90 lines
2.3 KiB
Go
90 lines
2.3 KiB
Go
// goupnp is an implementation of a client for UPnP devices.
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package goupnp
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import (
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"encoding/xml"
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"fmt"
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"net/http"
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"net/url"
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"github.com/huin/goupnp/httpu"
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"github.com/huin/goupnp/ssdp"
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)
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// ContextError is an error that wraps an error with some context information.
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type ContextError struct {
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Context string
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Err error
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}
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func (err ContextError) Error() string {
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return fmt.Sprintf("%s: %v", err.Context, err.Err)
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}
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// MaybeRootDevice contains either a RootDevice or an error.
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type MaybeRootDevice struct {
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Root *RootDevice
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Err error
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}
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// DiscoverDevices attempts to find targets of the given type. This is
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// typically the entry-point for this package. searchTarget is typically a URN
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// in the form "urn:schemas-upnp-org:device:..." or
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// "urn:schemas-upnp-org:service:...". A single error is returned for errors
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// while attempting to send the query. An error or RootDevice is returned for
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// each discovered RootDevice.
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func DiscoverDevices(searchTarget string) ([]MaybeRootDevice, error) {
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httpu, err := httpu.NewHTTPUClient()
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if err != nil {
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return nil, err
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}
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defer httpu.Close()
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responses, err := ssdp.SSDPRawSearch(httpu, string(searchTarget), 2, 3)
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if err != nil {
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return nil, err
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}
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results := make([]MaybeRootDevice, len(responses))
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for i, response := range responses {
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maybe := &results[i]
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loc, err := response.Location()
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if err != nil {
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maybe.Err = ContextError{"unexpected bad location from search", err}
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continue
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}
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locStr := loc.String()
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root := new(RootDevice)
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if err := requestXml(locStr, DeviceXMLNamespace, root); err != nil {
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maybe.Err = ContextError{fmt.Sprintf("error requesting root device details from %q", locStr), err}
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continue
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}
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urlBase, err := url.Parse(root.URLBaseStr)
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if err != nil {
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maybe.Err = ContextError{fmt.Sprintf("error parsing URLBase %q from %q: %v", root.URLBaseStr, locStr), err}
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continue
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}
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root.SetURLBase(urlBase)
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maybe.Root = root
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}
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return results, nil
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}
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func requestXml(url string, defaultSpace string, doc interface{}) error {
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resp, err := http.Get(url)
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if err != nil {
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return err
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}
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defer resp.Body.Close()
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if resp.StatusCode != 200 {
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return fmt.Errorf("goupnp: got response status %s from %q",
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resp.Status, url)
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}
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decoder := xml.NewDecoder(resp.Body)
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decoder.DefaultSpace = defaultSpace
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return decoder.Decode(doc)
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}
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