Permit sorting of files in automatic directory listings by various factors.

README.md

@@ -92,3 +92,5 @@ The following options can be set in `/etc/molly.conf`:
 * `LogPath`: Path to log file (default value `molly.log`).  Note that
   all intermediate directories must exist, Molly Brown won't create
   them for you.
+* `DirectorySort`: A string specifying how to sort files in automatically generated directory listings.  Must be one of "Name", "Size" or "Time" (default value "Name").
+* `DirectoryReverse`: Boolean, if true automatically generated directory listings will list files in descending order of whatever `DirectorySort` is set to (default value false).

config.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"github.com/BurntSushi/toml"
 )
 
@@ -18,6 +19,8 @@ type Config struct {
 	PermRedirects    map[string]string
 	CGIPaths         []string
 	SCGIPaths        map[string]string
+	DirectorySort    string
+	DirectoryReverse bool
 }
 
 type MollyFile struct {
@@ -43,6 +46,7 @@ func getConfig(filename string) (Config, error) {
 	config.PermRedirects = make(map[string]string)
 	config.CGIPaths = make([]string, 0)
 	config.SCGIPaths = make(map[string]string)
+	config.DirectorySort = "Name"
 
 	// Return defaults if no filename given
 	if filename == "" {
@@ -54,5 +58,13 @@ func getConfig(filename string) (Config, error) {
 	if err != nil {
 		return config, err
 	}
+
+	// Validate pseudo-enums
+	switch config.DirectorySort {
+	case "Name", "Size", "Time":
+	default:
+		return config, errors.New("Invalid DirectorySort value.")
+	}
+
 	return config, nil
 }

handler.go

@@ -14,6 +14,7 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+	"sort"
 	"strings"
 	"time"
 )
@@ -154,7 +155,7 @@ func handleGeminiRequest(conn net.Conn, config Config, logEntries chan LogEntry)
 		} else {
 			conn.Write([]byte("20 text/gemini\r\n"))
 			log.Status = 20
-			conn.Write([]byte(generateDirectoryListing(URL, path)))
+			conn.Write([]byte(generateDirectoryListing(URL, path, config)))
 		}
 		return
 	}
@@ -263,7 +264,7 @@ func parseMollyFiles(path string, info os.FileInfo, config *Config) {
 
 }
 
-func generateDirectoryListing(URL *url.URL, path string) string {
+func generateDirectoryListing(URL *url.URL, path string, config Config) string {
 	var listing string
 	files, err := ioutil.ReadDir(path)
 	if err != nil {
@@ -287,6 +288,21 @@ func generateDirectoryListing(URL *url.URL, path string) string {
 		up := filepath.Dir(URL.Path)
 		listing += fmt.Sprintf("=> %s %s\n", up, "..")
 	}
+	// Sort files
+	sort.SliceStable(files, func(i, j int) bool {
+		if config.DirectoryReverse {
+			i, j = j, i
+		}
+		if config.DirectorySort == "Name" {
+			return files[i].Name() < files[j].Name()
+		} else if config.DirectorySort == "Size" {
+			return files[i].Size() < files[j].Size()
+		} else if config.DirectorySort == "Time" {
+			return files[i].ModTime().Before(files[j].ModTime())
+		}
+		return false // Should not happen
+	})
+	// Format lines
 	for _, file := range files {
 		// Skip dotfiles
 		if strings.HasPrefix(file.Name(), ".") {