json: Add wrapper to add a secret to a JSON result

Signed-off-by: Christian Decker <decker.christian@gmail.com>

lightningd/json.c

@@ -440,3 +440,9 @@ void json_add_time(struct json_stream *result, const char *fieldname,
 		(unsigned)ts.tv_nsec);
 	json_add_string(result, fieldname, timebuf);
 }
+
+void json_add_secret(struct json_stream *response, const char *fieldname,
+		     const struct secret *secret)
+{
+	json_add_hex(response, fieldname, secret, sizeof(struct secret));
+}

lightningd/json.h

@@ -5,6 +5,7 @@
 #ifndef LIGHTNING_LIGHTNINGD_JSON_H
 #define LIGHTNING_LIGHTNINGD_JSON_H
 #include "config.h"
+#include <bitcoin/privkey.h>
 #include <ccan/short_types/short_types.h>
 #include <ccan/tal/tal.h>
 #include <ccan/time/time.h>
@@ -42,6 +43,11 @@ void json_add_pubkey(struct json_stream *response,
 		     const char *fieldname,
 		     const struct pubkey *key);
 
+/* '"fieldname" : "89abcdef..."' or "89abcdef..." if fieldname is NULL */
+void json_add_secret(struct json_stream *response,
+		     const char *fieldname,
+		     const struct secret *secret);
+
 /* '"fieldname" : "0289abcdef..."' or "0289abcdef..." if fieldname is NULL */
 void json_add_node_id(struct json_stream *response,
 				const char *fieldname,