1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
|
package fzf
import (
"bufio"
"bytes"
"errors"
"fmt"
"net"
"strconv"
"strings"
"time"
)
const (
crlf = "\r\n"
httpOk = "HTTP/1.1 200 OK" + crlf
httpBadRequest = "HTTP/1.1 400 Bad Request" + crlf
httpReadTimeout = 10 * time.Second
maxContentLength = 1024 * 1024
)
func startHttpServer(port int, channel chan []*action) error {
if port == 0 {
return nil
}
listener, err := net.Listen("tcp", fmt.Sprintf("localhost:%d", port))
if err != nil {
return fmt.Errorf("port not available: %d", port)
}
go func() {
for {
conn, err := listener.Accept()
if err != nil {
if errors.Is(err, net.ErrClosed) {
break
} else {
continue
}
}
conn.Write([]byte(handleHttpRequest(conn, channel)))
conn.Close()
}
listener.Close()
}()
return nil
}
// Here we are writing a simplistic HTTP server without using net/http
// package to reduce the size of the binary.
//
// * No --listen: 2.8MB
// * --listen with net/http: 5.7MB
// * --listen w/o net/http: 3.3MB
func handleHttpRequest(conn net.Conn, channel chan []*action) string {
contentLength := 0
body := ""
bad := func(message string) string {
message += "\n"
return httpBadRequest + fmt.Sprintf("Content-Length: %d%s", len(message), crlf+crlf+message)
}
conn.SetReadDeadline(time.Now().Add(httpReadTimeout))
scanner := bufio.NewScanner(conn)
scanner.Split(func(data []byte, atEOF bool) (int, []byte, error) {
found := bytes.Index(data, []byte(crlf))
if found >= 0 {
token := data[:found+len(crlf)]
return len(token), token, nil
}
if atEOF || len(body)+len(data) >= contentLength {
return 0, data, bufio.ErrFinalToken
}
return 0, nil, nil
})
section := 0
for scanner.Scan() {
text := scanner.Text()
switch section {
case 0:
if !strings.HasPrefix(text, "POST / HTTP") {
return bad("invalid request method")
}
section++
case 1:
if text == crlf {
if contentLength == 0 {
return bad("content-length header missing")
}
section++
continue
}
pair := strings.SplitN(text, ":", 2)
if len(pair) == 2 && strings.ToLower(pair[0]) == "content-length" {
length, err := strconv.Atoi(strings.TrimSpace(pair[1]))
if err != nil || length <= 0 || length > maxContentLength {
return bad("invalid content length")
}
contentLength = length
}
case 2:
body += text
}
}
if len(body) < contentLength {
return bad("incomplete request")
}
body = body[:contentLength]
errorMessage := ""
actions := parseSingleActionList(strings.Trim(string(body), "\r\n"), func(message string) {
errorMessage = message
})
if len(errorMessage) > 0 {
return bad(errorMessage)
}
if len(actions) == 0 {
return bad("no action specified")
}
channel <- actions
return httpOk
}
|
