added LRU caching and communities data

database/community.go

@@ -0,0 +1,77 @@
+/*
+ * Amsterdam Web Communities System
+ * Copyright (c) 2025 Erbosoft Metaverse Design Solutions, All Rights Reserved
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+// The database package contains database management and storage logic.
+package database
+
+import (
+	"fmt"
+	"time"
+
+	lru "github.com/hashicorp/golang-lru"
+)
+
+// Community struct contains the high level data for a community.
+type Community struct {
+	Id                int32      `db:"commid"`
+	CreateDate        time.Time  `db:"createdate"`
+	LastAccess        *time.Time `db:"lastaccess"`
+	LastUpdate        *time.Time `db:"lastupdate"`
+	ReadLevel         uint16     `db:"read_lvl"`
+	WriteLevel        uint16     `db:"write_lvl"`
+	CreateLevel       uint16     `db:"create_lvl"`
+	JoinLevel         uint16     `db:"join_lvl"`
+	ContactId         int32      `db:"contactid"`
+	HostUid           *int32     `db:"host_uid"`
+	CategoryId        int32      `db:"catid"`
+	HideFromDirectory bool       `db:"hide_dir"`
+	HideFromSearch    bool       `db:"hide_search"`
+	MembersOnly       bool       `db:"membersonly"`
+	IsAdmin           bool       `db:"is_admin"`
+	InitFeature       int16      `db:"init_ftr"`
+	Name              string     `db:"commname"`
+	Language          *string    `db:"language"`
+	Synopsis          *string    `db:"synopsis"`
+	Rules             *string    `dd:"rules"`
+	JoinKey           *string    `db:"joinkey"`
+	Alias             string     `db:"alias"`
+}
+
+// communityCache is the cache for Community objects.
+var communityCache *lru.TwoQueueCache = nil
+
+/* AmGetCommunity returns a reference to the specified community.
+ * Parameters:
+ *     id - The ID of the community.
+ * Returns:
+ *     Pointer to Community containing community data, or nil
+ *     Standard Go error status
+ */
+func AmGetCommunity(id int32) (*Community, error) {
+	var err error = nil
+	if communityCache == nil {
+		communityCache, err = lru.New2Q(50)
+		if err != nil {
+			return nil, err
+		}
+	}
+	rc, ok := communityCache.Get(id)
+	if !ok {
+		var dbdata []Community
+		err = amdb.Select(&dbdata, "SELECT * from communities WHERE commid = ?", id)
+		if err != nil {
+			return nil, err
+		}
+		if len(dbdata) > 1 {
+			return nil, fmt.Errorf("AmGetCommunity(%d): too many responses(%d)", id, len(dbdata))
+		}
+		rc = &(dbdata[0])
+		communityCache.Add(id, rc)
+	}
+	return rc.(*Community), err
+}

database/user.go

@@ -10,8 +10,11 @@
 package database
 
 import (
+	"database/sql"
 	"fmt"
 	"time"
+
+	lru "github.com/hashicorp/golang-lru"
 )
 
 // User represents a user in the Amsterdam database.
@@ -34,6 +37,12 @@ type User struct {
 	DOB          *time.Time `db:"dob"`
 }
 
+// userCache is the cache for User objects.
+var userCache *lru.TwoQueueCache = nil
+
+// anonUid is the UID of the "anonymous" user.
+var anonUid int32 = -1
+
 /* AmGetUser returns a reference to the specified user.
  * Parameters:
  *     uid - The UID of the user.
@@ -42,15 +51,27 @@ type User struct {
  *     Standard Go error status
  */
 func AmGetUser(uid int32) (*User, error) {
-	var rc []User
-	err := amdb.Select(&rc, "SELECT * from users WHERE uid = ?", uid)
-	if err != nil {
-		return nil, err
+	var err error = nil
+	if userCache == nil {
+		userCache, err = lru.New2Q(100)
+		if err != nil {
+			return nil, err
+		}
 	}
-	if len(rc) > 1 {
-		return nil, fmt.Errorf("AmGetUser(%d): too many responses(%d)", uid, len(rc))
+	rc, ok := userCache.Get(uid)
+	if !ok {
+		var dbdata []User
+		err = amdb.Select(&dbdata, "SELECT * from users WHERE uid = ?", uid)
+		if err != nil {
+			return nil, err
+		}
+		if len(dbdata) > 1 {
+			return nil, fmt.Errorf("AmGetUser(%d): too many responses(%d)", uid, len(dbdata))
+		}
+		rc = &(dbdata[0])
+		userCache.Add(uid, rc)
 	}
-	return &(rc[0]), err
+	return rc.(*User), err
 }
 
 /* AmGetAnonUser returns a reference to the anonymous user.
@@ -59,13 +80,25 @@ func AmGetUser(uid int32) (*User, error) {
  *     Standard Go error status
  */
 func AmGetAnonUser() (*User, error) {
-	var rc []User
-	err := amdb.Select(&rc, "SELECT * from users WHERE is_anon = 1")
-	if err != nil {
-		return nil, err
+	var err error = nil
+	if anonUid < 0 {
+		var rows *sql.Rows
+		rows, err = amdb.Query("SELECT uid FROM users WHERE is_anon = 1")
+		if err == nil {
+			defer rows.Close()
+			if rows.Next() {
+				err = rows.Scan(&anonUid)
+				if err == nil && rows.Next() {
+					err = fmt.Errorf("should be only one anonymous user in Amsterdam database")
+				}
+			} else {
+				err = fmt.Errorf("no anonymous user in Amsterdam database")
+			}
+		}
 	}
-	if len(rc) > 1 {
-		return nil, fmt.Errorf("AmGetAnonUser: too many responses(%d)", len(rc))
+	var rc *User = nil
+	if err == nil {
+		rc, err = AmGetUser(anonUid)
 	}
-	return &(rc[0]), err
+	return rc, err
 }