this-city/engine/modules/jsonrpc/jsonrpc.cpp

/**************************************************************************/
/*  jsonrpc.cpp                                                           */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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#include "jsonrpc.h"
#include "jsonrpc.compat.inc"

#include "core/io/json.h"
#include "core/object/class_db.h"

JSONRPC::JSONRPC() {
}

JSONRPC::~JSONRPC() {
}

void JSONRPC::_bind_methods() {
	ClassDB::bind_method(D_METHOD("set_method", "name", "callback"), &JSONRPC::set_method);
	ClassDB::bind_method(D_METHOD("process_action", "action", "recurse"), &JSONRPC::process_action, DEFVAL(false));
	ClassDB::bind_method(D_METHOD("process_string", "action"), &JSONRPC::process_string);

	ClassDB::bind_method(D_METHOD("make_request", "method", "params", "id"), &JSONRPC::make_request);
	ClassDB::bind_method(D_METHOD("make_response", "result", "id"), &JSONRPC::make_response);
	ClassDB::bind_method(D_METHOD("make_notification", "method", "params"), &JSONRPC::make_notification);
	ClassDB::bind_method(D_METHOD("make_response_error", "code", "message", "id"), &JSONRPC::make_response_error, DEFVAL(Variant()));

	BIND_ENUM_CONSTANT(PARSE_ERROR);
	BIND_ENUM_CONSTANT(INVALID_REQUEST);
	BIND_ENUM_CONSTANT(METHOD_NOT_FOUND);
	BIND_ENUM_CONSTANT(INVALID_PARAMS);
	BIND_ENUM_CONSTANT(INTERNAL_ERROR);
}

Dictionary JSONRPC::make_response_error(int p_code, const String &p_message, const Variant &p_id) const {
	Dictionary dict;
	dict["jsonrpc"] = "2.0";

	Dictionary err;
	err["code"] = p_code;
	err["message"] = p_message;

	dict["error"] = err;
	dict["id"] = p_id;

	return dict;
}

Dictionary JSONRPC::make_response(const Variant &p_value, const Variant &p_id) {
	Dictionary dict;
	dict["jsonrpc"] = "2.0";
	dict["id"] = p_id;
	dict["result"] = p_value;
	return dict;
}

Dictionary JSONRPC::make_notification(const String &p_method, const Variant &p_params) {
	Dictionary dict;
	dict["jsonrpc"] = "2.0";
	dict["method"] = p_method;
	dict["params"] = p_params;
	return dict;
}

Dictionary JSONRPC::make_request(const String &p_method, const Variant &p_params, const Variant &p_id) {
	Dictionary dict;
	dict["jsonrpc"] = "2.0";
	dict["method"] = p_method;
	dict["params"] = p_params;
	dict["id"] = p_id;
	return dict;
}

static inline bool _is_response(const Variant &p_obj) {
	return p_obj.get_type() == Variant::DICTIONARY && !p_obj.operator Dictionary().has("method");
}

Variant JSONRPC::process_action(const Variant &p_action, bool p_process_arr_elements) {
	if (p_action.get_type() == Variant::DICTIONARY) {
		if (!_is_response(p_action)) {
			return process_request(p_action);
		}
		process_response(p_action);
	} else if (p_action.get_type() == Variant::ARRAY && p_process_arr_elements) {
		Array arr = p_action;
		if (!arr.is_empty()) {
			Array arr_ret;

			bool response_mode = _is_response(arr[0]);

			for (const Variant &var : arr) {
				if (_is_response(var) != response_mode) {
					return make_response_error(JSONRPC::INVALID_REQUEST, "Batch Request with mixed response and request objects.");
				}

				Variant res = process_action(var);

				if (res.get_type() != Variant::NIL) {
					arr_ret.push_back(res);
				}
			}

			/// If there are no Response objects contained within the Response array as it is to be sent to the client, the server MUST NOT return an empty Array and should return nothing at all.
			if (!arr_ret.is_empty()) {
				return arr_ret;
			}
		} else {
			/// If the batch rpc call itself fails to be recognized ... as an Array with at least one value, the response from the Server MUST be a single Response object.
			return make_response_error(JSONRPC::INVALID_REQUEST, "Invalid Request");
		}
	} else {
		return make_response_error(JSONRPC::INVALID_REQUEST, "Invalid Request");
	}
	return Variant();
}

Variant JSONRPC::process_request(const Dictionary &p_request_object) {
	ERR_FAIL_COND_V(!p_request_object.has("method"), Variant());

	Variant ret;
	String method = p_request_object["method"];

	Array args;
	if (p_request_object.has("params")) {
		Variant params = p_request_object["params"];
		if (params.get_type() == Variant::ARRAY) {
			args = params;
		} else {
			args.push_back(params);
		}
	}

	/// A Notification is a Request object without an "id" member.
	bool is_notification = !p_request_object.has("id");

	Variant id;
	if (!is_notification) {
		id = p_request_object["id"];

		// Account for implementations that discern between int and float on the json serialization level, by using an int if there is a .0 fraction. See #100914
		if (id.get_type() == Variant::FLOAT && id.operator float() == (float)(id.operator int())) {
			id = id.operator int();
		}
	}

	if (methods.has(method)) {
		Variant call_ret = methods[method].callv(args);
		ret = make_response(call_ret, id);
	} else {
		ret = make_response_error(JSONRPC::METHOD_NOT_FOUND, "Method not found: " + method, id);
	}

	/// The Server MUST NOT reply to a Notification
	if (is_notification) {
		ret = Variant();
	}
	return ret;
}

void JSONRPC::process_response(const Dictionary &p_response_object) {
	ERR_FAIL_COND_MSG(!p_response_object.has("id"), "JSONRPC: Received response object without id.");

	const Variant id_var = p_response_object["id"];
	ERR_FAIL_COND_MSG(!id_var.is_num(), "JSONRPC: Received response object with non-numeric id: " + id_var.operator String());
	const int id = id_var.operator int();
	ERR_FAIL_COND_MSG(!response_handlers.has(id), "JSONRPC: No response handler registered for id: " + id_var.operator String());

	if (p_response_object.has("result")) {
		response_handlers[id].call(p_response_object["result"]);
	} else if (p_response_object.has("error")) {
		ERR_PRINT("JSONRPC: Received error response object: " + p_response_object["error"].to_json_string());
	} else {
		ERR_PRINT("JSONRPC: Received response object without 'result' or 'error' field.");
	}

	response_handlers.erase(id);
}

String JSONRPC::process_string(const String &p_input) {
	if (p_input.is_empty()) {
		return String();
	}

	Variant ret;
	JSON json;
	if (json.parse(p_input) == OK) {
		ret = process_action(json.get_data(), true);
	} else {
		ret = make_response_error(JSONRPC::PARSE_ERROR, "Parse error");
	}

	if (ret.get_type() == Variant::NIL) {
		return "";
	}
	return ret.to_json_string();
}

void JSONRPC::set_method(const String &p_name, const Callable &p_callback) {
	methods[p_name] = p_callback;
}

void JSONRPC::set_response_handler(int p_id, const Callable &p_callback) {
	response_handlers[p_id] = p_callback;
}