Merge pull request 'complete the sample example for tcp/ip using zig.' (#2) from tcp_demo into main

Reviewed-on: http://198.12.122.141:3121/zig/nation/pulls/2

src/client.zig

@@ -17,7 +17,8 @@ pub fn main() !void {
     const allocator = gpa.allocator();
 
     const stream = try net.tcpConnectToHost(allocator, ip, port);
-    _ = try stream.writeAll("hello");
+    const s = "Hello, World!";
+    _ = try stream.writeAll(s);
     defer {
         stream.close();
     }

src/server.zig

@@ -6,6 +6,11 @@ pub fn main() !void {
     const ip = "127.0.0.1";
     const port: u16 = 10010;
 
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer {
+        _ = gpa.deinit();
+    }
+    // const allocator = gpa.allocator();
     // listen to local ip:port
     const address = try net.Address.parseIp(ip, port);
     log.info("server listen to {s}:{d}", .{ ip, port });
@@ -16,8 +21,16 @@ pub fn main() !void {
     while (true) {
         // accept from client
         const client = try server.accept();
-        var buffer: [1024]u8 = undefined;
-        const len = try client.stream.readAll(buffer[0..]);
-        log.info("data from client: {s}\n", .{buffer[0..len]});
+        log.info("has a client connected: {any}", .{client});
+        defer client.stream.close();
+
+        var message: [4]u8 = undefined;
+        var total_len: usize = 0;
+        r: while (true) {
+            const bytesRead = try client.stream.readAll(&message);
+            if (bytesRead == 0) break :r;
+            total_len += bytesRead;
+            std.debug.print("Received: {s}\n", .{message[0..bytesRead]});
+        }
     }
 }