func requestTopic(publisher_uri, caller_id, topic string, response_data interface{}) error {
fmt.Printf(" talking to publisher '%s'\n", publisher_uri)
pub_rpc := xmlrpc.NewClient(publisher_uri)
tcpros_string := "TCPROS"
tcpros := make([]xmlrpc.Value, 1)
tcpros[0] = xmlrpc.Value{String: &tcpros_string}
protocols := make([]xmlrpc.Value, 1)
protocols[0] = xmlrpc.Value{Array: &tcpros}
params := make([]xmlrpc.Param, 3)
params[0] = xmlrpc.Param{xmlrpc.Value{String: &caller_id}}
params[1] = xmlrpc.Param{xmlrpc.Value{String: &topic}}
params[2] = xmlrpc.Param{xmlrpc.Value{Array: &protocols}}
return pub_rpc.Call("requestTopic", params, response_data)
}
func Subscribe(node_name, topic_name, type_name string,
channel interface{}) (*TcpRosSubscriber, error) {
rpc_client := xmlrpc.NewClient("http://localhost:11311")
hostname, err := os.Hostname()
if err != nil {
return nil, err
}
msg_port := 11317
msg_uri := fmt.Sprintf("http://%s:%d", hostname, msg_port)
var response2 xmlrpc.MethodResponse
err = rpc_client.CallStrings("registerSubscriber",
[]string{node_name, topic_name, type_name, msg_uri},
&response2)
if err != nil {
return nil, err
}
var sub TcpRosSubscriber
array := *response2.Params[0].Val.Array
code := *array[0].Int
status := *array[1].String
fmt.Printf("got response code: %d, status '%s'\n", code, status)
pub_ptr := array[2].Array
if pub_ptr == nil {
// No publishers yet. TODO: implement updatePublishers() xmlrpc call.
return &sub, nil
}
publishers := *pub_ptr
caller_id := node_name
for i := range publishers {
publisher_uri := *publishers[i].String
var response xmlrpc.MethodResponse
err := requestTopic(publisher_uri, caller_id, "/chatter", &response)
if err != nil {
fmt.Printf(" error from requestTopic: %v\n", err)
continue
}
fmt.Printf("response to requestTopic():\n")
response.Params[0].Val.Print()
fmt.Printf("woot\n")
array := response.Params[0].Val.GetArray()
code, _ := array[0].GetInt()
status, _ := array[1].GetString()
fmt.Printf(" requestTopic got response code: %d, status '%s'\n", code, status)
protocol := array[2].GetArray()
protocol_name, _ := protocol[0].GetString()
host, _ := protocol[1].GetString()
port, _ := protocol[2].GetInt()
fmt.Printf(" protocol %s %s %d\n", protocol_name, host, port)
publisher := new(publisherConnection)
publisher.host = host
publisher.port = port
publisher.recvr_node_name = node_name
publisher.topic_name = topic_name
publisher.type_name = type_name
sub.publishers = append(sub.publishers, publisher)
go publisher.read(channel)
}
return &sub, nil
}
