Add fallback for /path to /path/index.html

Author: n4bb12

lib/fastify-static.ts

@@ -1,16 +1,58 @@
 import { FastifyInstance } from "fastify"
 import fastifyStatic from "fastify-static"
+import globby from "globby"
 import path from "path"
 
-import { Config } from "./types"
+import { Config, StaticFallbacks } from "./types"
+
+//
+// Unfortunately I couldn't make fastify-static add a fallback to /path/index.html when /path is requested.
+// Therefore this collects those fallbacks once on startup.
+//
+function collectFallbacks(staticDir: string) {
+  const files = globby.sync("", { cwd: staticDir, onlyFiles: true })
+
+  const fallbacks = files.reduce((result, filename) => {
+    if (!filename.includes("/")) {
+      return result
+    }
+    if (!filename.endsWith(".html") && !filename.endsWith(".htm")) {
+      return result
+    }
+
+    const directory = path.dirname(filename)
+    const url = "/" + directory
+
+    if (result[url]) {
+      return result
+    }
+
+    if (!result[directory]) {
+      const fallbackDir = path.resolve(staticDir, directory)
+      result["/" + directory] = fallbackDir
+    }
+
+    return result
+  }, {} as StaticFallbacks)
+
+  return fallbacks
+}
 
 //
 // https://github.com/fastify/fastify-static#fastify-static
 //
 export function registerServeStatic(server: FastifyInstance, config: Config) {
+  const fallbacks = collectFallbacks(config.staticDir)
+
   server.setNotFoundHandler(async (req, res) => {
-    res.sendFile("index.html", config.staticDir)
+    const fallbackDir = fallbacks[req.url]
+    if (fallbackDir) {
+      res.sendFile("index.html", fallbackDir)
+    } else {
+      res.sendFile("index.html", config.staticDir)
+    }
   })
+
   server.register(fastifyStatic, {
     root: path.resolve(config.staticDir),
     extensions: ["html", "htm"],

lib/types.ts

@@ -94,3 +94,7 @@ export interface GitHubUser {
   two_factor_authentication: boolean
   plan: GitHubPlan
 }
+
+export interface StaticFallbacks {
+  [url: string]: string
+}

package.json

@@ -29,6 +29,7 @@
     "fastify": "^3.9.2",
     "fastify-cookie": "^5.0.2",
     "fastify-static": "^3.3.0",
+    "globby": "^11.0.1",
     "nanoid": "^3.1.20",
     "ow": "^0.21.0"
   },

yarn.lock

@@ -1038,6 +1038,18 @@ [email protected]:
     merge2 "^1.3.0"
     slash "^3.0.0"
 
+globby@^11.0.1:
+  version "11.0.1"
+  resolved "https://registry.npmjs.org/globby/-/globby-11.0.1.tgz#9a2bf107a068f3ffeabc49ad702c79ede8cfd357"
+  integrity sha512-iH9RmgwCmUJHi2z5o2l3eTtGBtXek1OYlHrbcxOYugyHLmAsZrPj43OtHThd62Buh/Vv6VyCBD2bdyWcGNQqoQ==
+  dependencies:
+    array-union "^2.1.0"
+    dir-glob "^3.0.1"
+    fast-glob "^3.1.1"
+    ignore "^5.1.4"
+    merge2 "^1.3.0"
+    slash "^3.0.0"
+
 [email protected]:
   version "11.8.0"
   resolved "https://registry.yarnpkg.com/got/-/got-11.8.0.tgz#be0920c3586b07fd94add3b5b27cb28f49e6545f"