Removed unnecessary -sending flag

README.md

@@ -27,26 +27,6 @@ Thus, with a connection and a way of communication, the sender will send some pa
 
 ---
 
-## Usage
-`./FTU [FLAGS_HERE]` or `FTU [FLAGS_HERE]`
-
-### Flags
-
-- `-sending` (bool) - if true - creates a server (sender) (also need to provide a `-sharefile` flag in that case), if false - creates a client (receiver) 
-- `-port` (int) - specifies a port; if `-sending` == true - listens on that port, else - connects to given port
-- `addr` (string) - specifies an address to connect to (used when `-sending=false`)
-- `-sharefile` (string) - specifies path to a file you want to share (used in pair with `-sending=true`), if given a valid path - a server will offer to share this file to a client
-- `-downloadto` (string) - specifies path to a folder where the client wants to store downloaded file
-
-### Examples
-
-- `./FTU -sending=true -sharefile="/home/some_path_here/FILETOSHARE.zip"` - creates a server that will share `FILETOSHARE.zip` on port `8080`
-- `./FTU -sending=true -sharefile="/home/some_path_here/FILETOSHARE.zip" - port=727` - same as before, but on port `727`
-- `./FTU -sending=false -downloadto="/home/some_path_here/Downloads/" -addr="192.168.1.104"` - creates a client (receiver) that will try to connect to `192.168.1.104` (local device) on port `8080` and if successful - downloads a file to given path
-- `./FTU -sending=false -downloadto="/home/some_path_here/Downloads/" -addr=145.125.53.212 -port=8888` - same as before, but will try to connect to `145.125.53.212` on port `8888`
-
-
----
 
 ## Known issues|problems|lack of features|reasons why it`s bad
 - **VERY** slow; somewhat FIXED - [x], now **faster** than before   
@@ -56,19 +36,39 @@ Thus, with a connection and a way of communication, the sender will send some pa
 - Lack of information about the process of transferring (ETA, lost packets, etc.); FIXED - [ ]
 - No way to verify if the transferred file is not corrupted; FIXED via checksum- [x]
 - No encryption; FIXED - [ ] 
-- Messy and hard to follow code && file structure; partially FIXED (protocol is looking fairly good rn) - [ X ]
+- Messy and hard to follow code && file structure; FIXED? - [x]
 - No way to stop the download/upload and resume it later or even during the next connection; FIXED - [ ] 
 - No tests; FIXED - [ ]
 
 ## Good points
 - It works.
 
+---
+
+## Usage
+`./FTU [FLAGS_HERE]` or `FTU [FLAGS_HERE]`
+
+### Flags
+ 
+- `-port` (int) - specifies a working port (if sending - listens on this port, else - tries to connect to this port);
+- `addr` (string) - specifies an address to connect to;
+- `-sharefile` (string) - specifies path to a file you want to share, if given a valid path - sender will offer to download this file to receiver;
+- `-downloadto` (string) - specifies path to a folder where the receiver wants to store downloaded file;
+
+### Examples
+
+- `./FTU -sharefile="/home/some_path_here/FILETOSHARE.zip"` - creates a server that will share `FILETOSHARE.zip` on port `8080`
+- `./FTU -sharefile="/home/some_path_here/FILETOSHARE.zip" - port=727` - same as before, but on port `727`
+- `./FTU -downloadto="/home/some_path_here/Downloads/" -addr="192.168.1.104"` - creates a client (receiver) that will try to connect to `192.168.1.104` (local device) on port `8080` and if successful - downloads a file to given path
+- `./FTU -downloadto="/home/some_path_here/Downloads/" -addr=145.125.53.212 -port=8888` - same as before, but will try to connect to `145.125.53.212` on port `8888`
+
+
 ---
 
 ## IMPORTANT NOTE
 This is NOT intended to be a serious application. I'm learning and this is a product of my curiosity. If you're a beginner too, please don't try to find something useful in my code, I am not an expert.
 
-Also, this utility only works if both the server and the client have a port-forwarding enabled and configured. Fortunatelly, locally it works without any port-forwarding.
+Also, this utility only works if both the server and the client have a port-forwarding|virtual server enabled and configured. Fortunatelly, locally it works without any port-forwarding|virtual servers.
 
 ---
 

main.go

@@ -11,59 +11,66 @@ import (
 )
 
 // flags
-var PORT *int = flag.Int("port", 8080, "Specifies a port for a sender")
+var PORT *int = flag.Int("port", 8080, "Specifies a port for a sender|port to connect to")
 var SENDERADDR *string = flag.String("addr", "", "Specifies an IP for connection")
-var SENDING *bool = flag.Bool("sending", false, "Send or receive")
 var DOWNLOADSFOLDER *string = flag.String("downloadto", "", "Specifies where the receiver will store downloaded file")
 var SHAREDFILE *string = flag.String("sharefile", "", "Specifies what file sender will send")
 
+var SENDING bool
+
 // helpMessage
 var HELPMSG string = `
-"-port", default: 8080, Specifies a port for a sender
+"-port", default: 8080, Specifies a port for a sender|port to connect to
 "-addr", default: "", Specifies an IP for connection
-"-sending", default: false, Send or receive
 "-downloadto", default: "", Specifies where the receiver will store downloaded file
 "-sharefile", default: "", Specifies what file sender will send`
 
 // Input-validation
-func checkFlags() {
-	if *SENDING {
-		if strings.TrimSpace(*SHAREDFILE) == "" {
-			fmt.Println("No file specified !\n", HELPMSG)
-			os.Exit(1)
-		}
-		if *PORT <= 0 {
+func processFlags() {
+	if *PORT < 0 {
 		fmt.Println("Invalid port !\n", HELPMSG)
-			os.Exit(1)
+		os.Exit(-1)
+	}
+
+	// going to send file -> sending
+	if strings.TrimSpace(*SHAREDFILE) != "" {
+		SENDING = true
+	}
+	// specifying address to connect to -> receiving
+	if strings.TrimSpace(*SENDERADDR) != "" {
+		if SENDING {
+			fmt.Println("Cannot specify an address when sharing !\n", HELPMSG)
+			os.Exit(-1)
 		}
-	} else if !*SENDING {
-		if strings.TrimSpace(*SENDERADDR) == "" {
-			fmt.Println("Invalid IP address !\n", HELPMSG)
-			os.Exit(1)
+		SENDING = false
 	}
-		if strings.TrimSpace(*DOWNLOADSFOLDER) == "" {
-			*DOWNLOADSFOLDER = "./downloads/"
-			fmt.Println("Empty downloads folder. Changed to ./downloads/")
+	// specifying path to download to -> receiving
+	if strings.TrimSpace(*DOWNLOADSFOLDER) != "" {
+		if SENDING {
+			fmt.Println("Cannot specify a downloads directory when sharing !\n", HELPMSG)
+			os.Exit(-1)
 		}
+		SENDING = false
 	}
+
 }
 
 // parse flags, validate given values
 func init() {
 	flag.Parse()
-	checkFlags()
+	processFlags()
 }
 
 func main() {
-	if *SENDING {
+	if SENDING {
 		// 1) create sender -> 2) wait for a connection ->|
-		// 3) send fileinfo packet -> 4) if accepted - upload file
+		// 3) send info about the file -> 4) if accepted - upload file
 		sender := sender.NewSender(*PORT, *SHAREDFILE)
 		sender.WaitForConnection()
 		sender.MainLoop()
 
 	} else {
-		// 1) create receiver -> 2) try to connect to a sender -> 3) wait for a fileinfo packet ->|
+		// 1) create receiver -> 2) try to connect to a sender -> 3) wait for an info on the file ->|
 		// 4) accept or refuse -> 5) download|don`t_download file
 		receiver := receiver.NewReceiver(*DOWNLOADSFOLDER)
 		receiver.Connect(fmt.Sprintf("%s:%d", *SENDERADDR, *PORT))