fixed concurrency in users & communities, implemented Communities sidebox

database/community.go

@@ -11,6 +11,7 @@ package database
 
 import (
 	"fmt"
+	"sync"
 	"time"
 
 	lru "github.com/hashicorp/golang-lru"
@@ -18,6 +19,7 @@ import (
 
 // Community struct contains the high level data for a community.
 type Community struct {
+	Mutex             sync.RWMutex
 	Id                int32      `db:"commid"`
 	CreateDate        time.Time  `db:"createdate"`
 	LastAccess        *time.Time `db:"lastaccess"`
@@ -25,6 +27,7 @@ type Community struct {
 	ReadLevel         uint16     `db:"read_lvl"`
 	WriteLevel        uint16     `db:"write_lvl"`
 	CreateLevel       uint16     `db:"create_lvl"`
+	DeleteLevel       uint16     `db:"delete_lvl"`
 	JoinLevel         uint16     `db:"join_lvl"`
 	ContactId         int32      `db:"contactid"`
 	HostUid           *int32     `db:"host_uid"`
@@ -45,6 +48,18 @@ type Community struct {
 // communityCache is the cache for Community objects.
 var communityCache *lru.TwoQueueCache = nil
 
+// getCommunityMutex is a mutex on AmGetCommunity.
+var getCommunityMutex sync.Mutex
+
+// init initializes the community cache.
+func init() {
+	var err error
+	communityCache, err = lru.New2Q(50)
+	if err != nil {
+		panic(err)
+	}
+}
+
 /* AmGetCommunity returns a reference to the specified community.
  * Parameters:
  *     id - The ID of the community.
@@ -54,12 +69,8 @@ var communityCache *lru.TwoQueueCache = nil
  */
 func AmGetCommunity(id int32) (*Community, error) {
 	var err error = nil
-	if communityCache == nil {
+	getCommunityMutex.Lock()
-		communityCache, err = lru.New2Q(50)
+	defer getCommunityMutex.Unlock()
-		if err != nil {
-			return nil, err
-		}
-	}
 	rc, ok := communityCache.Get(id)
 	if !ok {
 		var dbdata []Community
@@ -75,3 +86,28 @@ func AmGetCommunity(id int32) (*Community, error) {
 	}
 	return rc.(*Community), err
 }
+
+/* AmGetCommunitiesForUser returns a list of communities the user is a member of.
+ * Parameters:
+ *     uid - The ID of the user.
+ * Returns:
+ *	   Array of pointers to communities for the user
+ *     Standard Go error status
+ */
+func AmGetCommunitiesForUser(uid int32) ([]*Community, error) {
+	var rc []*Community = make([]*Community, 0)
+	rows, err := amdb.Queryx("SELECT commid FROM commmember WHERE uid = ?", uid)
+	if err == nil {
+		defer rows.Close()
+		for err == nil && rows.Next() {
+			var cid int32
+			var c *Community
+			rows.Scan(&cid)
+			c, err = AmGetCommunity(cid)
+			if err == nil {
+				rc = append(rc, c)
+			}
+		}
+	}
+	return rc, err
+}

database/user.go

@@ -10,8 +10,8 @@
 package database
 
 import (
-	"database/sql"
 	"fmt"
+	"sync"
 	"time"
 
 	lru "github.com/hashicorp/golang-lru"
@@ -19,6 +19,7 @@ import (
 
 // User represents a user in the Amsterdam database.
 type User struct {
+	Mutex        sync.RWMutex
 	Uid          int32      `db:"uid"`
 	Username     string     `db:"username"`
 	Passhash     string     `db:"passhash"`
@@ -40,9 +41,21 @@ type User struct {
 // userCache is the cache for User objects.
 var userCache *lru.TwoQueueCache = nil
 
+// getUserMutex is a mutex on AmGetUser.
+var getUserMutex sync.Mutex
+
 // anonUid is the UID of the "anonymous" user.
 var anonUid int32 = -1
 
+// init initializes the user cache.
+func init() {
+	var err error
+	userCache, err = lru.New2Q(100)
+	if err != nil {
+		panic(err)
+	}
+}
+
 /* AmGetUser returns a reference to the specified user.
  * Parameters:
  *     uid - The UID of the user.
@@ -52,12 +65,8 @@ var anonUid int32 = -1
  */
 func AmGetUser(uid int32) (*User, error) {
 	var err error = nil
-	if userCache == nil {
+	getUserMutex.Lock()
-		userCache, err = lru.New2Q(100)
+	defer getUserMutex.Unlock()
-		if err != nil {
-			return nil, err
-		}
-	}
 	rc, ok := userCache.Get(uid)
 	if !ok {
 		var dbdata []User
@@ -74,16 +83,10 @@ func AmGetUser(uid int32) (*User, error) {
 	return rc.(*User), err
 }
 
-/* AmGetAnonUser returns a reference to the anonymous user.
+// getAnonUserID retrieves the UID of the "anonymous" user from the database.
- * Returns:
+func getAnonUserID() (int32, error) {
- *     Pointer to User containing anonymous user data, or nil
- *     Standard Go error status
- */
-func AmGetAnonUser() (*User, error) {
-	var err error = nil
 	if anonUid < 0 {
-		var rows *sql.Rows
+		rows, err := amdb.Query("SELECT uid FROM users WHERE is_anon = 1")
-		rows, err = amdb.Query("SELECT uid FROM users WHERE is_anon = 1")
 		if err == nil {
 			defer rows.Close()
 			if rows.Next() {
@@ -95,10 +98,35 @@ func AmGetAnonUser() (*User, error) {
 				err = fmt.Errorf("no anonymous user in Amsterdam database")
 			}
 		}
+		if err != nil {
+			return -1, err
 		}
+	}
+	return anonUid, nil
+}
+
+/* AmIsUserAnon returns true if the specified user ID is the anonymous one.
+ * Parameters:
+ *     uid = The user ID to test.
+ * Returns:
+ *     true if the user is anonymous, false if not
+ *     Standard Go error status
+ */
+func AmIsUserAnon(uid int32) (bool, error) {
+	auid, err := getAnonUserID()
+	return (uid == auid), err
+}
+
+/* AmGetAnonUser returns a reference to the anonymous user.
+ * Returns:
+ *     Pointer to User containing anonymous user data, or nil
+ *     Standard Go error status
+ */
+func AmGetAnonUser() (*User, error) {
 	var rc *User = nil
+	auid, err := getAnonUserID()
 	if err == nil {
-		rc, err = AmGetUser(anonUid)
+		rc, err = AmGetUser(auid)
 	}
 	return rc, err
 }

top.go

@@ -31,7 +31,7 @@ type RenderedSidebox struct {
 	Items        []RenderedSideboxItem
 }
 
-/* buildFeaturedCommunities creates the data for the "Featured Communities" sidebox.
+/* buildCommunitiesSidebox creates the data for the "My/Featured Communities" sidebox.
  * Parameters:
  *     uid - UID of the user rendering the page.
  *     out - The RenderedSidebox to be built.
@@ -39,9 +39,30 @@ type RenderedSidebox struct {
  * Returns:
  *     Standard Go error status.
  */
-func buildFeaturedCommunities(uid int32, out *RenderedSidebox, in *database.Sidebox) error {
+func buildCommunitiesSidebox(uid int32, out *RenderedSidebox, in *database.Sidebox) error {
+	var err error
+	var anon bool
+	anon, err = database.AmIsUserAnon(uid)
+	if err == nil {
+		if anon {
+			out.Title = "Featured Communities"
+		} else {
+			out.Title = "Your Communities"
+		}
+		var l []*database.Community
+		l, err = database.AmGetCommunitiesForUser(uid)
+		if err == nil {
+			out.Items = make([]RenderedSideboxItem, len(l))
+			for i, c := range l {
+				out.Items[i].Text = c.Name
+				out.Items[i].Link = new(string)
+				*out.Items[i].Link = "/TODO/community/" + c.Alias
+				out.Items[i].Flags = make([]string, 0)
+			}
 			out.TemplateName = "sb_ftrcomm.jet"
-	return nil
+		}
+	}
+	return err
 }
 
 /* buildFeaturedConferences creates the data for the "Featured Conferences" sidebox.
@@ -81,7 +102,7 @@ func buildUsersOnline(uid int32, out *RenderedSidebox, in *database.Sidebox) err
 func buildRenderedSidebox(uid int32, out *RenderedSidebox, in *database.Sidebox) error {
 	switch in.Boxid {
 	case 1:
-		return buildFeaturedCommunities(uid, out, in)
+		return buildCommunitiesSidebox(uid, out, in)
 	case 2:
 		return buildFeaturedConferences(uid, out, in)
 	case 3:

ui/amcontext.go

@@ -28,11 +28,11 @@ type AmContext interface {
 	RC() int
 	OutputType() string
 	Render(string) error
-	Scratchpad() map[string]any
 	SubRender(string) ([]byte, error)
 	Session() *sessions.Session
 	SetOutputType(string)
 	SetRC(int)
+	GetScratch(string) any
 	SetScratch(string, any)
 	URLPath() string
 	VarMap() jet.VarMap
@@ -117,6 +117,13 @@ func (c *amContext) SetRC(rc int) {
 	c.httprc = rc
 }
 
+func (c *amContext) GetScratch(name string) any {
+	if c.scratchpad == nil {
+		return nil
+	}
+	return c.scratchpad[name]
+}
+
 func (c *amContext) SetScratch(name string, val any) {
 	if c.scratchpad == nil {
 		c.scratchpad = make(map[string]any)

ui/views/sb_ftrcomm.jet

@@ -6,20 +6,24 @@
  * 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/.
  *}
-<!-- Featured Communities -->
+<!-- Communities sidebox -->
+{{ sb := .GetScratch("__sidebox") }}
 <div class="mb-4">
     <div class="bg-blue-600 px-2 py-1 rounded-t">
-        {{ if .CurrentUser().IsAnon }}
+        <h3 class="text-white font-bold text-base">{{ sb.Title }}</h3>
-            <h3 class="text-white font-bold text-base">Featured Communities:</h3>
-        {{ else }}
-            <h3 class="text-white font-bold text-base">Your Communities:</h3>
-        {{ end }}
     </div>
     <div class="bg-blue-400 px-2 py-2 rounded-b">
         <div class="flex items-center">
+            {{ if len(sb.Items) > 0 }}
+                {{ range sb.Items }}
+                    <div class="text-small">
                         <span class="mr-2">🟣</span>
-            <a href="http://necrovenice:8080/venice/community/Piazza" 
+                        <a href="{{ .Link }}" class="text-blue-700 hover:text-blue-900 font-bold text-sm">{{ .Text }}</a>
-                class="text-blue-700 hover:text-blue-900 font-bold text-sm">La Piazza</a>
+                    </div>
+                {{ end }}
+            {{ else }}
+                <div class="text-small">You are not a member of any communities.</div>
+            {{ end }}
         </div>
     </div>
 </div>