Better CAPABILITIES command implementation using declared types, use textproto package for connection i/o

cmd/yans/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"flag"
+	"github.com/ChronosX88/yans/internal/common"
 	"github.com/ChronosX88/yans/internal/config"
 	"github.com/ChronosX88/yans/internal/server"
 	"log"
@@ -26,7 +27,7 @@ func main() {
 	c := make(chan os.Signal, 1)
 	signal.Notify(c, os.Interrupt)
 
-	log.Println("Starting YANS...")
+	log.Printf("Starting %s...", common.ServerName)
 	ns, err := server.NewNNTPServer(cfg)
 	if err != nil {
 		log.Fatal(err)
@@ -35,10 +36,11 @@ func main() {
 	if err := ns.Start(); err != nil {
 		log.Fatal(err)
 	}
-	log.Println("YANS has been successfully started!")
+	log.Printf("%s has been successfully started!", common.ServerName)
+	log.Printf("Version: %s", common.ServerVersion)
 
 	for range c {
-		log.Println("Stopping YANS...")
+		log.Printf("Stopping %s...", common.ServerName)
 		ns.Stop()
 		break
 	}

internal/common/const.go

@@ -0,0 +1,6 @@
+package common
+
+const (
+	ServerName    = "YANS"
+	ServerVersion = "0.0.1"
+)

internal/protocol/capabilities.go

@@ -0,0 +1,80 @@
+package protocol
+
+import (
+	"fmt"
+	"strings"
+)
+
+type CapabilityType int
+
+const (
+	VersionCapability CapabilityType = iota
+	ReaderCapability
+	IHaveCapability
+	PostCapability
+	NewNewsCapability
+	HdrCapability
+	OverCapability
+	ListCapability
+	ImplementationCapability
+	ModeReaderCapability
+)
+
+func (ct CapabilityType) String() string {
+	switch ct {
+	case VersionCapability:
+		return CapabilityNameVersion
+	case ReaderCapability:
+		return CapabilityNameReader
+	case IHaveCapability:
+		return CapabilityNameIHave
+	case PostCapability:
+		return CapabilityNamePost
+	case NewNewsCapability:
+		return CapabilityNameNewNews
+	case HdrCapability:
+		return CapabilityNameHdr
+	case OverCapability:
+		return CapabilityNameOver
+	case ListCapability:
+		return CapabilityNameList
+	case ImplementationCapability:
+		return CapabilityNameImplementation
+	case ModeReaderCapability:
+		return CapabilityNameModeReader
+	default:
+		return ""
+	}
+}
+
+type Capability struct {
+	Type   CapabilityType
+	Params string // optional
+}
+
+type Capabilities []Capability
+
+func (cs Capabilities) Add(c Capability) {
+	for _, v := range cs {
+		if v.Type == c.Type {
+			return // allowed only unique items
+		}
+	}
+	cs = append(cs, c)
+}
+
+func (cs Capabilities) String() string {
+	sb := strings.Builder{}
+	sb.Write([]byte("101 Capability list:" + CRLF))
+
+	for _, v := range cs {
+		if v.Params != "" {
+			sb.Write([]byte(fmt.Sprintf("%s %s%s", v.Type, v.Params, CRLF)))
+		} else {
+			sb.Write([]byte(fmt.Sprintf("%s%s", v.Type, CRLF)))
+		}
+	}
+	sb.Write([]byte(MultilineEnding))
+
+	return sb.String()
+}

internal/protocol/constants.go

@@ -1,5 +1,10 @@
 package protocol
 
+const (
+	CRLF            = "\r\n"
+	MultilineEnding = "."
+)
+
 const (
 	CommandCapabilities = "CAPABILITIES"
 	CommandQuit         = "QUIT"
@@ -9,9 +14,23 @@ const (
 )
 
 const (
-	MessageNNTPServiceReadyPostingProhibited = "201 YANS NNTP Service Ready, posting prohibited\n"
+	CapabilityNameVersion        = "VERSION"
+	CapabilityNameReader         = "READER"
+	CapabilityNameIHave          = "IHAVE"
+	CapabilityNamePost           = "POST"
+	CapabilityNameNewNews        = "NEWNEWS"
+	CapabilityNameHdr            = "HDR"
+	CapabilityNameOver           = "OVER"
+	CapabilityNameList           = "LIST"
+	CapabilityNameImplementation = "IMPLEMENTATION"
+	CapabilityNameModeReader     = "MODE-READER"
+)
+
+const (
+	MessageNNTPServiceReadyPostingProhibited = "201 YANS NNTP Service Ready, posting prohibited"
 	MessageReaderModePostingProhibited       = "201 Reader mode, posting prohibited"
 	MessageNNTPServiceExitsNormally          = "205 NNTP Service exits normally"
 	MessageUnknownCommand                    = "500 Unknown command"
 	MessageErrorHappened                     = "403 Failed to process command: "
+	MessageListOfNewsgroupsFollows           = "215 list of newsgroups follows"
 )

internal/server/nntp_server.go

@@ -1,10 +1,10 @@
 package server
 
 import (
-	"bufio"
 	"context"
 	"fmt"
 	"github.com/ChronosX88/yans/internal"
+	"github.com/ChronosX88/yans/internal/common"
 	"github.com/ChronosX88/yans/internal/config"
 	"github.com/ChronosX88/yans/internal/models"
 	"github.com/ChronosX88/yans/internal/protocol"
@@ -14,10 +14,20 @@ import (
 	"io"
 	"log"
 	"net"
+	"net/textproto"
 	"strings"
 	"time"
 )
 
+var (
+	Capabilities = protocol.Capabilities{
+		{Type: protocol.VersionCapability, Params: "2"},
+		{Type: protocol.ImplementationCapability, Params: fmt.Sprintf("%s %s", common.ServerName, common.ServerVersion)},
+		{Type: protocol.ModeReaderCapability},
+		{Type: protocol.ListCapability, Params: "ACTIVE NEWSGROUPS"},
+	}
+)
+
 type NNTPServer struct {
 	ctx        context.Context
 	cancelFunc context.CancelFunc
@@ -81,19 +91,21 @@ func (ns *NNTPServer) Start() error {
 }
 
 func (ns *NNTPServer) handleNewConnection(ctx context.Context, conn net.Conn) {
-	_, err := conn.Write([]byte(protocol.MessageNNTPServiceReadyPostingProhibited))
+	_, err := conn.Write([]byte(protocol.MessageNNTPServiceReadyPostingProhibited + protocol.CRLF))
 	if err != nil {
 		log.Print(err)
 		conn.Close()
 		return
 	}
+
+	tconn := textproto.NewConn(conn)
 	for {
 		select {
 		case <-ctx.Done():
 			break
 		default:
 			{
-				message, err := bufio.NewReader(conn).ReadString('\n')
+				message, err := tconn.ReadLine()
 				if err != nil {
 					if err == io.EOF || err.(*net.OpError).Unwrap() == net.ErrClosed {
 						log.Printf("Client %s has diconnected!", conn.RemoteAddr().String())
@@ -104,7 +116,7 @@ func (ns *NNTPServer) handleNewConnection(ctx context.Context, conn net.Conn) {
 					return
 				}
 				log.Printf("Received message from %s: %s", conn.RemoteAddr().String(), string(message))
-				err = ns.handleMessage(conn, message)
+				err = ns.handleMessage(tconn, message)
 				if err != nil {
 					log.Print(err)
 					conn.Close()
@@ -115,8 +127,7 @@ func (ns *NNTPServer) handleNewConnection(ctx context.Context, conn net.Conn) {
 	}
 }
 
-func (ns *NNTPServer) handleMessage(conn net.Conn, msg string) error {
+func (ns *NNTPServer) handleMessage(conn *textproto.Conn, msg string) error {
-	msg = strings.TrimSuffix(msg, "\r\n")
 	splittedMessage := strings.Split(msg, " ")
 	command := splittedMessage[0]
 
@@ -126,7 +137,7 @@ func (ns *NNTPServer) handleMessage(conn net.Conn, msg string) error {
 	switch command {
 	case protocol.CommandCapabilities:
 		{
-			reply = "101 Capability list:\r\nVERSION 2\r\nIMPLEMENTATION\r\n."
+			reply = Capabilities.String()
 			break
 		}
 	case protocol.CommandDate:
@@ -158,11 +169,11 @@ func (ns *NNTPServer) handleMessage(conn net.Conn, msg string) error {
 				log.Println(err)
 			}
 			sb := strings.Builder{}
-			sb.Write([]byte("215 list of newsgroups follows\n"))
+			sb.Write([]byte(protocol.MessageListOfNewsgroupsFollows + protocol.CRLF))
 			if len(splittedMessage) == 1 || splittedMessage[1] == "ACTIVE" {
 				for _, v := range groups {
 					// TODO set high/low mark and posting status to actual values
-					sb.Write([]byte(fmt.Sprintf("%s 0 0 n\r\n", v.GroupName)))
+					sb.Write([]byte(fmt.Sprintf("%s 0 0 n"+protocol.CRLF, v.GroupName)))
 				}
 			} else if splittedMessage[1] == "NEWSGROUPS" {
 				for _, v := range groups {
@@ -189,7 +200,7 @@ func (ns *NNTPServer) handleMessage(conn net.Conn, msg string) error {
 		}
 	}
 
-	_, err := conn.Write([]byte(reply + "\r\n"))
+	err := conn.PrintfLine(reply)
 	if quit {
 		conn.Close()
 	}