spartan FS server

1 files changed, 124 insertions, 0 deletions

diff --git a/contrib/fs/spartan.go b/contrib/fs/spartan.go
new file mode 100644
index 0000000..550f549
--- /dev/null
+++ b/contrib/fs/spartan.go
@@ -0,0 +1,124 @@
+package fs
+
+import (
+	"context"
+	"io/fs"
+	"strings"
+	"text/template"
+
+	"tildegit.org/tjp/gus"
+	"tildegit.org/tjp/gus/spartan"
+)
+
+// SpartanFileHandler builds a handler which serves up files from a filesystem.
+//
+// It only serves responses for paths which do not correspond to directories on disk.
+func SpartanFileHandler(fileSystem fs.FS) gus.Handler {
+	return gus.HandlerFunc(func(ctx context.Context, request *gus.Request) *gus.Response {
+		filepath, file, err := ResolveFile(request, fileSystem)
+		if err != nil {
+			return spartan.ClientError(err)
+		}
+
+		if file == nil {
+			return nil
+		}
+
+		return spartan.Success(mediaType(filepath), file)
+	})
+}
+
+// SpartanDirectoryDefault 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 spartan 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 the same URL with the slash appended. This is necessary for relative
+// links not in 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 SpartanDirectoryDefault(fileSystem fs.FS, filenames ...string) gus.Handler {
+	return gus.HandlerFunc(func(ctx context.Context, request *gus.Request) *gus.Response {
+		dirpath, dir, response := handleDirSpartan(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 spartan.ServerError(err)
+		}
+		if file == nil {
+			return nil
+		}
+
+		return spartan.Success(mediaType(filepath), file)
+	})
+}
+
+// SpartanDirectoryListing produces a listing of the contents of any requested directories.
+//
+// It returns "4 Resource 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 not in the directory's
+// contents to function properly.
+//
+// It requires that files provided by the fs.FS implement fs.ReadDirFile. If they don't, it will
+// produce "4 Resource not found" responses for any directory paths.
+//
+// The tmeplate may be nil, in which cause DefaultSpartanDirectoryList is used instead. The
+// template is then processed with RenderDirectoryListing.
+func SpartanDirectoryListing(filesystem fs.FS, template *template.Template) gus.Handler {
+	return gus.HandlerFunc(func(ctx context.Context, request *gus.Request) *gus.Response {
+		dirpath, dir, response := handleDirSpartan(request, filesystem)
+		if response != nil {
+			return response
+		}
+		if dir == nil {
+			return nil
+		}
+		defer func() { _ = dir.Close() }()
+
+		if template == nil {
+			template = DefaultSpartanDirectoryList
+		}
+		body, err := RenderDirectoryListing(dirpath, dir, template, request.Server)
+		if err != nil {
+			return spartan.ServerError(err)
+		}
+
+		return spartan.Success("text/gemini", body)
+	})
+}
+
+// DefaultSpartanDirectoryList is a template which renders a reasonable gemtext dir listing.
+var DefaultSpartanDirectoryList = DefaultGeminiDirectoryList
+
+func handleDirSpartan(request *gus.Request, filesystem fs.FS) (string, fs.ReadDirFile, *gus.Response) {
+	path, dir, err := ResolveDirectory(request, filesystem)
+	if err != nil {
+		return "", nil, spartan.ServerError(err)
+	}
+
+	if dir == nil {
+		return "", nil, nil
+	}
+
+	if !strings.HasSuffix(request.Path, "/") {
+		_ = dir.Close()
+		url := *request.URL
+		url.Path += "/"
+		return "", nil, spartan.Redirect(url.String())
+	}
+
+	return path, dir, nil
+}