Merge pull request #11 from DimVlas/hw11_telnet_client

Hw11 telnet client

hw09_struct_validator/rules/errors.go

@@ -16,10 +16,6 @@ var (
 
 var (
 	// программные ошибки функций валидации.
-	// // правило применимо только к строкам
-	// ErrOnlyStringRule = errors.New("rule applies only to the string")
-	// // правило применимо только к целым
-	// ErrOnlyIntRule = errors.New("rule applies only to the int")
 	// недопустимое условие для правила.
 	ErrInvalidCond = errors.New("invalid condition for the rule")
 	// ошибка компиляции регулярного выражения.
@@ -40,7 +36,7 @@ var (
 var (
 	// целое не может быть меньше условия.
 	ErrIntCantBeLess = errors.New("cannot be less")
-	// целое не может быть меньше больше.
+	// целое не может быть больше условия.
 	ErrIntCantBeGreater = errors.New("cannot be greater")
 	// целое на входит в список.
 	ErrIntNotInList = errors.New("int is not in the list")

hw09_struct_validator/validator.go

@@ -7,18 +7,6 @@ import (
 	r "github.com/DimVlas/otus_hw/hw09_struct_validator/rules"
 )
 
-// implemented in errors.go file
-// type ValidationError struct {
-// 	Field string
-// 	Err   error
-// }
-
-// type ValidationErrors []ValidationError
-
-// func (v ValidationErrors) Error() string {
-// 	panic("implement me")
-// }
-
 func Validate(v interface{}) error {
 	// nothing to validate
 	if v == nil {

hw09_struct_validator/validator_test.go

@@ -10,7 +10,6 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-// Test the function on different structures and other types.
 type (
 	UserRole string
 

hw11_telnet_client/go.mod

@@ -1,4 +1,4 @@
-module github.com/fixme_my_friend/hw11_telnet_client
+module github.com/DimVlas/otus_hw/hw11_telnet_client
 
 go 1.22
 

hw11_telnet_client/main.go

@@ -1,6 +1,92 @@
 package main
 
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"path"
+	"syscall"
+	"time"
+)
+
+var (
+	ErrParseArgs = errors.New("parse args error")
+	// соединение не установлено.
+	ErrConnNotEstablish = errors.New("connection is not established")
+	// завершение клиента.
+	ErrClientExit = errors.New("connection was closed by client")
+	// завершение сервера.
+	ErrServerExit = errors.New("connection was closed by peer")
+)
+
 func main() {
-	// Place your code here,
-	// P.S. Do not rush to throw context down, think think if it is useful with blocking operation?
+	var (
+		timeout time.Duration
+		host    string
+		port    int
+	)
+
+	if err := parseArgs(os.Args[1:], &timeout, &host, &port); err != nil {
+		log.Println(err)
+		log.Println("Usage: go-telnet [--timeout=<timeout>] <host> <port>")
+		os.Exit(1)
+	}
+
+	addr := fmt.Sprintf("%s:%d", host, port)
+	client := NewTelnetClient(addr, timeout, os.Stdin, os.Stdout)
+
+	if err := client.Connect(); err != nil {
+		log.Fatalln(err)
+	}
+
+	log.Printf("...Connected to %s", addr)
+
+	c := make(chan os.Signal, 1)
+	clientErr := make(chan error)
+
+	defer func() {
+		client.Close()
+		close(c)
+		close(clientErr)
+	}()
+
+	signal.Notify(c, syscall.SIGINT)
+
+	go func() {
+		err := client.Send()
+		if err != nil {
+			clientErr <- err
+			return
+		}
+
+		clientErr <- ErrClientExit
+	}()
+
+	go func() {
+		err := client.Receive()
+		if err != nil {
+			clientErr <- err
+			return
+		}
+		clientErr <- ErrServerExit
+	}()
+
+	select {
+	case <-c:
+		log.Println("...Connection was closed by", path.Base(os.Args[0]))
+		return
+	case err := <-clientErr:
+		if errors.Is(err, ErrClientExit) {
+			log.Println("...EOF")
+			return
+		}
+		if errors.Is(err, ErrServerExit) {
+			log.Println("...Connection was closed by peer")
+			return
+		}
+		log.Println(err)
+		return
+	}
 }

hw11_telnet_client/params.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"bytes"
+	"errors"
+	"flag"
+	"fmt"
+	"regexp"
+	"strconv"
+	"time"
+)
+
+func parseArgs(args []string, timeout *time.Duration, host *string, port *int) error {
+	fs := flag.NewFlagSet("telnet", flag.ContinueOnError)
+	fs.SetOutput(bytes.NewBuffer(nil))
+
+	fs.DurationVar(timeout, "timeout", 10*time.Second, "Connection timeout")
+	if err := fs.Parse(args); err != nil {
+		return fmt.Errorf("%w: %w", ErrParseArgs, err)
+	}
+
+	if fs.NArg() != 2 {
+		return fmt.Errorf("%w: %w", ErrParseArgs, errors.New("not enough arguments"))
+	}
+
+	h := fs.Arg(0)
+	b, _ := regexp.MatchString(`^[A-Za-z0-9-.]+$`, h)
+	if !b {
+		return fmt.Errorf("%w %w", ErrParseArgs, errors.New("host: string \""+h+"\" cannot be a host name or address"))
+	}
+	*host = h
+
+	p, err := strconv.Atoi(fs.Arg(1))
+	if err != nil {
+		return fmt.Errorf("%w %w", ErrParseArgs, fmt.Errorf("port: %w", err))
+	}
+	*port = p
+
+	return nil
+}

hw11_telnet_client/telnet.go

@@ -1,7 +1,10 @@
 package main
 
 import (
+	"bufio"
+	"errors"
 	"io"
+	"net"
 	"time"
 )
 
@@ -13,9 +16,70 @@ type TelnetClient interface {
 }
 
 func NewTelnetClient(address string, timeout time.Duration, in io.ReadCloser, out io.Writer) TelnetClient {
-	// Place your code here.
+	return &telnetClient{
+		addr:    address,
+		timeout: timeout,
+		in:      in,
+		out:     out,
+	}
+}
+
+type telnetClient struct {
+	timeout time.Duration
+	addr    string
+	conn    net.Conn
+	in      io.ReadCloser
+	out     io.Writer
+}
+
+func (tc *telnetClient) Connect() (err error) {
+	tc.conn, err = net.DialTimeout("tcp", tc.addr, tc.timeout)
+	return
+}
+
+func (tc *telnetClient) Close() error {
+	if tc.conn != nil {
+		return tc.conn.Close()
+	}
 	return nil
 }
 
-// Place your code here.
-// P.S. Author's solution takes no more than 50 lines.
+func (tc *telnetClient) Send() error {
+	if tc.conn == nil {
+		return ErrConnNotEstablish
+	}
+
+	scanner := bufio.NewScanner(tc.in)
+	for scanner.Scan() {
+		mess := append(scanner.Bytes(), '\n')
+		if _, err := tc.conn.Write(mess); err != nil {
+			return err
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (tc *telnetClient) Receive() error {
+	if tc.conn == nil {
+		return ErrConnNotEstablish
+	}
+
+	reader := bufio.NewReader(tc.conn)
+	for {
+		message, err := reader.ReadBytes('\n')
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				return nil
+			}
+			return err
+		}
+		_, err = tc.out.Write(message)
+		if err != nil {
+			return err
+		}
+	}
+}