Refactor and move parsing and stanza to a separate package

2019-06-26 17:14:52 +02:00
parent 0acf824217
commit 428787d7ab
51 changed files with 614 additions and 580 deletions
--- a/stanza/parser.go
+++ b/stanza/parser.go
@@ -0,0 +1,151 @@
+package stanza
+
+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 InitStream(p *xml.Decoder) (sessionID string, err error) {
+	for {
+		var t xml.Token
+		t, err = p.Token()
+		if err != nil {
+			return sessionID, err
+		}
+
+		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 sessionID, err
+			}
+
+			// Parse XMPP stream attributes
+			for _, attrs := range elem.Attr {
+				switch attrs.Name.Local {
+				case "id":
+					sessionID = attrs.Value
+				}
+			}
+			return sessionID, err
+		}
+	}
+}
+
+// NextPacket scans XML token stream for next complete XMPP stanza.
+// Once the type of stanza has been identified, a structure is created to decode
+// that stanza and returned.
+// TODO Use an interface to return packets interface xmppDecoder
+// TODO make auth and bind use NextPacket instead of directly NextStart
+func NextPacket(p *xml.Decoder) (Packet, error) {
+	// Read start element to find out how we want to parse the XMPP packet
+	se, err := NextStart(p)
+	if err != nil {
+		return nil, err
+	}
+
+	// Decode one of the top level XMPP namespace
+	switch se.Name.Space {
+	case NSStream:
+		return decodeStream(p, se)
+	case NSSASL:
+		return decodeSASL(p, se)
+	case NSClient:
+		return decodeClient(p, se)
+	case NSComponent:
+		return decodeComponent(p, se)
+	default:
+		return nil, errors.New("unknown namespace " +
+			se.Name.Space + " <" + se.Name.Local + "/>")
+	}
+}
+
+// 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{}, errors.New("connection closed")
+		}
+		if err != nil {
+			return xml.StartElement{}, fmt.Errorf("NextStart %s", err)
+		}
+		switch t := t.(type) {
+		case xml.StartElement:
+			return t, nil
+		}
+	}
+}
+
+/*
+TODO: From all the decoder, we can return a pointer to the actual concrete type, instead of directly that
+   type.
+   That way, we have a consistent way to do type assertion, always matching against pointers.
+*/
+
+// decodeStream will fully decode a stream packet
+func decodeStream(p *xml.Decoder, se xml.StartElement) (Packet, error) {
+	switch se.Name.Local {
+	case "error":
+		return streamError.decode(p, se)
+	case "features":
+		return streamFeatures.decode(p, se)
+	default:
+		return nil, errors.New("unexpected XMPP packet " +
+			se.Name.Space + " <" + se.Name.Local + "/>")
+	}
+}
+
+// decodeSASL decodes a packet related to SASL authentication.
+func decodeSASL(p *xml.Decoder, se xml.StartElement) (Packet, error) {
+	switch se.Name.Local {
+	case "success":
+		return saslSuccess.decode(p, se)
+	case "failure":
+		return saslFailure.decode(p, se)
+	default:
+		return nil, errors.New("unexpected XMPP packet " +
+			se.Name.Space + " <" + se.Name.Local + "/>")
+	}
+}
+
+// decodeClient decodes all known packets in the client namespace.
+func decodeClient(p *xml.Decoder, se xml.StartElement) (Packet, error) {
+	switch se.Name.Local {
+	case "message":
+		return message.decode(p, se)
+	case "presence":
+		return presence.decode(p, se)
+	case "iq":
+		return iq.decode(p, se)
+	default:
+		return nil, errors.New("unexpected XMPP packet " +
+			se.Name.Space + " <" + se.Name.Local + "/>")
+	}
+}
+
+// decodeClient decodes all known packets in the component namespace.
+func decodeComponent(p *xml.Decoder, se xml.StartElement) (Packet, error) {
+	switch se.Name.Local {
+	case "handshake": // handshake is used to authenticate components
+		return handshake.decode(p, se)
+	case "message":
+		return message.decode(p, se)
+	case "presence":
+		return presence.decode(p, se)
+	case "iq":
+		return iq.decode(p, se)
+	default:
+		return nil, errors.New("unexpected XMPP packet " +
+			se.Name.Space + " <" + se.Name.Local + "/>")
+	}
+}