error処理を簡素化

Author: hide5stm

chapter2/src/2_4_4/server.rs

@@ -1,44 +1,40 @@
 use std::net::{TcpStream, TcpListener};
 use std::io::{Write, BufReader, BufRead};
 
-fn get_operation(stream: &mut TcpStream) {
+fn get_operation(stream: &mut TcpStream) -> std::io::Result<()> {
     let body = "HTTP server sample";
-    writeln!(stream, "HTTP/1.1 200 OK").unwrap();
-    writeln!(stream, "Content-Type: text/html; charset=UTF-8").unwrap();
-    writeln!(stream, "Content-Length: {}", body.len()).unwrap();
-    writeln!(stream).unwrap();
+    writeln!(stream, "HTTP/1.1 200 OK")?;
+    writeln!(stream, "Content-Type: text/plain; charset=UTF-8")?;
+    writeln!(stream, "Content-Length: {}", body.len())?;
+    writeln!(stream)?;
 
-    writeln!(stream, "{}", body).unwrap();
+    writeln!(stream, "{}", body)?;
+    Ok(())
 }
 
-fn handle_client(stream: TcpStream) {
+fn handle_client(stream: TcpStream) -> std::io::Result<()> {
     let mut reader = BufReader::new(stream);
 
     let mut first_line = String::new();
-    if let Err(err) = reader.read_line(&mut first_line) {
-        panic!("error during receive a line: {}", err);
-    }
+    reader.read_line(&mut first_line)?;
 
     let mut params = first_line.split_whitespace();
     let method = params.next();
     let path = params.next();
     match (method, path) {
         (Some("GET"), Some(_)) => {
-            get_operation(reader.get_mut());
+            get_operation(reader.get_mut())?;
         }
         _ => panic!("failed to parse"),
     }
+    Ok(())
 }
 
-fn main() {
-    let listener = TcpListener::bind("127.0.0.1:8080").unwrap();
+fn main() -> std::io::Result<()> {
+    let listener = TcpListener::bind("127.0.0.1:8080")?;
 
     for stream in listener.incoming() {
-        match stream {
-            Ok(stream) => {
-                handle_client(stream)
-            }
-            Err(_) => { panic!("connection failed") }
-        };
+        handle_client(stream?)?;
     }
+    Ok(())
 }