feat: add fileFetchHandler

examples/static_assets_server.ts

@@ -1,29 +1,12 @@
 // Copyright 2021 Deno Land Inc. All rights reserved. MIT license.
 
-import { createWorker } from "../mod.ts";
-import {
-  contentType,
-  lookup,
-} from "https://deno.land/x/media_types@v2.9.0/mod.ts";
+import { createWorker, handlers } from "../mod.ts";
 
 const staticAssets = await createWorker(
   "./examples/deploy_scripts/static_assets.ts",
   {
     name: "staticAssets",
-    async fetchHandler(evt) {
-      const url = new URL(evt.request.url);
-      if (url.protocol === "file:") {
-        const ct = contentType(lookup(evt.request.url) ?? "") ??
-          "text/plain";
-        const body = await Deno.readFile(url);
-        const response = new Response(body, {
-          headers: {
-            "content-type": ct,
-          },
-        });
-        evt.respondWith(response);
-      }
-    },
+    fetchHandler: handlers.fileFetchHandler,
   },
 );
 

lib/handlers.ts

@@ -0,0 +1,35 @@
+import {
+  contentType,
+  lookup,
+} from "https://deno.land/x/media_types@v2.9.0/mod.ts";
+
+import type { RequestEvent } from "../types.d.ts";
+
+/**
+ * A fetch handler that returns local files that are requested by the worker.
+ *
+ * This is useful when the worker is attempting to access static assets from
+ * its repo using `import.meta.url` as the base for a fetch request.
+ */
+export async function fileFetchHandler(evt: RequestEvent) {
+  const url = new URL(evt.request.url);
+  if (url.protocol === "file:") {
+    const stat = await Deno.stat(url);
+    let response: Response;
+    if (stat.isFile) {
+      const ct = contentType(lookup(evt.request.url) ?? "") ?? "text/plain";
+      const body = await Deno.readFile(url);
+      response = new Response(body, {
+        headers: {
+          "content-type": ct,
+        },
+      });
+    } else {
+      response = new Response(null, {
+        status: 404,
+        statusText: "Not Found",
+      });
+    }
+    evt.respondWith(response);
+  }
+}

mod.ts

@@ -2,6 +2,7 @@
 
 export { createWorker } from "./lib/deploy_worker.ts";
 export type { DeployWorker } from "./lib/deploy_worker.ts";
+export * as handlers from "./lib/handlers.ts";
 export { LogLevel, setLevel as setLogLevel } from "./lib/logger.ts";
 export * as testing from "./lib/testing.ts";
 export type { DeployOptions, DeployWorkerInfo } from "./types.d.ts";