From e42716c43e0241e9d6d2ca7f7efe8d33a27127c2 Mon Sep 17 00:00:00 2001
From: tjpcc <tjp@ctrl-c.club>
Date: Wed, 3 May 2023 13:21:34 -0600
Subject: hide private files from the FS

- ResolveFile acts like ErrNotFound
- ResolveDirectory acts like ErrNotFound
- RenderDirectoryListing strips out dot-prefixed entries
---
 contrib/fs/dir.go                           | 11 +++++++++++
 contrib/fs/file.go                          | 14 ++++++++++++++
 contrib/fs/testdata/.secret-dir/public-file |  0
 contrib/fs/testdata/.secret-file            |  0
 4 files changed, 25 insertions(+)
 create mode 100644 contrib/fs/testdata/.secret-dir/public-file
 create mode 100644 contrib/fs/testdata/.secret-file

diff --git a/contrib/fs/dir.go b/contrib/fs/dir.go
index bb2d933..69d17e9 100644
--- a/contrib/fs/dir.go
+++ b/contrib/fs/dir.go
@@ -24,6 +24,10 @@ func ResolveDirectory(
 		path = "."
 	}
 
+	if isPrivate(path) {
+		return "", nil, nil
+	}
+
 	file, err := fileSystem.Open(path)
 	if isNotFound(err) {
 		return "", nil, nil
@@ -124,6 +128,13 @@ func dirlistNamespace(path string, dirFile fs.ReadDirFile, server sr.Server) (ma
 		return nil, err
 	}
 
+	for i := len(entries) - 1; i >= 0; i-- {
+		if strings.HasPrefix(entries[i].Name(), ".") {
+			copy(entries[i:], entries[i+1:])
+			entries = entries[:len(entries)-1]
+		}
+	}
+
 	sort.Slice(entries, func(i, j int) bool {
 		return entries[i].Name() < entries[j].Name()
 	})
diff --git a/contrib/fs/file.go b/contrib/fs/file.go
index 591c1bd..d231466 100644
--- a/contrib/fs/file.go
+++ b/contrib/fs/file.go
@@ -15,6 +15,11 @@ import (
 // returned.
 func ResolveFile(request *sr.Request, fileSystem fs.FS) (string, fs.File, error) {
 	filepath := strings.TrimPrefix(request.Path, "/")
+
+	if isPrivate(filepath) {
+		return "", nil, nil
+	}
+
 	file, err := fileSystem.Open(filepath)
 	if isNotFound(err) {
 		return "", nil, nil
@@ -57,3 +62,12 @@ func mediaType(filePath string) string {
 	}
 	return mtype
 }
+
+func isPrivate(fullpath string) bool {
+	for _, segment := range strings.Split(fullpath, "/") {
+		if len(segment) > 1 && segment[0] == '.' {
+			return true
+		}
+	}
+	return false
+}
diff --git a/contrib/fs/testdata/.secret-dir/public-file b/contrib/fs/testdata/.secret-dir/public-file
new file mode 100644
index 0000000..e69de29
diff --git a/contrib/fs/testdata/.secret-file b/contrib/fs/testdata/.secret-file
new file mode 100644
index 0000000..e69de29
-- 
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