refactor: update message handling to support pagination with limit and timestamp

Readme.md

@@ -10,14 +10,14 @@
   - [ ] status
   - [ ] bio
   - [ ] profile picture
-- [ ] provide user info
+- [x] provide user info
 - manage rights and roles
   - [ ] edit roles
   - [ ] bind roles to users
 - manage messages
-  - [ ] send
+  - [x] send
-  - [ ] alert
+  - [x] alert
-  - [ ] query
+  - [x] query
 - files
   - [ ] upload
   - [ ] serve

api/chat.go

@@ -4,13 +4,17 @@ import (
 	"fmt"
 	"net/http"
 	"strconv"
+	"time"
 
 	"git.tek.govt.hu/dowerx/chat/server/model"
 	"github.com/gin-gonic/gin"
 	"github.com/gorilla/websocket"
 )
 
-const CHANNEL_ID string = "id"
+const (
+	CHANNEL_ID            string = "id"
+	DEFAULT_MESSAGE_LIMIT int    = 100
+)
 
 var upgrader = websocket.Upgrader{
 	ReadBufferSize:  1024,
@@ -42,7 +46,36 @@ func getMessages(c *gin.Context) {
 		return
 	}
 
-	messages, msgErr := chatController.GetMessages(id)
+	limitStr := c.Query("limit")
+	fromStr := c.Query("from")
+
+	var limit int = DEFAULT_MESSAGE_LIMIT
+	var from time.Time = time.Now().UTC()
+	var parseErr error
+
+	if limitStr != "" {
+		limit, parseErr = strconv.Atoi(limitStr)
+		if parseErr != nil {
+			c.JSON(http.StatusBadRequest, gin.H{
+				"error": "invalid limit parameter",
+			})
+			return
+		}
+	}
+
+	if fromStr != "" {
+		from, parseErr = time.Parse(time.RFC3339, fromStr)
+		if parseErr != nil {
+			c.JSON(http.StatusBadRequest, gin.H{
+				"error": "invalid from parameter",
+			})
+			return
+		}
+	}
+
+	fmt.Println(from, limit)
+
+	messages, msgErr := chatController.GetMessages(id, from, limit)
 	if msgErr != nil {
 		sendError(c, msgErr)
 		return

controller/ChatController.go

@@ -26,8 +26,8 @@ func (c ChatController) ListAvailableChannels(token string) ([]model.Channel, *u
 	return c.channelDAO.ListAvailableChannels(userID)
 }
 
-func (c ChatController) GetMessages(channel int) ([]model.Message, *util.ChatError) {
+func (c ChatController) GetMessages(channel int, from time.Time, limit int) ([]model.Message, *util.ChatError) {
-	return c.messageDAO.List(model.Channel{ID: channel})
+	return c.messageDAO.List(model.Channel{ID: channel}, from, limit)
 }
 
 func (c ChatController) SendMessage(token string, channel int, content string) *util.ChatError {

dao/IMessageDAO.go

@@ -1,6 +1,8 @@
 package dao
 
 import (
+	"time"
+
 	"git.tek.govt.hu/dowerx/chat/server/model"
 	"git.tek.govt.hu/dowerx/chat/server/util"
 )
@@ -8,7 +10,7 @@ import (
 type IMessageDAO interface {
 	Create(message model.Message) (int, *util.ChatError)
 	Read(id int) (model.Message, *util.ChatError)
-	List(channel model.Channel) ([]model.Message, *util.ChatError)
+	List(channel model.Channel, from time.Time, limit int) ([]model.Message, *util.ChatError)
 	Update(message model.Message) *util.ChatError
 	Delete(id int) *util.ChatError
 }

dao/postgres/MessageDAO.go

@@ -1,6 +1,9 @@
 package postgres
 
 import (
+	"slices"
+	"time"
+
 	"git.tek.govt.hu/dowerx/chat/server/model"
 	"git.tek.govt.hu/dowerx/chat/server/util"
 	"github.com/jmoiron/sqlx"
@@ -50,9 +53,18 @@ func (d MessageDAO) Read(id int) (model.Message, *util.ChatError) {
 }
 
 // List all messages in channel by ID or name
-func (d MessageDAO) List(channel model.Channel) ([]model.Message, *util.ChatError) {
+func (d MessageDAO) List(channel model.Channel, from time.Time, limit int) ([]model.Message, *util.ChatError) {
+
+	type queryInfo struct {
+		ID    int       `db:"id"`
+		Name  string    `db:"name"`
+		From  time.Time `db:"from"`
+		Limit int       `db:"limit"`
+	}
+
 	var rows *sqlx.Rows
 	var err error
+
 	if channel.ID != 0 {
 		rows, err = d.db.NamedQuery(
 			`select
@@ -63,8 +75,10 @@ func (d MessageDAO) List(channel model.Channel) ([]model.Message, *util.ChatErro
 				"m"."content" as "content"
 			from "message" as "m"
 			inner join "user" "u" on "u"."id" = "m"."sender_id"
-			where "m"."channel_id" = :id order by "time"`,
+			where "m"."channel_id" = :id and "m"."time" < :from
-			&channel)
+			order by "time" desc
+			limit :limit`,
+			&queryInfo{ID: channel.ID, From: from, Limit: limit})
 	} else {
 		rows, err = d.db.NamedQuery(
 			`select
@@ -76,8 +90,10 @@ func (d MessageDAO) List(channel model.Channel) ([]model.Message, *util.ChatErro
 			from "message" as "m"
 			inner join "user" "u" on "u"."id" = "m"."sender_id"
 			inner join "channel" "c" on "c"."id" = "m"."channel_id"
-			where "c"."name" = :name order by "time"`,
+			where "c"."name" = :name and "m"."time" < :from
-			&channel)
+			order by "time" desc
+			limit :limit`,
+			&queryInfo{Name: channel.Name, From: from, Limit: limit})
 	}
 
 	if err != nil {
@@ -98,6 +114,7 @@ func (d MessageDAO) List(channel model.Channel) ([]model.Message, *util.ChatErro
 		messages = append(messages, message)
 	}
 
+	slices.Reverse(messages)
 	return messages, util.MakeError(err, util.DATABASE_QUERY_FAULT)
 }