satellite-provider/_docs/02_document/contracts/api/tile-inventory.md

Contract: tile-inventory

Component: WebApi (SatelliteProvider.Api) producing rows via TileDownloader (SatelliteProvider.Services.TileDownloader) Producer task: AZ-505 — _docs/02_tasks/todo/AZ-505_tile_inventory_http2_leaflet_index.md Consumer tasks: gps-denied-onboard AZ-316 (c11_tile_downloader), future mission-planner UI cache-sizing flows Version: 1.0.0 Status: frozen Last Updated: 2026-05-12

Purpose

Defines the HTTP contract for the POST /api/satellite/tiles/inventory bulk-lookup endpoint. Callers submit either a list of slippy-map coords or a list of pre-computed location_hash UUIDs and receive one response entry per input — in the same order — telling them whether each tile is already cached server-side and (if so) which row to expect on a subsequent GET /tiles/{z}/{x}/{y}.

The endpoint is the consumer-facing payload that justifies the AZ-503-foundation schema work (the deterministic location_hash column) plus the AZ-505 tiles_leaflet_path covering index. It is designed for pre-flight cache sizing on the gps-denied-onboard side.

Endpoint

POST /api/satellite/tiles/inventory
Content-Type: application/json
Authorization: Bearer <JWT>

The request MUST carry a valid JWT (AZ-487). No permissions claim is required — inventory is a metadata-only read; the GPS permission gate only applies to UAV writes. Anonymous requests are rejected with HTTP 401.

Shape

Request body

Exactly one of tiles OR locationHashes MUST be populated. Sending both, or neither, is HTTP 400.

// Form A — coord-keyed
{
  "tiles": [
    { "tileZoom": 18, "tileX": 154321, "tileY": 95812 },
    { "tileZoom": 18, "tileX": 154322, "tileY": 95812 }
  ]
}

// Form B — hash-keyed
{
  "locationHashes": [
    "ad8c1c4c-2b27-5af4-902f-9c8baeed1e84",
    "5b8d0c2e-7f1a-5d3b-9c5e-1f3a8e7d2b6c"
  ]
}

Per-field constraints:

Field	Type	Required	Description	Constraints
tiles	TileCoord[]	yes (XOR locationHashes)	Slippy-map tile coords	Up to 5000 entries per request. Each entry MUST have all three of tileZoom, tileX, tileY.
locationHashes	UUID[]	yes (XOR tiles)	Pre-computed UUIDv5 location_hash values	Up to 5000 entries per request. Each entry MUST be RFC 4122 UUID.

Hard cap: 5000 entries per request (SatelliteProvider.Common.DTO.TileInventoryLimits.MaxEntriesPerRequest). Anything larger → HTTP 400. The cap is 2× the AC-4 perf gate (2500 tiles).

TileCoord (per entry under tiles)

Field	Type	Required	Description
tileZoom	integer	yes	Slippy-map zoom level
tileX	integer	yes	Slippy-map tile column
tileY	integer	yes	Slippy-map tile row

Response body

{
  "results": [
    {
      "tileZoom": 18,
      "tileX": 154321,
      "tileY": 95812,
      "locationHash": "ad8c1c4c-2b27-5af4-902f-9c8baeed1e84",
      "present": true,
      "id": "5d83…",
      "capturedAt": "2026-05-12T13:24:50.123456Z",
      "source": "uav",
      "flightId": "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa",
      "resolutionMPerPx": 0.78125
    },
    {
      "tileZoom": 18,
      "tileX": 154322,
      "tileY": 95812,
      "locationHash": "5b8d0c2e-7f1a-5d3b-9c5e-1f3a8e7d2b6c",
      "present": false,
      "id": null,
      "capturedAt": null,
      "source": null,
      "flightId": null,
      "resolutionMPerPx": null
    }
  ]
}

Per-entry fields:

Field	Type	Present when...	Description
tileZoom	integer	always (Form A); zeroed (Form B)	Echoes the request entry's tileZoom when input was tiles; 0 when input was locationHashes (caller already knows the cell).
tileX	integer	always (Form A); zeroed (Form B)	Same as tileZoom.
tileY	integer	always (Form A); zeroed (Form B)	Same as tileZoom.
locationHash	UUIDv5	always	UUIDv5(TileNamespace, "{tileZoom}/{tileX}/{tileY}"). Populated even when present=false so callers can persist the deterministic hash.
present	bool	always	true iff a row exists in tiles with this location_hash.
id	UUID	present=true	Most-recent row's tiles.id. Deterministic UUIDv5 for AZ-503+ rows; random for legacy rows.
capturedAt	ISO-8601 UTC	present=true	tiles.captured_at.
source	string enum	present=true	tiles.source wire value ("google_maps" or "uav").
flightId	UUID	present=true (may be null)	tiles.flight_id; null for google_maps rows and pre-AZ-503 legacy UAV rows.
resolutionMPerPx	number	present=true	tile_size_meters / tile_size_pixels. Derived; not a stored column.

Order invariant: results[i] corresponds to request.tiles[i] (or request.locationHashes[i]). Always. Even when entries are absent. Even when the request contains duplicates (each duplicate yields its own response entry).

Endpoint summary

Method	Path	Request body	Response	Status codes
POST	/api/satellite/tiles/inventory	TileInventoryRequest	TileInventoryResponse	200, 400, 401

Invariants

• Inv-1: Exactly one of request.tiles and request.locationHashes is populated and non-empty. Both-populated → 400; both-empty → 400.
• Inv-2: len(response.results) == len(request.tiles) OR len(request.locationHashes) — never less, never more.
• Inv-3: response.results[i].locationHash is deterministic from request.tiles[i] (UUIDv5 over "{zoom}/{x}/{y}" with Uuidv5.TileNamespace) when Form A is used, or equals request.locationHashes[i] when Form B is used.
• Inv-4: response.results[i].present == true iff a row exists in tiles with location_hash = response.results[i].locationHash.
• Inv-5: When present=true, the returned row is the most-recent across sources/flights ordered by (captured_at DESC, updated_at DESC, id DESC) — same rule as ITileRepository.GetByTileCoordinatesAsync per tile-storage v2.0.0.
• Inv-6: When present=false, id / capturedAt / source / flightId / resolutionMPerPx are all null.
• Inv-7: request.tiles.length and request.locationHashes.length MUST be ≤ TileInventoryLimits.MaxEntriesPerRequest (5000); over the cap → 400.

Non-Goals

• Not covered: byte-size hints (estimatedBytes). Deferred until production profiling justifies the per-file stat() cost.
• Not covered: voting / trust-promotion filtering. The voting_status filter is part of the future voting layer (gps-denied-onboard Design Task #2); inventory always returns the most-recent row regardless of any future trust state.
• Not covered: tile body download. This endpoint returns metadata only; callers fetch bodies via GET /tiles/{z}/{x}/{y}.
• Not covered: HTTP/3 / QUIC. Kestrel is set to Http1AndHttp2; the HTTP/3 plumbing requires ALPN + UDP verification that's deferred per AZ-505 scope.
• Not covered: browser-side multiplexing. h2c (HTTP/2 over plaintext) is not supported by mainstream browsers; only programmatic clients (httpx http2=True, .NET HttpClient with HttpVersionPolicy.RequestVersionExact) realize the HTTP/2 multiplexing benefit. Browser Leaflet wins come from the covering-index hot path, not multiplexing.
• Not covered: PMTiles or tar/multipart bundle endpoints. Rejected by AZ-503 parent rationale (HTTP/2 multistream is sufficient).
• Not covered: write operations. Inventory is read-only; UAV writes go through POST /api/satellite/upload (uav-tile-upload.md v1.1.0).

Versioning Rules

• Patch (1.0.x): Documentation clarifications, additional invariants that do not change wire behavior.
• Minor (1.x.0): Adding an optional response field that consumers may safely ignore (e.g., the future estimatedBytes); raising the entry cap; adding a third request form alongside the current two.
• Major (2.0.0): Changing the response ordering rule; removing present; lowering the entry cap; making flightId required; adding voting / trust filtering to the read path.

Test Cases

Case	Input	Expected	Notes
ordering-mixed-present-absent	25 coords, 12 seeded + 13 absent, interleaved	25 entries in request order; 12 present (id/capturedAt/source populated), 13 absent (only locationHash populated)	AC-1
most-recent-across-sources	Cell with google_maps captured_at=T1 and uav captured_at=T2 > T1; coord request	present=true, source='uav', id = UAV row's id	Inv-5
validation-both-populated	Body with both tiles and locationHashes	HTTP 400	Inv-1
validation-neither-populated	Empty body or body with both fields empty	HTTP 400	Inv-1
validation-over-cap	5001 entries	HTTP 400	Inv-7
auth-anonymous	No Bearer token	HTTP 401	Standard .RequireAuthorization() baseline
perf-2500-tiles	2500-entry request against populated DB	p95 ≤ 1000 ms over 20 calls	AC-4
http2-multiplexing	20 concurrent GET /tiles/{z}/{x}/{y} over a single H2 connection	All 20 responses HttpResponseMessage.Version == 2.0; ETag + Cache-Control preserved	AC-5; cross-references tile-inventory.md because Kestrel H2 is configured in the same PBI

Change Log

Version	Date	Change	Author
1.0.0	2026-05-12	Initial contract — POST /api/satellite/tiles/inventory with Form A (coords) / Form B (hashes) XOR validation, 5000-entry cap, most-recent-across-sources selection rule, ordering invariant. Produced by AZ-505.	autodev (Step 10, cycle 6)