// Definition for the SOAP structure required for UPnP's SOAP usage.
package soap
import (
"bytes"
"encoding/xml"
"fmt"
"io/ioutil"
"net/http"
"net/url"
"reflect"
)
const (
soapEncodingStyle = "http://schemas.xmlsoap.org/soap/encoding/"
soapPrefix = xml.Header + `<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><s:Body>`
soapSuffix = `</s:Body></s:Envelope>`
)
type SOAPClient struct {
EndpointURL url.URL
HTTPClient http.Client
}
func NewSOAPClient(endpointURL url.URL) *SOAPClient {
return &SOAPClient{
EndpointURL: endpointURL,
}
}
// PerformSOAPAction makes a SOAP request, with the given action.
// inAction and outAction must both be pointers to structs with string fields
// only.
func (client *SOAPClient) PerformAction(actionNamespace, actionName string, inAction interface{}, outAction interface{}) error {
requestBytes, err := encodeRequestAction(actionNamespace, actionName, inAction)
if err != nil {
return err
}
response, err := client.HTTPClient.Do(&http.Request{
Method: "POST",
URL: &client.EndpointURL,
Header: http.Header{
"SOAPACTION": []string{`"` + actionNamespace + "#" + actionName + `"`},
"CONTENT-TYPE": []string{"text/xml; charset=\"utf-8\""},
},
Body: ioutil.NopCloser(bytes.NewBuffer(requestBytes)),
// Set ContentLength to avoid chunked encoding - some servers might not support it.
ContentLength: int64(len(requestBytes)),
})
if err != nil {
return fmt.Errorf("goupnp: error performing SOAP HTTP request: %v", err)
}
defer response.Body.Close()
if response.StatusCode != 200 {
return fmt.Errorf("goupnp: SOAP request got HTTP %s", response.Status)
}
responseEnv := newSOAPEnvelope()
decoder := xml.NewDecoder(response.Body)
if err := decoder.Decode(responseEnv); err != nil {
return fmt.Errorf("goupnp: error decoding response body: %v", err)
}
if responseEnv.Body.Fault != nil {
return responseEnv.Body.Fault
}
if outAction != nil {
if err := xml.Unmarshal(responseEnv.Body.RawAction, outAction); err != nil {
return fmt.Errorf("goupnp: error unmarshalling out action: %v, %v", err, responseEnv.Body.RawAction)
}
}
return nil
}
// newSOAPAction creates a soapEnvelope with the given action and arguments.
func newSOAPEnvelope() *soapEnvelope {
return &soapEnvelope{
EncodingStyle: soapEncodingStyle,
}
}
// encodeRequestAction is a hacky way to create an encoded SOAP envelope
// containing the given action. Experiments with one router have shown that it
// 500s for requests where the outer default xmlns is set to the SOAP
// namespace, and then reassigning the default namespace within that to the
// service namespace. Hand-coding the outer XML to work-around this.
func encodeRequestAction(actionNamespace, actionName string, inAction interface{}) ([]byte, error) {
requestBuf := new(bytes.Buffer)
requestBuf.WriteString(soapPrefix)
requestBuf.WriteString(`<u:`)
xml.EscapeText(requestBuf, []byte(actionName))
requestBuf.WriteString(` xmlns:u="`)
xml.EscapeText(requestBuf, []byte(actionNamespace))
requestBuf.WriteString(`">`)
if inAction != nil {
if err := encodeRequestArgs(requestBuf, inAction); err != nil {
return nil, err
}
}
requestBuf.WriteString(`</u:`)
xml.EscapeText(requestBuf, []byte(actionName))
requestBuf.WriteString(`>`)
requestBuf.WriteString(soapSuffix)
return requestBuf.Bytes(), nil
}
func encodeRequestArgs(w *bytes.Buffer, inAction interface{}) error {
in := reflect.Indirect(reflect.ValueOf(inAction))
if in.Kind() != reflect.Struct {
return fmt.Errorf("goupnp: SOAP inAction is not a struct but of type %v", in.Type())
}
enc := xml.NewEncoder(w)
nFields := in.NumField()
inType := in.Type()
for i := 0; i < nFields; i++ {
field := inType.Field(i)
argName := field.Name
if nameOverride := field.Tag.Get("soap"); nameOverride != "" {
argName = nameOverride
}
value := in.Field(i)
if value.Kind() != reflect.String {
return fmt.Errorf("goupnp: SOAP arg %q is not of type string, but of type %v", argName, value.Type())
}
if err := enc.EncodeElement(value.Interface(), xml.StartElement{xml.Name{"", argName}, nil}); err != nil {
return fmt.Errorf("goupnp: error encoding SOAP arg %q: %v", argName, err)
}
}
enc.Flush()
return nil
}
type soapEnvelope struct {
XMLName xml.Name `xml:"http://schemas.xmlsoap.org/soap/envelope/ Envelope"`
EncodingStyle string `xml:"http://schemas.xmlsoap.org/soap/envelope/ encodingStyle,attr"`
Body soapBody `xml:"http://schemas.xmlsoap.org/soap/envelope/ Body"`
}
type soapBody struct {
Fault *SOAPFaultError `xml:"Fault"`
RawAction []byte `xml:",innerxml"`
}
// SOAPFaultError implements error, and contains SOAP fault information.
type SOAPFaultError struct {
FaultCode string `xml:"faultcode"`
FaultString string `xml:"faultstring"`
Detail string `xml:"detail"`
}
func (err *SOAPFaultError) Error() string {
return fmt.Sprintf("SOAP fault: %s", err.FaultString)
}