go-xmpp/parser.go
2018-01-12 19:08:47 +01:00

103 lines
2.8 KiB
Go

package xmpp // import "fluux.io/xmpp"
import (
"encoding/xml"
"errors"
"fmt"
"io"
)
// Reads and checks the opening XMPP stream element.
// TODO It returns a stream structure containing:
// - Host: You can check the host against the host you were expecting to connect to
// - Id: the Stream ID is a temporary shared secret used for some hash calculation. It is also used by ProcessOne
// reattach features (allowing to resume an existing stream at the point the connection was interrupted, without
// getting through the authentication process.
// TODO We should handle stream error from XEP-0114 ( <conflict/> or <host-unknown/> )
func initDecoder(p *xml.Decoder) (sessionID string, err error) {
for {
var t xml.Token
t, err = p.Token()
if err != nil {
return
}
switch elem := t.(type) {
case xml.StartElement:
if elem.Name.Space != NSStream || elem.Name.Local != "stream" {
err = errors.New("xmpp: expected <stream> but got <" + elem.Name.Local + "> in " + elem.Name.Space)
return
}
// Parse Stream attributes
for _, attrs := range elem.Attr {
switch attrs.Name.Local {
case "id":
sessionID = attrs.Value
}
}
return
}
}
panic("unreachable")
}
// Scan XML token stream to find next StartElement.
func nextStart(p *xml.Decoder) (xml.StartElement, error) {
for {
t, err := p.Token()
if err == io.EOF {
return xml.StartElement{}, nil
}
if err != nil {
return xml.StartElement{}, fmt.Errorf("nextStart %s", err)
}
switch t := t.(type) {
case xml.StartElement:
return t, nil
}
}
panic("unreachable")
}
// Scan XML token stream for next element and save into val.
// If val == nil, allocate new element based on proto map.
// Either way, return val.
// TODO Use an interface to return packets interface xmppDecoder
func next(p *xml.Decoder) (xml.Name, interface{}, error) {
// Read start element to find out what type we want.
se, err := nextStart(p)
if err != nil {
return xml.Name{}, nil, err
}
// Put it in an interface and allocate one.
var nv interface{}
switch se.Name.Space + " " + se.Name.Local {
case NSStream + " error":
nv = &StreamError{}
// TODO: general case = Parse IQ / presence / message => split SASL case
case nsSASL + " success":
nv = &saslSuccess{}
case nsSASL + " failure":
nv = &saslFailure{}
case NSClient + " message":
nv = &ClientMessage{}
case NSClient + " presence":
nv = &ClientPresence{}
case NSClient + " iq":
nv = &ClientIQ{}
case NSComponent + " handshake":
nv = &Handshake{}
default:
return xml.Name{}, nil, errors.New("unexpected XMPP message " +
se.Name.Space + " <" + se.Name.Local + "/>")
}
// Decode element into pointer storage
if err = p.DecodeElement(nv, &se); err != nil {
return xml.Name{}, nil, err
}
return se.Name, nv, err
}