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328 lines (307 loc) · 8.98 KB
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import {
createTimeout,
jsonResponse,
readLimitedBytes,
} from "./http.js";
export const OVERPASS_URL = "https://overpass-api.de/api/interpreter";
export const MAP_RADIUS_METERS = 650;
const MAX_BYTES = 1_000_000;
const MAX_ROADS = 180;
const MAX_POINTS = 4_000;
const MAX_LABELS = 24;
const MAX_LABEL_CODE_POINTS = 40;
const MAX_LOCALIZED_NAMES = 8;
const TIMEOUT_MS = 8_000;
const MAP_CELL_DEGREES = 0.0018;
const MAJOR_HIGHWAYS = new Set([
"motorway",
"trunk",
"primary",
"secondary",
"tertiary",
"motorway_link",
"trunk_link",
"primary_link",
"secondary_link",
"tertiary_link",
]);
function mapError(code, message, status) {
return jsonResponse({ error: { code, message } }, { status });
}
function coordinateParameter(value, minimum, maximum) {
if (value === null || value.trim() === "") return null;
const parsed = Number(value);
if (!Number.isFinite(parsed) || parsed < minimum || parsed > maximum) {
return null;
}
return parsed;
}
export function mapCell(latitude, longitude) {
const lat = Math.floor(latitude / MAP_CELL_DEGREES) * MAP_CELL_DEGREES;
const lng = Math.floor(longitude / MAP_CELL_DEGREES) * MAP_CELL_DEGREES;
return `${lat.toFixed(4)},${lng.toFixed(4)}`;
}
export function buildOverpassQuery(latitude, longitude) {
const around = `(around:${MAP_RADIUS_METERS},${latitude},${longitude})`;
return [
"[out:json][timeout:8];",
`way["highway"]${around}->.roads;`,
`nwr["name"][~"^(railway|public_transport|place|leisure|tourism|amenity)$"` +
`~"^(station|halt|city|town|village|suburb|quarter|neighbourhood|locality|square|park|garden|stadium|museum|attraction|gallery|hospital|university|school|library|marketplace|townhall)$"]${around}->.named;`,
".roads out geom;",
".named out center;",
].join("");
}
function normalizedRoad(element) {
const highway = element?.tags?.highway;
if (element?.type !== "way" || typeof highway !== "string") return null;
const points = Array.isArray(element.geometry)
? element.geometry.flatMap((point) => {
const latitude = Number(point?.lat);
const longitude = Number(point?.lon);
return Number.isFinite(latitude) && Number.isFinite(longitude)
? [[latitude, longitude]]
: [];
})
: [];
if (points.length < 2) return null;
return {
kind: MAJOR_HIGHWAYS.has(highway) ? "major" : "minor",
points,
};
}
function normalizedName(raw) {
if (typeof raw !== "string") return null;
const clean = raw
.replace(/[\u0000-\u001f\u007f]/g, " ")
.replace(/\s+/g, " ")
.trim();
if (!clean) return null;
return [...clean].slice(0, MAX_LABEL_CODE_POINTS).join("");
}
function normalizedNames(tags) {
const name = normalizedName(tags?.name);
if (!name) return null;
const localizedNames = Object.entries(tags ?? {})
.flatMap(([key, value]) => {
if (!key.startsWith("name:")) return [];
const language = key.slice(5);
if (!/^[a-z]{2,3}(?:-[a-z0-9]{2,8})*$/i.test(language)) return [];
const localized = normalizedName(value);
return localized ? [[language, localized]] : [];
})
.sort(([left], [right]) => left.localeCompare(right))
.slice(0, MAX_LOCALIZED_NAMES);
return {
name,
...(localizedNames.length > 0 && {
localizedNames: Object.fromEntries(localizedNames),
}),
};
}
function geographicPoint(latitudeValue, longitudeValue) {
const latitude = Number(latitudeValue);
const longitude = Number(longitudeValue);
return Number.isFinite(latitude)
&& latitude >= -90
&& latitude <= 90
&& Number.isFinite(longitude)
&& longitude >= -180
&& longitude <= 180
? [latitude, longitude]
: null;
}
function labelPoint(element, road) {
if (element?.type === "node") {
const point = geographicPoint(element.lat, element.lon);
if (point) return point;
}
const center = geographicPoint(element?.center?.lat, element?.center?.lon);
if (center) return center;
if (!road) return null;
return road.points[Math.floor(road.points.length / 2)] ?? null;
}
function labelKind(element, road) {
if (
["station", "halt"].includes(element?.tags?.railway)
|| element?.tags?.public_transport === "station"
) {
return { kind: "transit", priority: 0 };
}
if (typeof element?.tags?.place === "string") {
return { kind: "place", priority: 1 };
}
if (road?.kind === "major") {
return { kind: "road", priority: 2 };
}
if (
element?.tags?.leisure
|| element?.tags?.tourism
|| element?.tags?.amenity
) {
return { kind: "landmark", priority: 3 };
}
if (road) return { kind: "road", priority: 4 };
return null;
}
function normalizedLabels(elements) {
const candidates = elements.flatMap((element, sourceIndex) => {
const road = normalizedRoad(element);
const classification = labelKind(element, road);
const names = normalizedNames(element?.tags);
const point = labelPoint(element, road);
if (!classification || !names || !point) return [];
return [{
...classification,
...names,
point,
sourceIndex,
}];
});
candidates.sort(
(left, right) =>
left.priority - right.priority
|| left.sourceIndex - right.sourceIndex,
);
const labels = [];
const seen = new Set();
for (const candidate of candidates) {
const key = candidate.name.toLocaleLowerCase("ko-KR");
if (seen.has(key)) continue;
seen.add(key);
labels.push({
kind: candidate.kind,
name: candidate.name,
...(candidate.localizedNames && {
localizedNames: candidate.localizedNames,
}),
point: candidate.point,
});
if (labels.length >= MAX_LABELS) break;
}
return labels;
}
function normalizeMapPayload(payload, cell) {
const elements = Array.isArray(payload?.elements) ? payload.elements : [];
const candidates = elements.map(normalizedRoad).filter(Boolean);
candidates.sort((left, right) => {
if (left.kind === right.kind) return 0;
return left.kind === "major" ? -1 : 1;
});
const roads = [];
let pointCount = 0;
for (const candidate of candidates) {
if (roads.length >= MAX_ROADS) break;
const remaining = MAX_POINTS - pointCount;
if (remaining < 2) break;
const points = candidate.points.slice(0, remaining);
if (points.length < 2) continue;
roads.push({ kind: candidate.kind, points });
pointCount += points.length;
}
return {
cell,
attribution: "© OSM CONTRIBUTORS",
roads,
labels: normalizedLabels(elements),
};
}
function cacheRequest(cell) {
return new Request(
`https://sandevistan-map-cache.invalid/roads-labels-v5?cell=${encodeURIComponent(cell)}`,
);
}
export async function handleMapRequest(
request,
_env,
{
fetchImpl = fetch,
cache = globalThis.caches?.default,
setTimeoutImpl = setTimeout,
clearTimeoutImpl = clearTimeout,
} = {},
) {
const url = new URL(request.url);
const latitude = coordinateParameter(
url.searchParams.get("lat"),
-90,
90,
);
const longitude = coordinateParameter(
url.searchParams.get("lng"),
-180,
180,
);
if (latitude === null || longitude === null) {
return mapError(
"INVALID_COORDINATE",
"Latitude or longitude is invalid",
400,
);
}
const cell = mapCell(latitude, longitude);
const key = cacheRequest(cell);
if (cache) {
try {
const cached = await cache.match(key);
if (cached) return cached;
} catch {
// A cache outage must not prevent a live map response.
}
}
const timeout = createTimeout(
TIMEOUT_MS,
setTimeoutImpl,
clearTimeoutImpl,
);
try {
const upstream = await fetchImpl(OVERPASS_URL, {
method: "POST",
headers: {
"content-type": "application/x-www-form-urlencoded;charset=UTF-8",
"user-agent": "SANDEVISTAN-G2-Personal-Prototype/0.1",
},
body: new URLSearchParams({
data: buildOverpassQuery(latitude, longitude),
}),
redirect: "error",
signal: timeout.signal,
});
if (!upstream.ok) {
return mapError(
"MAP_UPSTREAM_ERROR",
"Map upstream request failed",
502,
);
}
const bytes = await readLimitedBytes(upstream, MAX_BYTES);
const payload = JSON.parse(new TextDecoder().decode(bytes));
const response = jsonResponse(normalizeMapPayload(payload, cell), {
headers: {
"cache-control": "public, max-age=3600, s-maxage=86400",
},
});
if (cache) {
try {
await cache.put(key, response.clone());
} catch {
// The current response remains usable when cache persistence fails.
}
}
return response;
} catch (error) {
if (timeout.signal.aborted || error?.name === "AbortError") {
return mapError("MAP_TIMEOUT", "Map request timed out", 504);
}
if (error instanceof Error && error.message === "RESPONSE_TOO_LARGE") {
return mapError("MAP_TOO_LARGE", "Map response is too large", 502);
}
return mapError(
"MAP_UPSTREAM_ERROR",
"Map upstream request failed",
502,
);
} finally {
timeout.dispose();
}
}