fix(api): don't forward body headers to internal content requests

src/runtime/internal/api.ts

@@ -9,6 +9,10 @@ async function fetchContent<T>(
 ): Promise<T> {
   const headers = event ? getRequestHeaders(event) : {}
   headers['accept-encoding'] = undefined // prevent unsupported enconding issue (https://github.com/nuxt/content/pull/3701)
+  // The internal request has its own body, so never inherit the incoming request's body framing headers
+  for (const name of ['content-length', 'transfer-encoding', 'content-encoding', 'expect']) {
+    headers[name] = undefined
+  }
 
   const url = `/__nuxt_content/${collection}/${path}`
   const fetchOptions = {

test/unit/fetchContent.test.ts

@@ -0,0 +1,55 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import type { H3Event } from 'h3'
+import { fetchDatabase, fetchQuery } from '../../src/runtime/internal/api'
+
+vi.mock('h3', async importOriginal => ({
+  ...(await importOriginal<typeof import('h3')>()),
+  getRequestHeaders: () => ({
+    'content-length': '700000',
+    'transfer-encoding': 'chunked',
+    'content-encoding': 'gzip',
+    'expect': '100-continue',
+    'cookie': 'a=b',
+    'authorization': 'Bearer token',
+  }),
+}))
+
+const $fetch = vi.fn().mockResolvedValue([])
+const event = { $fetch } as unknown as H3Event
+
+describe('fetchContent', () => {
+  beforeEach(() => {
+    $fetch.mockClear()
+  })
+
+  const expectForwardedHeaders = (headers: Record<string, string | undefined>) => {
+    expect(headers['content-length']).toBeUndefined()
+    expect(headers['transfer-encoding']).toBeUndefined()
+    expect(headers['content-encoding']).toBeUndefined()
+    expect(headers.expect).toBeUndefined()
+    expect(headers.cookie).toBe('a=b')
+    expect(headers.authorization).toBe('Bearer token')
+  }
+
+  it('does not forward body headers of the incoming request to the query endpoint', async () => {
+    await fetchQuery(event, 'test', 'SELECT 1')
+
+    expect($fetch).toHaveBeenCalledTimes(1)
+    const [url, options] = $fetch.mock.calls[0]!
+    expect(url).toBe('/__nuxt_content/test/query')
+    expect(options.method).toBe('POST')
+    expect(options.body).toEqual({ sql: 'SELECT 1' })
+    expectForwardedHeaders(options.headers)
+    expect(options.headers['content-type']).toBe('application/json')
+  })
+
+  it('does not forward body headers of the incoming request to the dump endpoint', async () => {
+    await fetchDatabase(event, 'test')
+
+    expect($fetch).toHaveBeenCalledTimes(1)
+    const [url, options] = $fetch.mock.calls[0]!
+    expect(url).toBe('/__nuxt_content/test/sql_dump.txt')
+    expectForwardedHeaders(options.headers)
+    expect(options.headers['content-type']).toBe('text/plain')
+  })
+})