feat: add proxyRequest util (#226)

Author: pi0

README.md

@@ -137,6 +137,7 @@ H3 has concept of compasable utilities that accept `event` (from `eventHandler((
 - `assertMethod(event, expected, allowHead?)`
 - `createError({ statusCode, statusMessage, data? })`
 - `sendProxy(event, { target, headers?, fetchOptions?, fetch?, sendStream? })`
+- `proxyRequest(event, { target, headers?, fetchOptions?, fetch?, sendStream? })`
 
 👉 You can learn more about usage in [JSDocs Documentation](https://www.jsdocs.io/package/h3#package-functions).
 

src/utils/proxy.ts

@@ -1,14 +1,61 @@
 import type { H3Event } from '../event'
 import type { RequestHeaders } from '../types'
+import { getMethod, getRequestHeaders } from './request'
+import { readRawBody } from './body'
 
-export interface SendProxyOptions {
+export interface ProxyOptions {
   headers?: RequestHeaders | HeadersInit
   fetchOptions?: RequestInit
   fetch?: typeof fetch
   sendStream?: boolean
 }
 
-export async function sendProxy (event: H3Event, target: string, opts: SendProxyOptions = {}) {
+const PayloadMethods = ['PATCH', 'POST', 'PUT', 'DELETE']
+const ignoredHeaders = [
+  'transfer-encoding',
+  'connection',
+  'keep-alive',
+  'upgrade',
+  'expect'
+]
+
+export async function proxyRequest (event: H3Event, target: string, opts: ProxyOptions = {}) {
+  // Method
+  const method = getMethod(event)
+
+  // Body
+  let body
+  if (PayloadMethods.includes(method)) {
+    body = await readRawBody(event).catch(() => undefined)
+  }
+
+  // Headers
+  const headers = Object.create(null)
+  const reqHeaders = getRequestHeaders(event)
+  for (const name in reqHeaders) {
+    if (!ignoredHeaders.includes(name)) {
+      headers[name] = reqHeaders[name]
+    }
+  }
+  if (opts.fetchOptions?.headers) {
+    Object.assign(headers, opts.fetchOptions!.headers)
+  }
+  if (opts.headers) {
+    Object.assign(headers, opts.headers)
+  }
+
+  return sendProxy(event, target, {
+    ...opts,
+    fetchOptions: {
+      headers,
+      method,
+      body,
+      ...opts.fetchOptions
+    }
+  })
+}
+
+export async function sendProxy (event: H3Event, target: string, opts: ProxyOptions = {}) {
   const _fetch = opts.fetch || globalThis.fetch
   if (!_fetch) {
     throw new Error('fetch is not available. Try importing `node-fetch-native/polyfill` for Node.js.')

test/proxy.test.ts

@@ -1,16 +1,27 @@
+import { Server } from 'node:http'
 import supertest, { SuperTest, Test } from 'supertest'
-import { describe, it, expect, beforeEach } from 'vitest'
+import { describe, it, expect, beforeEach, afterEach } from 'vitest'
 import { fetch } from 'node-fetch-native'
-import { createApp, toNodeListener, App, eventHandler } from '../src'
-import { sendProxy } from '../src/utils/proxy'
+import { createApp, toNodeListener, App, eventHandler, getHeaders, getMethod, readRawBody } from '../src'
+import { sendProxy, proxyRequest } from '../src/utils/proxy'
 
 describe('', () => {
   let app: App
   let request: SuperTest<Test>
 
-  beforeEach(() => {
+  let server: Server
+  let url: string
+
+  beforeEach(async () => {
     app = createApp({ debug: false })
     request = supertest(toNodeListener(app))
+    server = new Server(toNodeListener(app))
+    await new Promise((resolve) => { server.listen(0, () => resolve(null)) })
+    url = 'http://localhost:' + (server.address() as any).port
+  })
+
+  afterEach(async () => {
+    await new Promise((resolve) => { server.close(() => resolve(null)) })
   })
 
   describe('sendProxy', () => {
@@ -19,10 +30,36 @@ describe('', () => {
         return sendProxy(event, 'https://example.com', { fetch })
       }))
 
-      const result = await request
-        .get('/')
+      const result = await request.get('/')
 
       expect(result.text).toContain('a href="https://www.iana.org/domains/example">More information...</a>')
     })
   })
+
+  describe('proxyRequest', () => {
+    it('can proxy request', async () => {
+      app.use('/debug', eventHandler(async (event) => {
+        const headers = getHeaders(event)
+        delete headers.host
+        let body
+        try { body = await readRawBody(event) } catch {}
+        return {
+          method: getMethod(event),
+          headers,
+          body
+        }
+      }))
+
+      app.use('/', eventHandler((event) => {
+        return proxyRequest(event, url + '/debug', { fetch })
+      }))
+
+      const result = await fetch(url + '/', {
+        method: 'POST',
+        body: 'hello'
+      }).then(r => r.text())
+
+      expect(result).toMatchInlineSnapshot('"{\\"method\\":\\"POST\\",\\"headers\\":{\\"accept\\":\\"*/*\\",\\"accept-encoding\\":\\"gzip, deflate, br\\",\\"connection\\":\\"close\\",\\"content-length\\":\\"5\\",\\"content-type\\":\\"text/plain;charset=UTF-8\\",\\"user-agent\\":\\"node-fetch\\"},\\"body\\":\\"hello\\"}"')
+    })
+  })
 })