1 files changed, 130 insertions, 0 deletions
diff --git a/contrib/fs/gemini.go b/contrib/fs/gemini.go
new file mode 100644
index 0000000..b41cb75
--- /dev/null
+++ b/contrib/fs/gemini.go
@@ -0,0 +1,130 @@
+package fs
+
+import (
+	"context"
+	"io/fs"
+	"strings"
+	"text/template"
+
+	"tildegit.org/tjp/gus"
+	"tildegit.org/tjp/gus/gemini"
+)
+
+// GeminiFileHandler builds a handler which serves up files from a file system.
+//
+// It only serves responses for paths which do not correspond to directories on disk.
+func GeminiFileHandler(fileSystem fs.FS) gus.Handler {
+	return func(ctx context.Context, request *gus.Request) *gus.Response {
+		filepath, file, err := ResolveFile(request, fileSystem)
+		if err != nil {
+			return gemini.Failure(err)
+		}
+
+		if file == nil {
+			return nil
+		}
+
+		return gemini.Success(mediaType(filepath), file)
+	}
+}
+
+// GeminiDirectoryDefault serves up default files for directory path requests.
+//
+// If any of the supported filenames are found, the contents of the file is returned
+// as the gemini response.
+//
+// It returns nil for any paths which don't correspond to a directory.
+//
+// When it encounters a directory path which doesn't end in a trailing slash (/) it
+// redirects to a URL with the trailing slash appended. This is necessary for relative
+// links inot the directory's contents to function properly.
+//
+// It requires that files from the provided fs.FS implement fs.ReadDirFile. If they
+// don't, it will produce nil responses for any directory paths.
+func GeminiDirectoryDefault(fileSystem fs.FS, filenames ...string) gus.Handler {
+	return func(ctx context.Context, request *gus.Request) *gus.Response {
+		dirpath, dir, response := handleDirGemini(request, fileSystem)
+		if response != nil {
+			return response
+		}
+		if dir == nil {
+			return nil
+		}
+		defer func() { _ = dir.Close() }()
+
+		filepath, file, err := ResolveDirectoryDefault(fileSystem, dirpath, dir, filenames)
+		if err != nil {
+			return gemini.Failure(err)
+		}
+		if file == nil {
+			return nil
+		}
+
+		return gemini.Success(mediaType(filepath), file)
+	}
+}
+
+// GeminiDirectoryListing produces a listing of the contents of any requested directories.
+//
+// It returns "51 Not Found" for any paths which don't correspond to a filesystem directory.
+//
+// When it encounters a directory path which doesn't end in a trailing slash (/) it
+// redirects to a URL with the trailing slash appended. This is necessary for relative
+// links inot the directory's contents to function properly.
+//
+// It requires that files from the provided fs.FS implement fs.ReadDirFile. If they
+// don't, it will produce "51 Not Found" responses for any directory paths.
+//
+// The template may be nil, in which case DefaultGeminiDirectoryList is used instead. The
+// template is then processed with RenderDirectoryListing.
+func GeminiDirectoryListing(fileSystem fs.FS, template *template.Template) gus.Handler {
+	return func(ctx context.Context, request *gus.Request) *gus.Response {
+		dirpath, dir, response := handleDirGemini(request, fileSystem)
+		if response != nil {
+			return response
+		}
+		if dir == nil {
+			return nil
+		}
+		defer func() { _ = dir.Close() }()
+
+		if template == nil {
+			template = DefaultGeminiDirectoryList
+		}
+		body, err := RenderDirectoryListing(dirpath, dir, template, request.Server)
+		if err != nil {
+			return gemini.Failure(err)
+		}
+
+		return gemini.Success("text/gemini", body)
+	}
+}
+
+// DefaultGeminiDirectoryList is a template which renders a reasonable gemtext dir list.
+var DefaultGeminiDirectoryList = template.Must(template.New("gemini_dirlist").Parse(`
+# {{ .DirName }}
+{{ range .Entries }}
+=> {{ .Name }}{{ if .IsDir }}/{{ end -}}
+{{ end }}
+=> ../
+`[1:]))
+
+func handleDirGemini(request *gus.Request, fileSystem fs.FS) (string, fs.ReadDirFile, *gus.Response) {
+	path, dir, err := ResolveDirectory(request, fileSystem)
+	if err != nil {
+		return "", nil, gemini.Failure(err)
+	}
+
+	if dir == nil {
+		return "", nil, nil
+	}
+
+	if !strings.HasSuffix(request.Path, "/") {
+		_ = dir.Close()
+		url := *request.URL
+		url.Path += "/"
+		return "", nil, gemini.Redirect(url.String())
+	}
+
+	return path, dir, nil
+}