Registry¶

o6.ns is the process-wide namespace registry. It associates shortnames, URIs, scopes, versions, and Python declaration modules with global indices. See Namespace for OPC UA namespace arrays.

flowchart LR
    P[Python NodeId: global index] --> M[Endpoint namespace mapping]
    M --> U[OPC UA NodeId: endpoint-local index]
    U --> M
    M --> P

Identity and lookup¶

import o6

print(o6.ns)                         # Registered names and metadata
namespace = o6.ns.di
assert o6.ns[namespace.index] is namespace
declaration = o6.ns["ns=di;i=5001"]
node_id = o6.NodeId("ns=di;i=5001")
browse_name = o6.QualifiedName("ns=di;DeviceSet")

• Attribute lookup returns a namespace module.
• Numeric lookup returns the module at that global index.
• NodeId lookup returns a registered declaration.
• o6.ns.filter() selects entries by URI, scope, or version.
• Different versions of one URI require distinct shortnames and global indices.

Do not persist dynamically assigned global indices as portable identifiers. Store the namespace URI and node identifier, then resolve the index in the current process.

Endpoint mappings¶

Clients establish a local-to-global mapping during connection setup. Servers establish mappings when publishing namespaces. Conversion applies these mappings to namespace-bearing values, including nested values.

An endpoint-local index need not equal its process-wide index. A remote application namespace is scoped to that endpoint. Shared ::global definitions should be treated as immutable; the registry does not enforce that a remote server leaves its namespace contents unchanged.

Packaged models¶

Companion models are generated from the OPC Foundation UA-Nodeset sources. Use print(o6.ns) to inspect the names, URIs, and versions in the installed package. Access declarations through o6.ns.<shortname>; publish the required module through server.ns.append(...) when building a server address space.