fileserver: Implement natural sort for browse templates

modules/caddyhttp/fileserver/browsetplcontext.go

@@ -329,7 +329,7 @@ func (l byName) Len() int      { return len(l.Items) }
 func (l byName) Swap(i, j int) { l.Items[i], l.Items[j] = l.Items[j], l.Items[i] }
 
 func (l byName) Less(i, j int) bool {
-	return strings.ToLower(l.Items[i].Name) < strings.ToLower(l.Items[j].Name)
+	return naturalLess(strings.ToLower(l.Items[i].Name), strings.ToLower(l.Items[j].Name))
 }
 
 func (l byNameDirFirst) Len() int      { return len(l.Items) }
@@ -338,7 +338,7 @@ func (l byNameDirFirst) Swap(i, j int) { l.Items[i], l.Items[j] = l.Items[j], l.
 func (l byNameDirFirst) Less(i, j int) bool {
 	// sort by name if both are dir or file
 	if l.Items[i].IsDir == l.Items[j].IsDir {
-		return strings.ToLower(l.Items[i].Name) < strings.ToLower(l.Items[j].Name)
+		return naturalLess(strings.ToLower(l.Items[i].Name), strings.ToLower(l.Items[j].Name))
 	}
 	// sort dir ahead of file
 	return l.Items[i].IsDir

modules/caddyhttp/fileserver/natsort.go

@@ -0,0 +1,65 @@
+package fileserver
+
+func isDigit(b byte) bool { return '0' <= b && b <= '9' }
+
+// naturalLess compares two strings using natural ordering. This means that e.g.
+// "abc2" < "abc12".
+//
+// Non-digit sequences and numbers are compared separately. The former are
+// compared bytewise, while digits are compared numerically (except that
+// the number of leading zeros is used as a tie-breaker, so e.g. "2" < "02")
+//
+// Limitation: only ASCII digits (0-9) are considered.
+//
+// This implementation is copied from https://github.com/fvbommel/sortorder,
+// which is MIT licensed.
+func naturalLess(str1, str2 string) bool {
+	idx1, idx2 := 0, 0
+	for idx1 < len(str1) && idx2 < len(str2) {
+		c1, c2 := str1[idx1], str2[idx2]
+		dig1, dig2 := isDigit(c1), isDigit(c2)
+		switch {
+		case dig1 != dig2: // Digits before other characters.
+			return dig1 // True if LHS is a digit, false if the RHS is one.
+		case !dig1: // && !dig2, because dig1 == dig2
+			// UTF-8 compares bytewise-lexicographically, no need to decode
+			// codepoints.
+			if c1 != c2 {
+				return c1 < c2
+			}
+			idx1++
+			idx2++
+		default: // Digits
+			// Eat zeros.
+			for ; idx1 < len(str1) && str1[idx1] == '0'; idx1++ {
+			}
+			for ; idx2 < len(str2) && str2[idx2] == '0'; idx2++ {
+			}
+			// Eat all digits.
+			nonZero1, nonZero2 := idx1, idx2
+			for ; idx1 < len(str1) && isDigit(str1[idx1]); idx1++ {
+			}
+			for ; idx2 < len(str2) && isDigit(str2[idx2]); idx2++ {
+			}
+			// If lengths of numbers with non-zero prefix differ, the shorter
+			// one is less.
+			if len1, len2 := idx1-nonZero1, idx2-nonZero2; len1 != len2 {
+				return len1 < len2
+			}
+			// If they're equally long, string comparison is correct.
+			if nr1, nr2 := str1[nonZero1:idx1], str2[nonZero2:idx2]; nr1 != nr2 {
+				return nr1 < nr2
+			}
+			// Otherwise, the one with less zeros is less.
+			// Because everything up to the number is equal, comparing the index
+			// after the zeros is sufficient.
+			if nonZero1 != nonZero2 {
+				return nonZero1 < nonZero2
+			}
+		}
+		// They're identical so far, so continue comparing.
+	}
+	// So far they are identical. At least one is ended. If the other continues,
+	// it sorts last.
+	return len(str1) < len(str2)
+}

modules/caddyhttp/fileserver/natsort_test.go

@@ -0,0 +1,63 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// 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 fileserver
+
+import (
+	"context"
+	"io/fs"
+	"net/http/httptest"
+	"os"
+	"testing"
+
+	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
+)
+
+// TestNatSort confirms that, although an ASCIIbetical sort would order foo2.txt
+// after foo10.txt, Caddy will return them in a "natural" human-intuitive order.
+func TestNatSort(t *testing.T) {
+	fsrv := &FileServer{Browse: &Browse{}}
+
+	base := "./testdata"
+	dirName := "natsort"
+
+	fsys := os.DirFS(base)
+	f, err := fsys.Open(dirName)
+	if err != nil {
+		t.Fatalf("opening testdata dir: %v", err)
+	}
+	defer f.Close()
+
+	repl := caddyhttp.NewTestReplacer(httptest.NewRequest("GET", "/", nil))
+
+	listing, err := fsrv.loadDirectoryContents(context.Background(), fsys, f.(fs.ReadDirFile), base, "/natsort/", repl)
+	if err != nil {
+		t.Fatalf("loadDirectoryContents returned error: %v", err)
+	}
+
+	if len(listing.Items) != 3 {
+		t.Fatalf("expected 3 items in listing, got %d", len(listing.Items))
+	}
+
+	listing.applySortAndLimit(sortByNameDirFirst, sortOrderAsc, "", "")
+
+	got := []string{listing.Items[0].Name, listing.Items[1].Name, listing.Items[2].Name}
+	want := []string{"foo1.txt", "foo2.txt", "foo10.txt"}
+
+	for i := range want {
+		if got[i] != want[i] {
+			t.Fatalf("unexpected item at index %v: got %v, want %v", i, got, want)
+		}
+	}
+}

modules/caddyhttp/fileserver/testdata/natsort/foo1.txt

@@ -0,0 +1 @@
+foo1.txt

modules/caddyhttp/fileserver/testdata/natsort/foo10.txt

@@ -0,0 +1 @@
+foo10.txt

modules/caddyhttp/fileserver/testdata/natsort/foo2.txt

@@ -0,0 +1 @@
+foo2.txt