feat(server): create server route and tileset path function

packages/server/src/route.link.ts

@@ -0,0 +1,27 @@
+import { BasemapsConfigProvider, getAllImagery, } from '@basemaps/config';
+import { Epsg } from '@basemaps/geo';
+import { getPreviewUrl } from '@basemaps/shared';
+
+/**
+ * If a tileset layer of the given id and projection exists, this function returns a Basemaps URL
+ * path that is already zoomed to the extent of the tileset. Otherwise, this function returns null.
+ * 
+ * @param id - The id of the tileset.
+ * @example "ashburton-2023-0.1m"
+ * 
+ * @param projection - The projection from the tileset's layers to consider.
+ * @example Epsg.Google = 3857
+ */
+export async function getTileSetPath(cfg: BasemapsConfigProvider, id: string, projection: Epsg): Promise<string | null> {
+    const tileSet = await cfg.TileSet.get(id)
+    if (!tileSet) return null
+
+    const imageryMap = await getAllImagery(cfg, tileSet.layers, [projection]);
+
+    const [_, imagery] = Array.from(imageryMap)[0]
+    if (!imagery) return null
+
+    const url = getPreviewUrl({ imagery })
+
+    return (`${url.slug}?i=${url.name}`)
+}

packages/server/src/server.ts

@@ -1,5 +1,6 @@
 // Fastfiy uses a lot of floating promises
 /* eslint-disable @typescript-eslint/no-floating-promises */
+import { Epsg } from '@basemaps/geo';
 import { handler } from '@basemaps/lambda-tiler';
 import { Env, fsa, getDefaultConfig, LogType, setDefaultConfig } from '@basemaps/shared';
 import formBodyPlugin from '@fastify/formbody';
@@ -14,6 +15,7 @@ import { URL } from 'url';
 
 import { loadConfig, ServerOptions } from './config.js';
 import { createLayersHtml } from './route.layers.js';
+import { getTileSetPath } from './route.link.js';
 
 const instanceId = ulid.ulid();
 
@@ -95,5 +97,26 @@ export async function createServer(opts: ServerOptions, logger: LogType): Promis
     res.send(doc);
   });
 
+  /**
+   * @route GET /link/:tileSetId
+   * 
+   * @example /link/ashburton-2023-0.1m
+   * 
+   * @description If a tileset layer of the given id and 3857 projection exists, the server redirects the client to a Basemaps
+   * URL that is already zoomed to the extent of the layer. Otherwise, the server returns an 'HTTP 404 Not found' status code.
+   * 
+   */
+  BasemapsServer.get('/link/:tileSetId', async (req: FastifyRequest<{ Params: { tileSetId: string } }>, res: FastifyReply) => {
+    const { tileSetId } = req.params
+
+    const path = await getTileSetPath(cfg, tileSetId, Epsg.Google);
+
+    if (path) {
+      res.redirect(`/${path}`)
+    } else {
+      res.status(404)
+    }
+  });
+
   return BasemapsServer;
 }