节点HTTP2：客户端和服务器之间的多个消息使用相同的流是可能的吗？

Question

节点和HTTP2允许服务器向客户端提供多个响应。但是，如果客户端想要发送一个初始请求，而在服务器响应后，客户端想要发送进一步的消息呢？一个解决方案是创建一个新请求——但这似乎否定了双工流的好处。

简单服务器代码：

import http2 from 'http2'

const options = {
  key: fs.readFileSync('./dev certificate/selfsigned.key'),
  cert: fs.readFileSync('./dev certificate/selfsigned.crt'),
}

const server = http2.createSecureServer()

server.on('stream', (stream, headers) => {
  stream.on('data', (chunk) => {
    console.log(`server: ${chunk.toString()}`)
    stream.respond({
      'content-type': 'application/json',
      ':status': 200
    })
    stream.write(chunk) // echo message received
  })
})

server.listen(8443)

测试客户端代码：

import http2 from 'http2'

describe('http2 messaging test', () => {
  it('http2 messaging', (done) => {
    const client = http2.connect('https://localhost:8443', {
      rejectUnauthorized: false,
    })
    const msg1 = 'message 1'

    const stream = client.request({
      ':method': 'POST',
      ':path': '/',
      'Content-Type': 'text/plain',
      'Content-Length': msg1.length,
    })

    stream.on('response', async (headers, flags) => {
      stream.write('next message') // send the next message after response to first one
                                   // server doesn't receive this
    })

    stream.write(msg1)

    stream.on('data', (chunk) => {
      console.log(`client: ${chunk.toString()}`)
      if (chunk.toString() === 'next message') done()
    })
  })
})

生成ERR_HTTP2_STREAM_ERROR，因为我假设节点不支持客户端向同一个流写入两次？

Answer 1

是的，但是，报头只能发送一次，而不是每次通信！

更新的服务器代码：

import http2 from 'http2'

const options = {
  key: fs.readFileSync('./dev certificate/selfsigned.key'),
  cert: fs.readFileSync('./dev certificate/selfsigned.crt'),
}

const server = http2.createSecureServer()

server.on('stream', (stream, headers) => {
  stream.respond({   // Headers is now only sent once when the stream is connected!
    'content-type': 'application/json',
    ':status': 200
  })
  stream.on('data', (chunk) => {
    console.log(`server: ${chunk.toString()}`)
    stream.write(chunk) // echo message received
  })
})

server.listen(8443)