From 2fa885d421548e4958861c5bade5d663118b33f2 Mon Sep 17 00:00:00 2001
From: tjh <x@tjh.dev>
Date: Fri, 12 Dec 2025 15:47:52 +0000
Subject: [PATCH] knotserver: support git-upload-archive service over http
Change-Id: knmpmozlkyqontpwrzpmxrqtoukzrspk

Allows a knotserver-hosted repository to be the target of a `git archive --remote=https://<remote>` command.

Signed-off-by: tjh <x@tjh.dev>
---
 knotserver/git.go                 | 47 +++++++++++++++++++++++++++++++
 knotserver/git/service/service.go | 13 +++++++++
 knotserver/router.go              |  1 +
 3 files changed, 61 insertions(+)

diff --git a/knotserver/git.go b/knotserver/git.go
index 4c89a90a..e2018c46 100644
--- a/knotserver/git.go
+++ b/knotserver/git.go
@@ -56,6 +56,53 @@ func (h *Knot) InfoRefs(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func (h *Knot) UploadArchive(w http.ResponseWriter, r *http.Request) {
+	did := chi.URLParam(r, "did")
+	name := chi.URLParam(r, "name")
+	repo, err := securejoin.SecureJoin(h.c.Repo.ScanPath, filepath.Join(did, name))
+	if err != nil {
+		gitError(w, err.Error(), http.StatusInternalServerError)
+		h.l.Error("git: failed to secure join repo path", "handler", "UploadPack", "error", err)
+		return
+	}
+
+	const expectedContentType = "application/x-git-upload-archive-request"
+	contentType := r.Header.Get("Content-Type")
+	if contentType != expectedContentType {
+		gitError(w, fmt.Sprintf("Expected Content-Type: '%s', but received '%s'.", expectedContentType, contentType), http.StatusUnsupportedMediaType)
+	}
+
+	var bodyReader io.ReadCloser = r.Body
+	if r.Header.Get("Content-Encoding") == "gzip" {
+		gzipReader, err := gzip.NewReader(r.Body)
+		if err != nil {
+			gitError(w, err.Error(), http.StatusInternalServerError)
+			h.l.Error("git: failed to create gzip reader", "handler", "UploadArchive", "error", err)
+			return
+		}
+		defer gzipReader.Close()
+		bodyReader = gzipReader
+	}
+
+	w.Header().Set("Content-Type", "application/x-git-upload-archive-result")
+
+	h.l.Info("git: executing git-upload-archive", "handler", "UploadArchive", "repo", repo)
+
+	cmd := service.ServiceCommand{
+		GitProtocol: r.Header.Get("Git-Protocol"),
+		Dir:         repo,
+		Stdout:      w,
+		Stdin:       bodyReader,
+	}
+
+	w.WriteHeader(http.StatusOK)
+
+	if err := cmd.UploadArchive(); err != nil {
+		h.l.Error("git: failed to execute git-upload-pack", "handler", "UploadPack", "error", err)
+		return
+	}
+}
+
 func (h *Knot) UploadPack(w http.ResponseWriter, r *http.Request) {
 	did := chi.URLParam(r, "did")
 	name := chi.URLParam(r, "name")
diff --git a/knotserver/git/service/service.go b/knotserver/git/service/service.go
index bd6438b2..24411afc 100644
--- a/knotserver/git/service/service.go
+++ b/knotserver/git/service/service.go
@@ -95,6 +95,19 @@ func (c *ServiceCommand) InfoRefs() error {
 	return c.RunService(cmd)
 }
 
+func (c *ServiceCommand) UploadArchive() error {
+	cmd := exec.Command("git", []string{
+		"upload-archive",
+		".",
+	}...)
+
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	cmd.Env = append(cmd.Env, fmt.Sprintf("GIT_PROTOCOL=%s", c.GitProtocol))
+	cmd.Dir = c.Dir
+
+	return c.RunService(cmd)
+}
+
 func (c *ServiceCommand) UploadPack() error {
 	cmd := exec.Command("git", []string{
 		"-c", "uploadpack.allowFilter=true",
diff --git a/knotserver/router.go b/knotserver/router.go
index 482f932d..3b27d832 100644
--- a/knotserver/router.go
+++ b/knotserver/router.go
@@ -82,6 +82,7 @@ func (h *Knot) Router() http.Handler {
 		r.Route("/{name}", func(r chi.Router) {
 			// routes for git operations
 			r.Get("/info/refs", h.InfoRefs)
+			r.Post("/git-upload-archive", h.UploadArchive)
 			r.Post("/git-upload-pack", h.UploadPack)
 			r.Post("/git-receive-pack", h.ReceivePack)
 		})
-- 
2.51.1.dirty