refactor: extract CCTV media and radio directory providers

server/providers/cctv/constants.js

@@ -0,0 +1,38 @@
+export const DEFAULT_CCTV_SOURCE_FILE = 'config/cctv_sources.austin.json';
+/** Austin Open Data portal endpoint for traffic camera records. */
+export const DEFAULT_AUSTIN_ROWS_URL = 'https://data.austintexas.gov/api/views/b4k4-adkb/rows.json?accessType=DOWNLOAD';
+/** Default cap on Austin cameras after distance-based prioritization. */
+export const DEFAULT_AUSTIN_MAX_SOURCES = 250;
+/** Global cap on total CCTV sources served by the proxy. */
+export const DEFAULT_CCTV_MAX_SOURCES = 900;
+/** Reference point for Austin camera prioritization (Congress & 6th). */
+export const AUSTIN_DOWNTOWN = { lat: 30.2672, lon: -97.7431 };
+/** Caltrans CCTV: one JSON feed per district, identical schema statewide. */
+export const CALTRANS_CCTV_URL = (district) =>
+  `https://cwwp2.dot.ca.gov/data/d${district}/cctv/cctvStatusD${String(district).padStart(2, '0')}.json`;
+/** Districts fetched by default: SF Bay (4), LA (7), San Diego (11), Sacramento (3). */
+export const DEFAULT_CALTRANS_DISTRICTS = '4,7,11,3';
+export const DEFAULT_CALTRANS_MAX_SOURCES = 300;
+/** Prioritization anchors: downtown cores of the four default metros. */
+export const CALTRANS_ANCHORS = [
+  { lat: 37.7793, lon: -122.4193 }, // San Francisco
+  { lat: 34.0537, lon: -118.2428 }, // Los Angeles
+  { lat: 32.7157, lon: -117.1611 }, // San Diego
+  { lat: 38.5816, lon: -121.4944 }, // Sacramento
+];
+/** TfL JamCams: one keyless list endpoint; frames live on a public S3 bucket. */
+export const TFL_JAMCAM_URL = 'https://api.tfl.gov.uk/Place/Type/JamCam';
+export const TFL_IMAGE_ORIGIN = 'https://s3-eu-west-1.amazonaws.com/jamcams.tfl.gov.uk/';
+export const DEFAULT_TFL_MAX_SOURCES = 250;
+export const LONDON_CENTER = { lat: 51.5074, lon: -0.1278 };
+/** Camera CATALOGS change rarely; 15 min keeps multi-megabyte upstream list refetches (Austin rows.json + 4 Caltrans districts + TfL) infrequent. Frames are fetched per-request and are unaffected. */
+export const CCTV_SOURCE_CACHE_MS = 15 * 60 * 1000;
+/** Per-provider catalog-fetch timeout. Bounds the worst-case refresh so one
+ * stalled upstream can't leave getCctvSources (and thus every CCTV route)
+ * pending forever — a hung fetch aborts, the loader returns [], and
+ * serve-stale/other packs take over. */
+export const CCTV_SOURCE_FETCH_TIMEOUT_MS = 15 * 1000;
+/** Individual CCTV image fetches must settle before the active 10-second
+ * client refresh cadence. A bounded miss can fall through to Street View or
+ * the synthetic frame instead of leaving the browser preview pending. */
+export const CCTV_FRAME_FETCH_TIMEOUT_MS = 8 * 1000;