goupnp/goupnp.go
2013-10-06 13:23:11 +01:00

105 lines
2.9 KiB
Go

// goupnp is an implementation of a client for UPnP devices.
package goupnp
import (
"encoding/xml"
"fmt"
"net/http"
"net/url"
"github.com/huin/goupnp/httpu"
"github.com/huin/goupnp/ssdp"
)
// Non-exhaustive set of UPnP service types.
const (
ServiceTypeLayer3Forwarding = "urn:schemas-upnp-org:service:Layer3Forwarding:1"
ServiceTypeWANCommonInterfaceConfig = "urn:schemas-upnp-org:service:WANCommonInterfaceConfig:1"
// WANPPPConnection is typically useful with regard to the external IP and
// port forwarding.
// http://upnp.org/specs/gw/UPnP-gw-WANPPPConnection-v1-Service.pdf
ServiceTypeWANPPPConnection = "urn:schemas-upnp-org:service:WANPPPConnection:1"
)
// Non-exhaustive set of UPnP device types.
const (
// Device type for InternetGatewayDevice.
// http://upnp.org/specs/gw/upnp-gw-internetgatewaydevice-v1-device.pdf
DeviceTypeInternetGatewayDevice = "urn:schemas-upnp-org:device:InternetGatewayDevice:1"
)
// ContextError is an error that wraps an error with some context information.
type ContextError struct {
Context string
Err error
}
func (err ContextError) Error() string {
return fmt.Sprintf("%s: %v", err.Context, err.Err)
}
// MaybeRootDevice contains either a RootDevice or an error.
type MaybeRootDevice struct {
Root *RootDevice
Err error
}
// DiscoverDevices attempts to find targets of the given type. searchTarget is
// typically a value from a DeviceType* or ServiceType* constant. An error is
// returned for errors while attempting to send the query. An error or
// RootDevice is returned for each discovered service.
func DiscoverDevices(searchTarget string) ([]MaybeRootDevice, error) {
httpu, err := httpu.NewHTTPUClient()
if err != nil {
return nil, err
}
defer httpu.Close()
responses, err := ssdp.SSDPRawSearch(httpu, string(searchTarget), 2, 3)
if err != nil {
return nil, err
}
results := make([]MaybeRootDevice, len(responses))
for i, response := range responses {
maybe := &results[i]
loc, err := response.Location()
if err != nil {
maybe.Err = ContextError{"unexpected bad location from search", err}
continue
}
locStr := loc.String()
root := new(RootDevice)
if err := requestXml(locStr, DeviceXMLNamespace, root); err != nil {
maybe.Err = ContextError{fmt.Sprintf("error requesting root device details from %q", locStr), err}
continue
}
urlBase, err := url.Parse(root.URLBaseStr)
if err != nil {
maybe.Err = ContextError{fmt.Sprintf("error parsing URLBase %q from %q: %v", root.URLBaseStr, locStr), err}
continue
}
root.SetURLBase(urlBase)
maybe.Root = root
}
return results, nil
}
func requestXml(url string, defaultSpace string, doc interface{}) error {
resp, err := http.Get(url)
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode != 200 {
return fmt.Errorf("goupnp: got response status %s from %q",
resp.Status, url)
}
decoder := xml.NewDecoder(resp.Body)
decoder.DefaultSpace = defaultSpace
return decoder.Decode(doc)
}