o6.client.Client¶

High-level OPC UA client. See the client guide for more details.

o6.client.Client ¶

Bases: Client

High-level OPC UA client. See the client guide for more details.

Attributes¶

ns `instance-attribute` ¶

ns = Namespaces(self)

Namespace manager for the client. See the Namespaces API for details.

Example:

client = Client("opc.tcp://localhost:4840")
client.ns.append(o6.ns.di)
client.ns.load("nodesets/MyCustomTypes.xml", short_name="MyTypes")
client.connect()

After connecting, server-side namespaces that were not already loaded can be discovered through client.ns.remote.discover().

Important

All namespace registration or loading must happen before connect(). client.ns.append() and client.ns.load() are required pre-connection so that namespace index translation can be set up correctly. Attempting to add namespaces after the session is established raises RuntimeError.

root `instance-attribute` ¶

root = ObjectNode(
    ClientBackend(self), "i=84", QualifiedName(0, "Root")
)

The OPC UA Root folder node (i=84) and primary entry point for the node-style API.

objects `instance-attribute` ¶

objects = ObjectNode(
    ClientBackend(self), "i=85", QualifiedName(0, "Objects")
)

The Objects folder node (i=85); shortcut into the application-level address space.

types `instance-attribute` ¶

types = ObjectNode(
    ClientBackend(self), "i=86", QualifiedName(0, "Types")
)

The Types folder node (i=86); entry point for browsing the server's type hierarchies.

views `instance-attribute` ¶

views = ObjectNode(
    ClientBackend(self), "i=87", QualifiedName(0, "Views")
)

The Views folder node (i=87); entry point for server-defined address-space views.

loop `property` ¶

loop

The asyncio event loop used by this client. Set at construction time, not modifiable afterwards.

state `property` ¶

state

Return (channel_state, session_state, connect_status).

connected `property` ¶

connected

Test if a client has both SecureChannel and Session connected.

Functions¶

init ¶

__init__(
    endpoint_url=None,
    loop=None,
    *,
    logger=None,
    certificate=None,
    private_key=None,
    trust_list=None,
    revocation_list=None,
    security_mode=None,
    security_policy=None,
    application_uri=None,
    username=None,
    password=None
)

Create a new OPC UA client.

The constructor accepts the most commonly needed settings as keyword arguments. All remaining configuration — such as session_name, requested_session_timeout, session_locale_ids, endpoint, and any other ClientConfig property — can be set lazily on client.config before calling connect():

.. code-block:: python

client = Client("opc.tcp://localhost:4840")
client.config.session_name = "my-session"
client.config.requested_session_timeout = 60_000
client.config.session_locale_ids = ["en-US"]
client.config.endpoint = my_endpoint_description
client.config.set_username_password("user", "secret")
client.connect()

Parameters:

Name	Type	Description	Default
`endpoint_url`	`str \| None`	OPC UA endpoint to connect to, e.g. `"opc.tcp://localhost:4840"`. Can also be passed to `connect()`.	`None`
`loop`	`AbstractEventLoop \| None`	Asyncio event loop to use. Defaults to the running loop, or a newly created one if none is running.	`None`
`logger`	`Logger \| None`	Python logger used for all client-level log output. Equivalent to `client.config.logger`.	`None`
`certificate`	`str \| Path \| bytes \| None`	Client certificate as a file path (`str` / `Path`) or raw bytes (DER/PEM). Equivalent to `client.config.certificate`.	`None`
`private_key`	`str \| Path \| bytes \| None`	Private key matching certificate, as a file path or raw bytes. Equivalent to `client.config.private_key`.	`None`
`trust_list`	`list[str \| Path \| bytes] \| None`	Trusted server certificates, each as a file path or raw bytes. Equivalent to `client.config.trust_list`.	`None`
`revocation_list`	`list[str \| Path \| bytes] \| None`	Certificate revocation lists (CRL), each as a file path or raw bytes. Equivalent to `client.config.revocation_list`.	`None`
`security_mode`	`int \| None`	OPC UA message security mode (`UA_MessageSecurityMode` integer or `o6.MessageSecurityMode` enum). Equivalent to `client.config.security_mode`.	`None`
`security_policy`	`str \| None`	URI or short name of the security policy, e.g. `"Basic256Sha256"`. Equivalent to `client.config.security_policy`.	`None`
`application_uri`	`str \| None`	Application URI sent in the `ApplicationDescription`. Equivalent to `client.config.application_uri`.	`None`
`username`	`str \| None`	Username for `UserNameIdentityToken` authentication. Equivalent to calling `client.config.set_username_password(username, password)`.	`None`
`password`	`str \| None`	Password for `UserNameIdentityToken` authentication. Used together with username.	`None`

connect ¶

connect(no_session=False)

Connect to the server.

Establishes a SecureChannel and, by default, a Session. Finalizes encryption settings (certificate / key) before connecting.

If no_session is True, only the SecureChannel is opened (useful for discovery or when a session will be activated manually later).

Creates the default subscription.

Starts the background worker thread.

.. code-block:: python

# sync
client.connect()

# async
await client.connect()

Parameters:

Name	Type	Description	Default
`no_session`	`bool`	Open only the SecureChannel, skip Session creation.	`False`

disconnect ¶

disconnect(close_session=True, delete_subscriptions=True)

Disconnect from the server.

By default closes all subscriptions, ends the Session, and closes the SecureChannel, then stops the background worker thread.

Pass close_session=False to close only the SecureChannel while keeping the Session alive (e.g. for session transfer). In that case delete_subscriptions is ignored.

Safe to call when already disconnected or when the event loop is closed — returns None without raising.

.. code-block:: python

# sync
client.disconnect()

# async
await client.disconnect()

Parameters:

Name	Type	Description	Default
`close_session`	`bool`	Close the Session (and SecureChannel). When `False`, only the SecureChannel is closed.	`True`
`delete_subscriptions`	`bool`	Delete all active subscriptions before disconnecting. Ignored when `close_session` is `False`.	`True`

start_reverse_connect ¶

start_reverse_connect(port, hostnames=None)

Listen for an incoming OPC UA reverse connection from the server.

In the reverse-connect scenario the server initiates the TCP connection to the client. The client opens a listen socket on port and waits for the server to connect.

Close the connection with the standard disconnect.

.. code-block:: python

client.start_reverse_connect(port=4840, hostnames=["0.0.0.0"])
# ... use client ...
client.disconnect()

Parameters:

Name	Type	Description	Default
`port`	`int`	TCP port to listen on.	required
`hostnames`	`list[str] \| None`	Network interfaces to advertise. `None` or an empty list lets the stack decide (typically all interfaces).	`None`

activate_current_session ¶

activate_current_session()

Re-activate the session that is already associated with this client.

Sends an ActivateSession request using the client's stored identity token and credentials. Also creates the default subscription.

Typical use — session transfer, step 2 on the receiving client when the session was originally opened by this client and the SecureChannel has been renewed or re-established:

.. code-block:: python

client.connect()                  # establishes session
# ... channel re-established ...
client.activate_current_session() # re-bind session to new channel

activate_session ¶

activate_session(auth_token, server_nonce)

Activate a session that was created by another client.

Used for session transfer: client A's session is handed off to client B. Client B must first open a SecureChannel without a session (connect(no_session=True)), then call this method with the token and nonce retrieved from client A via get_session_authentication_token().

.. code-block:: python

# Client A — get transfer credentials
token, nonce = client_a.get_session_authentication_token()

# Client B — take over the session
client_b.connect(no_session=True)
client_b.activate_session(token, nonce)

Parameters:

Name	Type	Description	Default
`auth_token`	`NodeId`	Authentication token (`NodeId`) from the originating client's `get_session_authentication_token()`.	required
`server_nonce`	`bytes`	Server nonce bytes from the same call.	required

enter ¶

__enter__()

Enter the sync context manager; connect if not already connected.

Calls connect when the client is not yet connected, then returns self. __exit__ calls disconnect if the client is still connected when the block ends.

.. code-block:: python

with Client("opc.tcp://localhost:4840") as client:
    value = client.read("ns=1;s=Temperature")

exit ¶

__exit__(exc_type, exc_value, traceback)

Exit the sync context manager; disconnect if still connected.

Calls disconnect when the client is still connected. Exceptions from the with block are not suppressed. See __enter__ for full usage.

aenter `async` ¶

__aenter__()

Async counterpart of __enter__.

Same semantics — connects if not already connected and returns self — but uses await internally. __aexit__ awaits disconnect.

.. code-block:: python

async with Client("opc.tcp://localhost:4840") as client:
    value = await client.read("ns=1;s=Temperature")

aexit `async` ¶

__aexit__(exc_type, exc_value, traceback)

Exit the async context manager; disconnect if still connected.

Awaits disconnect when the client is still connected. Exceptions from the async with block are not suppressed. See __aenter__ for full usage.

getitem ¶

__getitem__(key)

Resolve a node ID to a typed Node object.

Reads NodeClass and BrowseName from the server and returns the matching Node subclass (e.g. VariableNode, ObjectNode, …).

key accepts anything that can be converted to a NodeId: a string ("ns=1;s=Temperature"), an integer (numeric node id in namespace 0), or a [NodeId][o6.NodeId] instance.

.. code-block:: python

node = client["ns=1;s=Temperature"]        # sync
node = await client["ns=1;s=Temperature"]  # async

service_find_servers ¶

service_find_servers(request)

Raw FindServers service call — discover servers known to a discovery server.

OPC UA Part 4 §5.5.2

service_find_servers_on_network ¶

service_find_servers_on_network(request)

Raw FindServersOnNetwork service call — enumerate servers registered via mDNS/LDS.

OPC UA Part 4 §5.5.3

service_get_endpoints ¶

service_get_endpoints(request)

Raw GetEndpoints service call — retrieve the endpoint descriptions of a server.

OPC UA Part 4 §5.5.4

service_add_nodes ¶

service_add_nodes(request)

Raw AddNodes service call — add one or more nodes to the address space.

OPC UA Part 4 §5.8.2

service_delete_nodes ¶

service_delete_nodes(request)

Raw DeleteNodes service call — remove one or more nodes from the address space.

OPC UA Part 4 §5.8.4

service_add_references ¶

service_add_references(request)

Raw AddReferences service call — add references between nodes.

OPC UA Part 4 §5.8.3

service_delete_references ¶

service_delete_references(request)

Raw DeleteReferences service call — remove references between nodes.

OPC UA Part 4 §5.8.5

service_browse ¶

service_browse(request)

Raw Browse service call — navigate the address space from one or more start nodes.

Returns references according to the BrowseDescription filter in the request. Use service_browse_next to continue if the response indicates more results are available.

OPC UA Part 4 §5.9.2

service_browse_next ¶

service_browse_next(request)

Raw BrowseNext service call — continue a Browse that returned a continuation point.

OPC UA Part 4 §5.9.3

service_translate_browse_paths_to_nodeids ¶

service_translate_browse_paths_to_nodeids(request)

Raw TranslateBrowsePathsToNodeIds service call — resolve browse paths to NodeIds.

OPC UA Part 4 §5.9.4

service_register_nodes ¶

service_register_nodes(request)

Raw RegisterNodes service call — obtain optimised NodeIds for repeated access.

OPC UA Part 4 §5.9.5

service_unregister_nodes ¶

service_unregister_nodes(request)

Raw UnregisterNodes service call — release NodeIds obtained via RegisterNodes.

OPC UA Part 4 §5.9.6

service_read ¶

service_read(request)

Raw Read service call — read one or more node attributes.

OPC UA Part 4 §5.11.2

service_history_read ¶

service_history_read(request)

Raw HistoryRead service call — read historical values or events from nodes.

OPC UA Part 4 §5.11.3

service_write ¶

service_write(request)

Raw Write service call — write one or more node attribute values.

OPC UA Part 4 §5.11.4

service_history_update ¶

service_history_update(request)

Raw HistoryUpdate service call — insert, replace, or delete historical data.

OPC UA Part 4 §5.11.5

service_call ¶

service_call(request)

Raw Call service call — invoke one or more OPC UA methods.

OPC UA Part 4 §5.12.2

get_remote_data_types ¶

get_remote_data_types(type_nodes=None)

Read custom StructureDefinition data types from the server.

Browses the server's DataType hierarchy (rooted at Structure, NodeId i=22) and reads the DataTypeDefinition and BrowseName attributes for every discovered node. Only nodes that carry a StructureDefinition (structs, structs-with-optional-fields, and unions) are included in the result.

Pass type_nodes to restrict the query to a specific set of DataType NodeIds instead of walking the full hierarchy. Passing an empty list returns [] immediately without contacting the server.

Each entry in the returned list is a dict with the following keys:

type_name (str) — BrowseName.name of the DataType node.
type_id (NodeId) — NodeId of the DataType node.
binary_encoding_id (NodeId) — default binary encoding NodeId (StructureDefinition.defaultEncodingId).
type_kind (DataTypeKind) — Structure, OptStruct (structure with optional fields), or Union.
members_size (int) — number of fields in the structure.

The result can be passed directly to [register_data_types][o6.register_data_types] to enable encoding/decoding of these types on the client.

Parameters:

Name	Type	Description	Default
`type_nodes`	`list[NodeIdLike] \| None`	Explicit DataType NodeIds to query. `None` (default) walks the full `Structure` subtype hierarchy.	`None`

get_endpoints ¶

get_endpoints(
    endpoint_url, *, locale_ids=None, profile_uris=None
)

Return the endpoints advertised by a server.

Sends a GetEndpoints request to endpoint_url. No active session is required — connect with connect(no_session=True) first if the client is not yet connected.

Each [EndpointDescription][o6.EndpointDescription] in the result describes one available endpoint and includes the endpoint URL, security mode, security policy URI, transport profile URI, server certificate, and the list of supported [UserTokenPolicy][o6.UserTokenPolicy] entries.

client.connect(no_session=True)
endpoints = client.get_endpoints("opc.tcp://localhost:4840")
for ep in endpoints:
    print(ep.endpoint_url, ep.security_mode, ep.security_policy_uri)

Parameters:

Name	Type	Description	Default
`endpoint_url`	`str`	URL of the server to query, e.g. `"opc.tcp://localhost:4840"`.	required
`locale_ids`	`list[str] \| None`	Preferred locales for localised strings in the response (e.g. `["en-US", "de-DE"]`). `None` returns the server's default locale.	`None`
`profile_uris`	`list[str] \| None`	Restrict the result to endpoints that match one of these transport profile URIs. `None` returns all endpoints.	`None`

find_servers ¶

find_servers(
    endpoint_url, *, server_uris=None, locale_ids=None
)

Return servers registered at a discovery server or known to a server.

Sends a FindServers request to endpoint_url. Typically called against a Local Discovery Server (LDS) at "opc.tcp://localhost:4840" to enumerate all servers registered on the host, or against any server to retrieve its own [ApplicationDescription][o6.ApplicationDescription].

No active session is required — connect(no_session=True) is sufficient.

Each [ApplicationDescription][o6.ApplicationDescription] in the result contains the application name, application URI, application type, product URI, and a list of discovery URLs that can be passed to get_endpoints.

.. code-block:: python

client.connect(no_session=True)
servers = client.find_servers("opc.tcp://localhost:4840")
for srv in servers:
    print(srv.application_uri, srv.discovery_urls)

Parameters:

Name	Type	Description	Default
`endpoint_url`	`str`	URL of the discovery server or server to query.	required
`locale_ids`	`list[str] \| None`	Preferred locales for the `ApplicationDescription.application_name` field. `None` uses the server's default locale.	`None`
`server_uris`	`list[str] \| None`	Restrict the result to servers whose `applicationUri` matches one of these strings. `None` returns all known servers.	`None`

find_servers_on_network ¶

find_servers_on_network(
    starting_record_id=0,
    max_records_to_return=0,
    server_capability_filter=None,
)

Return servers visible on the network via a Local Discovery Server (LDS).

Sends a FindServersOnNetwork request to the connected LDS. The LDS maintains a registry of servers that have announced themselves via mDNS or the RegisterServer2 service. This call is only meaningful when connected to an LDS; a regular OPC UA server will return an empty list or an error.

The result is paginated: use starting_record_id and max_records_to_return to page through large registries. The record_id field on each [ServerOnNetwork][o6.ServerOnNetwork] entry can be used as the starting_record_id for the next page.

Each [ServerOnNetwork][o6.ServerOnNetwork] entry contains the server name, discovery URL, and a list of capability strings (e.g. "DA" for Data Access, "HE" for Historical Events).

.. code-block:: python

# Fetch the first 100 servers that support Data Access
servers = client.find_servers_on_network(
    max_records_to_return=100,
    server_capability_filter=["DA"],
)

Parameters:

Name	Type	Description	Default
`starting_record_id`	`int`	Record ID to start from for pagination. `0` starts from the beginning of the registry.	`0`
`max_records_to_return`	`int`	Maximum number of entries to return. `0` lets the server decide (typically returns all entries).	`0`
`server_capability_filter`	`list[str] \| None`	Restrict the result to servers that advertise all of the given capability strings. `None` returns servers regardless of capabilities.	`None`

call ¶

call(object_id, method_id, input_args=[])

Invoke a method on a node.

Parameters:

Name	Description	Default
`object_id`	The object node id that owns the method.	required
`method_id`	The method node id to invoke.	required
`input_args`	Positional input arguments to pass to the method.	required

Returns:

Type	Description
`MaybeAwaitable[tuple[StatusCode, ...]]`	A tuple of status codes for the method outputs.

browse ¶

browse(
    target,
    *,
    direction=o6.BrowseDirection.FORWARD,
    reftype=o6.ns.ns0.reftypes.References.HierarchicalReferences,
    refsubtypes=True,
    nodeclass_mask=o6.NodeClass.UNSPECIFIED,
    result_mask=o6.BrowseResultMask(0)
)

Browse references from a node.

The method transparently follows server-issued continuation points by calling BrowseNext until all references have been collected, so the returned list is always complete even when the server splits the response into multiple batches.

Parameters:

Name	Type	Description	Default
`target`	`NodeIdLike`	The node id to browse from.	required
`direction`	`BrowseDirection`	The browse direction (forward, inverse, or both).	`...`
`reftype`	`NodeIdLike`	A reference type to filter by, or `None` for all types.	`...`
`refsubtypes`	`bool`	If `True`, include subtypes of the reference type.	`True`
`nodeclass_mask`	`NodeClass`	A node-class mask to filter the target nodes.	`...`
`result_mask`	`BrowseResultMask`	A browse result mask to customize returned fields.	`...`

Returns:

Type	Description
`MaybeAwaitable[list[ReferenceDescription]]`	A list of `ReferenceDescription` objects describing the found
`MaybeAwaitable[list[ReferenceDescription]]`	references.

history_read ¶

history_read(
    target,
    start_time,
    end_time,
    num_values_per_node=0,
    return_bounds=False,
    timestamps_to_return=o6.TimestampsToReturn.BOTH,
)

Read raw historical values for one or more nodes.

Parameters:

Name	Type	Description	Default
`target`	`NodeIdLike \| list[NodeIdLike]`	A node id or list of node ids to read history from.	required
`start_time`	`datetime`	The start time for the history interval.	required
`end_time`	`datetime`	The end time for the history interval.	required
`num_values_per_node`	`int`	Maximum number of values to return per node.	`0`
`return_bounds`	`bool`	If `True`, include boundary values at the interval edges.	`False`
`timestamps_to_return`	`TimestampsToReturn`	Which timestamps to return with each value.	`...`

Returns:

Type	Description
`Any`	Historical values or data values for the requested nodes.

history_update_insert ¶

history_update_insert(target, values)

Insert new historical values into a node's history.

Insertion fails for any timestamp that already has a value stored. Use history_update_replace to overwrite existing entries.

Parameters:

Name	Type	Description	Default
`target`	`NodeIdLike`	The node id whose history is being updated.	required
`values`	`list[DataValue]`	The historical values to insert.	required

Returns:

Type	Description
`Any`	The raw result of the history update operation.

history_update_replace ¶

history_update_replace(target, values)

Replace existing historical values for a node.

Replacement requires that a value already exists at each provided timestamp. Use history_update_insert to add new entries.

Parameters:

Name	Type	Description	Default
`target`	`NodeIdLike`	The node id whose history is being updated.	required
`values`	`list[DataValue]`	The historical values to replace existing entries with.	required

Returns:

Type	Description
`Any`	The raw result of the history update operation.

history_update_delete ¶

history_update_delete(target, start_time, end_time)

Delete historical values from a node.

Parameters:

Name	Type	Description	Default
`target`	`NodeIdLike`	The node id whose history should be deleted.	required
`start_time`	`datetime`	The start of the deletion interval.	required
`end_time`	`datetime`	The end of the deletion interval.	required

Returns:

Type	Description
`Any`	The raw result of the history delete operation.

add_variable_node ¶

add_variable_node(
    *,
    parent,
    parent_reference=o6.ns.ns0.reftypes.References.HierarchicalReferences.HasChild.Aggregates.HasComponent,
    browsename,
    requested_nodeid=None,
    attributes,
    type_definition=o6.ns.ns0.vartypes.BaseVariableType.BaseDataVariableType
)

Add a variable node to the server.

Parameters:

Name	Type	Description	Default
`parent`	`NodeIdLike`	The parent node id for the variable.	required
`browsename`	`QualifiedName \| str`	The BrowseName for the variable.	required
`attributes`	`VariableAttributes \| None`	The variable attributes.	required
`requested_nodeid`	`NodeIdLike \| None`	Optionally request a specific node id.	`None`
`parent_reference`	`NodeIdLike`	The reference type used to link the variable.	`HasComponent`
`type_definition`	`NodeIdLike`	The variable type definition node id.	`BaseDataVariableType`

Returns:

Type	Description
`MaybeAwaitable[NodeId]`	The newly created variable node id.

add_variable_type_node ¶

add_variable_type_node(
    *,
    parent,
    parent_reference=o6.ns.ns0.reftypes.References.HierarchicalReferences.HasChild.HasSubtype,
    browsename,
    requested_nodeid=None,
    attributes
)

Add a variable type node to the server.

Parameters:

Name	Type	Description	Default
`parent`	`NodeIdLike`	The parent node id for the type node.	required
`browsename`	`QualifiedName \| str`	The BrowseName for the variable type.	required
`attributes`	`VariableTypeAttributes`	The variable type attributes.	required
`requested_nodeid`	`NodeIdLike \| None`	Optionally request a specific node id.	`None`
`parent_reference`	`NodeIdLike`	The reference type used to link the type node.	`HasSubtype`

Returns:

Type	Description
`MaybeAwaitable[NodeId]`	The newly created variable type node id.

add_object_node ¶

add_object_node(
    *,
    parent,
    parent_reference=o6.ns.ns0.reftypes.References.HierarchicalReferences.HasChild.Aggregates.HasComponent,
    browsename,
    requested_nodeid=None,
    attributes,
    type_definition=o6.ns.ns0.objtypes.BaseObjectType
)

Add an object node to the server.

Parameters:

Name	Type	Description	Default
`parent`	`NodeIdLike`	The parent node id for the object.	required
`browsename`	`QualifiedName \| str`	The BrowseName for the object.	required
`attributes`	`ObjectAttributes`	The object attributes.	required
`requested_nodeid`	`NodeIdLike \| None`	Optionally request a specific node id.	`None`
`parent_reference`	`NodeIdLike`	The reference type used to link the object.	`HasComponent`
`type_definition`	`NodeIdLike`	The object type definition node id.	`BaseObjectType`

Returns:

Type	Description
`MaybeAwaitable[NodeId]`	The newly created object node id.

add_object_type_node ¶

add_object_type_node(
    *,
    parent,
    parent_reference=o6.ns.ns0.reftypes.References.HierarchicalReferences.HasChild.HasSubtype,
    browsename,
    requested_nodeid=None,
    attributes
)

Add an object type node to the server.

Parameters:

Name	Type	Description	Default
`parent`	`NodeIdLike`	The parent node id for the type.	required
`browsename`	`QualifiedName \| str`	The BrowseName for the object type.	required
`attributes`	`ObjectTypeAttributes`	The object type attributes.	required
`requested_nodeid`	`NodeIdLike \| None`	Optionally request a specific node id.	`None`
`parent_reference`	`NodeIdLike`	The reference type used to link the type node.	`HasSubtype`

Returns:

Type	Description
`MaybeAwaitable[NodeId]`	The newly created object type node id.

add_view_node ¶

add_view_node(
    *,
    parent,
    parent_reference=o6.ns.ns0.reftypes.References.HierarchicalReferences.HasChild.Aggregates.HasComponent,
    browsename,
    requested_nodeid=None,
    attributes
)

Add a view node to the server.

Parameters:

Name	Type	Description	Default
`parent`	`NodeIdLike`	The parent node id for the view.	required
`browsename`	`QualifiedName \| str`	The BrowseName for the view.	required
`attributes`	`ViewAttributes`	The view attributes.	required
`requested_nodeid`	`NodeIdLike \| None`	Optionally request a specific node id.	`None`
`parent_reference`	`NodeIdLike`	The reference type used to link the view.	`HasComponent`

Returns:

Type	Description
`MaybeAwaitable[NodeId]`	The newly created view node id.

add_reference_type_node ¶

add_reference_type_node(
    *,
    parent,
    parent_reference=o6.ns.ns0.reftypes.References.HierarchicalReferences.HasChild.HasSubtype,
    browsename,
    requested_nodeid=None,
    attributes
)

Add a reference type node to the server.

Parameters:

Name	Type	Description	Default
`parent`	`NodeIdLike`	The parent node id for the reference type.	required
`browsename`	`QualifiedName \| str`	The BrowseName for the reference type.	required
`attributes`	`ReferenceTypeAttributes`	The reference type attributes.	required
`requested_nodeid`	`NodeIdLike \| None`	Optionally request a specific node id.	`None`
`parent_reference`	`NodeIdLike`	The reference type used to link the node.	`HasSubtype`

Returns:

Type	Description
`MaybeAwaitable[NodeId]`	The newly created reference type node id.

add_data_type_node ¶

add_data_type_node(
    *,
    parent,
    parent_reference=o6.ns.ns0.reftypes.References.HierarchicalReferences.HasChild.HasSubtype,
    browsename,
    requested_nodeid=None,
    attributes
)

Add a data type node to the server.

Parameters:

Name	Type	Description	Default
`parent`	`NodeIdLike`	The parent node id for the data type.	required
`browsename`	`QualifiedName \| str`	The BrowseName for the data type.	required
`attributes`	`DataTypeAttributes`	The data type attributes.	required
`requested_nodeid`	`NodeIdLike \| None`	Optionally request a specific node id.	`None`
`parent_reference`	`NodeIdLike`	The reference type used to link the node.	`HasSubtype`

Returns:

Type	Description
`MaybeAwaitable[NodeId]`	The newly created data type node id.

add_method_node ¶

add_method_node(
    *,
    parent,
    parent_reference=o6.ns.ns0.reftypes.References.HierarchicalReferences.HasChild.Aggregates.HasComponent,
    browsename,
    requested_nodeid=None,
    attributes
)

Add a method node to the server.

Parameters:

Name	Type	Description	Default
`parent`	`NodeIdLike`	The parent node id for the method.	required
`browsename`	`QualifiedName \| str`	The BrowseName for the method.	required
`attributes`	`MethodAttributes`	The method attributes.	required
`requested_nodeid`	`NodeIdLike \| None`	Optionally request a specific node id.	`None`
`parent_reference`	`NodeIdLike`	The reference type used to link the method.	`HasComponent`

Returns:

Type	Description
`MaybeAwaitable[NodeId]`	The newly created method node id.

delete_node ¶

delete_node(nodeid, delete_target_references=True)

Delete one or more nodes from the address space.

Parameters:

Name	Type	Description	Default
`nodeid`	`NodeIdLike \| list[NodeIdLike]`	A single node id or list of node ids to delete.	required
`delete_target_references`	`bool`	If `True`, also delete references to the node targets.	`True`

Returns:

Type	Description
`MaybeAwaitable[StatusCode]`	The first non-Good `StatusCode` from the per-node results, or
`MaybeAwaitable[StatusCode]`	`StatusCode.Good` if all deletions succeeded.

add_reference ¶

add_reference(
    source,
    reftype,
    target,
    forward=True,
    target_nodeclass=o6.NodeClass.UNSPECIFIED,
    target_server_uri="",
)

Add a reference between two nodes.

Parameters:

Name	Type	Description	Default
`source`	`NodeIdLike`	The source node id for the reference.	required
`reftype`	`NodeIdLike`	The reference type id.	required
`target`	`NodeIdLike \| ExpandedNodeId`	The target node id.	required
`forward`	`bool`	If `True`, create a forward reference.	`True`
`target_nodeclass`	`NodeClass`	Optional target node class for the reference.	`...`
`target_server_uri`	`str`	Optional server uri when referencing an external node.	`''`

Returns:

Type	Description
`MaybeAwaitable[StatusCode]`	The `StatusCode` returned by the server for this reference.

delete_reference ¶

delete_reference(
    source,
    reftype,
    target,
    forward=True,
    delete_bidirectional=True,
)

Delete a reference between two nodes.

Parameters:

Name	Type	Description	Default
`source`	`NodeIdLike`	The source node id for the reference.	required
`reftype`	`NodeIdLike`	The reference type id.	required
`target`	`NodeIdLike`	The target node id.	required
`forward`	`bool`	If `True`, delete the forward reference.	`True`
`delete_bidirectional`	`bool`	If `True`, also delete the reverse reference.	`True`

Returns:

Type	Description
`MaybeAwaitable[StatusCode]`	The `StatusCode` returned by the server for this deletion.

create_subscription ¶

create_subscription(
    publishing_interval=100.0,
    lifetime_count=36000,
    max_keepalive_count=10,
    max_notifications_per_publish=10,
    publishing_enabled=True,
    *,
    on_created=None,
    on_status_change=None,
    on_deleted=None
)

Create a subscription to monitor data or events.

Parameters:

Name	Type	Description	Default
`req`		Optional raw create subscription request object.	required
`publishing_interval`	`float`	The desired publishing interval in milliseconds.	`100.0`
`lifetime_count`	`int`	The subscription lifetime count.	`36000`
`max_keepalive_count`	`int`	The maximum keepalive count.	`10`
`max_notifications_per_publish`	`int`	The maximum number of notifications per publish.	`10`
`publishing_enabled`	`bool`	Whether the subscription is initially enabled.	`True`
`on_created`	`Callable[[Subscription, CreateSubscriptionResponse], None] \| None`	Optional callback invoked with `(subscription, response)` once the server has acknowledged subscription creation.	`None`
`on_status_change`	`Callable[[Subscription, StatusChangeNotification], None] \| None`	Optional callback invoked with `(subscription, notification)` when the server publishes a `StatusChangeNotification` for this subscription.	`None`
`on_deleted`	`Callable[[Subscription], None] \| None`	Optional callback invoked with `(subscription,)` when the subscription is destroyed — explicitly via `delete()`, or implicitly on session close / disconnect.	`None`

Returns:

Type	Description
`MaybeAwaitable[Subscription]`	A `Subscription` object representing the created subscription.

monitor ¶

monitor(
    target,
    callback=None,
    sampling_interval=100.0,
    *,
    value_only=True,
    subscription=None,
    filter=None,
    monitoring_mode=o6.MonitoringMode.REPORTING,
    queue_size=1,
    discard_oldest=True,
    on_created=None,
    on_deleted=None
)

Monitor data changes on one or more nodes.

Parameters:

Name	Type	Description	Default
`target`	`NodeIdLike \| ReadValueId \| list[NodeIdLike \| ReadValueId]`	A node id, [ReadValueId][o6.ReadValueId], or list thereof to monitor.	required
`callback`	`DataChangeCallback \| None`	Optional callback invoked for each data change. If `None`, a default callback that prints `MonitoredItem {id}: {value}` to stdout is used.	`None`
`sampling_interval`	`float`	The requested sampling interval in milliseconds.	`100.0`
`value_only`	`bool`	If `True` (default), the callback receives the unwrapped value. If `False`, it receives the full [DataValue][o6.DataValue].	`True`
`subscription`	`Subscription \| None`	Optional subscription to attach the monitored items to. If `None` (default), the clients' default subscription is used.	`None`
`filter`	`DataChangeFilter \| None`	Optional [DataChangeFilter][o6.DataChangeFilter] to control triggering.	`None`
`monitoring_mode`	`MonitoringMode`	Monitoring mode for the item (default: `REPORTING`).	`...`
`queue_size`	`int`	Requested queue size (default: `1`).	`1`
`discard_oldest`	`bool`	Whether to discard the oldest entry when the queue is full (default: `True`).	`True`
`on_created`	`CreatedCallback \| None`	Optional lifecycle callback; see `MonitoredItem._data_change`.	`None`
`on_deleted`	`DeletedCallback \| None`	Optional lifecycle callback; see `MonitoredItem._data_change`.	`None`

Returns:

Type	Description
`MaybeAwaitable[MonitoredItem \| list[MonitoredItem]]`	A monitored item or list of monitored items created for the target nodes.

monitor_event ¶

monitor_event(
    nodeid,
    callback,
    filter=None,
    *,
    subscription=None,
    monitoring_mode=o6.MonitoringMode.REPORTING,
    queue_size=100,
    discard_oldest=True,
    on_created=None,
    on_deleted=None
)

Monitor events on a node.

Parameters:

Name	Type	Description	Default
`nodeid`	`NodeIdLike`	The node id to monitor for events.	required
`callback`	`EventCallback`	Callback invoked for each matching event.	required
`filter`	`EventFilter \| str \| None`	Optional event filter or filter expression string. If `None`, a default filter selecting `EventId`, `EventType`, `SourceName`, `Time`, `Message`, and `Severity` is used.	`None`
`subscription`	`Subscription \| None`	Optional subscription to attach the monitored item to. Defaults to :attr:`default_subscription`.	`None`
`monitoring_mode`	`MonitoringMode`	Monitoring mode for the item (default: `REPORTING`).	`...`
`queue_size`	`int`	Requested queue size (default: `100`).	`100`
`discard_oldest`	`bool`	Whether to discard the oldest entry when the queue is full (default: `True`).	`True`
`on_created`	`CreatedCallback \| None`	Optional lifecycle callback; see `MonitoredItem._event`.	`None`
`on_deleted`	`DeletedCallback \| None`	Optional lifecycle callback; see `MonitoredItem._event`.	`None`

Returns:

Type	Description
`MaybeAwaitable[MonitoredItem]`	The created monitored event item.

o6.client.Client¶

o6.client.Client ¶

Attributes¶

ns instance-attribute ¶

root instance-attribute ¶

objects instance-attribute ¶

types instance-attribute ¶

views instance-attribute ¶

loop property ¶

state property ¶

connected property ¶

Functions¶

__init__ ¶

connect ¶

disconnect ¶

start_reverse_connect ¶

activate_current_session ¶

activate_session ¶

__enter__ ¶

__exit__ ¶

__aenter__ async ¶

__aexit__ async ¶

__getitem__ ¶

service_find_servers ¶

service_find_servers_on_network ¶

service_get_endpoints ¶

service_add_nodes ¶

service_delete_nodes ¶

service_add_references ¶

service_delete_references ¶

service_browse ¶

service_browse_next ¶

service_translate_browse_paths_to_nodeids ¶

service_register_nodes ¶

service_unregister_nodes ¶

service_read ¶

service_history_read ¶

service_write ¶

service_history_update ¶

service_call ¶

get_remote_data_types ¶

get_endpoints ¶

find_servers ¶

find_servers_on_network ¶

call ¶

browse ¶

history_read ¶

history_update_insert ¶

history_update_replace ¶

history_update_delete ¶

add_variable_node ¶

add_variable_type_node ¶

add_object_node ¶

add_object_type_node ¶

add_view_node ¶

add_reference_type_node ¶

add_data_type_node ¶

add_method_node ¶

delete_node ¶

add_reference ¶

delete_reference ¶

create_subscription ¶

monitor ¶

monitor_event ¶

ns `instance-attribute` ¶

root `instance-attribute` ¶

objects `instance-attribute` ¶

types `instance-attribute` ¶

views `instance-attribute` ¶

loop `property` ¶

state `property` ¶

connected `property` ¶

init ¶

enter ¶

exit ¶

aenter `async` ¶

aexit `async` ¶

getitem ¶