Allow 200 response for endpoints in build (#5258)

.changeset/cool-ducks-mix.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Allow 200 response for endpoints in build

packages/astro/src/core/build/generate.ts

@@ -21,7 +21,7 @@ import {
 } from '../../core/path.js';
 import { runHookBuildGenerated } from '../../integrations/index.js';
 import { BEFORE_HYDRATION_SCRIPT_ID, PAGE_SCRIPT_ID } from '../../vite-plugin-scripts/index.js';
-import { call as callEndpoint } from '../endpoint/index.js';
+import { call as callEndpoint, throwIfRedirectNotAllowed } from '../endpoint/index.js';
 import { debug, info } from '../logger/core.js';
 import { createEnvironment, createRenderContext, renderPage } from '../render/index.js';
 import { callGetStaticPaths } from '../render/route-cache.js';
@@ -374,18 +374,19 @@ async function generatePath(
 		const result = await callEndpoint(endpointHandler, env, ctx);
 
 		if (result.type === 'response') {
-			throw new Error(`Returning a Response from an endpoint is not supported in SSG mode.`);
+			throwIfRedirectNotAllowed(result.response, opts.settings.config);
+			// If there's no body, do nothing
+			if (!result.response.body) return;
+			body = await result.response.text();
+		} else {
+			body = result.body;
+			encoding = result.encoding;
 		}
-		body = result.body;
-		encoding = result.encoding;
 	} else {
 		const response = await renderPage(mod, ctx, env);
-
+		throwIfRedirectNotAllowed(response, opts.settings.config);
-		// If there's a redirect or something, just do nothing.
+		// If there's no body, do nothing
-		if (response.status !== 200 || !response.body) {
+		if (!response.body) return;
-			return;
-		}
-
 		body = await response.text();
 	}
 

packages/astro/src/core/endpoint/index.ts

@@ -1,4 +1,4 @@
-import type { APIContext, EndpointHandler, Params } from '../../@types/astro';
+import type { APIContext, AstroConfig, EndpointHandler, Params } from '../../@types/astro';
 import type { Environment, RenderContext } from '../render/index';
 
 import { renderEndpoint } from '../../runtime/server/index.js';
@@ -113,3 +113,15 @@ export async function call(
 		cookies: context.cookies,
 	};
 }
+
+function isRedirect(statusCode: number) {
+	return statusCode >= 300 && statusCode < 400;
+}
+
+export function throwIfRedirectNotAllowed(response: Response, config: AstroConfig) {
+	if (config.output !== 'server' && isRedirect(response.status)) {
+		throw new Error(
+			`Redirects are only available when using output: 'server'. Update your Astro config if you need SSR features.`
+		);
+	}
+}

packages/astro/src/vite-plugin-astro-server/index.ts

@@ -19,6 +19,7 @@ import { createRequest } from '../core/request.js';
 import { createRouteManifest, matchAllRoutes } from '../core/routing/index.js';
 import { resolvePages } from '../core/util.js';
 import notFoundTemplate, { subpathNotUsedTemplate } from '../template/4xx.js';
+import { throwIfRedirectNotAllowed } from '../core/endpoint/index.js';
 
 interface AstroPluginOptions {
 	settings: AstroSettings;
@@ -293,18 +294,6 @@ async function handleRequest(
 	}
 }
 
-function isRedirect(statusCode: number) {
-	return statusCode >= 300 && statusCode < 400;
-}
-
-function throwIfRedirectNotAllowed(response: Response, config: AstroConfig) {
-	if (config.output !== 'server' && isRedirect(response.status)) {
-		throw new Error(
-			`Redirects are only available when using output: 'server'. Update your Astro config if you need SSR features.`
-		);
-	}
-}
-
 async function handleRoute(
 	matchedRoute: AsyncReturnType<typeof matchRoute>,
 	url: URL,

packages/astro/test/fixtures/with-endpoint-routes/src/pages/invalid-redirect.json.ts

@@ -0,0 +1,11 @@
+export const get = () => {
+  return new Response(
+    undefined,
+    {
+      status: 301,
+      headers: {
+        Location: 'https://example.com',
+      }
+    }
+  );
+};