Implement LISTGROUP command

README.md

@@ -27,7 +27,7 @@
 - :x: `HELP`
 - :x: `IHAVE`
 - :x: `LAST`
-- :x: `LISTGROUP`
+- :heavy_check_mark: `LISTGROUP`
 - :heavy_check_mark: `NEWGROUPS`
 - :x: `NEWNEWS`
 - :x: `NEXT`

internal/backend/sqlite/sqlite.go

@@ -72,17 +72,17 @@ func (sb *SQLiteBackend) ListGroupsByPattern(pattern string) ([]models.Group, er
 	return groups, sb.db.Select(&groups, "SELECT * FROM groups WHERE group_name REGEXP ?", r.String())
 }
 
-func (sb *SQLiteBackend) GetArticlesCount(g models.Group) (int, error) {
+func (sb *SQLiteBackend) GetArticlesCount(g *models.Group) (int, error) {
 	var count int
 	return count, sb.db.Get(&count, "SELECT COUNT(*) FROM articles_to_groups WHERE group_id = ?", g.ID)
 }
 
-func (sb *SQLiteBackend) GetGroupHighWaterMark(g models.Group) (int, error) {
+func (sb *SQLiteBackend) GetGroupHighWaterMark(g *models.Group) (int, error) {
 	var waterMark int
 	return waterMark, sb.db.Get(&waterMark, "SELECT article_id FROM articles_to_groups WHERE group_id = ? ORDER BY article_id DESC LIMIT 1", g.ID)
 }
 
-func (sb *SQLiteBackend) GetGroupLowWaterMark(g models.Group) (int, error) {
+func (sb *SQLiteBackend) GetGroupLowWaterMark(g *models.Group) (int, error) {
 	var waterMark int
 	return waterMark, sb.db.Get(&waterMark, "SELECT article_id FROM articles_to_groups WHERE group_id = ? ORDER BY article_id LIMIT 1", g.ID)
 }
@@ -134,3 +134,29 @@ func (sb *SQLiteBackend) GetArticle(messageID string) (models.Article, error) {
 	}
 	return a, json.Unmarshal([]byte(a.HeaderRaw), &a.Header)
 }
+
+func (sb *SQLiteBackend) GetArticleNumbers(g *models.Group, low, high int64) ([]int64, error) {
+	var numbers []int64
+
+	if high == 0 && low == 0 {
+		if err := sb.db.Select(&numbers, "SELECT article_id FROM articles_to_groups WHERE group_id = ?", g.ID); err != nil {
+			return nil, err
+		}
+	} else if low == -1 && high != 0 {
+		if err := sb.db.Select(&numbers, "SELECT article_id FROM articles_to_groups WHERE group_id = ? AND article_id = ?", g.ID, high); err != nil {
+			return nil, err
+		}
+	} else if low != 0 && high == -1 {
+		if err := sb.db.Select(&numbers, "SELECT article_id FROM articles_to_groups WHERE group_id = ? AND article_id > ?", g.ID, low); err != nil {
+			return nil, err
+		}
+	} else if low == -1 && high == -1 {
+		return nil, nil
+	} else {
+		if err := sb.db.Select(&numbers, "SELECT article_id FROM articles_to_groups WHERE group_id = ? AND article_id > ? AND article_id < ?", g.ID, low, high); err != nil {
+			return nil, err
+		}
+	}
+
+	return numbers, nil
+}

internal/backend/storage_backend.go

@@ -11,9 +11,10 @@ type StorageBackend interface {
 	ListGroupsByPattern(pattern string) ([]models.Group, error)
 	GetGroup(groupName string) (models.Group, error)
 	GetNewGroupsSince(timestamp int64) ([]models.Group, error)
-	GetArticlesCount(g models.Group) (int, error)
+	GetArticlesCount(g *models.Group) (int, error)
-	GetGroupLowWaterMark(g models.Group) (int, error)
+	GetGroupLowWaterMark(g *models.Group) (int, error)
-	GetGroupHighWaterMark(g models.Group) (int, error)
+	GetGroupHighWaterMark(g *models.Group) (int, error)
 	SaveArticle(article models.Article, groups []string) error
 	GetArticle(messageID string) (models.Article, error)
+	GetArticleNumbers(g *models.Group, low, high int64) ([]int64, error)
 }

internal/protocol/constants.go

@@ -55,6 +55,7 @@ const (
 	CommandGroup        = "GROUP"
 	CommandNewGroups    = "NEWGROUPS"
 	CommandPost         = "POST"
+	CommandListGroup    = "LISTGROUP"
 )
 
 const (
@@ -74,7 +75,6 @@ const (
 	MessageNNTPServiceReadyPostingProhibited = "201 YANS NNTP Service Ready, posting prohibited"
 	MessageReaderModePostingProhibited       = "201 Reader mode, posting prohibited"
 	MessageNNTPServiceExitsNormally          = "205 NNTP Service exits normally, bye!"
-	MessageUnknownCommand                    = "500 Unknown command"
 	MessageErrorHappened                     = "403 Failed to process command:"
 	MessageListOfNewsgroupsFollows           = "215 list of newsgroups follows"
 	MessageNoSuchGroup                       = "411 No such newsgroup"

internal/server/handler.go

@@ -7,9 +7,11 @@ import (
 	"github.com/ChronosX88/yans/internal/backend"
 	"github.com/ChronosX88/yans/internal/models"
 	"github.com/ChronosX88/yans/internal/protocol"
+	"github.com/ChronosX88/yans/internal/utils"
 	"github.com/google/uuid"
 	"io"
 	"net/mail"
+	"strconv"
 	"strings"
 	"time"
 )
@@ -32,6 +34,7 @@ func NewHandler(b backend.StorageBackend, serverDomain string) *Handler {
 		protocol.CommandGroup:        h.handleGroup,
 		protocol.CommandNewGroups:    h.handleNewGroups,
 		protocol.CommandPost:         h.handlePost,
+		protocol.CommandListGroup:    h.handleListgroup,
 	}
 	h.serverDomain = serverDomain
 	return h
@@ -85,16 +88,16 @@ func (h *Handler) handleList(s *Session, arguments []string, id uint) error {
 			sb.Write([]byte(protocol.MessageListOfNewsgroupsFollows + protocol.CRLF))
 			for _, v := range groups {
 				// TODO set actual post permission status
-				c, err := h.backend.GetArticlesCount(v)
+				c, err := h.backend.GetArticlesCount(&v)
 				if err != nil {
 					return err
 				}
 				if c > 0 {
-					highWaterMark, err := h.backend.GetGroupHighWaterMark(v)
+					highWaterMark, err := h.backend.GetGroupHighWaterMark(&v)
 					if err != nil {
 						return err
 					}
-					lowWaterMark, err := h.backend.GetGroupLowWaterMark(v)
+					lowWaterMark, err := h.backend.GetGroupLowWaterMark(&v)
 					if err != nil {
 						return err
 					}
@@ -169,15 +172,15 @@ func (h *Handler) handleGroup(s *Session, arguments []string, id uint) error {
 			return err
 		}
 	}
-	highWaterMark, err := h.backend.GetGroupHighWaterMark(g)
+	highWaterMark, err := h.backend.GetGroupHighWaterMark(&g)
 	if err != nil && err != sql.ErrNoRows {
 		return err
 	}
-	lowWaterMark, err := h.backend.GetGroupLowWaterMark(g)
+	lowWaterMark, err := h.backend.GetGroupLowWaterMark(&g)
 	if err != nil && err != sql.ErrNoRows {
 		return err
 	}
-	articlesCount, err := h.backend.GetArticlesCount(g)
+	articlesCount, err := h.backend.GetArticlesCount(&g)
 	if err != nil && err != sql.ErrNoRows {
 		return err
 	}
@@ -230,16 +233,16 @@ func (h *Handler) handleNewGroups(s *Session, arguments []string, id uint) error
 	dw.Write([]byte(protocol.NNTPResponse{Code: 231, Message: "list of new newsgroups follows"}.String() + protocol.CRLF))
 	for _, v := range g {
 		// TODO set actual post permission status
-		c, err := h.backend.GetArticlesCount(v)
+		c, err := h.backend.GetArticlesCount(&v)
 		if err != nil {
 			return err
 		}
 		if c > 0 {
-			highWaterMark, err := h.backend.GetGroupHighWaterMark(v)
+			highWaterMark, err := h.backend.GetGroupHighWaterMark(&v)
 			if err != nil {
 				return err
 			}
-			lowWaterMark, err := h.backend.GetGroupLowWaterMark(v)
+			lowWaterMark, err := h.backend.GetGroupLowWaterMark(&v)
 			if err != nil {
 				return err
 			}
@@ -321,6 +324,66 @@ func (h *Handler) handlePost(s *Session, arguments []string, id uint) error {
 	return s.tconn.PrintfLine(protocol.MessageArticleReceived)
 }
 
+func (h *Handler) handleListgroup(s *Session, arguments []string, id uint) error {
+	s.tconn.StartResponse(id)
+	defer s.tconn.EndResponse(id)
+
+	currentGroup := s.currentGroup
+	var low, high int64
+	if len(arguments) == 1 {
+		g, err := h.backend.GetGroup(arguments[0])
+		if err != nil {
+			return s.tconn.PrintfLine(protocol.NNTPResponse{Code: 411, Message: "No such newsgroup"}.String())
+		}
+		currentGroup = &g
+	} else if len(arguments) == 2 {
+		g, err := h.backend.GetGroup(arguments[0])
+		if err != nil {
+			return s.tconn.PrintfLine(protocol.NNTPResponse{Code: 411, Message: "No such newsgroup"}.String())
+		}
+		currentGroup = &g
+
+		low, high, err = utils.ParseRange(arguments[1])
+		if err != nil {
+			low = 0
+			high = 0
+		}
+		if high != -1 && low > high {
+			low = -1
+			high = -1
+		}
+	}
+
+	if currentGroup == nil {
+		return s.tconn.PrintfLine(protocol.NNTPResponse{Code: 412, Message: "No newsgroup selected"}.String())
+	}
+
+	highWaterMark, err := h.backend.GetGroupHighWaterMark(currentGroup)
+	if err != nil && err != sql.ErrNoRows {
+		return err
+	}
+	lowWaterMark, err := h.backend.GetGroupLowWaterMark(currentGroup)
+	if err != nil && err != sql.ErrNoRows {
+		return err
+	}
+	articlesCount, err := h.backend.GetArticlesCount(currentGroup)
+	if err != nil && err != sql.ErrNoRows {
+		return err
+	}
+
+	nums, err := h.backend.GetArticleNumbers(currentGroup, low, high)
+	if err != nil && err != sql.ErrNoRows {
+		return err
+	}
+
+	dw := s.tconn.DotWriter()
+	dw.Write([]byte(protocol.NNTPResponse{Code: 211, Message: fmt.Sprintf("%d %d %d %s list follows%s", articlesCount, lowWaterMark, highWaterMark, currentGroup.GroupName, protocol.CRLF)}.String()))
+	for _, v := range nums {
+		dw.Write([]byte(strconv.FormatInt(v, 10) + protocol.CRLF))
+	}
+	return dw.Close()
+}
+
 func (h *Handler) Handle(s *Session, message string, id uint) error {
 	splittedMessage := strings.Split(message, " ")
 	for i, v := range splittedMessage {
@@ -331,7 +394,7 @@ func (h *Handler) Handle(s *Session, message string, id uint) error {
 	if !ok {
 		s.tconn.StartResponse(id)
 		defer s.tconn.EndResponse(id)
-		return s.tconn.PrintfLine(protocol.MessageUnknownCommand)
+		return s.tconn.PrintfLine(protocol.NNTPResponse{Code: 500, Message: "Unknown command"}.String())
 	}
 	return handler(s, splittedMessage[1:], id)
 }

internal/utils/range.go

@@ -0,0 +1,27 @@
+package utils
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+func ParseRange(spec string) (int64, int64, error) {
+	if spec == "" {
+		return 0, 0, fmt.Errorf("no range specified")
+	}
+	parts := strings.Split(spec, "-")
+	if len(parts) == 1 {
+		h, err := strconv.ParseInt(parts[0], 10, 64)
+		return -1, h, err
+	}
+	l, err := strconv.ParseInt(parts[0], 10, 64)
+	if err != nil {
+		return 0, 0, err
+	}
+	if parts[1] == "" {
+		return l, -1, nil
+	}
+	h, err := strconv.ParseInt(parts[1], 10, 64)
+	return l, h, err
+}