4 files changed, 77 insertions, 8 deletions
diff --git a/packages/astro/CHANGELOG.md b/packages/astro/CHANGELOG.md
index aa3d02e32..2d5bd7070 100644
--- a/packages/astro/CHANGELOG.md
+++ b/packages/astro/CHANGELOG.md
@@ -1,5 +1,74 @@
 # astro
 
+## 5.0.0-beta.8
+
+### Minor Changes
+
+- [#12373](https://github.com/withastro/astro/pull/12373) [`d10f918`](https://github.com/withastro/astro/commit/d10f91815e63f169cff3d1daef5505aef077c76c) Thanks [@bholmesdev](https://github.com/bholmesdev)! - Changes the default behavior for Astro Action form requests to a standard POST submission.
+
+  In Astro 4.x, actions called from an HTML form would trigger a redirect with the result forwarded using cookies. This caused issues for large form errors and return values that exceeded the 4 KB limit of cookie-based storage.
+
+  Astro 5.0 now renders the result of an action as a POST result without any forwarding. This will introduce a "confirm form resubmission?" dialog when a user attempts to refresh the page, though it no longer imposes a 4 KB limit on action return value.
+
+  ## Customize form submission behavior
+
+  If you prefer to address the "confirm form resubmission?" dialog on refresh, or to preserve action results across sessions, you can now [customize action result handling from middleware](https://5-0-0-beta.docs.astro.build/en/guides/actions/#advanced-persist-action-results-with-a-session).
+
+  We recommend using a session storage provider [as described in our Netlify Blob example](https://5-0-0-beta.docs.astro.build/en/guides/actions/#advanced-persist-action-results-with-a-session). However, if you prefer the cookie forwarding behavior from 4.X and accept the 4 KB size limit, you can implement the pattern as shown in this sample snippet:
+
+  ```ts
+  // src/middleware.ts
+  import { defineMiddleware } from 'astro:middleware';
+  import { getActionContext } from 'astro:actions';
+
+  export const onRequest = defineMiddleware(async (context, next) => {
+    // Skip requests for prerendered pages
+    if (context.isPrerendered) return next();
+
+    const { action, setActionResult, serializeActionResult } = getActionContext(context);
+
+    // If an action result was forwarded as a cookie, set the result
+    // to be accessible from `Astro.getActionResult()`
+    const payload = context.cookies.get('ACTION_PAYLOAD');
+    if (payload) {
+      const { actionName, actionResult } = payload.json();
+      setActionResult(actionName, actionResult);
+      context.cookies.delete('ACTION_PAYLOAD');
+      return next();
+    }
+
+    // If an action was called from an HTML form action,
+    // call the action handler and redirect with the result as a cookie.
+    if (action?.calledFrom === 'form') {
+      const actionResult = await action.handler();
+
+      context.cookies.set('ACTION_PAYLOAD', {
+        actionName: action.name,
+        actionResult: serializeActionResult(actionResult),
+      });
+
+      if (actionResult.error) {
+        // Redirect back to the previous page on error
+        const referer = context.request.headers.get('Referer');
+        if (!referer) {
+          throw new Error('Internal: Referer unexpectedly missing from Action POST request.');
+        }
+        return context.redirect(referer);
+      }
+      // Redirect to the destination page on success
+      return context.redirect(context.originPathname);
+    }
+
+    return next();
+  });
+  ```
+
+### Patch Changes
+
+- [#12339](https://github.com/withastro/astro/pull/12339) [`bdb75a8`](https://github.com/withastro/astro/commit/bdb75a87f24d7f032797483164fb2f82aa691fee) Thanks [@ematipico](https://github.com/ematipico)! - Adds an error when `Astro.rewrite()` is used to rewrite an on-demand route with a static route when using the `"server"` output.
+
+  This is a forbidden rewrite because Astro can't retrieve the emitted static route at runtime. This route is served by the hosting platform, and not Astro itself.
+
 ## 5.0.0-beta.7
 
 ### Minor Changes
diff --git a/packages/astro/package.json b/packages/astro/package.json
index a678ba60b..d29b01932 100644
--- a/packages/astro/package.json
+++ b/packages/astro/package.json
@@ -1,6 +1,6 @@
 {
   "name": "astro",
-  "version": "5.0.0-beta.7",
+  "version": "5.0.0-beta.8",
   "description": "Astro is a modern site builder with web best practices, performance, and DX front-of-mind.",
   "type": "module",
   "author": "withastro",
diff --git a/packages/astro/src/actions/integration.ts b/packages/astro/src/actions/integration.ts
index 23fbd904a..d7c99fc42 100644
--- a/packages/astro/src/actions/integration.ts
+++ b/packages/astro/src/actions/integration.ts
@@ -3,7 +3,7 @@ import { AstroError } from '../core/errors/errors.js';
 import { viteID } from '../core/util.js';
 import type { AstroSettings } from '../types/astro.js';
 import type { AstroIntegration } from '../types/public/integrations.js';
-import { ACTIONS_TYPES_FILE, VIRTUAL_MODULE_ID, ACTION_RPC_ROUTE_PATTERN } from './consts.js';
+import { ACTIONS_TYPES_FILE, ACTION_RPC_ROUTE_PATTERN, VIRTUAL_MODULE_ID } from './consts.js';
 
 /**
  * This integration is applied when the user is using Actions in their project.
diff --git a/packages/astro/src/actions/runtime/virtual/server.ts b/packages/astro/src/actions/runtime/virtual/server.ts
index f8fac557a..f28b3c239 100644
--- a/packages/astro/src/actions/runtime/virtual/server.ts
+++ b/packages/astro/src/actions/runtime/virtual/server.ts
@@ -1,13 +1,17 @@
 import { z } from 'zod';
 import { ActionCalledFromServerError } from '../../../core/errors/errors-data.js';
 import { AstroError } from '../../../core/errors/errors.js';
+import type { APIContext } from '../../../types/public/index.js';
+import { ACTION_RPC_ROUTE_PATTERN } from '../../consts.js';
 import {
-	formContentTypes,
-	hasContentType,
 	type ActionAPIContext,
 	type ErrorInferenceObject,
 	type MaybePromise,
+	formContentTypes,
+	hasContentType,
 } from '../utils.js';
+import type { Locals } from '../utils.js';
+import { getAction } from './get-action.js';
 import {
 	ACTION_QUERY_PARAMS,
 	ActionError,
@@ -18,10 +22,6 @@ import {
 	deserializeActionResult,
 	serializeActionResult,
 } from './shared.js';
-import type { Locals } from '../utils.js';
-import { getAction } from './get-action.js';
-import type { APIContext } from '../../../types/public/index.js';
-import { ACTION_RPC_ROUTE_PATTERN } from '../../consts.js';
 
 export * from './shared.js';