Trait DataSource

pub trait DataSource {
    // Required method
    fn read(&mut self, context: &mut DataSourceReadContext) -> DataSourceResult;

    // Provided method
    fn write(
        &mut self,
        context: &mut DataSourceWriteContext,
    ) -> DataSourceResult { ... }
}

Data source with callbacks.

The read and write callbacks implement the operations on the variable when it is added via Server::add_data_source_variable_node().

Required Methods

fn read(&mut self, context: &mut DataSourceReadContext) -> DataSourceResult

Reads from variable.

This is called when a client wants to read the value from the variable. The value is expected to be returned through the context argument. See DataSourceReadContext::set_value() for details.

Errors

This should return an appropriate error when the read is not possible. The underlying status code is forwarded to the client.

Provided Methods

fn write(&mut self, context: &mut DataSourceWriteContext) -> DataSourceResult

Writes to variable.

This is called when a client wants to write the value to the variable. The value is transmitted through the context argument. See DataSourceWriteContext::value() for details.

If this method is not implemented, ua::StatusCode::BADNOTSUPPORTED is returned to the client.

Errors

This should return an appropriate error when the write is not possible. The underlying status code is forwarded to the client.

Implementors