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// goupnp is an implementation of a client for various UPnP services.
//
// For most uses, it is recommended to use the code-generated packages under
// github.com/huin/goupnp/dcps. Example use is shown at
// http://godoc.org/github.com/huin/goupnp/example
//
// A commonly used client is internetgateway1.WANPPPConnection1:
// http://godoc.org/github.com/huin/goupnp/dcps/internetgateway1#WANPPPConnection1
//
// Currently only a couple of schemas have code generated for them from the
// UPnP example XML specifications. Not all methods will work on these clients,
// because the generated stubs contain the full set of specified methods from
// the XML specifications, and the discovered services will likely support a
// subset of those methods.
package goupnp
import (
"encoding/xml"
"fmt"
"net/http"
"net/url"
"time"
"golang.org/x/net/html/charset"
"github.com/huin/goupnp/httpu"
"github.com/huin/goupnp/ssdp"
)
// 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 {
// Set iff Err == nil.
Root *RootDevice
// The location the device was discovered at. This can be used with
// DeviceByURL, assuming the device is still present. A location represents
// the discovery of a device, regardless of if there was an error probing it.
Location *url.URL
// Any error encountered probing a discovered device.
Err error
}
// DiscoverDevices attempts to find targets of the given type. This is
// typically the entry-point for this package. searchTarget is typically a URN
// in the form "urn:schemas-upnp-org:device:..." or
// "urn:schemas-upnp-org:service:...". A single error is returned for errors
// while attempting to send the query. An error or RootDevice is returned for
// each discovered RootDevice.
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
}
maybe.Location = loc
if root, err := DeviceByURL(loc); err != nil {
maybe.Err = err
} else {
maybe.Root = root
}
}
return results, nil
}
func DeviceByURL(loc *url.URL) (*RootDevice, error) {
locStr := loc.String()
root := new(RootDevice)
if err := requestXml(locStr, DeviceXMLNamespace, root); err != nil {
return nil, ContextError{fmt.Sprintf("error requesting root device details from %q", locStr), err}
}
var urlBaseStr string
if root.URLBaseStr != "" {
urlBaseStr = root.URLBaseStr
} else {
urlBaseStr = locStr
}
urlBase, err := url.Parse(urlBaseStr)
if err != nil {
return nil, ContextError{fmt.Sprintf("error parsing location URL %q", locStr), err}
}
root.SetURLBase(urlBase)
return root, nil
}
func requestXml(url string, defaultSpace string, doc interface{}) error {
timeout := time.Duration(3 * time.Second)
client := http.Client{
Timeout: timeout,
}
resp, err := client.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
decoder.CharsetReader = charset.NewReaderLabel
return decoder.Decode(doc)
}
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