├── .gitignore
├── README.md
└── main.go


/.gitignore:
--------------------------------------------------------------------------------
1 | jungle_smtp
2 | 


--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
1 | # jungle_smtp
2 | 
3 | golang smtp server that just writes every incoming email to a text file 
4 | 
5 | 
6 | 


--------------------------------------------------------------------------------
/main.go:
--------------------------------------------------------------------------------
 1 | package main
 2 | 
 3 | import "net"
 4 | import "fmt"
 5 | import "bufio"
 6 | import "time"
 7 | import "os"
 8 | import "io"
 9 | 
10 | type Client struct {
11 | 	conn    net.Conn
12 | 	address string
13 | 	time    int64
14 | 	bufin   *bufio.Reader
15 | 	bufout  *bufio.Writer
16 | }
17 | 
18 | func (c *Client) w(s string) {
19 | 	c.bufout.WriteString(s + "\r\n")
20 | 	c.bufout.Flush()
21 | }
22 | func (c *Client) r() string {
23 | 	reply, err := c.bufin.ReadString('\n')
24 | 	if err != nil {
25 | 		fmt.Println("e ", err)
26 | 	}
27 | 	return reply
28 | }
29 | 
30 | func appendToFile(text string) {
31 | 	of, _ := os.OpenFile("incoming_emails.txt", os.O_CREATE|os.O_APPEND|os.O_RDWR, 0660)
32 | 	defer of.Close()
33 | 	of.Seek(0, os.SEEK_END)
34 | 	io.WriteString(of, text+"\n")
35 | }
36 | 
37 | func handleClient(c *Client) {
38 | 	fmt.Println("here")
39 | 	c.w("220 Welcome to the Jungle")
40 | 	text := c.r()
41 | 	appendToFile(text)
42 | 	c.w("250 No one says helo anymore")
43 | 	text = c.r()
44 | 	appendToFile(text)
45 | 	c.w("250 Sender")
46 | 	text = c.r()
47 | 	appendToFile(text)
48 | 	c.w("250 Recipient")
49 | 	text = c.r()
50 | 	appendToFile(text)
51 | 	c.w("354 Ok Send data ending with <CRLF>.<CRLF>")
52 | 	for {
53 | 		text = c.r()
54 | 		bytes := []byte(text)
55 | 		appendToFile(text)
56 | 		// 46 13 10
57 | 		if bytes[0] == 46 && bytes[1] == 13 && bytes[2] == 10 {
58 | 			break
59 | 		}
60 | 	}
61 | 	c.w("250 server has transmitted the message")
62 | 	c.conn.Close()
63 | }
64 | 
65 | func main() {
66 | 	listener, err := net.Listen("tcp", "0.0.0.0:25")
67 | 	if err != nil {
68 | 		fmt.Println("run as root")
69 | 		return
70 | 	}
71 | 
72 | 	for {
73 | 		fmt.Println("waiting...")
74 | 		conn, err := listener.Accept()
75 | 		if err != nil {
76 | 			continue
77 | 		}
78 | 		go handleClient(&Client{
79 | 			conn:    conn,
80 | 			address: conn.RemoteAddr().String(),
81 | 			time:    time.Now().Unix(),
82 | 			bufin:   bufio.NewReader(conn),
83 | 			bufout:  bufio.NewWriter(conn),
84 | 		})
85 | 	}
86 | }
87 | 


--------------------------------------------------------------------------------