feat: add environment variables and dedicated flags for ipv4/6 only (#…

…307)

* feat: add environment variables and dedicated flags for ipv4/6 only

* fix(readme): mention all flags on README

README.md

@@ -404,6 +404,17 @@ REDLIB_DEFAULT_USE_HLS = "on"
 >
 > If using Docker Compose, no changes are needed as the `.env` file is already referenced in `compose.yaml` via the `env_file: .env` line.
 
+## Command Line Flags
+
+Redlib supports the following command line flags:
+
+- `-4`, `--ipv4-only`: Listen on IPv4 only.
+- `-6`, `--ipv6-only`: Listen on IPv6 only.
+- `-r`, `--redirect-https`: Redirect all HTTP requests to HTTPS (no longer functional).
+- `-a`, `--address <ADDRESS>`: Sets address to listen on. Default is `[::]`.
+- `-p`, `--port <PORT>`: Port to listen on. Default is `8080`.
+- `-H`, `--hsts <EXPIRE_TIME>`: HSTS header to tell browsers that this site should only be accessed over HTTPS. Default is `604800`.
+
 ## Instance settings
 
 Assign a default value for each instance-specific setting by passing environment variables to Redlib in the format `REDLIB_{X}`. Replace `{X}` with the setting name (see list below) in capital letters.

src/main.rs

@@ -108,6 +108,20 @@ async fn main() {
 	let matches = Command::new("Redlib")
 		.version(env!("CARGO_PKG_VERSION"))
 		.about("Private front-end for Reddit written in Rust ")
+		.arg(
+			Arg::new("ipv4-only")
+				.short('4')
+				.long("ipv4-only")
+				.help("Listen on IPv4 only")
+				.num_args(0),
+		)
+		.arg(
+			Arg::new("ipv6-only")
+				.short('6')
+				.long("ipv6-only")
+				.help("Listen on IPv6 only")
+				.num_args(0),
+		)
 		.arg(
 			Arg::new("redirect-https")
 				.short('r')
@@ -164,7 +178,16 @@ async fn main() {
 	let port = matches.get_one::<String>("port").unwrap();
 	let hsts = matches.get_one("hsts").map(|m: &String| m.as_str());
 
-	let listener = [address, ":", port].concat();
+	let ipv4_only = std::env::var("IPV4_ONLY").is_ok() || matches.get_flag("ipv4-only");
+	let ipv6_only = std::env::var("IPV6_ONLY").is_ok() || matches.get_flag("ipv6-only");
+
+	let listener = if ipv4_only {
+		format!("0.0.0.0:{}", port)
+	} else if ipv6_only {
+		format!("[::]:{}", port)
+	} else {
+		[address, ":", port].concat()
+	};
 
 	println!("Starting Redlib...");