Add group chat validation example

README.md

@@ -268,6 +268,8 @@ out, _ := evt.ToXML()
 Note: the `groupOwner` attribute is mandatory for TAK chat messages. It must be
 present for schema validation to succeed when using the TAK chat format.
 
+See `examples/group_chat_example.go` for an example of parsing and validating a TAK group chat message.
+
 Delivery or read receipts can be sent by populating `Detail.ChatReceipt` with
 the appropriate `Ack`, `ID`, and `MessageID` fields.
 

examples/group_chat_example.go

@@ -0,0 +1,60 @@
+//go:build ignore
+
+package main
+
+import (
+	"context"
+	"encoding/xml"
+	"fmt"
+	"log/slog"
+	"os"
+
+	"github.com/NERVsystems/cotlib"
+	"github.com/NERVsystems/cotlib/validator"
+)
+
+func main() {
+	logger := slog.New(slog.NewTextHandler(os.Stdout, nil))
+	cotlib.SetLogger(logger)
+	ctx := cotlib.WithLogger(context.Background(), logger)
+
+	xmlInput := `<?xml version="1.0" encoding="UTF-8"?>
+<event version="2.0" uid="CHAT-2" type="b-t-f" time="2020-01-01T00:00:00Z" start="2020-01-01T00:00:00Z" stale="2020-01-01T01:00:00Z">
+  <point lat="10" lon="20" ce="1" le="1"/>
+  <detail>
+    <__chat chatroom="room" groupOwner="false" id="1" senderCallsign="Bravo">
+      <chatgrp id="room" uid0="Bravo"/>
+    </__chat>
+  </detail>
+</event>`
+
+	evt, err := cotlib.UnmarshalXMLEvent(ctx, []byte(xmlInput))
+	if err != nil {
+		logger.Error("failed to parse event", "err", err)
+		return
+	}
+
+	c := evt.Detail.Chat
+	fmt.Printf("Chatroom: %s\n", c.Chatroom)
+	fmt.Printf("GroupOwner: %s\n", c.GroupOwner)
+	fmt.Printf("SenderCallsign: %s\n", c.SenderCallsign)
+
+	if err := evt.Validate(); err != nil {
+		logger.Error("Event validation failed", "err", err)
+		return
+	}
+	fmt.Println("Event validated via Event.Validate")
+
+	data, err := xml.Marshal(c)
+	if err != nil {
+		logger.Error("marshal chat", "err", err)
+		return
+	}
+	if err := validator.ValidateAgainstSchema("tak-details-__chat", data); err != nil {
+		logger.Error("schema validation failed", "err", err)
+		return
+	}
+	fmt.Println("Chat validated with tak-details-__chat schema")
+
+	cotlib.ReleaseEvent(evt)
+}