Add file_limit option for file_server browse

modules/caddyhttp/fileserver/browse.go

@@ -66,8 +66,15 @@ type Browse struct {
 	//   - `sort size` will sort by size in ascending order
 	// The first option must be `sort_by` and the second option must be `order` (if exists).
 	SortOptions []string `json:"sort,omitempty"`
+
+	// FileLimit limits the number of up to n DirEntry values in directory order.
+	FileLimit int `json:"file_limit,omitempty"`
 }
 
+const (
+	defaultMaxDirLimit = 10000
+)
+
 func (fsrv *FileServer) serveBrowse(fileSystem fs.FS, root, dirPath string, w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
 	if c := fsrv.logger.Check(zapcore.DebugLevel, "browse enabled; listing directory contents"); c != nil {
 		c.Write(zap.String("path", dirPath), zap.String("root", root))
@@ -206,7 +213,11 @@ func (fsrv *FileServer) serveBrowse(fileSystem fs.FS, root, dirPath string, w ht
 }
 
 func (fsrv *FileServer) loadDirectoryContents(ctx context.Context, fileSystem fs.FS, dir fs.ReadDirFile, root, urlPath string, repl *caddy.Replacer) (*browseTemplateContext, error) {
-	files, err := dir.ReadDir(10000) // TODO: this limit should probably be configurable
+	dirLimit := defaultMaxDirLimit
+	if fsrv.Browse.FileLimit != 0 {
+		dirLimit = fsrv.Browse.FileLimit
+	}
+	files, err := dir.ReadDir(dirLimit)
 	if err != nil && err != io.EOF {
 		return nil, err
 	}

modules/caddyhttp/fileserver/caddyfile.go

@@ -16,6 +16,7 @@ package fileserver
 
 import (
 	"path/filepath"
+	"strconv"
 	"strings"
 
 	"github.com/caddyserver/caddy/v2"
@@ -58,6 +59,7 @@ func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error)
 //	    browse        [<template_file>]
 //	    precompressed <formats...>
 //	    status        <status>
+//	    file_limit    <limit>
 //	    disable_canonical_uris
 //	}
 //
@@ -168,6 +170,17 @@ func (fsrv *FileServer) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 			falseBool := false
 			fsrv.CanonicalURIs = &falseBool
 
+		case "file_limit":
+			fileLimit := d.RemainingArgs()
+			if len(fileLimit) != 1 {
+				return d.Err("file_limit should have an integer value")
+			}
+			val, _ := strconv.Atoi(fileLimit[0])
+			if fsrv.Browse.FileLimit != 0 {
+				return d.Err("file_limit is already enabled")
+			}
+			fsrv.Browse.FileLimit = val
+
 		case "pass_thru":
 			if d.NextArg() {
 				return d.ArgErr()

modules/caddyhttp/fileserver/command.go

@@ -66,6 +66,7 @@ respond with a file listing.`,
 			cmd.Flags().BoolP("templates", "t", false, "Enable template rendering")
 			cmd.Flags().BoolP("access-log", "a", false, "Enable the access log")
 			cmd.Flags().BoolP("debug", "v", false, "Enable verbose debug logs")
+			cmd.Flags().IntP("file-limit", "f", defaultMaxDirLimit, "Max directories to read")
 			cmd.Flags().BoolP("no-compress", "", false, "Disable Zstandard and Gzip compression")
 			cmd.Flags().StringSliceP("precompressed", "p", []string{}, "Specify precompression file extensions. Compression preference implied from flag order.")
 			cmd.RunE = caddycmd.WrapCommandFuncForCobra(cmdFileServer)
@@ -91,6 +92,7 @@ func cmdFileServer(fs caddycmd.Flags) (int, error) {
 	browse := fs.Bool("browse")
 	templates := fs.Bool("templates")
 	accessLog := fs.Bool("access-log")
+	fileLimit := fs.Int("file-limit")
 	debug := fs.Bool("debug")
 	revealSymlinks := fs.Bool("reveal-symlinks")
 	compress := !fs.Bool("no-compress")
@@ -151,7 +153,7 @@ func cmdFileServer(fs caddycmd.Flags) (int, error) {
 	}
 
 	if browse {
-		handler.Browse = &Browse{RevealSymlinks: revealSymlinks}
+		handler.Browse = &Browse{RevealSymlinks: revealSymlinks, FileLimit: fileLimit}
 	}
 
 	handlers = append(handlers, caddyconfig.JSONModuleObject(handler, "handler", "file_server", nil))