MCP Streamable HTTP: add stateless Mcp-Session-Id support (#22000)
Co-authored-by: Costa Tsaousis <costa@netdata.cloud>
Copilot committed
Apr 8, 2026 at 09:18 UTC
92a40a16bb395c1e11d34888503958beb910748a
5 files changed
+22
-1
src/web/api/http_header.c
+9
@@ -217,6 +217,12 @@ static void http_header_x_netdata_auth(struct web_client *w, const char *v, size
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}
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}
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+// MCP HTTP transport session identifier
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+static void http_header_mcp_session_id(struct web_client *w, const char *v, size_t len __maybe_unused) {
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+ if (uuid_parse(v, w->mcp_session_id) != 0)
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+ uuid_clear(w->mcp_session_id);
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+}
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+
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// Handle WebSocket-specific headers
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static void http_header_upgrade(struct web_client *w, const char *v, size_t len __maybe_unused) {
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if(strcasecmp(v, "websocket") == 0) {
@@ -365,6 +371,9 @@ struct {
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// there are a few nightly versions of netdata UI that incorrectly use this instead of X-Netdata-Auth
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{ .hash = 0, .key = "Authorization", .cb = http_header_x_netdata_auth },
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+ // MCP HTTP transport session identifier
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+ { .hash = 0, .key = "Mcp-Session-Id", .cb = http_header_mcp_session_id },
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+
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// terminator
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{ .hash = 0, .key = NULL, .cb = NULL }
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};
src/web/mcp/adapters/mcp-http.c
+8
@@ -208,6 +208,14 @@ int mcp_http_handle_request(struct rrdhost *host __maybe_unused, struct web_clie
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result_code = w->response.code;
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}
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+ // Stateless Mcp-Session-Id: generate if absent, then emit as response header
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+ if (uuid_is_null(w->mcp_session_id))
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+ uuid_generate_random(w->mcp_session_id);
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+
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+ char session_id_str[UUID_STR_LEN];
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+ uuid_unparse_lower(w->mcp_session_id, session_id_str);
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+ buffer_sprintf(w->response.header, "Mcp-Session-Id: %s\r\n", session_id_str);
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+
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json_object_put(root);
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mcp_free_client(mcpc);
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return result_code;
src/web/server/web_client.c
+3
-1
@@ -164,7 +164,9 @@ static void web_client_reset_allocations(struct web_client *w, bool free_all) {
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freez(w->auth_bearer_token);
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w->auth_bearer_token = NULL;
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-
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+
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+ memset(w->mcp_session_id, 0, sizeof(w->mcp_session_id));
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+
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// Free WebSocket resources
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freez(w->websocket.key);
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w->websocket.key = NULL;
src/web/server/web_client.h
+1
@@ -195,6 +195,7 @@ struct web_client {
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char *forwarded_host; // the X-Forwarded-Host: header
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char *origin; // the Origin: header
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char *user_agent; // the User-Agent: header
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+ nd_uuid_t mcp_session_id; // the Mcp-Session-Id: header (MCP HTTP transport)
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// WebSocket related data - NEED TO BE FREED
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struct {
src/web/server/web_client_cache.c
+1
@@ -121,6 +121,7 @@ struct web_client *web_client_get_from_cache(void) {
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w->mode = HTTP_REQUEST_MODE_GET;
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web_client_reset_permissions(w);
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memset(w->transaction, 0, sizeof(w->transaction));
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+ memset(w->mcp_session_id, 0, sizeof(w->mcp_session_id));
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memset(&w->auth, 0, sizeof(w->auth));
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return w;