fix(standard-server): unify empty body parsing behavior across envs (#533)

Empty body parsing can be `undefined` in some environments (e.g., Bun),
but now it always follows the headers.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Bug Fixes**
- Improved handling of empty or null input streams, ensuring consistent
behavior and preventing errors.
- Adjusted body processing logic to handle all HTTP methods, including
GET and HEAD, for more robust request handling.

- **Tests**
- Added a new test to verify correct behavior when processing empty
streams.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: dinwwwh

packages/standard-server-fetch/src/body.ts

@@ -5,14 +5,6 @@ import { generateContentDisposition, getFilenameFromContentDisposition } from '@
 import { toEventIterator, toEventStream } from './event-iterator'
 
 export async function toStandardBody(re: Request | Response): Promise<StandardBody> {
-  /**
-   * In native environments like React Native, the body may be `undefined` due to lack of streaming support.
-   * Therefore, we explicitly check for `null` to indicate an intentionally empty body.
-   */
-  if (re.body === null) {
-    return undefined
-  }
-
   const contentDisposition = re.headers.get('content-disposition')
 
   if (typeof contentDisposition === 'string') {

packages/standard-server-fetch/src/event-iterator.test.ts

@@ -82,6 +82,13 @@ describe('toEventIterator', () => {
     await expect(stream.getReader().closed).resolves.toBe(undefined)
   })
 
+  it('with empty stream', async () => {
+    const generator = toEventIterator(null)
+    expect(generator).toSatisfy(isAsyncIteratorObject)
+    expect(await generator.next()).toEqual({ done: true, value: undefined })
+    expect(await generator.next()).toEqual({ done: true, value: undefined })
+  })
+
   it('with error event', async () => {
     const stream = new ReadableStream<string>({
       async pull(controller) {

packages/standard-server-fetch/src/event-iterator.ts

@@ -8,16 +8,20 @@ import {
 } from '@orpc/standard-server'
 
 export function toEventIterator(
-  stream: ReadableStream<Uint8Array>,
+  stream: ReadableStream<Uint8Array> | null,
 ): AsyncIteratorObject<unknown | void, unknown | void, void> & AsyncGenerator<unknown | void, unknown | void, void> {
   const eventStream = stream
-    .pipeThrough(new TextDecoderStream())
+    ?.pipeThrough(new TextDecoderStream())
     .pipeThrough(new EventDecoderStream())
 
-  const reader = eventStream.getReader()
+  const reader = eventStream?.getReader()
 
   return createAsyncIteratorObject(async () => {
     while (true) {
+      if (reader === undefined) {
+        return { done: true, value: undefined }
+      }
+
       const { done, value } = await reader.read()
 
       if (done) {
@@ -57,7 +61,7 @@ export function toEventIterator(
       }
     }
   }, async () => {
-    await reader.cancel()
+    await reader?.cancel()
   })
 }
 

packages/standard-server-node/src/body.ts

@@ -8,12 +8,6 @@ import { flattenHeader, generateContentDisposition, getFilenameFromContentDispos
 import { toEventIterator, toEventStream } from './event-iterator'
 
 export async function toStandardBody(req: NodeHttpRequest): Promise<StandardBody> {
-  const method = req.method ?? 'GET'
-
-  if (method === 'GET' || method === 'HEAD') {
-    return undefined
-  }
-
   const contentDisposition = req.headers['content-disposition']
   const contentType = req.headers['content-type']