#endif /* UA_SERVERCOMPONENT_H_ / / This Source Code Form is subject to the terms of the Mozilla Public

  • License, v. 2.0. If a copy of the MPL was not distributed with this

  • file, You can obtain one at http://mozilla.org/MPL/2.0/.

  • Copyright 2026 (c) o6 Automation GmbH (Author: Julius Pfrommer)

*/

#ifndef UA_SERVERCOMPONENT_H_ #define UA_SERVERCOMPONENT_H_

#include <open62541/util.h> #include <open62541/common.h>

_UA_BEGIN_DECLS

struct UA_ServerComponent; typedef struct UA_ServerComponent UA_ServerComponent;

/* ServerComponents are different from other “plugins” in that they have an

  • explicit stateful lifecycle and can be started/stopped at runtime. They

  • typically register connections and timers in the server’s EventLoop and can

  • also register nodes in the server’s information model.

  • ServerComponents can be registered by the application using the public C API.

  • Some ServerComponents define core functionality and are added internally in

  • the server implementation. */

/* Type-tag for some well-known extensions of the general ServerComponent

  • structure. See below. */

typedef enum {

UA_SERVERCOMPONENTTYPE_NORMAL = 0

} UA_ServerComponentType;

struct UA_ServerComponent {

UA_ServerComponent next; / linked-list */ UA_ServerComponentType serverComponentType;

UA_String name; UA_LifecycleState state;

/* Backpointer to the server. Needs to be set before the ServerComponent is

  • started. */

UA_Server *server;

/* Start the ServerComponent. It will typically register timers/connections

  • in the EventLoop and may add nodes in the server’s information model.

  • Starting can fail if the server is not already started also.

  • During startup, the server calls start on all registered

  • ServerComponents. */

UA_StatusCode (*start)(UA_ServerComponent *sc);

/* Stopping is asynchronous and might need a few iterations of the eventloop

  • to succeed. All ServerComponents are stopped during the shutdown of the

  • server. Once fully stopped, the ServerComponent must no longer rely on

  • the server backpointer. So it can be detached and _free’d at runtime of

  • the server. */

void (*stop)(UA_ServerComponent *sc);

/* Clean up and delete the ServerComponent. Can fail if it is not fully

  • stopped. When successfully removed, the ServerComponent must no longer be

  • accessed from the server.

  • ServerComponents are all free’d when the server is deleted. If a

  • ServerComponent is manually removed before, then it needs to be unlinked

  • from the server’s internal linked-list before. */

UA_StatusCode (*free)(UA_ServerComponent *sc);

};

/* Adds the ServerComponent to the server.

  • Starts the component if the server is started. */

UA_StatusCode UA_Server_addServerComponent(UA_Server *server, UA_ServerComponent *sc);

/* Remove the ServerComponent from the server.

  • This will fail if the ServerComponent is not already fully stopped. */

UA_StatusCode UA_Server_removeServerComponent(UA_Server *server, UA_ServerComponent *sc);