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Node

Canonical path: o6.node.Node

Root shortcut: o6.Node

Node

Bases: _NativeNodeBase, HasNodeId

Base class providing dot, index, and call syntax for OPC UA nodes.

A node handle is a live view of one node in an address space, obtained from a client, a server, or by browsing from another handle. Attribute reads and writes go to the server; client child navigation uses a refreshable cache.

Three syntaxes cover the whole API. Attribute access browses one level (client.objects.server), the call operator reads or writes an attribute (node(), node(23.5), node(attr="browseName")), and the index operator resolves a browse path when a name is ambiguous or relative.

Public helpers on this class carry a leading underscore, because ordinary names would collide with OPC UA child lookup. Subclasses may still keep application state under ordinary Python names.

See the Node API.

Functions

__init__ 

__init__(backend, nodeId, browseName)

Wrap an existing node. Handles come from a client, server, or browsing.

Parameters:

Name Type Description Default
backend Any

The client or server backend that carries out operations.

 required
nodeId NodeIdLike

NodeId of the node.

 required
browseName QualifiedName

BrowseName of the node.

 required

__lshift__ 

__lshift__(other)

Reject event emission on any NodeClass but Object and View.

Overridden by ObjectNode and ViewNode -- the only NodeClasses OPC UA defines an EventNotifier attribute for -- with the real implementation.

__call__ 

__call__(value=_UNSET, attr=None)

Read or write one attribute of this node.

Called without a value it reads, and with a value it writes. The attribute defaults to Value. Reads return values for all Good-severity statuses and raise for Uncertain or Bad; use the owning client/server's read(..., valueOnly=False) to inspect status and timestamp metadata.

Parameters:

Name Type Description Default
value Any

The value to write. Omit it to read instead.

 _UNSET
attr Optional[AttributeId | str]

The attribute to address, as an o6.AttributeId or a case-insensitive attribute name such as "browseName".

 None

Returns:

Type Description
MaybeAwaitable[Any]

The attribute value when reading, None when writing. Async tasks
MaybeAwaitable[Any]

always receive an awaitable, including for immediate local results.

Raises:

Type Description
StatusCodeError

The read or write operation failed.

__getitem__ 

__getitem__(key)

Resolve a browse path relative to this node.

Use this where attribute access cannot reach: a BrowseName that is not a Python identifier, an ambiguous name, or a multi-step relative path.

Parameters:

Name Type Description Default
key str | 'ns0.datatypes.RelativePath'

A relative-path string such as "1:DeviceSet/1:Motor", or a ns0.datatypes.RelativePath.

 required

Returns:

Type Description
MaybeAwaitable[list[Any]]

Every node the path resolves to, as a list; awaitable in async tasks.

Raises:

Type Description
KeyError

The path matches no node.