ref: 8a1c637c4494751046142e0ef345fce38fc1431b
dir: /resources/page/pagemeta/page_frontmatter.go/
// Copyright 2019 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 pagemeta
import (
"strings"
"time"
"github.com/gohugoio/hugo/common/loggers"
"github.com/gohugoio/hugo/helpers"
"github.com/gohugoio/hugo/resources/resource"
"github.com/gohugoio/hugo/config"
"github.com/spf13/cast"
)
// FrontMatterHandler maps front matter into Page fields and .Params.
// Note that we currently have only extracted the date logic.
type FrontMatterHandler struct {
fmConfig frontmatterConfig
dateHandler frontMatterFieldHandler
lastModHandler frontMatterFieldHandler
publishDateHandler frontMatterFieldHandler
expiryDateHandler frontMatterFieldHandler
// A map of all date keys configured, including any custom.
allDateKeys map[string]bool
logger loggers.Logger
}
// FrontMatterDescriptor describes how to handle front matter for a given Page.
// It has pointers to values in the receiving page which gets updated.
type FrontMatterDescriptor struct {
// This the Page's front matter.
Frontmatter map[string]interface{}
// This is the Page's base filename (BaseFilename), e.g. page.md., or
// if page is a leaf bundle, the bundle folder name (ContentBaseName).
BaseFilename string
// The content file's mod time.
ModTime time.Time
// May be set from the author date in Git.
GitAuthorDate time.Time
// The below are pointers to values on Page and will be modified.
// This is the Page's params.
Params map[string]interface{}
// This is the Page's dates.
Dates *resource.Dates
// This is the Page's Slug etc.
PageURLs *URLPath
}
var (
dateFieldAliases = map[string][]string{
fmDate: {},
fmLastmod: {"modified"},
fmPubDate: {"pubdate", "published"},
fmExpiryDate: {"unpublishdate"},
}
)
// HandleDates updates all the dates given the current configuration and the
// supplied front matter params. Note that this requires all lower-case keys
// in the params map.
func (f FrontMatterHandler) HandleDates(d *FrontMatterDescriptor) error {
if d.Dates == nil {
panic("missing dates")
}
if f.dateHandler == nil {
panic("missing date handler")
}
if _, err := f.dateHandler(d); err != nil {
return err
}
if _, err := f.lastModHandler(d); err != nil {
return err
}
if _, err := f.publishDateHandler(d); err != nil {
return err
}
if _, err := f.expiryDateHandler(d); err != nil {
return err
}
return nil
}
// IsDateKey returns whether the given front matter key is considered a date by the current
// configuration.
func (f FrontMatterHandler) IsDateKey(key string) bool {
return f.allDateKeys[key]
}
// A Zero date is a signal that the name can not be parsed.
// This follows the format as outlined in Jekyll, https://jekyllrb.com/docs/posts/:
// "Where YEAR is a four-digit number, MONTH and DAY are both two-digit numbers"
func dateAndSlugFromBaseFilename(name string) (time.Time, string) {
withoutExt, _ := helpers.FileAndExt(name)
if len(withoutExt) < 10 {
// This can not be a date.
return time.Time{}, ""
}
// Note: Hugo currently have no custom timezone support.
// We will have to revisit this when that is in place.
d, err := time.Parse("2006-01-02", withoutExt[:10])
if err != nil {
return time.Time{}, ""
}
// Be a little lenient with the format here.
slug := strings.Trim(withoutExt[10:], " -_")
return d, slug
}
type frontMatterFieldHandler func(d *FrontMatterDescriptor) (bool, error)
func (f FrontMatterHandler) newChainedFrontMatterFieldHandler(handlers ...frontMatterFieldHandler) frontMatterFieldHandler {
return func(d *FrontMatterDescriptor) (bool, error) {
for _, h := range handlers {
// First successful handler wins.
success, err := h(d)
if err != nil {
f.logger.Errorln(err)
} else if success {
return true, nil
}
}
return false, nil
}
}
type frontmatterConfig struct {
date []string
lastmod []string
publishDate []string
expiryDate []string
}
const (
// These are all the date handler identifiers
// All identifiers not starting with a ":" maps to a front matter parameter.
fmDate = "date"
fmPubDate = "publishdate"
fmLastmod = "lastmod"
fmExpiryDate = "expirydate"
// Gets date from filename, e.g 218-02-22-mypage.md
fmFilename = ":filename"
// Gets date from file OS mod time.
fmModTime = ":filemodtime"
// Gets date from Git
fmGitAuthorDate = ":git"
)
// This is the config you get when doing nothing.
func newDefaultFrontmatterConfig() frontmatterConfig {
return frontmatterConfig{
date: []string{fmDate, fmPubDate, fmLastmod},
lastmod: []string{fmGitAuthorDate, fmLastmod, fmDate, fmPubDate},
publishDate: []string{fmPubDate, fmDate},
expiryDate: []string{fmExpiryDate},
}
}
func newFrontmatterConfig(cfg config.Provider) (frontmatterConfig, error) {
c := newDefaultFrontmatterConfig()
defaultConfig := c
if cfg.IsSet("frontmatter") {
fm := cfg.GetStringMap("frontmatter")
for k, v := range fm {
loki := strings.ToLower(k)
switch loki {
case fmDate:
c.date = toLowerSlice(v)
case fmPubDate:
c.publishDate = toLowerSlice(v)
case fmLastmod:
c.lastmod = toLowerSlice(v)
case fmExpiryDate:
c.expiryDate = toLowerSlice(v)
}
}
}
expander := func(c, d []string) []string {
out := expandDefaultValues(c, d)
out = addDateFieldAliases(out)
return out
}
c.date = expander(c.date, defaultConfig.date)
c.publishDate = expander(c.publishDate, defaultConfig.publishDate)
c.lastmod = expander(c.lastmod, defaultConfig.lastmod)
c.expiryDate = expander(c.expiryDate, defaultConfig.expiryDate)
return c, nil
}
func addDateFieldAliases(values []string) []string {
var complete []string
for _, v := range values {
complete = append(complete, v)
if aliases, found := dateFieldAliases[v]; found {
complete = append(complete, aliases...)
}
}
return helpers.UniqueStringsReuse(complete)
}
func expandDefaultValues(values []string, defaults []string) []string {
var out []string
for _, v := range values {
if v == ":default" {
out = append(out, defaults...)
} else {
out = append(out, v)
}
}
return out
}
func toLowerSlice(in interface{}) []string {
out := cast.ToStringSlice(in)
for i := 0; i < len(out); i++ {
out[i] = strings.ToLower(out[i])
}
return out
}
// NewFrontmatterHandler creates a new FrontMatterHandler with the given logger and configuration.
// If no logger is provided, one will be created.
func NewFrontmatterHandler(logger loggers.Logger, cfg config.Provider) (FrontMatterHandler, error) {
if logger == nil {
logger = loggers.NewErrorLogger()
}
frontMatterConfig, err := newFrontmatterConfig(cfg)
if err != nil {
return FrontMatterHandler{}, err
}
allDateKeys := make(map[string]bool)
addKeys := func(vals []string) {
for _, k := range vals {
if !strings.HasPrefix(k, ":") {
allDateKeys[k] = true
}
}
}
addKeys(frontMatterConfig.date)
addKeys(frontMatterConfig.expiryDate)
addKeys(frontMatterConfig.lastmod)
addKeys(frontMatterConfig.publishDate)
f := FrontMatterHandler{logger: logger, fmConfig: frontMatterConfig, allDateKeys: allDateKeys}
if err := f.createHandlers(); err != nil {
return f, err
}
return f, nil
}
func (f *FrontMatterHandler) createHandlers() error {
var err error
if f.dateHandler, err = f.createDateHandler(f.fmConfig.date,
func(d *FrontMatterDescriptor, t time.Time) {
d.Dates.FDate = t
setParamIfNotSet(fmDate, t, d)
}); err != nil {
return err
}
if f.lastModHandler, err = f.createDateHandler(f.fmConfig.lastmod,
func(d *FrontMatterDescriptor, t time.Time) {
setParamIfNotSet(fmLastmod, t, d)
d.Dates.FLastmod = t
}); err != nil {
return err
}
if f.publishDateHandler, err = f.createDateHandler(f.fmConfig.publishDate,
func(d *FrontMatterDescriptor, t time.Time) {
setParamIfNotSet(fmPubDate, t, d)
d.Dates.FPublishDate = t
}); err != nil {
return err
}
if f.expiryDateHandler, err = f.createDateHandler(f.fmConfig.expiryDate,
func(d *FrontMatterDescriptor, t time.Time) {
setParamIfNotSet(fmExpiryDate, t, d)
d.Dates.FExpiryDate = t
}); err != nil {
return err
}
return nil
}
func setParamIfNotSet(key string, value interface{}, d *FrontMatterDescriptor) {
if _, found := d.Params[key]; found {
return
}
d.Params[key] = value
}
func (f FrontMatterHandler) createDateHandler(identifiers []string, setter func(d *FrontMatterDescriptor, t time.Time)) (frontMatterFieldHandler, error) {
var h *frontmatterFieldHandlers
var handlers []frontMatterFieldHandler
for _, identifier := range identifiers {
switch identifier {
case fmFilename:
handlers = append(handlers, h.newDateFilenameHandler(setter))
case fmModTime:
handlers = append(handlers, h.newDateModTimeHandler(setter))
case fmGitAuthorDate:
handlers = append(handlers, h.newDateGitAuthorDateHandler(setter))
default:
handlers = append(handlers, h.newDateFieldHandler(identifier, setter))
}
}
return f.newChainedFrontMatterFieldHandler(handlers...), nil
}
type frontmatterFieldHandlers int
func (f *frontmatterFieldHandlers) newDateFieldHandler(key string, setter func(d *FrontMatterDescriptor, t time.Time)) frontMatterFieldHandler {
return func(d *FrontMatterDescriptor) (bool, error) {
v, found := d.Frontmatter[key]
if !found {
return false, nil
}
date, err := cast.ToTimeE(v)
if err != nil {
return false, nil
}
// We map several date keys to one, so, for example,
// "expirydate", "unpublishdate" will all set .ExpiryDate (first found).
setter(d, date)
// This is the params key as set in front matter.
d.Params[key] = date
return true, nil
}
}
func (f *frontmatterFieldHandlers) newDateFilenameHandler(setter func(d *FrontMatterDescriptor, t time.Time)) frontMatterFieldHandler {
return func(d *FrontMatterDescriptor) (bool, error) {
date, slug := dateAndSlugFromBaseFilename(d.BaseFilename)
if date.IsZero() {
return false, nil
}
setter(d, date)
if _, found := d.Frontmatter["slug"]; !found {
// Use slug from filename
d.PageURLs.Slug = slug
}
return true, nil
}
}
func (f *frontmatterFieldHandlers) newDateModTimeHandler(setter func(d *FrontMatterDescriptor, t time.Time)) frontMatterFieldHandler {
return func(d *FrontMatterDescriptor) (bool, error) {
if d.ModTime.IsZero() {
return false, nil
}
setter(d, d.ModTime)
return true, nil
}
}
func (f *frontmatterFieldHandlers) newDateGitAuthorDateHandler(setter func(d *FrontMatterDescriptor, t time.Time)) frontMatterFieldHandler {
return func(d *FrontMatterDescriptor) (bool, error) {
if d.GitAuthorDate.IsZero() {
return false, nil
}
setter(d, d.GitAuthorDate)
return true, nil
}
}