Crate open62541

Expand description

Rust wrapper for the open62541 library.

§Examples

§Client: Connect to server

Use AsyncClient to asynchronously connect to an OPC UA server:

use open62541::AsyncClient;

let client = AsyncClient::new("opc.tcp://opcuademo.sterfive.com:26543")?;

This requires an async runtime such as tokio.

§Client: Read node’s value attribute

Read a variable node’s value attribute with AsyncClient::read_value():

use open62541::ua;

let node_id = ua::NodeId::numeric(0, 2258); // Server/ServerStatus/CurrentTime

let value = client.read_value(&node_id).await?;

println!("Received value: {value:?}");

Use AsyncClient::read_attribute() and related methods to read other attributes other than the value.

§Client: Watch node for changes in value attribute

Subscribe to a node’s value by creating a subscription with AsyncClient::create_subscription() and adding monitored items to it with AsyncSubscription::create_monitored_item():

// Create subscription that receives the updates.
let subscription = client.create_subscription().await?;
// Create monitored item to receive node updates.
let mut monitored_item = subscription.create_monitored_item(&node_id).await?;

while let Some(value) = monitored_item.next().await {
    println!("Received value: {value:?}");
}

§Server: Run server

Create an OPC UA server with Server::new(). When instantiating a server, you receive a ServerRunner along with the Server. Use it to run the server until interrupted:

use open62541::Server;

let (server, runner) = Server::new();

// Define data nodes on `server`.

runner.run_until_interrupt()?;

By default, ServerRunner::run() runs on the current thread. Use thread::spawn() to run it in a different thread.

§Server: Define object and managed variable nodes

Define nodes with Server::add_object_node() and related methods:

use open62541::{ObjectNode, ua, VariableNode};
use open62541_sys::{
    UA_NS0ID_BASEDATAVARIABLETYPE, UA_NS0ID_FOLDERTYPE, UA_NS0ID_OBJECTSFOLDER,
    UA_NS0ID_ORGANIZES, UA_NS0ID_STRING,
};

let object_node_id = server.add_object_node(ObjectNode {
    requested_new_node_id: None,
    parent_node_id: ua::NodeId::ns0(UA_NS0ID_OBJECTSFOLDER),
    reference_type_id: ua::NodeId::ns0(UA_NS0ID_ORGANIZES),
    browse_name: ua::QualifiedName::new(1, "SomeFolder"),
    type_definition: ua::NodeId::ns0(UA_NS0ID_FOLDERTYPE),
    attributes: ua::ObjectAttributes::default(),
})?;

let variable_node_id = server.add_variable_node(VariableNode {
    requested_new_node_id: None,
    parent_node_id: object_node_id,
    reference_type_id: ua::NodeId::ns0(UA_NS0ID_ORGANIZES),
    browse_name: ua::QualifiedName::new(1, "SomeVariable"),
    type_definition: ua::NodeId::ns0(UA_NS0ID_BASEDATAVARIABLETYPE),
    attributes: ua::VariableAttributes::default()
        .with_data_type(&ua::NodeId::ns0(UA_NS0ID_STRING)),
})?;

server.write_value(
    &variable_node_id,
    &ua::Variant::scalar(ua::String::new("Lorem Ipsum")?),
)?;

Nodes may also be added (and removed) while the server is running.

§Server: Define data source variable nodes (callback-driven)

Implement DataSource for custom types to enable callback-driven read and write access through OPC UA variables.

Use DataSourceReadContext and DataSourceWriteContext to set the value to return to the client, or access the incoming value received from the client:

use open62541::{DataSource, DataSourceReadContext, DataSourceResult, DataSourceWriteContext};

struct SomeDataSource {
    some_value: u32,
}

impl DataSource for SomeDataSource {
    fn read(&mut self, ctx: &mut DataSourceReadContext) -> DataSourceResult {
        let value = format!("This is #{value}", value = self.some_value);
        ctx.set_variant(ua::Variant::scalar(ua::String::new(&value)?));
        Ok(())
    }

    fn write(&mut self, ctx: &mut DataSourceWriteContext) -> DataSourceResult {
        println!("Received value: {value:?}", value = ctx.value());
        self.some_value += 1;
        Ok(())
    }
}

let variable_node = VariableNode {
    requested_new_node_id: None,
    parent_node_id: object_node_id,
    reference_type_id: ua::NodeId::ns0(UA_NS0ID_ORGANIZES),
    browse_name: ua::QualifiedName::new(1, "SomeVariable"),
    type_definition: ua::NodeId::ns0(UA_NS0ID_BASEDATAVARIABLETYPE),
    attributes: ua::VariableAttributes::default()
        .with_data_type(&ua::NodeId::ns0(UA_NS0ID_STRING))
        .with_access_level(
            &ua::AccessLevelType::NONE
                .with_current_read(true)
                .with_current_write(true),
        ),
};

let variable_node_id = server.add_data_source_variable_node(
    variable_node,
    SomeDataSource { some_value: 0 },
)?;

Modules§

ua: Thin wrappers for open62541_sys types.

Structs§

AsyncClient: Connected OPC UA client (with asynchronous API).
AsyncMonitoredItem: Monitored item (with asynchronous API).
AsyncSubscription: Subscription (with asynchronous API).
CallbackOnce: Type-erased one-shot callback.
CallbackStream: Type-erased stream sender.
Client: Connected OPC UA client.
ClientBuilder: Builder for Client.
DataSourceReadContext: Context when DataSource is being read from.
DataSourceWriteContext: Context when DataSource is being written to.
DataValue: Typed variant of ua::DataValue.
DefaultAccessControl: Default server access control.
DefaultAccessControlWithLoginCallback: Default server access control with login callback.
MethodCallbackContext: Context when MethodCallback is being called.
MethodNode
MonitoredItemBuilder
MonitoredItemValue: Value emitted from monitored item notification.
Node
ObjectNode
Server: OPC UA server.
ServerBuilder: Builder for Server.
ServerRunner
SubscriptionBuilder
Userdata: Type-erased user data.
UserdataSentinel: Sentinel for type-erased user data.
VariableNode

Enums§

DataSourceError
Error: Error type used in this crate.
MethodCallbackError
ScalarValue: Scalar value.
ValueType
VariantValue: Value of ua::Variant.

Constants§

DEFAULT_PORT_NUMBER: IANA-assigned OPC UA port number.

Traits§

AccessControl: Server access control.
Attribute: Node attribute.
Attributes: Server node attributes.
CustomCertificateVerification: Custom certificate verification.
DataSource: Data source with callbacks.
DataType: Transparent wrapper for OPC UA data type.
DataTypeExt: Extended values.
FilterOperand: Filter operand.
MethodCallback: Method callback.
MonitoredItemAttribute: Attribute for MonitoredItemBuilder::attribute().
MonitoredItemKind: Sealed typestate used in MonitoredItemBuilder.
MonitoringFilter: Monitoring filter.
ServiceRequest: A generic service request.
ServiceResponse: A generic service response.

Type Aliases§

BrowseResult: Result type for browsing.
DataSourceResult: Result from DataSource operations.
MethodCallbackResult: Result from MethodCallback operations.
Result: Result type used in this crate.

Crate open62541

Crate open62541 Copy item path

§Examples

§Client: Connect to server

§Client: Read node’s value attribute

§Client: Watch node for changes in value attribute

§Server: Run server

§Server: Define object and managed variable nodes

§Server: Define data source variable nodes (callback-driven)

Modules§

Structs§

Enums§

Constants§

Traits§

Type Aliases§

Crate open62541