Websocket 相关 API

连接到一个 websocket 服务器

• connect_to_websocket(addr,optional_header)

  • 范围：协程内
  • 参数：
    • addr: 服务器地址，e.g. ws://127.0.0.1:1042, ws://127.0.0.1:1042/path/to/ws_api
    • optional_header: 可选的 http header, 可忽略
  • 返回值为一个 WebSocketConn 对象

  -- 不使用 header
  coromega:start_new(function()
      local conn = coromega:connect_to_websocket("ws://127.0.0.1:1042")
      if conn == nil then
          coromega:print("connect fail")
          return
      end
      conn:when_new_msg(function(msg)
          if msg == nil then
              print("websocket connection closed!", msg)
          else
              print("websocket client received (not intercepted): ", msg)
          end
      end)
      conn:send_message("client hello")
      local received = conn:receive_message()
      if received == nil then
          print("websocket connection closed!")
      else
          print("websocket client received (first message): ", received)
      end
  end)
  
  -- 使用 header
  coromega:start_new(function()
      local headers = {
          header1 = { "a", 2, "c" }, -- 可以是多个 (2 会变成 "2")
          header2 = { "some headers" },
          header3 = "header3,some values" -- 可以是单个 string
      }
      local conn = coromega:connect_to_websocket("ws://127.0.0.1:1042",headers)
  end)
  

创建一个 websocket 服务器

• create_websocket_server(host,port)
  • 范围：任意
  • 参数：
    • host: 字符串，一般为 "127.0.0.1" (仅本机可访问) / "0.0.0.0" (可被其他主机访问)
    • port: 端口号，数字
  • 返回：监听器，监听器目前包含两个方法
    • when_new_conn: 当有客户端连接到服务器时，一个新协程被创建并启动指定的函数，函数的参数为 WebSocketConn 对象
    • when_dead: 当服务器关闭时，一个新协程被创建并启动指定的函数，函数的参数为字符串形式的服务器关闭的原因

  coromega:create_websocket_server("0.0.0.0", 1042):when_new_conn(function(conn)
      conn:when_new_msg(function(msg)
          if msg == nil then
              print("websocket connection closed!")
          else
              print("websocket server received (not intercepted): ", msg)
          end
          conn:send_message("server echo: " .. msg)
      end)
      conn:send_message("server hello")
      local received = conn:receive_message()
      if received == nil then
          print("websocket connection closed!")
      else
          print("websocket server received (first message): ", received)
      end
  end):when_dead(function(deadReason)
      print("websocket server dead, reason: ", deadReason)
  end)
  

WebSocketConn 对象的方法

发送消息 (字符串)

• send_message(message)
  • 范围：协程内
  • 参数：
    • message: 待发送的字符串形式的数据，以 TextMessage 形式发送
  • 返回：是否有错误，无错误时为 nil

  err=conn:send_message("hello")
  

发送消息

• send(message)
  • 范围：协程内
  • 参数：
    • message: 待发送的数据，以 TextMessage 形式发送其被 json.encode 后的结果
  • 返回：是否有错误，无错误时为 nil

  err=conn:send({author="somebody",age=18})
  

接收到消息时的回调

• when_new_msg(func)

  • 范围：协程内
  • 参数：
    • func: 当新消息到来且未被 receive_message 拦截时，一个新协程被创建并启动 func 函数
      函数的参数为字符串形式的消息，如果连接断开，则获得 nil
  • 返回：无

  conn:when_new_msg(function(msg)
      if msg == nil then
          print("websocket connection closed!")
      else
          print("websocket received (not intercepted): ")
      end
  end)
  

接收下一条消息

• receive_message()

  • 范围：协程内
  • 说明：接收下一条消息，下一条消息会做为该函数的返回值出现，而不会被 when_new_msg 处理
  • 参数：无
  • 返回：下一条即将被收到的消息，如果连接断开，则获得 nil

  local received = conn:receive_message()
  if msg == nil then
      print("websocket connection closed!")
  else
      print("websocket received: ", received)
  end
  
  

综合使用

local omega = require("omega")
package.path = ("%s;%s"):format(
    package.path,
    omega.storage_path.get_code_path("LuaLoader", "?.lua")
)
local coromega = require("coromega").from(omega)

coromega:create_websocket_server("0.0.0.0", 1042):when_new_conn(function(conn)
    conn:when_new_msg(function(msg)
        print("websocket server received (not intercepted): ", msg)
        conn:send_message("server echo: " .. msg)
    end)

    conn:send_message("server hello")
    local received = conn:receive_message()
    print("websocket server received (first message): ", received)
end):when_dead(function(deadReason)
    print("websocket server dead, reason: ", deadReason)
end)

coromega:start_new(function()
    coromega:sleep(1.0)
    local conn = coromega:connect_to_websocket("ws://127.0.0.1:1042")
    if conn == nil then
        coromega:print("connect fail")
        return
    end
    conn:when_new_msg(function(msg)
        print("websocket client received (not intercepted): ", msg)
    end)
    conn:send_message("client hello")
    local received = conn:receive_message()
    print("websocket client received (first message): ", received)
    conn:send_message("client hello 1")
    coromega:sleep(1.0)
    conn:send_message("client hello 2")
    coromega:sleep(1.0)
    conn:send_message("client hello 3")
    local received = conn:receive_message()
    print("websocket client received: ", received)
    coromega:sleep(1.0)
    conn:send_message("client hello 4")
    local received = conn:receive_message()
    print("websocket client received: ", received)
end)
coromega:run()