From dad73be727d38e8304c1160b9034ad9941a865e8 Mon Sep 17 00:00:00 2001
From: mhhcbon <mhhcbon@gmail.com>
Date: Mon, 21 Mar 2022 14:54:05 +0100
Subject: [PATCH] #48: Add local address information

---
 goupnp.go         |  5 +++++
 httpu/httpu.go    |  5 +++++
 service_client.go | 13 ++++++++++++-
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/goupnp.go b/goupnp.go
index 36081aa..ff91511 100644
--- a/goupnp.go
+++ b/goupnp.go
@@ -22,6 +22,7 @@ import (
 	"net/url"
 	"time"
 
+	"github.com/huin/goupnp/httpu"
 	"github.com/huin/goupnp/ssdp"
 )
 
@@ -63,6 +64,9 @@ type MaybeRootDevice struct {
 	// the discovery of a device, regardless of if there was an error probing it.
 	Location *url.URL
 
+	// The address from which the device was discovered (if known - otherwise nil).
+	LocalAddr string
+
 	// Any error encountered probing a discovered device.
 	Err error
 }
@@ -99,6 +103,7 @@ func DiscoverDevices(searchTarget string) ([]MaybeRootDevice, error) {
 		} else {
 			maybe.Root = root
 		}
+		maybe.LocalAddr = response.Header.Get(httpu.LocalAddress)
 	}
 
 	return results, nil
diff --git a/httpu/httpu.go b/httpu/httpu.go
index 3367c86..a7a302d 100644
--- a/httpu/httpu.go
+++ b/httpu/httpu.go
@@ -143,9 +143,14 @@ func (httpu *HTTPUClient) Do(
 			continue
 		}
 
+		// Set the related local address used to discover the device.
+		response.Header.Add(LocalAddress, httpu.conn.LocalAddr().(*net.UDPAddr).IP.String())
+
 		responses = append(responses, response)
 	}
 
 	// Timeout reached - return discovered responses.
 	return responses, nil
 }
+
+const LocalAddress = "goupnp-local-address"
diff --git a/service_client.go b/service_client.go
index 9111c93..a52ff2a 100644
--- a/service_client.go
+++ b/service_client.go
@@ -17,6 +17,7 @@ type ServiceClient struct {
 	RootDevice *RootDevice
 	Location   *url.URL
 	Service    *Service
+	localAddr  string
 }
 
 // NewServiceClients discovers services, and returns clients for them. err will
@@ -36,7 +37,7 @@ func NewServiceClients(searchTarget string) (clients []ServiceClient, errors []e
 			continue
 		}
 
-		deviceClients, err := NewServiceClientsFromRootDevice(maybeRootDevice.Root, maybeRootDevice.Location, searchTarget)
+		deviceClients, err := newServiceClientsFromRootDevice(maybeRootDevice.Root, maybeRootDevice.Location, searchTarget, maybeRootDevice.LocalAddr)
 		if err != nil {
 			errors = append(errors, err)
 			continue
@@ -61,6 +62,10 @@ func NewServiceClientsByURL(loc *url.URL, searchTarget string) ([]ServiceClient,
 // a given root device. The loc parameter is simply assigned to the
 // Location attribute of the returned ServiceClient(s).
 func NewServiceClientsFromRootDevice(rootDevice *RootDevice, loc *url.URL, searchTarget string) ([]ServiceClient, error) {
+	return newServiceClientsFromRootDevice(rootDevice, loc, searchTarget, "")
+}
+
+func newServiceClientsFromRootDevice(rootDevice *RootDevice, loc *url.URL, searchTarget string, lAddr string) ([]ServiceClient, error) {
 	device := &rootDevice.Device
 	srvs := device.FindService(searchTarget)
 	if len(srvs) == 0 {
@@ -75,6 +80,7 @@ func NewServiceClientsFromRootDevice(rootDevice *RootDevice, loc *url.URL, searc
 			RootDevice: rootDevice,
 			Location:   loc,
 			Service:    srv,
+			localAddr:  lAddr,
 		})
 	}
 	return clients, nil
@@ -86,3 +92,8 @@ func NewServiceClientsFromRootDevice(rootDevice *RootDevice, loc *url.URL, searc
 func (client *ServiceClient) GetServiceClient() *ServiceClient {
 	return client
 }
+
+// LocalAddr returns the address from which the device was discovered (if known - otherwise empty).
+func (client *ServiceClient) LocalAddr() string {
+	return client.localAddr
+}