put in the conferences vtable, which only needs an OnDeleteCommunity entry for now

database/conference.go

@@ -933,6 +933,81 @@ func (c *Conference) Delete(ctx context.Context, comm *Community, u *User, ipadd
 	return nil
 }
 
+// The service vtable (see services.go) for the conferencing service.
+type conferenceServiceVTable struct{}
+
+func (*conferenceServiceVTable) OnNewCommunity(context.Context, *sqlx.Tx, *Community) error {
+	return nil
+}
+
+func (*conferenceServiceVTable) OnDeleteCommunity(ctx context.Context, tx *sqlx.Tx, commid int32, background *util.WorkerPool) error {
+	// Get the list of conferences in this community.
+	var confids []int32
+	err := tx.SelectContext(ctx, &confids, "SELECT confid FROM commtoconf WHERE commid = ?", commid)
+	if err != nil {
+		return err
+	}
+	for i, confid := range confids {
+		// any references to conference other than this community?
+		row := tx.QueryRowContext(ctx, "SELECT COUNT(*) FROM commtoconf WHERE confid = ? AND commid <> ?", confid, commid)
+		refCount := 0
+		err = row.Scan(&refCount)
+		if err != nil {
+			return err
+		}
+		// break the link with the community
+		if _, err = tx.ExecContext(ctx, "DELETE FROM commtoconf WHERE commid = ? AND confid = ?", commid, confid); err != nil {
+			return err
+		}
+		if refCount > 0 {
+			confids[i] = -1
+			continue // done with this conference
+		}
+		// We have to delete all the conference core data now.
+		_, err = tx.ExecContext(ctx, "DELETE FROM confs WHERE confid = ?", confid)
+		if err == nil {
+			_, err = tx.ExecContext(ctx, "DELETE FROM confalias WHERE confid = ?", confid)
+		}
+		if err != nil {
+			return err
+		}
+		// kick the conference out of the cache
+		getConferenceMutex.Lock()
+		conferenceCache.Remove(confid)
+		getConferenceMutex.Unlock()
+	}
+
+	// Just dump the whole conference property cache.
+	getConferencePropMutex.Lock()
+	conferencePropCache.Purge()
+	getConferencePropMutex.Unlock()
+
+	// start a background job to remove all the conference data
+	background.Submit(func(ctx context.Context) {
+		start := time.Now()
+		// purge the conference data
+		for _, confid := range confids {
+			if confid > 0 {
+				err := backgroundPurgeConference(ctx, confid)
+				if err != nil {
+					log.Errorf("Conference purge(#%d) background job failed: %v", confid, err)
+				}
+			}
+		}
+		dur := time.Since(start)
+		log.Infof("conference deletion task completed in %v", dur)
+	})
+	return nil
+}
+
+func (*conferenceServiceVTable) OnUserJoinCommunity(context.Context, *sqlx.Tx, *Community, *User) error {
+	return nil
+}
+
+func (*conferenceServiceVTable) OnUserLeaveCommunity(context.Context, *sqlx.Tx, *Community, *User) error {
+	return nil
+}
+
 /* AmGetConference returns a conference given its ID.
  * Parameters:
  *     ctx - Standard Go context value.

database/services.go

@@ -1,6 +1,6 @@
 /*
  * Amsterdam Web Communities System
- * Copyright (c) 2025 Erbosoft Metaverse Design Solutions, All Rights Reserved
+ * Copyright (c) 2025-2026 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
@@ -17,15 +17,16 @@ import (
 	"sync"
 
 	"git.erbosoft.com/amy/amsterdam/config"
+	"git.erbosoft.com/amy/amsterdam/util"
 	lru "github.com/hashicorp/golang-lru"
 	"github.com/jmoiron/sqlx"
 	"gopkg.in/yaml.v3"
 )
 
-// ServiceVTable is a serioes of functions called for services on specific events.
+// ServiceVTable is a series of functions called for services on specific events.
 type ServiceVTable interface {
 	OnNewCommunity(context.Context, *sqlx.Tx, *Community) error
-	OnDeleteCommunity(context.Context, *sqlx.Tx, int32) error
+	OnDeleteCommunity(context.Context, *sqlx.Tx, int32, *util.WorkerPool) error
 	OnUserJoinCommunity(context.Context, *sqlx.Tx, *Community, *User) error
 	OnUserLeaveCommunity(context.Context, *sqlx.Tx, *Community, *User) error
 }
@@ -37,7 +38,7 @@ func (*emptyServiceVTable) OnNewCommunity(context.Context, *sqlx.Tx, *Community)
 	return nil
 }
 
-func (*emptyServiceVTable) OnDeleteCommunity(context.Context, *sqlx.Tx, int32) error {
+func (*emptyServiceVTable) OnDeleteCommunity(context.Context, *sqlx.Tx, int32, *util.WorkerPool) error {
 	return nil
 }
 
@@ -116,7 +117,7 @@ func init() {
 	dom.byId["Profile"].vtable = &empty
 	dom.byId["Admin"].vtable = &empty
 	dom.byId["SysAdmin"].vtable = &empty
-	dom.byId["Conference"].vtable = &empty // TODO
+	dom.byId["Conference"].vtable = &(conferenceServiceVTable{})
 	dom.byId["Members"].vtable = &empty
 }
 
@@ -247,14 +248,15 @@ func AmEstablishCommunityServices(ctx context.Context, tx *sqlx.Tx, c *Community
  *     ctx - Standard Go context value.
  *     tx - The transaction to use.
  *     cid - The ID of the departing community.
+ *     background - Pool in which background jobs can be submitted to clean up the database.
  * Returns:
  *     Standard Go error status.
  */
-func AmDeleteCommunityServices(ctx context.Context, tx *sqlx.Tx, cid int32) error {
+func AmDeleteCommunityServices(ctx context.Context, tx *sqlx.Tx, cid int32, background *util.WorkerPool) error {
 	arr, err := AmGetCommunityServices(ctx, cid)
 	if err == nil {
 		for _, svc := range arr {
-			if err = svc.vtable.OnDeleteCommunity(ctx, tx, cid); err != nil {
+			if err = svc.vtable.OnDeleteCommunity(ctx, tx, cid, background); err != nil {
 				break
 			}
 		}
@@ -310,6 +312,15 @@ func AmOnUserLeaveCommunityServices(ctx context.Context, tx *sqlx.Tx, c *Communi
 	return err
 }
 
+/* AmTestService checks whether the community supports a service.
+ * Parameters:
+ *     ctx - Standard Go context value.
+ *     c - The community that is being tested.
+ *     serviceId - The service ID to test.
+ * Returns:
+ *     true if the community supports that service, false if not.
+ *     Standard Go error status.
+ */
 func AmTestService(ctx context.Context, c *Community, serviceId string) (bool, error) {
 	arr, err := AmGetCommunityServices(ctx, c.Id)
 	if err == nil {

docs/MISSINGFUNCS.md

@@ -6,7 +6,7 @@ _(italicized items can be deferred)_
 - ~~Send out E-mails to topic subscribers when a post is made~~
 - _Error handling: shift titles and templates for different error codes_
 - ~~Find Posts~~
-- Services mechanism: Conference vtable
+- ~~Services mechanism: Conference vtable~~
 - ~~User creation: copy conference hotlists ~~
 - _Calendar (top menu link)_
 - _Chat (top menu link)_