Add __STATIC_CONTENT_MANIFEST module allowing module mode sites (#398)

Wrangler injects a text `__STATIC_CONTENT_MANIFEST` module in modules
mode for use with `@cloudflare/kv-asset-handler`.

See https://github.com/cloudflare/kv-asset-handler#es-modules.

Author: mrbbot

packages/tre/src/index.ts

@@ -23,6 +23,7 @@ import {
   Plugins,
   SERVICE_ENTRY,
   SOCKET_ENTRY,
+  maybeGetSitesManifestModule,
   normaliseDurableObject,
 } from "./plugins";
 import { HEADER_CUSTOM_SERVICE, getUserServiceName } from "./plugins/core";
@@ -33,6 +34,7 @@ import {
   Service,
   Socket,
   Worker_Binding,
+  Worker_Module,
   getSupportedRuntime,
   serializeConfig,
 } from "./runtime";
@@ -403,12 +405,20 @@ export class Miniflare {
 
     for (let i = 0; i < allWorkerOpts.length; i++) {
       const workerOpts = allWorkerOpts[i];
+
       // Collect all bindings from this worker
       const workerBindings: Worker_Binding[] = [];
+      const additionalModules: Worker_Module[] = [];
       for (const [key, plugin] of PLUGIN_ENTRIES) {
         const pluginBindings = await plugin.getBindings(workerOpts[key]);
         if (pluginBindings !== undefined) {
           workerBindings.push(...pluginBindings);
+
+          if (key === "kv") {
+            // Add "__STATIC_CONTENT_MANIFEST" module if sites enabled
+            const module = maybeGetSitesManifestModule(pluginBindings);
+            if (module !== undefined) additionalModules.push(module);
+          }
         }
       }
 
@@ -421,6 +431,7 @@ export class Miniflare {
           workerBindings,
           workerIndex: i,
           durableObjectClassNames,
+          additionalModules,
         });
         if (pluginServices !== undefined) {
           for (const service of pluginServices) {

packages/tre/src/plugins/core/index.ts

@@ -209,6 +209,7 @@ export const CORE_PLUGIN: Plugin<
     workerIndex,
     sharedOptions,
     durableObjectClassNames,
+    additionalModules,
   }) {
     // Define core/shared services.
     // Services get de-duped by name, so only the first worker's
@@ -232,6 +233,11 @@ export const CORE_PLUGIN: Plugin<
     // Define regular user worker if script is set
     const workerScript = getWorkerScript(options);
     if (workerScript !== undefined) {
+      // Add additional modules (e.g. "__STATIC_CONTENT_MANIFEST") if any
+      if ("modules" in workerScript) {
+        workerScript.modules.push(...additionalModules);
+      }
+
       const name = getUserServiceName(options.name);
       const classNames = durableObjectClassNames.get(name) ?? [];
       const compatibilityDate = validateCompatibilityDate(

packages/tre/src/plugins/kv/index.ts

@@ -88,4 +88,5 @@ export const KV_PLUGIN: Plugin<
 };
 
 export * from "./gateway";
+export { maybeGetSitesManifestModule } from "./sites";
 export { KV_PLUGIN_NAME };

packages/tre/src/plugins/kv/sites.ts

@@ -1,6 +1,6 @@
 import assert from "assert";
 import { pathToFileURL } from "url";
-import { Service, Worker_Binding } from "../../runtime";
+import { Service, Worker_Binding, Worker_Module } from "../../runtime";
 import {
   MatcherRegExps,
   deserialiseRegExps,
@@ -171,6 +171,17 @@ export async function getSitesBindings(
   ];
 }
 
+export function maybeGetSitesManifestModule(
+  bindings: Worker_Binding[]
+): Worker_Module | undefined {
+  for (const binding of bindings) {
+    if (binding.name === BINDING_JSON_SITE_MANIFEST) {
+      assert("json" in binding && binding.json !== undefined);
+      return { name: BINDING_JSON_SITE_MANIFEST, text: binding.json };
+    }
+  }
+}
+
 export function getSitesService(options: SitesOptions): Service {
   // `siteRegExps` should've been set in `getSitesBindings()`, and `options`
   // should be the same object reference as before.

packages/tre/src/plugins/shared/index.ts

@@ -1,5 +1,5 @@
 import { z } from "zod";
-import { Service, Worker_Binding } from "../../runtime";
+import { Service, Worker_Binding, Worker_Module } from "../../runtime";
 import { Awaitable, OptionalZodTypeOf } from "../../shared";
 import { GatewayConstructor } from "./gateway";
 import { RouterConstructor } from "./router";
@@ -16,6 +16,7 @@ export interface PluginServicesOptions<
   workerBindings: Worker_Binding[];
   workerIndex: number;
   durableObjectClassNames: DurableObjectClassNames;
+  additionalModules: Worker_Module[];
 }
 
 export interface PluginBase<