iptvnator/docs/architecture/stalker-epg.md

Stalker Portal EPG Architecture

This document describes the current EPG implementation for Stalker/Ministra ITV channels in IPTVnator.

Related architecture docs:

• Stalker Portal Architecture
• Remote Control Architecture

Overview

Stalker now uses two EPG paths with different purposes:

• The active channel EPG panel uses get_epg_info as a bulk endpoint, fetches a 7-day window once per playlist session, caches programs by channel id, and renders the selected channel through the shared app-epg-timeline component.
• Channel rows never send per-row EPG requests. The bulk EPG load is triggered eagerly when a category's channels first render (a constructor effect in StalkerLiveStreamLayoutComponent calls ensureBulkItvEpg(168) once ITV channels are present) — not only after the first channel is played — so the row "now playing" previews and the EPG panel populate immediately. Rows derive their current program and progress bar from the cached bulk map.
  • Effect ordering matters: the eager-EPG effect is registered after the playlist-change effect that calls clearBulkItvEpgCache(). On a portal switch the cache is cleared first and then refilled; if the order is reversed the clear clobbers the just-loaded bulk EPG on initial render.
  • ensureBulkItvEpg de-duplicates (via isLoadingBulkItvEpg / bulkItvEpgLoaded + matching playlist/period), so the eager trigger and the play-time loadEpgForChannel path never double-fetch.
• If a portal does not return usable bulk data for the selected channel, the active panel falls back to get_short_epg.

This keeps the live list cheap while giving the active panel the same date-navigator UI used in the M3U/Xtream flows.

Architecture

┌────────────────────────────────────────────────────────────────────────────┐
│                 StalkerLiveStreamLayoutComponent                          │
│  libs/portal/stalker/feature/src/lib/stalker-live-stream-layout/         │
│                                                                            │
│  sidebar rows                    active channel panel                      │
│  ────────────                    ───────────────────                      │
│  row preview map                 playChannel()                             │
│  from bulk cache                 │                                          │
│         │                        ▼                                          │
│         │                  ensureBulkItvEpg(168)                           │
│         │                  selectedItvEpgPrograms()                        │
│         ▼                        │                                          │
│  current program preview         ├── bulk hit → app-epg-timeline               │
│  after first bulk load           └── empty/unsupported → short fallback    │
└────────────────────────────────────────────────────────────────────────────┘
                   │                                │
                   ▼                                ▼
┌────────────────────────────────────────────────────────────────────────────┐
│                           with-stalker-epg.feature                         │
│                                                                            │
│  bulkItvEpgByChannel: Record<string, EpgProgram[]>                         │
│  bulkItvEpgPlaylistId / bulkItvEpgPeriodHours / bulkItvEpgLoaded           │
│  ensureBulkItvEpg()  selectedItvEpgPrograms()                              │
└────────────────────────────────────────────────────────────────────────────┘
                   │                                │
                   ▼                                ▼
┌────────────────────────────────────────────────────────────────────────────┐
│                            Stalker Portal API                              │
│                                                                            │
│  action=create_link      action=get_short_epg      action=get_epg_info     │
└────────────────────────────────────────────────────────────────────────────┘

Stalker EPG API

get_short_epg (active-panel fallback)

Request

GET load.php?type=itv&action=get_short_epg&ch_id={channel_id}&size={n}&JsHttpRequest=1-xml

Current usage

• Active panel fallback path: size=10

Response

{
    "js": {
        "data": [
            {
                "id": "123",
                "ch_id": "45",
                "name": "Program Title",
                "descr": "Program description",
                "time": "2025-01-15 14:00:00",
                "time_to": "2025-01-15 14:30:00",
                "duration": "1800",
                "start_timestamp": "1736949600",
                "stop_timestamp": "1736951400"
            }
        ]
    }
}

Notes

• The response is normalized into shared EpgItem[]
• The list-preview path uses this directly
• The active-panel fallback maps the result into controlled EpgProgram[]

get_epg_info (bulk active-panel source)

Request

GET load.php?type=itv&action=get_epg_info&period={hours}&JsHttpRequest=1-xml

Current usage

• Fetched once with period=168
• Scoped to the current playlist session
• Not refetched on active-channel change

Expected response

{
    "js": {
        "data": {
            "45": [
                {
                    "id": "1",
                    "name": "Program Title",
                    "descr": "Program description",
                    "time": "2025-01-15 14:00:00",
                    "time_to": "2025-01-15 16:00:00",
                    "start_timestamp": "1736949600",
                    "stop_timestamp": "1736956800"
                }
            ]
        }
    }
}

Notes

• The store supports the channel-keyed bulk shape above as the primary contract
• For weak or mock-style portals that still return array-style data, the store treats the result as compatibility input and leaves the short-EPG fallback path available

Data Mapping

Fallback data (get_short_epg) → EpgItem

The short EPG path now exists only for the active-panel fallback flow.

Key mapped fields:

Stalker field	EpgItem field
id	id
ch_id	channel_id
name	title
descr	description
time	start
time_to	end, stop
start_timestamp	start_timestamp
stop_timestamp	stop_timestamp

Active panel data (get_epg_info / fallback) → EpgProgram

The active panel uses controlled EpgProgram[] because app-epg-timeline filters and groups by day.

Normalization rules:

• start / end are converted to ISO strings
• startTimestamp / stopTimestamp are always populated
• Programs are sorted by start time per channel
• selectedItvId is used to project cached bulk data to the active channel

Implementation Details

Key files

File	Purpose
libs/portal/stalker/data-access/src/lib/stores/features/with-stalker-epg.feature.ts	bulk cache and fallback handling
libs/portal/stalker/feature/src/lib/stalker-live-stream-layout/stalker-live-stream-layout.component.ts	active-channel EPG loading and controlled app-epg-timeline wiring
libs/portal/stalker/feature/src/lib/stalker-live-stream-layout/stalker-live-stream-layout.component.html	active panel template
libs/ui/epg/src/lib/epg-timeline/epg-timeline.component.ts	shared controlled EPG timeline with date navigator

Store API

The Stalker EPG feature exposes one bulk method plus the short-EPG fallback:

fetchChannelEpg(channelId: number | string, size?: number): Promise<EpgItem[]>
ensureBulkItvEpg(periodHours = 168): Promise<void>

It also exposes:

• selectedItvEpgPrograms
• clearBulkItvEpgCache()

Bulk state is keyed by playlist so cached results do not leak between Stalker playlists.

Active panel flow

1. User activates a live channel
2. The component ensures playback link resolution as before
3. The component calls ensureBulkItvEpg(168) on first use for the playlist
4. selectedItvEpgPrograms() feeds app-epg-timeline
5. If the selected channel has no bulk programs, the component falls back to get_short_epg

The active panel no longer uses local EPG pagination or a "Load more" button. When Stalker live TV is playing through an internal player, the active panel is wrapped in the shared collapsible live EPG panel. The collapsed/expanded state uses the shared live-epg-panel-state preference and is only applied after a stream URL has been resolved; external playback keeps the full EPG-only panel.

Channel row preview flow

Before the first live-channel playback, channel rows do not fetch EPG at all.

After bulk EPG has been loaded once for the playlist, visible row previews are derived locally from bulkItvEpgByChannel:

• pick the current program for the channel, if one exists
• compute progress from the cached program timestamps
• leave the row in its existing placeholder state when no current program exists

Cache Lifecycle

• Bulk EPG is fetched once per playlist session
• Channel switches only read from bulkItvEpgByChannel
• The cache is cleared when the Stalker playlist changes
• This implementation does not add TTL-based refresh or background polling

Authentication

EPG requests follow the standard Stalker request path:

Portal type	Auth path
Full Stalker portal	StalkerSessionService.makeAuthenticatedRequest()
Simple Stalker portal	generic IPC request path via Electron

No EPG-specific backend transport was needed; the Electron Stalker request handler forwards portal params directly.

Fallback Behavior

Some providers do not implement get_epg_info consistently. The active panel therefore falls back to get_short_epg when:

• the bulk request fails
• the bulk response is empty
• the selected channel has no programs in the cached bulk map

This keeps the panel usable even on limited portals, while still taking advantage of the richer bulk API when it is available. Row previews do not fallback to per-channel requests in this mode; they remain empty until bulk EPG is available.

Manual EPG Mapping

Stalker channels carry no XMLTV identifier, so when the portal's own EPG is missing or wrong the only uploaded-EPG entry point is a manual mapping: right-click a channel in the ITV sidebar (or in global favorites) and pick "Map EPG channel" to attach it to a channel from an uploaded XMLTV guide.

• Mappings are stored in the shared epg_channel_mappings table under the playlist-scoped key stalker:{playlistId}:{channelId} (buildStalkerEpgMappingKey in libs/shared/interfaces/src/lib/epg-mapping-key.util.ts).
• withStalkerEpg().applyMappedItvEpg(channelIds) batch-resolves mappings (one getEpgMappingsBatch IPC per new id set) and overlays the mapped XMLTV programs onto bulkItvEpgByChannel, so both the active panel and the row previews pick them up with no template changes. Overrides are re-merged whenever ensureBulkItvEpg replaces the bulk record and are re-checked after the mapping dialog closes with a change.
• The collection views (global favorites/recent) resolve the same keys in StreamResolverService (loadStalkerEpgItems for the detail panel, loadStalkerEpgBatch + prefetchEpgMappings for row previews).
• Everything is gated behind supportsEpgMapping, so the PWA never shows the menu entry.

Future Enhancements

• add cache refresh / invalidation for long-running live sessions
• add Stalker catch-up support to app-epg-timeline once the playback flow exists
• optionally add category-level prefetch timing metrics for bulk EPG