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package main
import (
"encoding/json"
"errors"
"fmt"
"log"
"net"
"sync"
"time"
)
func readRequest(conn net.Conn) (Request, error) {
// 1 мегабайт
var maxBodySize uint32 = 1048576
var message Request
var err error
buf := make([]byte, 4096)
_, err = conn.Read(buf)
if err != nil {
return message, err
}
size := fromBytes(buf[:4])
if size > maxBodySize {
resp, _ := json.Marshal(Response{
Status: FAILURE,
Data: "Превышен максимальный размер запроса",
})
_ = sendMessage(conn, resp)
return message, errors.New("body size exceeded")
}
rawMessage := buf[4 : size+4]
return parseRequest(rawMessage)
}
func handleAuthentication(conn net.Conn) bool {
maxAuthAttempts := 5
authAttempts := 0
authenticated := false
for {
if authAttempts >= maxAuthAttempts {
resp, _ := json.Marshal(Response{
Status: FAILURE,
Data: "Превышено количество неавторизованных запросов",
})
_ = sendMessage(conn, resp)
break
}
message, err := readRequest(conn)
if err != nil {
break
}
authAttempts += 1
if message.Type == AUTHENTICATE {
// TODO(andrew): Добавить процесс аутентификации
if true {
authenticated = true
resp, _ := json.Marshal(Response{
Status: SUCCESS,
Data: "Аутентификация прошла успешно",
})
_ = sendMessage(conn, resp)
break
} else {
resp, _ := json.Marshal(Response{
Status: FAILURE,
Data: "При аутентификации произошла ошибка",
})
_ = sendMessage(conn, resp)
}
continue
}
resp, _ := json.Marshal(Response{
Status: FAILURE,
Data: "Для работы с сервером необходима аутентификация",
})
err = sendMessage(conn, resp)
if err != nil {
break
}
}
return authenticated
}
func handleConnection(conn net.Conn, c chan Request) {
defer conn.Close()
authenticated := handleAuthentication(conn)
if authenticated {
for {
message, err := readRequest(conn)
if err != nil {
break
}
channelLock.Lock()
c <- message
fmt.Printf("Got new message from %s: %s\n", message.User, message.Data)
if message.Type == EXIT {
break
}
resp, _ := json.Marshal(Response{
Status: SUCCESS,
Data: "some data",
})
err = sendMessage(conn, resp)
if err != nil {
break
}
}
}
fmt.Println("Closed connection (receiver handler)")
//received.RLock()
//sz := len(received.data)
//received.RUnlock()
//fmt.Printf("There is %d messages in storage\n", sz)
}
func reader(c chan Request) {
//const maxMessages uint64 = 65536
//var count uint64 = 0
for {
//fmt.Println("Waiting for message")
data := <-c
channelLock.Unlock()
//fmt.Println("Received message:", data.Data)
received.Lock()
//fmt.Println("Locked received")
//if count >= maxMessages {
// received.data = []Request{data}
// received.messageShift += maxMessages
//} else {
// received.data = append(received.data, data)
// count += 1
//}
received.data = append(received.data, data)
received.Unlock()
//fmt.Println("Unlocked received")
}
}
func handleSender(conn net.Conn) {
defer conn.Close()
authenticated := handleAuthentication(conn)
if !authenticated {
fmt.Println("Sender is not authenticated")
return
}
fmt.Println("Sender is authenticated")
lastIndex := 0
for {
var message Request
idx := uint64(lastIndex)
if idx < uint64(len(received.data)) {
received.RLock()
message = received.data[idx]
received.RUnlock()
resp, _ := json.Marshal(Response{
Status: SUCCESS,
Data: message.serialize(),
})
err := sendMessage(conn, resp)
if err != nil {
fmt.Printf("Failed to send %d: %s\n", idx, err)
break
} else {
message, err := readRequest(conn)
if err != nil {
break
}
if message.Data == SUCCESS {
lastIndex += 1
}
}
} else {
resp, _ := json.Marshal(Response{
Status: PING,
Data: PING,
})
err := sendMessage(conn, resp)
if err != nil {
fmt.Println("Closed connection (sender handler)")
break
}
time.Sleep(100 * time.Millisecond)
continue
}
}
}
var received struct {
sync.RWMutex
data []Request
}
var channelLock sync.Mutex
func main() {
var wg sync.WaitGroup
c := make(chan Request)
go reader(c)
sock, err := net.Listen("tcp", "localhost:8080")
handleError(err)
defer sock.Close()
wg.Add(1)
go func(sock net.Listener) {
for {
conn, err := sock.Accept()
if err == nil {
go handleConnection(conn, c)
} else {
break
}
}
wg.Done()
}(sock)
senderSock, err := net.Listen("tcp", "localhost:8081")
handleError(err)
defer senderSock.Close()
wg.Add(1)
go func(sock net.Listener) {
for {
conn, err := sock.Accept()
if err == nil {
go handleSender(conn)
} else {
break
}
}
wg.Done()
}(senderSock)
wg.Wait()
}
func handleError(err error) {
if err != nil {
log.Fatal(err)
}
}
|
