField := field
for _, match := range matches {
attr := match[0][1:]
callback, ok := knownPermalinkAttributes[attr]
if !ok {
return "", &permalinkExpandError{pattern: pp, section: strconv.Itoa(i), err: errPermalinkAttributeUnknown}
}
newAttr, err := callback(p, attr)
if err != nil {
return "", &permalinkExpandError{pattern: pp, section: strconv.Itoa(i), err: err}
}
newField = strings.Replace(newField, match[0], newAttr, 1)
}
sections[i] = newField
}
return strings.Join(sections, "/"), nil
}
func pageToPermalinkDate(p *Page, dateField string) (string, error) {
// a Page contains a Node which provides a field Date, time.Time
switch dateField {
case "year":
return strconv.Itoa(p.Date.Year()), nil
case "month":
return fmt.Sprintf("%02d", int(p.Date.Month())), nil
case "monthname":
return p.Date.Month().String(), nil
case "day":
return fmt.Sprintf("%02d", p.Date.Day()), nil
case "weekday":
return strconv.Itoa(int(p.Date.Weekday())), nil
case "weekdayname":
return p.Date.Weekday().String(), nil
case "yearday":
return strconv.Itoa(p.Date.YearDay()), nil
}
//TODO: support classic strftime escapes too
// (and pass those through despite not being in the map)
panic("coding error: should not be here")
}
// pageToPermalinkTitle returns the URL-safe form of the title
func pageToPermalinkTitle(p *Page, _ string) (string, error) {
// Page contains Node which has Title
// (also contains URLPath which has Slug, sometimes)
return p.s.PathSpec.URLize(p.title), nil
}
// pageToPermalinkFilename returns the URL-safe form of the filename
func pageToPermalinkFilename(p *Page, _ string) (string, error) {
name := p.File.TranslationBaseName()
if name == "index" {
// Page bundles; the directory name will hopefully have a better name.
dir := strings.TrimSuffix(p.File.Dir(), helpers.FilePathSeparator)
_, name = filepath.Split(dir)
}
return p.s.PathSpec.URLize(name), nil
}
// if the page has a slug, return the slug, else return the title
func pageToPermalinkSlugElseTitle(p *Page, a string) (string, error) {
if p.Slug != "" {
// Don't start or end with a -
// TODO(bep) this doesn't look good... Set the Slug once.
if strings.HasPrefix(p.Slug, "-") {
p.Slug = p.Slug[1:len(p.Slug)]
}
if strings.HasSuffix(p.Slug, "-") {
p.Slug = p.Slug[0 : len(p.Slug)-1]
}
return p.s.PathSpec.URLize(p.Slug), nil
}
return pageToPermalinkTitle(p, a)
}
func pageToPermalinkSection(p *Page, _ string) (string, error) {
return p.Section(), nil
}
func pageToPermalinkSections(p *Page, _ string) (string, error) {
return path.Join(p.CurrentSection().sections...), nil
}
func init() {
knownPermalinkAttributes = map[string]pageToPermaAttribute{
"year": pageToPermalinkDate,
"month": pageToPermalinkDate,
"monthname": pageToPermalinkDate,
"day": pageToPermalinkDate,
"weekday": pageToPermalinkDate,
"weekdayname": pageToPermalinkDate,
"yearday": pageToPermalinkDate,
"section": pageToPermalinkSection,
"sections": pageToPermalinkSections,
"title": pageToPermalinkTitle,
"slug": pageToPermalinkSlugElseTitle,
"filename": pageToPermalinkFilename,
}
}