Update copyright years

To make it more useful for debugging.  We might also tie this
to the --debug option, though that would be a bit chaotic.

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2014 - 2018, Přemysl Eric Janouch <p@janouch.name>
+Copyright (c) 2014 - 2020, Přemysl Eric Janouch <p@janouch.name>
 
 Permission to use, copy, modify, and/or distribute this software for any
 purpose with or without fee is hereby granted.

json-rpc-shell.c

@@ -1,7 +1,7 @@
 /*
  * json-rpc-shell.c: simple JSON-RPC 2.0 shell
  *
- * Copyright (c) 2014 - 2016, Přemysl Eric Janouch <p@janouch.name>
+ * Copyright (c) 2014 - 2020, Přemysl Eric Janouch <p@janouch.name>
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted.
@@ -2739,8 +2739,19 @@ display_via_pipeline (struct app_context *ctx,
 }
 
 static bool
-parse_response (struct app_context *ctx, struct str *buf, const char *pipeline)
+process_response (struct app_context *ctx, const json_t *id, struct str *buf,
+	const char *pipeline)
 {
+	if (!id)
+	{
+		printf ("[Notification]\n");
+		if (!buf->len)
+			return true;
+
+		print_warning ("we have been sent data back for a notification");
+		return false;
+	}
+
 	json_error_t e;
 	json_t *response;
 	if (!(response = json_loadb (buf->str, buf->len, JSON_DECODE_ANY, &e)))
@@ -2759,9 +2770,15 @@ parse_response (struct app_context *ctx, struct str *buf, const char *pipeline)
 	else if (!json_is_string (v) || strcmp (json_string_value (v), "2.0"))
 		print_warning ("invalid `%s' field in response", "jsonrpc");
 
-	json_t *result = json_object_get (response, "result");
-	json_t *error  = json_object_get (response, "error");
-	json_t *data   = NULL;
+	json_t *returned_id = json_object_get (response, "id");
+	json_t *result      = json_object_get (response, "result");
+	json_t *error       = json_object_get (response, "error");
+	json_t *data        = NULL;
+
+	if (!returned_id)
+		print_warning ("`%s' field not present in response", "id");
+	if (!json_equal (id, returned_id))
+		print_warning ("mismatching `%s' field in response", "id");
 
 	if (!result && !error)
 		PARSE_FAIL ("neither `result' nor `error' present in response");
@@ -2892,26 +2909,28 @@ make_json_rpc_call (struct app_context *ctx,
 		goto fail;
 	}
 
-	bool success = false;
-	if (id)
-		success = parse_response (ctx, &buf, pipeline);
-	else
+	if (ctx->verbose)
 	{
-		printf ("[Notification]\n");
-		if (buf.len)
-			print_warning ("we have been sent data back for a notification");
+		char *buf_term =
+			iconv_xstrdup (ctx->term_from_utf8, buf.str, buf.len, NULL);
+		if (!buf_term)
+			print_error ("%s: %s", "verbose", "character conversion failed");
 		else
-			success = true;
+		{
+			print_attributed (ctx, stdout, ATTR_INCOMING, "%s", buf_term);
+			fputs ("\n", stdout);
+		}
+		free (buf_term);
 	}
 
-	if (!success)
+	if (!process_response (ctx, id, &buf, pipeline))
 	{
 		char *s = iconv_xstrdup (ctx->term_from_utf8,
 			buf.str, buf.len + 1 /* null byte */, NULL);
 		if (!s)
 			print_error ("character conversion failed for `%s'",
 				"raw response data");
-		else
+		else if (!ctx->verbose /* already printed */)
 			printf ("%s: %s\n", "raw response data", s);
 		free (s);
 	}

json-rpc-test-server.c

@@ -1,7 +1,7 @@
 /*
  * json-rpc-test-server.c: JSON-RPC 2.0 demo server
  *
- * Copyright (c) 2015 - 2018, Přemysl Eric Janouch <p@janouch.name>
+ * Copyright (c) 2015 - 2020, Přemysl Eric Janouch <p@janouch.name>
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted.
@@ -1428,6 +1428,8 @@ end:
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
+/// Handlers must not set the `id` field in their responses, that will be filled
+/// in automatically according to whether the request is a notification or not.
 typedef json_t *(*json_rpc_handler_fn) (struct server_context *, json_t *);
 
 struct json_rpc_handler_info
@@ -1447,7 +1449,10 @@ static json_t *
 json_rpc_ping (struct server_context *ctx, json_t *params)
 {
 	(void) ctx;
-	(void) params;
+
+	if (params && !json_is_null (params))
+		return json_rpc_response (NULL, NULL,
+			json_rpc_error (JSON_RPC_ERROR_INVALID_PARAMS, NULL));
 
 	return json_rpc_response (NULL, json_string ("pong"), NULL);
 }
@@ -1493,7 +1498,10 @@ process_json_rpc_request (struct server_context *ctx, json_t *request)
 
 	json_t *response = handler->handler (ctx, params);
 	if (id)
+	{
+		(void) json_object_set (response, "id", id);
 		return response;
+	}
 
 	// Notifications don't get responses
 	json_decref (response);