Add net testing work

2018/July/net-testing/net.go

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+package net
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"net"
+	"strings"
+)
+
+// Server defines the minimum contract our
+// TCP and UDP server implementations must satisfy.
+type Server interface {
+	Run() error
+	Close() error
+}
+
+// NewServer creates a new Server using given protocol
+// and addr.
+func NewServer(protocol, addr string) (Server, error) {
+	switch strings.ToLower(protocol) {
+	case "tcp":
+		return &TCPServer{
+			addr: addr,
+		}, nil
+	case "udp":
+	}
+	return nil, errors.New("Invalid protocol given")
+}
+
+// TCPServer holds the structure of our TCP
+// implementation.
+type TCPServer struct {
+	addr   string
+	server net.Listener
+}
+
+// Run starts the TCP Server.
+func (t *TCPServer) Run() (err error) {
+	t.server, err = net.Listen("tcp", t.addr)
+	if err != nil {
+		return err
+	}
+	defer t.Close()
+
+	for {
+		conn, err := t.server.Accept()
+		if err != nil {
+			err = errors.New("could not accept connection")
+			break
+		}
+		if conn == nil {
+			err = errors.New("could not create connection")
+			break
+		}
+		return t.handleConnections()
+	}
+	return
+}
+
+// Close shuts down the TCP Server
+func (t *TCPServer) Close() (err error) {
+	return t.server.Close()
+}
+
+// handleConnections is used to accept connections on
+// the TCPServer and handle each of them in separate
+// goroutines.
+func (t *TCPServer) handleConnections() (err error) {
+	for {
+		conn, err := t.server.Accept()
+		if err != nil || conn == nil {
+			err = errors.New("could not accept connection")
+			break
+		}
+
+		go t.handleConnection(conn)
+	}
+	return
+}
+
+// handleConnections deals with the business logic of
+// each connection and their requests.
+func (t *TCPServer) handleConnection(conn net.Conn) {
+	defer conn.Close()
+
+	rw := bufio.NewReadWriter(bufio.NewReader(conn), bufio.NewWriter(conn))
+	for {
+		req, err := rw.ReadString('\n')
+		if err != nil {
+			rw.WriteString("failed to read input")
+			rw.Flush()
+			return
+		}
+
+		rw.WriteString(fmt.Sprintf("Request received: %s", req))
+		rw.Flush()
+	}
+}

2018/July/net-testing/net_test.go

@@ -0,0 +1,68 @@
+package net
+
+import (
+	"bytes"
+	"log"
+	"net"
+	"testing"
+)
+
+var srv Server
+
+func init() {
+	// Start the new server
+	srv, err := NewServer("tcp", ":1123")
+	if err != nil {
+		log.Println("error starting TCP server")
+		return
+	}
+
+	// Run the server in goroutine to stop blocking
+	go func() {
+		srv.Run()
+	}()
+}
+
+func TestNETServer_Running(t *testing.T) {
+	// Simply check that the server is up and can
+	// accept connections.
+	conn, err := net.Dial("tcp", ":1123")
+	if err != nil {
+		t.Error("could not connect to server: ", err)
+	}
+	defer conn.Close()
+}
+
+func TestNETServer_Request(t *testing.T) {
+	tt := []struct {
+		test    string
+		payload []byte
+		want    []byte
+	}{
+		{"Sending a simple request returns result", []byte("hello world\n"), []byte("Request received: hello world")},
+		{"Sending another simple request works", []byte("goodbye world\n"), []byte("Request received: goodbye world")},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.test, func(t *testing.T) {
+			conn, err := net.Dial("tcp", ":1123")
+			if err != nil {
+				t.Error("could not connect to TCP server: ", err)
+			}
+			defer conn.Close()
+
+			if _, err := conn.Write(tc.payload); err != nil {
+				t.Error("could not write payload to TCP server:", err)
+			}
+
+			out := make([]byte, 1024)
+			if _, err := conn.Read(out); err == nil {
+				if bytes.Compare(out, tc.want) == 0 {
+					t.Error("response did match expected output")
+				}
+			} else {
+				t.Error("could not read from connection")
+			}
+		})
+	}
+}

README.md

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+### DevTheWeb Post Source Code
+
+This repository holds all the source code for the posts and examples given on my personal site: [devtheweb.io](https://devtheweb.io).
+
+To find the code you want, simply find the date of the post you're looking at and navigate through the subfolders: `year/month/subject`.