hugolib: Add ability to sort by frontmatter parameters

diff --git a/docs/content/templates/list.md b/docs/content/templates/list.md
index 36ababff63182df72d1692ff45f27384a7f7c18b..c4f20d9865789c02a5c8612862ed651bdc811133 100644 (file)
--- a/docs/content/templates/list.md
+++ b/docs/content/templates/list.md
@@ -237,6 +237,18 @@ your list templates:
     </li>
     {{ end }}
 
+### Order by Parameter
+Order based on the specified frontmatter parameter. Pages without that
+parameter will use the site's `.Site.Params` default. If the parameter is not
+found at all in some entries, those entries will appear together at the end
+of the ordering.
+
+The below example sorts a list of posts by their rating.
+
+    {{ range (.Data.Pages.ByParam "rating") }}
+      <!-- ... -->
+    {{ end }}
+
 ### Reverse Order
 Can be applied to any of the above. Using Date for an example.
 

diff --git a/hugolib/pageSort.go b/hugolib/pageSort.go
index f0c2db33dd152c640cafae2e3d51d0f6e6d0b3f3..e12cf68e4a209e18f2c506069b363129bb5760f2 100644 (file)
--- a/hugolib/pageSort.go
+++ b/hugolib/pageSort.go
@@ -15,6 +15,8 @@ package hugolib
 
 import (
        "sort"
+
+       "github.com/spf13/cast"
 )
 
 var spc = newPageCache()
@@ -275,3 +277,28 @@ func (p Pages) Reverse() Pages {
 
        return pages
 }
+
+func (p Pages) ByParam(paramsKey interface{}) Pages {
+       paramsKeyStr := cast.ToString(paramsKey)
+       key := "pageSort.ByParam." + paramsKeyStr
+
+       paramsKeyComparator := func(p1, p2 *Page) bool {
+               v1, _ := p1.Param(paramsKeyStr)
+               v2, _ := p2.Param(paramsKeyStr)
+               s1 := cast.ToString(v1)
+               s2 := cast.ToString(v2)
+
+               // Sort nils last.
+               if s1 == "" {
+                       return false
+               } else if s2 == "" {
+                       return true
+               }
+
+               return s1 < s2
+       }
+
+       pages, _ := spc.get(key, p, pageBy(paramsKeyComparator).Sort)
+
+       return pages
+}

diff --git a/hugolib/pageSort_test.go b/hugolib/pageSort_test.go
index 126c1b4adcf8e24f718f0399cbf813dfab93af0e..c0dedbe2d044c278fd331b224a7a27bd1ec8269f 100644 (file)
--- a/hugolib/pageSort_test.go
+++ b/hugolib/pageSort_test.go
@@ -20,6 +20,7 @@ import (
        "testing"
        "time"
 
+       "github.com/spf13/cast"
        "github.com/spf13/hugo/helpers"
        "github.com/spf13/hugo/source"
        "github.com/stretchr/testify/assert"
@@ -113,6 +114,34 @@ func TestPageSortReverse(t *testing.T) {
        assert.True(t, probablyEqualPages(p2, p1.Reverse()))
 }
 
+func TestPageSortByParam(t *testing.T) {
+       var k interface{} = "arbitrary"
+
+       unsorted := createSortTestPages(10)
+       delete(unsorted[9].Params, cast.ToString(k))
+
+       firstSetValue, _ := unsorted[0].Param(k)
+       secondSetValue, _ := unsorted[1].Param(k)
+       lastSetValue, _ := unsorted[8].Param(k)
+       unsetValue, _ := unsorted[9].Param(k)
+
+       assert.Equal(t, "xyz100", firstSetValue)
+       assert.Equal(t, "xyz99", secondSetValue)
+       assert.Equal(t, "xyz92", lastSetValue)
+       assert.Equal(t, nil, unsetValue)
+
+       sorted := unsorted.ByParam("arbitrary")
+       firstSetSortedValue, _ := sorted[0].Param(k)
+       secondSetSortedValue, _ := sorted[1].Param(k)
+       lastSetSortedValue, _ := sorted[8].Param(k)
+       unsetSortedValue, _ := sorted[9].Param(k)
+
+       assert.Equal(t, firstSetValue, firstSetSortedValue)
+       assert.Equal(t, secondSetValue, lastSetSortedValue)
+       assert.Equal(t, lastSetValue, secondSetSortedValue)
+       assert.Equal(t, unsetValue, unsetSortedValue)
+}
+
 func BenchmarkSortByWeightAndReverse(b *testing.B) {
 
        p := createSortTestPages(300)
@@ -154,6 +183,9 @@ func createSortTestPages(num int) Pages {
                        },
                        Site:   &info,
                        Source: Source{File: *source.NewFile(filepath.FromSlash(fmt.Sprintf("/x/y/p%d.md", i)))},
+                       Params: map[string]interface{}{
+                               "arbitrary": "xyz" + fmt.Sprintf("%v", 100-i),
+                       },
                }
                w := 5