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App 2.39.1, server 2.8.0: map roads from OpenFreeMap, on demand

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The public Overpass answered 429/502 and needs ~40 s a tile while the
car gives up after 8 s, so the server cancelled its queries and the
car's retries added load. Now the server fetches only the tiles a car
asks for, as OpenStreetMap vector tiles from OpenFreeMap (MAP_TILES_URL),
decodes the transportation layer with a small reader of its own, and
keeps each tile 30 days on a volume (MAP_CACHE_DIR). A fetch finishes
even after the car has stopped waiting; the car hears 503 with
Retry-After and gets the tile on its next try.

App: OpenFreeMap/OpenMapTiles attribution on the map, retry after 15 s.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LhzAVaUyqcw5PkGjz4mWW6
This commit is contained in:
nils
2026-10-26 23:54:30 +01:00
co-authored by Claude Opus 5.5
parent d9c7c5ea9a
commit 6be2ba5193
17 changed files with 891 additions and 332 deletions
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server/README.md
+18 -12
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@@ -23,7 +23,8 @@ Environment only; the server refuses to start when a required value is missing.
| `APPROVAL_PASSWORD` | optional, at least 12 characters; switches pairing on (see below) |
| `PUBLIC_URL` | the address a phone uses, for the pairing QR code; derived from the request if empty |
| `FORGE_URL`, `FORGE_REPO`, `FORGE_TOKEN` | optional; app updates (below). The token only needs to read the repository |
| `OVERPASS_URL` | the Overpass API the map's roads come from; default `https://overpass-api.de/api/interpreter`, `off` switches maps off, otherwise https only |
| `MAP_TILES_URL` | a TileJSON naming the vector tiles the map's roads come from; default OpenFreeMap's `https://tiles.openfreemap.org/planet`, `off` switches maps off, otherwise https only |
| `MAP_CACHE_DIR` | where fetched map tiles are kept across restarts (the manifest mounts a volume there); empty keeps them in memory only |
| `LISTEN_ADDR` | default `:8080` |
## Endpoints
@@ -60,18 +61,23 @@ download cut short`. The forge's address and token never appear in the log.
## Map roads
`POST /v1/map/roads` `{z, x, y}`, with the car's token: the drivable roads (motorway to
residential) of one web-mercator tile at zoom 14, for the app's "Grid with map" style. The car
names the tile, not its position, and in the body, so it stays out of access logs. The answer is
`POST /v1/map/roads` `{z, x, y}`, with the car's token: the drivable roads (motorway to minor
streets) of one web-mercator tile at zoom 14, for the app's "Grid with map" style. The car names
the tile, not its position, and in the body, so it stays out of access logs. The answer is
`{z, x, y, extent: 4096, ways: [{c, p: [x, y, …]}]}`: per road its class (0 motorway and trunk,
1 primary and secondary, 2 tertiary and unclassified, 3 residential and living streets) and its
points in tile units, simplified to about 1.5 m; gzipped when the car accepts it (20–30 KB a tile
in a city before that). The roads come from OpenStreetMap through `OVERPASS_URL`, one request at
a time and at most one a second, with a User-Agent naming this service, and are kept in memory
for 30 days (up to 3000 tiles); the car keeps its own copy too. 400 for anything but zoom 14 or
a tile outside it, 503 when Overpass is busy or unreachable (not cached, the car tries again a
minute later), 404 when maps are off. The log says `map tile fetched` with the car's installation
and the size, never the tile. Map data © OpenStreetMap contributors, ODbL.
1 primary and secondary, 2 tertiary, 3 minor streets) and its points in tile units, simplified to
about 1.5 m; gzipped when the car accepts it (10–15 KB a tile in a city before that).
The roads are fetched **only for the tiles a car asks for**: the OpenStreetMap vector tile
(OpenMapTiles schema) of that square from the TileJSON at `MAP_TILES_URL` (by default
OpenFreeMap: free, no key, no request limits; its template moves with each weekly build and is
looked up every 6 hours), decoded by a small reader of our own (`mvt.go`, the `transportation`
layer only). Each tile is fetched once and kept for 30 days in `MAP_CACHE_DIR` (and the last 300
in memory); at most two fetches run at once. A request waits up to 6 s; a slower fetch goes on
and is kept, and the car hears 503 with `Retry-After: 10` and gets the tile on its next try.
400 for anything but zoom 14 or a tile outside it, 503 when the tile host fails (not cached),
404 when maps are off. The log says `map tile fetched` with the size, never the tile.
Map data © OpenStreetMap contributors (ODbL), tiles © OpenMapTiles, served by OpenFreeMap.
## Settings from a phone