init: parsing arguments and connecting

transmission-telegram.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/pyed/transmission"
+)
+
+var (
+	token    string
+	master   string
+	url      string
+	username string
+	password string
+
+	client *transmission.Client
+)
+
+func init() {
+	// define arguments and parse them.
+	flag.StringVar(&token, "token", "", "Telegram bot token")
+	flag.StringVar(&master, "master", "", "Your telegram handler, So the bot will only respond to you")
+	flag.StringVar(&url, "url", "http://localhost:9091/transmission/rpc", "Transmission RPC URL")
+	flag.StringVar(&username, "username", "", "Transmission username")
+	flag.StringVar(&password, "password", "", "Transmission password")
+
+	// set the usage message
+	flag.Usage = func() {
+		fmt.Fprintln(os.Stderr, "Usage: transmission-bot -token=<TOKEN> -master=<@tuser> -url=[http://] -username=[user] -password=[pass]\n")
+		flag.PrintDefaults()
+	}
+
+	flag.Parse()
+
+	// make sure that we have the two madatory arguments: telegram token & master's handler.
+	if token == "" ||
+		master == "" {
+		fmt.Fprintf(os.Stderr, "Error: Mandatory argument missing!\n\n")
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	// set transmission.Config, needed to establish a connection with transmission
+	conf := transmission.Config{
+		Address:  url,
+		User:     username,
+		Password: password,
+	}
+
+	// transmission.New() never returns an error, we will ignore it and test with client.Session.Update()
+	client, _ = transmission.New(conf)
+	if err := client.Session.Update(); err != nil {
+
+		// try to predict the error message, as it vague coming from pyed/transmission
+		if strings.HasPrefix(err.Error(), "invalid character") { // means the user or the pass is wrong.
+			fmt.Fprintln(os.Stderr, "Transmission's Username or Password is wrong.\n")
+
+		} else { // any other error is probaby because of the URL
+			fmt.Fprintf(os.Stderr, "Error: Couldn't connect to: %s\n", url)
+			fmt.Fprintln(os.Stderr, "Make sure to pass the right full RPC URL e.g. http://localhost:9091/transmission/rpc\n")
+		}
+		// send the vague error message too
+		fmt.Fprintln(os.Stderr, "RawError: "+err.Error())
+		os.Exit(1)
+	}
+}
+
+func main() {}