Adam French
8e50537333
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109 lines
1.9 KiB
Go
109 lines
1.9 KiB
Go
package services
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import (
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"net/http"
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"strings"
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"sync"
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"time"
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"adam-french.co.uk/backend/models"
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"gorm.io/gorm"
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"github.com/gorilla/websocket"
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)
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const maxMessages = 50
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var allowedDomain string
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var Upgrader = websocket.Upgrader{
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ReadBufferSize: 1024,
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WriteBufferSize: 1024,
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CheckOrigin: func(r *http.Request) bool {
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origin := r.Header.Get("Origin")
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if origin == "" {
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return false
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}
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origin = strings.TrimPrefix(origin, "https://")
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origin = strings.TrimPrefix(origin, "http://")
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return origin == allowedDomain || origin == "www."+allowedDomain
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},
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}
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var (
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clients = make(map[*websocket.Conn]bool)
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mu sync.Mutex
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wsDB *gorm.DB
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nextAuthorID uint
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)
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const (
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rateLimitWindow = time.Second
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rateLimitMaxMsgs = 10
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)
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func InitWebSocket(database *gorm.DB, domain string) {
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wsDB = database
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allowedDomain = domain
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}
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func HandleWebSocket(conn *websocket.Conn) {
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defer conn.Close()
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mu.Lock()
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clients[conn] = true
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nextAuthorID++
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authorID := nextAuthorID
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var history []models.Message
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wsDB.Order("created_at ASC").Limit(maxMessages).Find(&history)
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for _, msg := range history {
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if err := conn.WriteJSON(msg); err != nil {
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mu.Unlock()
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return
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}
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}
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mu.Unlock()
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msgCount := 0
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windowStart := time.Now()
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for {
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var incoming models.Message
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if err := conn.ReadJSON(&incoming); err != nil {
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break
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}
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now := time.Now()
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if now.Sub(windowStart) > rateLimitWindow {
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msgCount = 0
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windowStart = now
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}
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msgCount++
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if msgCount > rateLimitMaxMsgs {
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continue
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}
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incoming.AuthorID = authorID
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mu.Lock()
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wsDB.Create(&incoming)
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wsDB.Where("id NOT IN (?)",
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wsDB.Model(&models.Message{}).Select("id").Order("created_at DESC").Limit(maxMessages),
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).Delete(&models.Message{})
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for client := range clients {
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if err := client.WriteJSON(incoming); err != nil {
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client.Close()
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delete(clients, client)
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}
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}
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mu.Unlock()
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}
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mu.Lock()
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delete(clients, conn)
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mu.Unlock()
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}
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