From bebcfbf84662a0e6e8098f3bdf13de487b3697fe Mon Sep 17 00:00:00 2001
From: Joerg Lehmann <joerg.lehmann@nbit.ch>
Date: Thu, 18 Jun 2020 16:44:57 +0200
Subject: [PATCH] add TTN as possible datasource

---
 lorahandler.go | 72 +++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 60 insertions(+), 12 deletions(-)

diff --git a/lorahandler.go b/lorahandler.go
index 2635457..e13ff67 100644
--- a/lorahandler.go
+++ b/lorahandler.go
@@ -5,6 +5,7 @@ import (
 	"encoding/binary"
 	"encoding/hex"
 	"encoding/json"
+	"encoding/base64"
 	"fmt"
 	"io/ioutil"
 	"log"
@@ -22,6 +23,16 @@ const (
 	NOT_ATTACHED = -2147483648
 )
 
+type MetadataTTN struct {
+	Time string `json:"time"`
+}
+
+type MessageTTN struct {
+	Hardware_serial string `json:"hardware_serial"`
+	Metadata        MetadataTTN `json:"metadata"`
+	Payload_raw     string `json:"payload_raw"`
+}
+
 type MessageProperties struct {
 	Time        string  `json:"Time"`
 	Payload_hex string  `json:"payload_hex"`
@@ -344,6 +355,15 @@ func WriteStringToFile(s string) {
 	}
 }
 
+func Convert2Hex(payload_raw string) (string, error) {
+	res := "error"
+	p, err := base64.StdEncoding.DecodeString(payload_raw)
+	if err == nil {
+		res = hex.EncodeToString(p)
+	}
+	return res, err
+}
+
 func main() {
 	// Init Redis
 	initDB()
@@ -362,7 +382,8 @@ func main() {
 	defer file.Close()
 
 	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
-		var u Message
+		var message_swisscom Message
+		var message_ttn MessageTTN
 		if r.Body == nil {
 			http.Error(w, "Please send a request body", 400)
 			return
@@ -380,18 +401,45 @@ func main() {
 		log.Printf("BODY: %s", rdr1)
 		r.Body = rdr2
 
-		err := json.NewDecoder(r.Body).Decode(&u)
-		if err != nil {
-			http.Error(w, err.Error(), 400)
-			return
+		// We look for the text string "mini-beieli" in the buffer, then it is a TTN Packet, 
+                // otherwise it should be a Swisscom Packet...
+
+		fmt.Printf("Length of JSON Body: %d\n", len(buf))
+
+		if strings.Contains(string(buf),"mini-beieli") {
+		        fmt.Printf("Seems to be a TTN Packet...\n")
+			// it is probably a TTN  package...
+			err := json.NewDecoder(r.Body).Decode(&message_ttn)
+			if err != nil {
+				http.Error(w, err.Error(), 400)
+				return
+			}
+
+			fmt.Println("Time:        " + message_ttn.Metadata.Time)
+			fmt.Println("Payload Raw: " + message_ttn.Payload_raw)
+			fmt.Println("DevEUI:     " + message_ttn.Hardware_serial)
+			payload_hex, err := Convert2Hex(message_ttn.Payload_raw)
+			if err == nil {
+				DecodePayload(payload_hex, message_ttn.Hardware_serial, "N/A", 0, 0, true)
+			} else {
+				fmt.Println("Error: could not convert raw_package to hex: %s" + message_ttn.Payload_raw)
+			}
+		} else {
+		        fmt.Printf("Seems to be a Swisscom Packet...\n")
+			// it is probably a Swisscom package...
+			err := json.NewDecoder(r.Body).Decode(&message_swisscom)
+			if err != nil {
+				http.Error(w, err.Error(), 400)
+				return
+			}
+			fmt.Println("Time:        " + message_swisscom.Prop.Time)
+			fmt.Println("Payload Hex: " + message_swisscom.Prop.Payload_hex)
+			fmt.Println("DevEUI:     " + message_swisscom.Prop.DevEUI)
+			fmt.Println("DevAddr:     " + message_swisscom.Prop.DevAddr)
+			fmt.Printf("LrrLAT:     %f\n", message_swisscom.Prop.LrrLAT)
+			fmt.Printf("LrrLON:     %f\n", message_swisscom.Prop.LrrLON)
+			DecodePayload(message_swisscom.Prop.Payload_hex, message_swisscom.Prop.DevEUI, message_swisscom.Prop.DevAddr, message_swisscom.Prop.LrrLAT, message_swisscom.Prop.LrrLON, true)
 		}
-		fmt.Println("Time:        " + u.Prop.Time)
-		fmt.Println("Payload Hex: " + u.Prop.Payload_hex)
-		fmt.Println("DevEUI:     " + u.Prop.DevEUI)
-		fmt.Println("DevAddr:     " + u.Prop.DevAddr)
-		fmt.Printf("LrrLAT:     %f\n", u.Prop.LrrLAT)
-		fmt.Printf("LrrLON:     %f\n", u.Prop.LrrLON)
-		DecodePayload(u.Prop.Payload_hex, u.Prop.DevEUI, u.Prop.DevAddr, u.Prop.LrrLAT, u.Prop.LrrLON, true)
 	})
 	log.Fatal(http.ListenAndServe(":8080", nil))
 }