package hugolib import ( "errors" "fmt" "strconv" "strings" helper "github.com/spf13/hugo/template" ) // 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 // validate determines if a PathPattern is well-formed func (pp PathPattern) validate() bool { if pp[0] != '/' { return false } 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 } if !strings.HasPrefix(fragments[i], ":") { continue } k := strings.ToLower(fragments[i][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: "", err: errPermalinkIllFormed} } sections := strings.Split(string(pp), "/") for i, field := range sections { if len(field) == 0 || field[0] != ':' { continue } attr := field[1:] callback, ok := knownPermalinkAttributes[attr] if !ok { return "", &permalinkExpandError{pattern: pp, section: strconv.Itoa(i), err: errPermalinkAttributeUnknown} } newField, err := callback(p, attr) if err != nil { return "", &permalinkExpandError{pattern: pp, section: strconv.Itoa(i), err: err} } 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", int(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 helper.Urlize(p.Title), 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 != "" { return p.Slug, nil } return pageToPermalinkTitle(p, a) } func pageToPermalinkSection(p *Page, _ string) (string, error) { // Page contains Node contains UrlPath which has Section return p.Section, nil } func init() { knownPermalinkAttributes = map[string]PageToPermaAttribute{ "year": pageToPermalinkDate, "month": pageToPermalinkDate, "monthname": pageToPermalinkDate, "day": pageToPermalinkDate, "weekday": pageToPermalinkDate, "weekdayname": pageToPermalinkDate, "yearday": pageToPermalinkDate, "section": pageToPermalinkSection, "title": pageToPermalinkTitle, "slug": pageToPermalinkSlugElseTitle, } }