High level Functions and Node Class

High level node object, to access node attribute and browse address space

class opcua.common.node.Node(server, nodeid)[source]

High level node object, to access node attribute, browse and populate address space. Node objects are usefull as-is but they do not expose the entire OPC-UA protocol. Feel free to look at the code of this class and call directly UA services methods to optimize your code

get_browse_name()[source]

Get browse name of a node. A browse name is a QualifiedName object composed of a string(name) and a namespace index.

get_display_name()[source]

get description attribute of node

get_data_type()[source]

get data type of node as NodeId

get_data_type_as_variant_type()[source]

get data type of node as VariantType This only works if node is a variable, otherwise type may not be convertible to VariantType

get_access_level()[source]

Get the access level attribute of the node as a set of AccessLevel enum values.

get_user_access_level()[source]

Get the user access level attribute of the node as a set of AccessLevel enum values.

get_event_notifier()[source]

Get the event notifier attribute of the node as a set of EventNotifier enum values.

set_event_notifier(values)[source]

Set the event notifier attribute.

Parameters:values – an iterable of EventNotifier enum values.
get_node_class()[source]

get node class attribute of node

get_description()[source]

get description attribute class of node

get_value()[source]

Get value of a node as a python type. Only variables ( and properties) have values. An exception will be generated for other node types.

get_data_value()[source]

Get value of a node as a DataValue object. Only variables (and properties) have values. An exception will be generated for other node types. DataValue contain a variable value as a variant as well as server and source timestamps

set_array_dimensions(value)[source]

Set attribute ArrayDimensions of node make sure it has the correct data type

get_array_dimensions()[source]

Read and return ArrayDimensions attribute of node

set_value_rank(value)[source]

Set attribute ArrayDimensions of node

get_value_rank()[source]

Read and return ArrayDimensions attribute of node

set_value(value, varianttype=None)[source]

Set value of a node. Only variables(properties) have values. An exception will be generated for other node types. value argument is either: * a python built-in type, converted to opc-ua optionnaly using the variantype argument. * a ua.Variant, varianttype is then ignored * a ua.DataValue, you then have full control over data send to server

set_data_value(value, varianttype=None)

Set value of a node. Only variables(properties) have values. An exception will be generated for other node types. value argument is either: * a python built-in type, converted to opc-ua optionnaly using the variantype argument. * a ua.Variant, varianttype is then ignored * a ua.DataValue, you then have full control over data send to server

set_writable(writable=True)[source]

Set node as writable by clients. A node is always writable on server side.

set_attr_bit(attr, bit)[source]
unset_attr_bit(attr, bit)[source]
set_read_only()[source]

Set a node as read-only for clients. A node is always writable on server side.

set_attribute(attributeid, datavalue)[source]

Set an attribute of a node attributeid is a member of ua.AttributeIds datavalue is a ua.DataValue object

get_attribute(attr)[source]

Read one attribute of a node result code from server is checked and an exception is raised in case of error

get_attributes(attrs)[source]

Read several attributes of a node list of DataValue is returned

get_children(refs=33, nodeclassmask=<NodeClass.Unspecified: 0>)[source]

Get all children of a node. By default hierarchical references and all node classes are returned. Other reference types may be given: References = 31 NonHierarchicalReferences = 32 HierarchicalReferences = 33 HasChild = 34 Organizes = 35 HasEventSource = 36 HasModellingRule = 37 HasEncoding = 38 HasDescription = 39 HasTypeDefinition = 40 GeneratesEvent = 41 Aggregates = 44 HasSubtype = 45 HasProperty = 46 HasComponent = 47 HasNotifier = 48 HasOrderedComponent = 49

get_properties()[source]

return properties of node. properties are child nodes with a reference of type HasProperty and a NodeClass of Variable

get_variables()[source]

return variables of node. properties are child nodes with a reference of type HasComponent and a NodeClass of Variable

get_methods()[source]

return methods of node. properties are child nodes with a reference of type HasComponent and a NodeClass of Method

get_children_descriptions(refs=33, nodeclassmask=<NodeClass.Unspecified: 0>, includesubtypes=True)[source]
get_encoding_refs()[source]
get_description_refs()[source]
get_references(refs=31, direction=<BrowseDirection.Both: 2>, nodeclassmask=<NodeClass.Unspecified: 0>, includesubtypes=True)[source]

returns references of the node based on specific filter defined with:

refs = ObjectId of the Reference direction = Browse direction for references nodeclassmask = filter nodes based on specific class includesubtypes = If true subtypes of the reference (ref) are also included

get_referenced_nodes(refs=31, direction=<BrowseDirection.Both: 2>, nodeclassmask=<NodeClass.Unspecified: 0>, includesubtypes=True)[source]

returns referenced nodes based on specific filter Paramters are the same as for get_references

get_type_definition()[source]

returns type definition of the node.

get_path(max_length=20, as_string=False)[source]

Attempt to find path of node from root node and return it as a list of Nodes. There might several possible paths to a node, this function will return one Some nodes may be missing references, so this method may return an empty list Since address space may have circular references, a max length is specified

get_parent()[source]

returns parent of the node. A Node may have several parents, the first found is returned. This method uses reverse references, a node might be missing such a link, thus we will not find its parent.

get_child(path)[source]

get a child specified by its path from this node. A path might be: * a string representing a qualified name. * a qualified name * a list of string * a list of qualified names

read_raw_history(starttime=None, endtime=None, numvalues=0)[source]

Read raw history of a node result code from server is checked and an exception is raised in case of error If numvalues is > 0 and number of events in period is > numvalues then result will be truncated

history_read(details)[source]

Read raw history of a node, low-level function result code from server is checked and an exception is raised in case of error

read_event_history(starttime=None, endtime=None, numvalues=0, evtypes=2041)[source]

Read event history of a source node result code from server is checked and an exception is raised in case of error If numvalues is > 0 and number of events in period is > numvalues then result will be truncated

history_read_events(details)[source]

Read event history of a node, low-level function result code from server is checked and an exception is raised in case of error

delete(delete_references=True)[source]

Delete node from address space

add_folder(nodeid, bname)[source]
add_object(nodeid, bname, objecttype=None)[source]
add_variable(nodeid, bname, val, varianttype=None, datatype=None)[source]
add_object_type(nodeid, bname)[source]
add_variable_type(nodeid, bname, datatype)[source]
add_data_type(nodeid, bname, description=None)[source]
add_property(nodeid, bname, val, varianttype=None, datatype=None)[source]
add_method(*args)[source]
add_reference_type(parent, nodeid, bname)[source]
call_method(methodid, *args)[source]

High level functions to create nodes

opcua.common.manage_nodes.create_data_type(parent, nodeid, bname, description=None)[source]

Create a new data type to be used in new variables, etc .. arguments are nodeid, browsename or namespace index, name

opcua.common.manage_nodes.create_folder(parent, nodeid, bname)[source]

create a child node folder arguments are nodeid, browsename or namespace index, name

opcua.common.manage_nodes.create_method(parent, *args)[source]

create a child method object This is only possible on server side!! args are nodeid, browsename, method_to_be_called, [input argument types], [output argument types] or idx, name, method_to_be_called, [input argument types], [output argument types] if argument types is specified, child nodes advertising what arguments the method uses and returns will be created a callback is a method accepting the nodeid of the parent as first argument and variants after. returns a list of variants

opcua.common.manage_nodes.create_object(parent, nodeid, bname, objecttype=None)[source]

create a child node object arguments are nodeid, browsename, [objecttype] or namespace index, name, [objecttype] if objectype is given (a NodeId) then the type node is instantiated inclusive its child nodes

opcua.common.manage_nodes.create_object_type(parent, nodeid, bname)[source]

Create a new object type to be instanciated in address space. arguments are nodeid, browsename or namespace index, name

opcua.common.manage_nodes.create_property(parent, nodeid, bname, val, varianttype=None, datatype=None)[source]

create a child node property args are nodeid, browsename, value, [variant type] or idx, name, value, [variant type]

opcua.common.manage_nodes.create_reference_type(parent, nodeid, bname)[source]

Create a new reference type args are nodeid and browsename or idx and name

opcua.common.manage_nodes.create_variable(parent, nodeid, bname, val, varianttype=None, datatype=None)[source]

create a child node variable args are nodeid, browsename, value, [variant type], [data type] or idx, name, value, [variant type], [data type]

opcua.common.manage_nodes.create_variable_type(parent, nodeid, bname, datatype)[source]

Create a new variable type args are nodeid, browsename and datatype or idx, name and data type

opcua.common.manage_nodes.delete_nodes(server, nodes, recursive=False)[source]

Delete specified nodes. Optionally delete recursively all nodes with a downward hierachic references to the node

High level method related functions

opcua.common.methods.call_method(parent, methodid, *args)[source]

Call an OPC-UA method. methodid is browse name of child method or the nodeid of method as a NodeId object arguments are variants or python object convertible to variants. which may be of different types returns a list of variants which are output of the method

opcua.common.methods.to_variant(*args)[source]
opcua.common.methods.uamethod(func)[source]

Method decorator to automatically convert arguments and output to and from variants