Adds a per-voicemail-box option that diverts the caller to an arbitrary
dialable destination instead of leaving a message. Useful for handing
voicemail off to an external service (e.g. Microsoft Teams, a paging
group, an answering service) while keeping the caller's original
Caller-ID intact for downstream logging.
The setting lives on the voicemail box (v_voicemails) — not on the
extension's follow-me/forwarding settings — so it only fires when a call
actually reaches voicemail.lua. It does not interact with the existing
"No Answer" forward on the call-forward page, nor with call-center,
ring-group, or FIFO no-answer handling: those mechanisms route the call
elsewhere before voicemail.lua ever runs, so the divert never triggers
on those paths in the first place.
Schema (v_voicemails, registered in app/voicemails/app_config.php so
upgrades pick it up automatically):
* alternate_voicemail_enabled boolean
* alternate_voicemail_destination text (any dialable string —
extension number, external
number, etc.)
UI is added to the voicemail edit screen
(app/voicemails/voicemail_edit.php) directly under "Mail To", mirroring
the toggle + destination input pattern used on the call-forward page.
Sanitisation matches the existing forward_*_destination fields
([^\*0-9] stripped).
Voicemail behaviour change is in
app/switch/resources/scripts/app/voicemail/index.lua: when a caller hits
a valid voicemail box and the box has the alternate voicemail location
enabled, the script transfers the call via session:transfer(destination,
"XML", context) BEFORE the greeting plays. session:transfer preserves
channel variables so the original Caller-ID is carried into the diverted
leg.
Override semantics — when enabled, the alternate location always wins.
The voicemail menu (voicemail_action == "check") path is unaffected, so
extension owners can still log in and review their existing messages.
Group-call safety net: the divert is intentionally skipped when the leg
is part of a call-center, ring-group, or FIFO bridge (detected via the
cc_side, cc_queue, dialed_extension, ring_group_uuid, or fifo_role
channel variables). In normal use these paths shouldn't reach the
voicemail Lua at all — the queue / group manages its own no-answer
behaviour upstream — but if one does land here for any reason, we don't
want a session:transfer to yank the leg out of the queue's control and
hijack the call to the alternate destination.
This change reorders the status determination logic to check for
busy conditions first, ensuring successful transmissions are
correctly marked as 'sent' and trigger the proper success email.
Replaced unindexable CONCAT() with COALESCE(col, '') || ... and refactored dialplan lookup into a CTE with UNION to split destination-based and public-context paths.
CONCAT() is marked as STABLE in PostgreSQL and cannot be used in functional indexes, which forced sequential scans during dialplan lookups. To enable future indexing and improve query optimizability, we replace all CONCAT(a, b, c) calls with (COALESCE(a, '') || COALESCE(b, '') || COALESCE(c, '')), which is functionally equivalent for text columns (treating NULLs as empty) and composed only of IMMUTABLE operations.
Additionally, the query was refactored using a CTE with UNION to decompose a complex top-level OR condition into two independent branches:
1. Dialplans linked to matching destinations.
2. Public dialplans with domain_uuid IS NULL.
This structure allows the planner to optimize each path separately, avoid full-table scans, and leverage primary key lookups efficiently - even without additional indexes.
On a production dataset with 3kk records in v_dialplans, this change reduced dialplans query latency from ~1.5s to ~37ms (40.5x faster), with further gains possible via expression indexes.
FusionPBX