Do websocket implementations use http protocol internally?

Question

To establish a WebSocket connection, the client sends a WebSocket handshake request, for which the server returns a WebSocket handshake response, as shown in th

Answer 1

By design, the WebSocket protocol handshake uses HTTP so WebSockets can be utilized in existing HTTP servers and other HTTP-based technologies:

   The WebSocket Protocol is designed to supersede existing
   bidirectional communication technologies that use HTTP as a transport
   layer to benefit from existing infrastructure (proxies, filtering,
   authentication).  Such technologies were implemented as trade-offs
   between efficiency and reliability because HTTP was not initially
   meant to be used for bidirectional communication (see [RFC6202] for
   further discussion).  The WebSocket Protocol attempts to address the
   goals of existing bidirectional HTTP technologies in the context of
   the existing HTTP infrastructure; as such, it is designed to work
   over HTTP ports 80 and 443 as well as to support HTTP proxies and
   intermediaries, even if this implies some complexity specific to the
   current environment.  However, the design does not limit WebSocket to
   HTTP, and future implementations could use a simpler handshake over a
   dedicated port without reinventing the entire protocol.  This last
   point is important because the traffic patterns of interactive
   messaging do not closely match standard HTTP traffic and can induce
   unusual loads on some components.

But, once the WebSocket handshake is finished, only the WebSocket protocol is used, not HTTP anymore.

So, it doesn't matter if you use an HTTP server with WebSocket support, or a dedicated WebSocket server. ANY WebSocket implementation MUST use HTTP (and all semantics therein, including authentication, redirection, etc) for the initial handshake. It is mandated by the WebSocket protocol specification, RFC 6455.

   The opening handshake is intended to be compatible with HTTP-based
   server-side software and intermediaries, so that a single port can be
   used by both HTTP clients talking to that server and WebSocket
   clients talking to that server.  To this end, the WebSocket client's
   handshake is an HTTP Upgrade request

So, a dedicated WebSockets server must be able to handle HTTP requests during the handshake phase, at least. It is not that hard to implement.