Websocket Upgrade header should not be case sensitive

[dermotduffy]

• I confirm that this is an issue rather than a question.

Bug report

In playing with Python websocket connections to Hyperion, I ran into a problem: the connection was not properly being upgraded to a websocket:

Steps to reproduce

Run this, changing hyperion:8090 to a Hyperion host:

#!/usr/bin/python3

import aiohttp
import asyncio

async def routine():
  session = aiohttp.ClientSession()
  async with session.ws_connect('http://hyperion:8090') as ws:
    pass
  await session.close()
asyncio.get_event_loop().run_until_complete(routine())

The same code will execute cleanly with this connection code:

  async with session.ws_connect('http://hyperion:8090', headers={'Upgrade':'websocket'}) as ws:

This is caused by libsrc/webserver/QtHttpClientWrapper.cpp:

156           if(m_currentRequest->getHeader(QtHttpHeader::Upgrade) == "websocket")

Note the case sensitive comparison, which is inappropriate in this situation:

   An |Upgrade| header field containing the value "websocket",
        treated as an ASCII case-insensitive value.

What is expected?

It should exit cleanly.

What is actually happening?

Traceback (most recent call last):
  File "./ws.py", line 11, in <module>
    asyncio.get_event_loop().run_until_complete(routine())
  File "/usr/lib/python3.6/asyncio/base_events.py", line 484, in run_until_complete
    return future.result()
  File "./ws.py", line 8, in routine
    async with session.ws_connect('http://hyperion:8090') as ws:
  File "/usr/local/lib/python3.6/dist-packages/aiohttp/client.py", line 1012, in __aenter__
    self._resp = await self._coro
  File "/usr/local/lib/python3.6/dist-packages/aiohttp/client.py", line 738, in _ws_connect
    headers=resp.headers)
aiohttp.client_exceptions.WSServerHandshakeError: 200, message='Invalid response status', url=URL('http://hyperion:8090')
Unclosed client session
client_session: <aiohttp.client.ClientSession object at 0x7f994f4e4e80>

System

Hyperion Server: 
- Build:       master (GitHub-f719f0b/838092e-1597257777)
- Build time:  Aug 15 2020 04:03:20
- Git Remote:  https://github.com/hyperion-project/hyperion.ng.git
- Version:     2.0.0-alpha.7
- UI Lang:     auto (BrowserLang: en-US)
- UI Access:   default
- Avail Capt:  dispmanx,v4l2,framebuffer,qt

Hyperion Server OS: 
- Distribution: Raspbian GNU/Linux 10 (buster)
- Arch:         arm
- Kernel:       linux (5.4.51+ (WS: 32))
- Browser:      Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/53

[Paulchen-Panther]

Fixed in PR #1036

[dermotduffy]

@Paulchen-Panther Thank you, verified!