add cli for server/client (#4)

This PR adds a CLI to main.rs that allows you to run the redis server and eventually the redis client.

src/bin/client.rs

@@ -0,0 +1,40 @@
+use bytes::Bytes;
+use clap::Clap;
+use mini_redis::{client, DEFAULT_PORT};
+use std::{io, str};
+
+#[tokio::main]
+async fn main() -> io::Result<()> {
+    let cli = Cli::parse();
+    let port = cli.port.unwrap_or(DEFAULT_PORT.to_string());
+    let mut client = client::connect(&format!("127.0.0.1:{}", port)).await?;
+    match cli.command {
+        Client::Get { key } => {
+            let result = client.get(&key).await?;
+            if let Some(result) = result {
+                println!("\"{}\"", str::from_utf8(&result).unwrap());
+            } else {
+                println!("(nil)");
+            }
+            Ok(())
+        }
+        Client::Set { key, value } => client.set(&key, Bytes::from(value)).await,
+    }
+}
+
+#[derive(Clap, Debug)]
+#[clap(name = "mini-redis-client", version = env!("CARGO_PKG_VERSION"), author = env!("CARGO_PKG_AUTHORS"), about = "Opens a connection to a Redis server")]
+struct Cli {
+    #[clap(subcommand)]
+    command: Client,
+    #[clap(name = "port", long = "--port")]
+    port: Option<String>,
+}
+
+#[derive(Clap, Debug)]
+enum Client {
+    #[clap(about = "Gets a value associated with a key")]
+    Get { key: String },
+    #[clap(about = "Associates a value with a key")]
+    Set { key: String, value: String },
+}

src/bin/server.rs

@@ -0,0 +1,17 @@
+use clap::Clap;
+use mini_redis::{server, DEFAULT_PORT};
+use std::io;
+
+#[tokio::main]
+pub async fn main() -> io::Result<()> {
+    let cli = Cli::parse();
+    let port = cli.port.unwrap_or(DEFAULT_PORT.to_string());
+    server::run(&port).await
+}
+
+#[derive(Clap, Debug)]
+#[clap(name = "mini-redis-server", version = env!("CARGO_PKG_VERSION"), author = env!("CARGO_PKG_AUTHORS"), about = "A Redis server")]
+struct Cli {
+    #[clap(name = "port", long = "--port")]
+    port: Option<String>,
+}