opcua-client-ruby

WIP. Note from vdbijl. There are not many options to interact with OPC UA servers in Ruby. This is one of them. The other is opcua-smart, but I have some trouble getting it to work. I am trying to see if it's worthwile to extend this client with more functionality.

My wishlist:

• support for reading and writing all, or the mostly used, data types
• support for detection of objects on the server

Incomplete OPC-UA client library for Ruby. Wraps open62541: https://open62541.org.

Installation

Add it to your Gemfile:

gem 'opcua_client'

Basic usage

Use start helper to automatically close connections:

require 'opcua_client'

OPCUAClient.start("opc.tcp://127.0.0.1:4840") do |client|
  # write to ns=2;s=1
  client.write_int16(2, "1", 888)
  puts client.read_int16(2, "1")
end

Or handle connections manually:

require 'opcua_client'

client = OPCUAClient::Client.new
begin
  client.connect("opc.tcp://127.0.0.1:4840")
  # write to ns=2;s=1
  client.write_int16(2, "1", 888)
  puts client.read_int16(2, "1")

  client.multi_write_int16(2, (1..10).map{|x| "action_#{x}"}, (1..10).map{|x| x * 10}) # 10x writes
  client.multi_write_int32(2, (1..10).map{|x| "amount_#{x}"}, (1..10).map{|x| x * 10 + 1}) # 10x writes
ensure
  client.disconnect
end

Available methods - connection:

• client.connect(String url) - raises OPCUAClient::Error if unsuccessful
• client.disconnect => Fixnum - returns status

Available methods - reads and writes:

All methods raise OPCUAClient::Error if unsuccessful.

• client.read_byte(Fixnum ns, String name) => Fixnum
• client.read_sbyte(Fixnum ns, String name) => Fixnum
• client.read_int16(Fixnum ns, String name) => Fixnum
• client.read_uint16(Fixnum ns, String name) => Fixnum
• client.read_int32(Fixnum ns, String name) => Fixnum
• client.read_uint32(Fixnum ns, String name) => Fixnum
• client.read_int64(Fixnum ns, String name) => Fixnum
• client.read_uint64(Fixnum ns, String name) => Fixnum
• client.read_float(Fixnum ns, String name) => Float
• client.read_double(Fixnum ns, String name) => Float
• client.read_boolean(Fixnum ns, String name) => true/false
• client.read_string(Fixnum ns, String name) => String
• client.read_byte_array(Fixnum ns, String name) => Array[Fixnum]
• client.read_sbyte_array(Fixnum ns, String name) => Array[Fixnum]
• client.read_int16_array(Fixnum ns, String name) => Array[Fixnum]
• client.read_uint16_array(Fixnum ns, String name) => Array[Fixnum]
• client.read_int32_array(Fixnum ns, String name) => Array[Fixnum]
• client.read_uint32_array(Fixnum ns, String name) => Array[Fixnum]
• client.read_int64_array(Fixnum ns, String name) => Array[Fixnum]
• client.read_uint64_array(Fixnum ns, String name) => Array[Fixnum]
• client.read_float_array(Fixnum ns, String name) => Array[Float]
• client.read_double_array(Fixnum ns, String name) => Array[Float]
• client.read_boolean_array(Fixnum ns, String name) => Array[true/false]
• client.read_string_array(Fixnum ns, String name) => Array[String]
• client.write_byte(Fixnum ns, String name, Fixnum value)
• client.write_sbyte(Fixnum ns, String name, Fixnum value)
• client.write_int16(Fixnum ns, String name, Fixnum value)
• client.write_uint16(Fixnum ns, String name, Fixnum value)
• client.write_int32(Fixnum ns, String name, Fixnum value)
• client.write_uint32(Fixnum ns, String name, Fixnum value)
• client.write_int64(Fixnum ns, String name, Fixnum value)
• client.write_uint64(Fixnum ns, String name, Fixnum value)
• client.write_float(Fixnum ns, String name, Float value)
• client.write_double(Fixnum ns, String name, Float value)
• client.write_boolean(Fixnum ns, String name, bool value)
• client.write_string(Fixnum ns, String name, String value)
• client.write_byte_array(Fixnum ns, String name, Array[Fixnum] value)
• client.write_sbyte_array(Fixnum ns, String name, Array[Fixnum] value)
• client.write_int16_array(Fixnum ns, String name, Array[Fixnum] value)
• client.write_uint16_array(Fixnum ns, String name, Array[Fixnum] value)
• client.write_int32_array(Fixnum ns, String name, Array[Fixnum] value)
• client.write_uint32_array(Fixnum ns, String name, Array[Fixnum] value)
• client.write_int64_array(Fixnum ns, String name, Array[Fixnum] value)
• client.write_uint64_array(Fixnum ns, String name, Array[Fixnum] value)
• client.write_float_array(Fixnum ns, String name, Array[Float] value)
• client.write_double_array(Fixnum ns, String name, Array[Float] value)
• client.write_boolean_array(Fixnum ns, String name, Array[bool] value)
• client.write_string_array(Fixnum ns, String name, Array[String] value)
• client.multi_write_byte(Fixnum ns, Array[String] names, Array[Fixnum] values)
• client.multi_write_sbyte(Fixnum ns, Array[String] names, Array[Fixnum] values)
• client.multi_write_int16(Fixnum ns, Array[String] names, Array[Fixnum] values)
• client.multi_write_uint16(Fixnum ns, Array[String] names, Array[Fixnum] values)
• client.multi_write_int32(Fixnum ns, Array[String] names, Array[Fixnum] values)
• client.multi_write_uint32(Fixnum ns, Array[String] names, Array[Fixnum] values)
• client.multi_write_int64(Fixnum ns, Array[String] names, Array[Fixnum] values)
• client.multi_write_uint64(Fixnum ns, Array[String] names, Array[Fixnum] values)
• client.multi_write_float(Fixnum ns, Array[String] names, Array[Float] values)
• client.multi_write_double(Fixnum ns, Array[String] names, Array[Float] values)
• client.multi_write_boolean(Fixnum ns, Array[String] names, Array[bool] values)

Available methods - misc:

• client.state => Fixnum - client internal state
• client.human_state => String - human readable client internal state
• OPCUAClient::Client.human_status_code(Fixnum status) => String - returns human status for status

Subscriptions and monitoring

cli = OPCUAClient::Client.new

cli.after_session_created do |cli|
  subscription_id = cli.create_subscription
  ns_index = 1
  node_name = "the.answer"
  cli.add_monitored_item(subscription_id, ns_index, node_name)
end

cli.after_data_changed do |subscription_id, monitor_id, server_time, source_time, new_value|
  puts("data changed: " + [subscription_id, monitor_id, server_time, source_time, new_value].inspect)
end

cli.connect("opc.tcp://127.0.0.1:4840")

loop do
  cli.connect("opc.tcp://127.0.0.1:4840") # no-op if connected
  cli.run_mon_cycle
  sleep(0.2)
end

Available methods:

• client.create_subscription => Fixnum - nil if error
• client.add_monitored_item(Fixnum subscription, Fixnum ns, String name) => Fixnum - nil if error
• client.run_mon_cycle - returns status
• client.run_mon_cycle! - raises OPCUAClient::Error if unsuccessful

Available callbacks:

• after_session_created
• after_data_changed

Contribute

Set up

bundle

Build and start dummy OPCUA server

make -C tools/server/ clean all # clean+all
tools/server/server # run

Try out changes

$ bin/rake compile
$ bin/console
pry> client = OPCUAClient::Client.new
pry> client.connect("opc.tcp://127.0.0.1:4840")
pry> client.read_uint32(5, "uint32b")
pry> client.read_uint16(5, "uint16b")
pry> client.read_bool(5, "true_var")

Test it

$ bin/rake compile
$ bin/rake spec

Code Quality

This project uses RuboCop for code style enforcement, following the Ruby Style Guide and RSpec Style Guide.

The configuration uses StyleGuideBaseURL to link cop violations directly to the relevant style guide sections, making it easier to understand and learn from the recommendations.

Run RuboCop:

$ bundle exec rake rubocop

Auto-correct offenses (safe):

$ bundle exec rake rubocop:autocorrect

Auto-correct all offenses (safe and unsafe):

$ bundle exec rake rubocop:autocorrect_all

Run both RuboCop and RSpec tests:

$ bundle exec rake test