[PATCH 2/2] archive: support remote archive from stateless transport

[Jiang Xin <worldhello.net@gmail.com>]

From: Jiang Xin <zhiyou.jx@alibaba-inc.com>

Even though we can establish a stateless connection, we still cannot
archive the remote repository using a stateless HTTP protocol. Try the
following steps to make it work.

 1. Add support for "git-upload-archive" service in "http-backend".

 2. Unable to access the URL ".../info/refs?service=git-upload-archive"
    to detect the protocol version, use the "git-upload-pack" service
    instead.

 3. "git-archive" does not resolve the protocol version and capabilities
    when connecting to remote-helper, so the remote-helper should not
    send them.

 4. "git-archive" may not be able to disconnect the stateless
    connection. Run "do_take_over()" to take_over the transfer for
    a graceful disconnect function.

Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
---
 http-backend.c         | 15 +++++++++++++--
 remote-curl.c          | 14 +++++++++++---
 t/t5003-archive-zip.sh | 30 ++++++++++++++++++++++++++++++
 transport-helper.c     |  5 ++++-
 4 files changed, 58 insertions(+), 6 deletions(-)

diff --git a/http-backend.c b/http-backend.c
index ff07b87e64..ed3bed965a 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -38,6 +38,7 @@ struct rpc_service {
 static struct rpc_service rpc_service[] = {
 	{ "upload-pack", "uploadpack", 1, 1 },
 	{ "receive-pack", "receivepack", 0, -1 },
+	{ "upload-archive", "uploadarchive", 0, -1 },
 };
 
 static struct string_list *get_parameters(void)
@@ -639,10 +640,19 @@ static void check_content_type(struct strbuf *hdr, const char *accepted_type)
 
 static void service_rpc(struct strbuf *hdr, char *service_name)
 {
-	const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
+	const char *argv[4];
 	struct rpc_service *svc = select_service(hdr, service_name);
 	struct strbuf buf = STRBUF_INIT;
 
+	if (!strcmp(service_name, "git-upload-archive")) {
+		argv[1] = ".";
+		argv[2] = NULL;
+	} else {
+		argv[1] = "--stateless-rpc";
+		argv[2] = ".";
+		argv[3] = NULL;
+	}
+
 	strbuf_reset(&buf);
 	strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
 	check_content_type(hdr, buf.buf);
@@ -723,7 +733,8 @@ static struct service_cmd {
 	{"GET", "/objects/pack/pack-[0-9a-f]{64}\\.idx$", get_idx_file},
 
 	{"POST", "/git-upload-pack$", service_rpc},
-	{"POST", "/git-receive-pack$", service_rpc}
+	{"POST", "/git-receive-pack$", service_rpc},
+	{"POST", "/git-upload-archive$", service_rpc}
 };
 
 static int bad_request(struct strbuf *hdr, const struct service_cmd *c)
diff --git a/remote-curl.c b/remote-curl.c
index ef05752ca5..ce6cb8ac05 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -1447,8 +1447,14 @@ static int stateless_connect(const char *service_name)
 	 * establish a stateless connection, otherwise we need to tell the
 	 * client to fallback to using other transport helper functions to
 	 * complete their request.
+	 *
+	 * The "git-upload-archive" service is a read-only operation. Fallback
+	 * to use "git-upload-pack" service to discover protocol version.
 	 */
-	discover = discover_refs(service_name, 0);
+	if (!strcmp(service_name, "git-upload-archive"))
+		discover = discover_refs("git-upload-pack", 0);
+	else
+		discover = discover_refs(service_name, 0);
 	if (discover->version != protocol_v2) {
 		printf("fallback\n");
 		fflush(stdout);
@@ -1486,9 +1492,11 @@ static int stateless_connect(const char *service_name)
 
 	/*
 	 * Dump the capability listing that we got from the server earlier
-	 * during the info/refs request.
+	 * during the info/refs request. This does not work with the
+	 * "git-upload-archive" service.
 	 */
-	write_or_die(rpc.in, discover->buf, discover->len);
+	if (strcmp(service_name, "git-upload-archive"))
+		write_or_die(rpc.in, discover->buf, discover->len);
 
 	/* Until we see EOF keep sending POSTs */
 	while (1) {
diff --git a/t/t5003-archive-zip.sh b/t/t5003-archive-zip.sh
index fc499cdff0..80123c1e06 100755
--- a/t/t5003-archive-zip.sh
+++ b/t/t5003-archive-zip.sh
@@ -239,4 +239,34 @@ check_zip with_untracked2
 check_added with_untracked2 untracked one/untracked
 check_added with_untracked2 untracked two/untracked
 
+. "$TEST_DIRECTORY"/lib-httpd.sh
+start_httpd
+
+test_expect_success "setup for HTTP protocol" '
+	cp -R bare.git "$HTTPD_DOCUMENT_ROOT_PATH/bare.git" &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/bare.git" \
+		config http.uploadpack true &&
+	set_askpass user@host pass@host
+'
+
+setup_askpass_helper
+
+test_expect_success 'remote archive does not work with protocol v1' '
+	test_when_finished "rm -f d5.zip" &&
+	test_must_fail git -c protocol.version=1 archive \
+		--remote="$HTTPD_URL/auth/smart/bare.git" \
+		--output=d5.zip HEAD >actual 2>&1 &&
+	cat >expect <<-EOF &&
+	fatal: can${SQ}t connect to subservice git-upload-archive
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'archive remote http repository' '
+	test_when_finished "rm -f d5.zip" &&
+	git archive --remote="$HTTPD_URL/auth/smart/bare.git" \
+		--output=d5.zip HEAD &&
+	test_cmp_bin d.zip d5.zip
+'
+
 test_done
diff --git a/transport-helper.c b/transport-helper.c
index 2e127d24a5..91381be622 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -628,7 +628,8 @@ static int process_connect_service(struct transport *transport,
 		ret = run_connect(transport, &cmdbuf);
 	} else if (data->stateless_connect &&
 		   (get_protocol_version_config() == protocol_v2) &&
-		   !strcmp("git-upload-pack", name)) {
+		   (!strcmp("git-upload-pack", name) ||
+		    !strcmp("git-upload-archive", name))) {
 		strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
 		ret = run_connect(transport, &cmdbuf);
 		if (ret)
@@ -668,6 +669,8 @@ static int connect_helper(struct transport *transport, const char *name,
 
 	fd[0] = data->helper->out;
 	fd[1] = data->helper->in;
+
+	do_take_over(transport);
 	return 0;
 }
 
-- 
2.40.1.49.g40e13c3520.dirty