Add another GetExternalIPAddress example, using a common function.

example/example_test.go

@@ -4,19 +4,38 @@ import (
 	"fmt"
 	"os"
 
+	"github.com/huin/goupnp"
 	"github.com/huin/goupnp/dcps/internetgateway1"
 )
 
-// Discovering a internet gateway devices on the local network, and asking each
+// Use discovered WANPPPConnection1 services to find external IP addresses.
-// of them for their external IP address.
+func Example_WANPPPConnection1_GetExternalIPAddress() {
-func Example_getExternalIPAddress() {
-	// import (
-	//   "fmt"
-	//   "os"
-	//   "github.com/huin/goupnp/dcps/internetgateway1"
-	// )
-	fmt.Println("Running")
 	clients, errors, err := internetgateway1.NewWANPPPConnection1Clients()
+	extIPClients := make([]GetExternalIPAddresser, len(clients))
+	for i, client := range clients {
+		extIPClients[i] = client
+	}
+	DisplayExternalIPResults(extIPClients, errors, err)
+	// Output:
+}
+
+// Use discovered WANIPConnection services to find external IP addresses.
+func Example_WANIPConnection_GetExternalIPAddress() {
+	clients, errors, err := internetgateway1.NewWANIPConnection1Clients()
+	extIPClients := make([]GetExternalIPAddresser, len(clients))
+	for i, client := range clients {
+		extIPClients[i] = client
+	}
+	DisplayExternalIPResults(extIPClients, errors, err)
+	// Output:
+}
+
+type GetExternalIPAddresser interface {
+	GetExternalIPAddress() (NewExternalIPAddress string, err error)
+	GetServiceClient() *goupnp.ServiceClient
+}
+
+func DisplayExternalIPResults(clients []GetExternalIPAddresser, errors []error, err error) {
 	if err != nil {
 		fmt.Fprintln(os.Stderr, "Error discovering service with UPnP: ", err)
 		return
@@ -31,7 +50,7 @@ func Example_getExternalIPAddress() {
 
 	fmt.Fprintf(os.Stderr, "Successfully discovered %d services:\n", len(clients))
 	for _, client := range clients {
-		device := &client.RootDevice.Device
+		device := &client.GetServiceClient().RootDevice.Device
 
 		fmt.Fprintln(os.Stderr, "  Device:", device.FriendlyName)
 		if addr, err := client.GetExternalIPAddress(); err != nil {
@@ -40,9 +59,4 @@ func Example_getExternalIPAddress() {
 			fmt.Fprintf(os.Stderr, "    External IP address: %v\n", addr)
 		}
 	}
-	fmt.Println("Complete")
-
-	// Output:
-	// Running
-	// Complete
 }

service_client.go

@@ -47,3 +47,10 @@ func NewServiceClients(searchTarget string) (clients []ServiceClient, errors []e
 
 	return
 }
+
+// GetServiceClient returns the ServiceClient itself. This is provided so that the
+// service client attributes can be accessed via an interface method on a
+// wrapping type.
+func (client *ServiceClient) GetServiceClient() *ServiceClient {
+	return client
+}