fix(ssg): use response header to mark as disabled routes for SSG (#2477)

* fix(ssg): use response header to mark as disabled routes for SSG

* fix(ssg): fix initialization error of SSG_DISABLED_RESPONSE, and deprecate it.

* chore: denoify

deno_dist/helper/ssg/index.ts

@@ -1,2 +1,8 @@
 export * from './ssg.ts'
-export { SSG_DISABLED_RESPONSE, ssgParams, isSSGContext, disableSSG, onlySSG } from './middleware.ts'
+export {
+  X_HONO_DISABLE_SSG_HEADER_KEY,
+  ssgParams,
+  isSSGContext,
+  disableSSG,
+  onlySSG,
+} from './middleware.ts'

deno_dist/helper/ssg/middleware.ts

@@ -2,7 +2,23 @@ import type { Context } from '../../context.ts'
 import type { Env, MiddlewareHandler } from '../../types.ts'
 
 export const SSG_CONTEXT = 'HONO_SSG_CONTEXT'
-export const SSG_DISABLED_RESPONSE = new Response('SSG is disabled', { status: 404 })
+export const X_HONO_DISABLE_SSG_HEADER_KEY = 'x-hono-disable-ssg'
+
+/**
+ * @deprecated
+ * Use `X_HONO_DISABLE_SSG_HEADER_KEY` instead.
+ * This constant will be removed in the next minor version.
+ */
+export const SSG_DISABLED_RESPONSE = (() => {
+  try {
+    return new Response('SSG is disabled', {
+      status: 404,
+      headers: { [X_HONO_DISABLE_SSG_HEADER_KEY]: 'true' },
+    })
+  } catch (e) {
+    return null
+  }
+})() as Response
 
 interface SSGParam {
   [key: string]: string
@@ -43,7 +59,8 @@ export const isSSGContext = (c: Context): boolean => !!c.env?.[SSG_CONTEXT]
 export const disableSSG = (): MiddlewareHandler =>
   async function disableSSG(c, next) {
     if (isSSGContext(c)) {
-      return SSG_DISABLED_RESPONSE
+      c.header(X_HONO_DISABLE_SSG_HEADER_KEY, 'true')
+      return c.notFound()
     }
     await next()
   }

deno_dist/helper/ssg/ssg.ts

@@ -4,7 +4,7 @@ import type { Env, Schema } from '../../types.ts'
 import { createPool } from '../../utils/concurrent.ts'
 import { getExtension } from '../../utils/mime.ts'
 import type { AddedSSGDataRequest, SSGParams } from './middleware.ts'
-import { SSG_DISABLED_RESPONSE, SSG_CONTEXT } from './middleware.ts'
+import { X_HONO_DISABLE_SSG_HEADER_KEY, SSG_CONTEXT } from './middleware.ts'
 import { joinPaths, dirname, filterStaticGenerateRoutes } from './utils.ts'
 
 const DEFAULT_CONCURRENCY = 2 // default concurrency for ssg
@@ -168,7 +168,7 @@ export const fetchRoutesContent = function* <
                       [SSG_CONTEXT]: true,
                     })
                   )
-                  if (response === SSG_DISABLED_RESPONSE) {
+                  if (response.headers.get(X_HONO_DISABLE_SSG_HEADER_KEY)) {
                     resolveReq(undefined)
                     return
                   }

src/helper/ssg/index.ts

@@ -1,2 +1,8 @@
 export * from './ssg'
-export { SSG_DISABLED_RESPONSE, ssgParams, isSSGContext, disableSSG, onlySSG } from './middleware'
+export {
+  X_HONO_DISABLE_SSG_HEADER_KEY,
+  ssgParams,
+  isSSGContext,
+  disableSSG,
+  onlySSG,
+} from './middleware'

src/helper/ssg/middleware.ts

@@ -2,7 +2,23 @@ import type { Context } from '../../context'
 import type { Env, MiddlewareHandler } from '../../types'
 
 export const SSG_CONTEXT = 'HONO_SSG_CONTEXT'
-export const SSG_DISABLED_RESPONSE = new Response('SSG is disabled', { status: 404 })
+export const X_HONO_DISABLE_SSG_HEADER_KEY = 'x-hono-disable-ssg'
+
+/**
+ * @deprecated
+ * Use `X_HONO_DISABLE_SSG_HEADER_KEY` instead.
+ * This constant will be removed in the next minor version.
+ */
+export const SSG_DISABLED_RESPONSE = (() => {
+  try {
+    return new Response('SSG is disabled', {
+      status: 404,
+      headers: { [X_HONO_DISABLE_SSG_HEADER_KEY]: 'true' },
+    })
+  } catch (e) {
+    return null
+  }
+})() as Response
 
 interface SSGParam {
   [key: string]: string
@@ -43,7 +59,8 @@ export const isSSGContext = (c: Context): boolean => !!c.env?.[SSG_CONTEXT]
 export const disableSSG = (): MiddlewareHandler =>
   async function disableSSG(c, next) {
     if (isSSGContext(c)) {
-      return SSG_DISABLED_RESPONSE
+      c.header(X_HONO_DISABLE_SSG_HEADER_KEY, 'true')
+      return c.notFound()
     }
     await next()
   }

src/helper/ssg/ssg.test.tsx

@@ -3,7 +3,13 @@ import { Hono } from '../../hono'
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
 import { jsx } from '../../jsx'
 import { poweredBy } from '../../middleware/powered-by'
-import { SSG_DISABLED_RESPONSE, ssgParams, isSSGContext, disableSSG, onlySSG } from './middleware'
+import {
+  X_HONO_DISABLE_SSG_HEADER_KEY,
+  ssgParams,
+  isSSGContext,
+  disableSSG,
+  onlySSG,
+} from './middleware'
 import { fetchRoutesContent, saveContentToFile, toSSG, defaultExtensionMap } from './ssg'
 import type {
   BeforeRequestHook,
@@ -594,7 +600,9 @@ describe('disableSSG/onlySSG middlewares', () => {
   const app = new Hono()
   app.get('/', (c) => c.html(<h1>Hello</h1>))
   app.get('/api', disableSSG(), (c) => c.text('an-api'))
-  app.get('/disable-by-response', () => SSG_DISABLED_RESPONSE)
+  app.get('/disable-by-response', (c) =>
+    c.text('', 404, { [X_HONO_DISABLE_SSG_HEADER_KEY]: 'true' })
+  )
   app.get('/static-page', onlySSG(), (c) => c.html(<h1>Welcome to my site</h1>))
 
   const fsMock: FileSystemModule = {

src/helper/ssg/ssg.ts

@@ -4,7 +4,7 @@ import type { Env, Schema } from '../../types'
 import { createPool } from '../../utils/concurrent'
 import { getExtension } from '../../utils/mime'
 import type { AddedSSGDataRequest, SSGParams } from './middleware'
-import { SSG_DISABLED_RESPONSE, SSG_CONTEXT } from './middleware'
+import { X_HONO_DISABLE_SSG_HEADER_KEY, SSG_CONTEXT } from './middleware'
 import { joinPaths, dirname, filterStaticGenerateRoutes } from './utils'
 
 const DEFAULT_CONCURRENCY = 2 // default concurrency for ssg
@@ -168,7 +168,7 @@ export const fetchRoutesContent = function* <
                       [SSG_CONTEXT]: true,
                     })
                   )
-                  if (response === SSG_DISABLED_RESPONSE) {
+                  if (response.headers.get(X_HONO_DISABLE_SSG_HEADER_KEY)) {
                     resolveReq(undefined)
                     return
                   }