resources/page: Add :slugorfilename attribute

Fixes #4739, #385

3 files changed, 39 insertions, 14 deletions

diff --git a/docs/content/en/content-management/urls.md b/docs/content/en/content-management/urls.md
index f498d02ea..774bd9a58 100644
--- a/docs/content/en/content-management/urls.md
+++ b/docs/content/en/content-management/urls.md
@@ -91,6 +91,9 @@ The following is a list of values that can be used in a `permalink` definition i
 `:slug`
 : the content's slug (or title if no slug is provided in the front matter)
 
+`:slugorfilename`
+: the content's slug (or filename if no slug is provided in the front matter)
+
 `:filename`
 : the content's filename (without extension)
 
diff --git a/resources/page/permalinks.go b/resources/page/permalinks.go
index cd9c1dc15..c31d22a3c 100644
--- a/resources/page/permalinks.go
+++ b/resources/page/permalinks.go
@@ -72,18 +72,19 @@ func NewPermalinkExpander(ps *helpers.PathSpec) (PermalinkExpander, error) {
 	p := PermalinkExpander{ps: ps}
 
 	p.knownPermalinkAttributes = map[string]pageToPermaAttribute{
-		"year":        p.pageToPermalinkDate,
-		"month":       p.pageToPermalinkDate,
-		"monthname":   p.pageToPermalinkDate,
-		"day":         p.pageToPermalinkDate,
-		"weekday":     p.pageToPermalinkDate,
-		"weekdayname": p.pageToPermalinkDate,
-		"yearday":     p.pageToPermalinkDate,
-		"section":     p.pageToPermalinkSection,
-		"sections":    p.pageToPermalinkSections,
-		"title":       p.pageToPermalinkTitle,
-		"slug":        p.pageToPermalinkSlugElseTitle,
-		"filename":    p.pageToPermalinkFilename,
+		"year":           p.pageToPermalinkDate,
+		"month":          p.pageToPermalinkDate,
+		"monthname":      p.pageToPermalinkDate,
+		"day":            p.pageToPermalinkDate,
+		"weekday":        p.pageToPermalinkDate,
+		"weekdayname":    p.pageToPermalinkDate,
+		"yearday":        p.pageToPermalinkDate,
+		"section":        p.pageToPermalinkSection,
+		"sections":       p.pageToPermalinkSections,
+		"title":          p.pageToPermalinkTitle,
+		"slug":           p.pageToPermalinkSlugElseTitle,
+		"slugorfilename": p.pageToPermalinkSlugElseFilename,
+		"filename":       p.pageToPermalinkFilename,
 	}
 
 	patterns := ps.Cfg.GetStringMapString("permalinks")
@@ -266,6 +267,14 @@ func (l PermalinkExpander) pageToPermalinkSlugElseTitle(p Page, a string) (strin
 	return l.pageToPermalinkTitle(p, a)
 }
 
+// if the page has a slug, return the slug, else return the filename
+func (l PermalinkExpander) pageToPermalinkSlugElseFilename(p Page, a string) (string, error) {
+	if p.Slug() != "" {
+		return l.ps.URLize(p.Slug()), nil
+	}
+	return l.pageToPermalinkFilename(p, a)
+}
+
 func (l PermalinkExpander) pageToPermalinkSection(p Page, _ string) (string, error) {
 	return p.Section(), nil
 }
diff --git a/resources/page/permalinks_test.go b/resources/page/permalinks_test.go
index ca106c236..7baf16503 100644
--- a/resources/page/permalinks_test.go
+++ b/resources/page/permalinks_test.go
@@ -36,6 +36,7 @@ var testdataPermalinks = []struct {
 	{"/:section/", true, "/blue/"},                                  // Section
 	{"/:title/", true, "/spf13-vim-3.0-release-and-new-website/"},   // Title
 	{"/:slug/", true, "/the-slug/"},                                 // Slug
+	{"/:slugorfilename/", true, "/the-slug/"},                       // Slug or filename
 	{"/:filename/", true, "/test-page/"},                            // Filename
 	{"/:06-:1-:2-:Monday", true, "/12-4-6-Friday"},                  // Dates with Go formatting
 	{"/:2006_01_02_15_04_05.000", true, "/2012_04_06_03_01_59.000"}, // Complicated custom date format
@@ -102,9 +103,13 @@ func TestPermalinkExpansionMultiSection(t *testing.T) {
 	page.section = "blue"
 	page.slug = "The Slug"
 
+	page_slug_fallback := newTestPageWithFile("/page-filename/index.md")
+	page_slug_fallback.title = "Page Title"
+
 	permalinksConfig := map[string]string{
-		"posts": "/:slug",
-		"blog":  "/:section/:year",
+		"posts":   "/:slug",
+		"blog":    "/:section/:year",
+		"recipes": "/:slugorfilename",
 	}
 
 	ps := newTestPathSpec()
@@ -120,6 +125,14 @@ func TestPermalinkExpansionMultiSection(t *testing.T) {
 	expanded, err = expander.Expand("blog", page)
 	c.Assert(err, qt.IsNil)
 	c.Assert(expanded, qt.Equals, "/blue/2012")
+
+	expanded, err = expander.Expand("posts", page_slug_fallback)
+	c.Assert(err, qt.IsNil)
+	c.Assert(expanded, qt.Equals, "/page-title")
+
+	expanded, err = expander.Expand("recipes", page_slug_fallback)
+	c.Assert(err, qt.IsNil)
+	c.Assert(expanded, qt.Equals, "/page-filename")
 }
 
 func TestPermalinkExpansionConcurrent(t *testing.T) {