async communication stub, service discorvery via it

scenes/App.gd

@@ -1,6 +1,17 @@
 extends Node
 
+var _connection
+
+func _service_discovery():
+    var iq := yield() as Xml.XmlElement
+    print(iq.as_string())
+
 func _ready():
-    var connection = $Connections.establish_new_connection("poto.cafe", "veclavtalica", "-")
-    if connection == null:
+    _connection = $Connections.establish_new_connection("poto.cafe", "veclavtalica", "-")
+    if _connection == null:
+        push_error("Connection failed")
+
+    if _connection.push_iq(_connection.domain, "get",
+            "<query xmlns='http://jabber.org/protocol/disco#items'/>",
+            _service_discovery()) != OK:
         push_error("Connection failed")

scenes/Connections.gd

@@ -7,11 +7,92 @@ class Connection extends Reference:
     var bare_jid: String
     var jid: String
     var _id_counter: int = 0
+    var _pending_iqs: Dictionary # of id to GDScriptFunctionState
+    var _xml_parser := Xml.Parser.new()
+
+# warning-ignore:unused_signal
+    signal presence_received(presence)
+# warning-ignore:unused_signal
+    signal message_received(message)
+# warning-ignore:unused_signal
+    signal iq_received(iq)
 
     func generate_id() -> int:
         self._id_counter += 1
         return hash(self._id_counter)
 
+    func push_iq(to: String, action: String, payload: String, capture: GDScriptFunctionState) -> int: # Error
+        assert(action in ["get", "set"])
+
+        var id := self.generate_id()
+        if self.stream.put_data(
+            """<iq from='{from}' id='{id}' to='{to}' type='{action}'>{payload}</iq>""".format({
+                "from": self.jid.xml_escape(),
+                "id": id,
+                "to": to.xml_escape(),
+                "action": action,
+                "payload": payload
+               }).to_utf8()) != OK:
+            return ERR_CONNECTION_ERROR
+
+        assert(not id in self._pending_iqs)
+        self._pending_iqs[id] = capture
+
+        return OK
+
+## Registry of connections used for poking of pending iqs.
+var _connections: Array # of WeakRef to Connection
+
+func _ready():
+    # todo: Some better interval?
+    if get_tree().connect("physics_frame", self, "_process_connections") != OK:
+        assert("Bruh")
+
+func _process_connections() -> void:
+    var to_remove := PoolIntArray()
+
+    for idx in range(_connections.size()):
+        var connection := _connections[idx].get_ref() as Connection
+        if connection == null:
+            to_remove.push_back(idx)
+            continue
+
+        var response = _wait_blocking_for_utf8_data(connection.stream, 0)
+        if response == null:
+            continue
+
+        if connection._xml_parser.parse_a_bit(response):
+            var stanza := connection._xml_parser.root
+            if stanza.node_name == "iq":
+                if "to" in stanza.attributes and stanza.attributes["to"] != connection.jid:
+                    push_error("Stanza is not addressed to assigned jid")
+
+                if stanza.attributes["type"] in ["result", "error"]:
+                    var id := int(stanza.attributes["id"]) # todo: Use strings directly instead?
+                    var result = connection._pending_iqs[id].resume(stanza)
+                    if result is GDScriptFunctionState:
+                        connection._pending_iqs[id] = result
+                    elif result != null:
+                        assert("Ignored result of iq subroutine: " + result)
+                    else:
+                        var was_present := connection._pending_iqs.erase(id)
+                        assert(was_present)
+
+                elif stanza.attributes["type"] in ["set", "get"]:
+                    connection.emit_signal("iq_received", stanza)
+
+            elif stanza.node_name == "message":
+                connection.emit_signal("message_received", stanza)
+
+            elif stanza.node_name == "presence":
+                connection.emit_signal("presence_received", stanza)
+
+            connection._xml_parser = Xml.Parser.new()
+
+    ## Collect dropped connections.
+    for idx in range(to_remove.size() - 1, 0, -1):
+        _connections.remove(to_remove[idx])
+
 func establish_new_connection(domain: String, identity: String, password: String) -> Connection:
     var stream := StreamPeerTCP.new()
     if stream.connect_to_host(domain, 5222) != OK:
@@ -34,6 +115,8 @@ func establish_new_connection(domain: String, identity: String, password: String
     if _negotiate_connection(result, password) != OK:
         return null
 
+    _connections.push_back(weakref(result))
+
     return result
 
 # todo: Make it async

scenes/Xml.gd

@@ -19,7 +19,7 @@ class XmlElement extends XmlNode:
                 return child
         return null
 
-    func as_string(level = 0) -> String:
+    func as_string(level: int = 0) -> String:
         var result = '\t'.repeat(level) + "XmlElement \"%s\"" % self.node_name
         if self.attributes.size() > 0:
             result += ", Attributes: " + String(self.attributes)
@@ -32,11 +32,12 @@ class XmlText extends XmlNode:
 
     func is_text() -> bool: return true
 
-    func as_string(level = 0) -> String:
+    func as_string(_level: int = 0) -> String:
         return "XmlText \"%s\"" % self.data
 
 ## Wrapper over XMLParser for TCP stream oriented XML data.
 # todo: Save namespaces.
+# todo: Ability to parse from partially arrived data, with saving for future resume.
 class Parser extends Reference:
     var root: XmlElement = null
     var _element_stack: Array # of XmlElement
@@ -86,7 +87,11 @@ class Parser extends Reference:
                 text.data = parser.get_node_data()
                 self._element_stack[self._element_stack.size() - 1].children.push_back(text)
 
+            elif parser.get_node_type() == XMLParser.NODE_UNKNOWN:
+                ## Needed for things like <?xml ?> version specification.
+                pass
+
             else:
-                push_warning("Node type unimplemented and ignored")
+                push_error("Node type unimplemented")
 
         return self._element_stack.size() == 0