cookieなしログインなしでアクセスするとsocket.io接続できない

[shokai]

  semirara:socket:middleware set socket.user +239ms
TypeError: argument str must be a string
    at Object.parse (/Users/sho/src/nodejs/semirara/node_modules/cookie/index.js:49:11)
    at Array._callee$ (middleware.es6:10:28)
    at tryCatch (/Users/sho/src/nodejs/semirara/node_modules/babel-regenerator-runtime/runtime.js:61:40)
    at GeneratorFunctionPrototype.invoke [as _invoke] (/Users/sho/src/nodejs/semirara/node_modules/babel-regenerator-runtime/runtime.js:329:22)
    at GeneratorFunctionPrototype.prototype.(anonymous function) [as next] (/Users/sho/src/nodejs/semirara/node_modules/babel-regenerator-runtime/runtime.js:94:21)
    at step (middleware.es6:4:1)
    at middleware.es6:4:1
    at new Promise (/Users/sho/src/nodejs/semirara/node_modules/babel-polyfill/node_modules/core-js/modules/es6.promise.js:193:7)
    at Array.<anonymous> (middleware.es6:4:1)
    at Array.setUserContext (middleware.es6:7:23)
    at run (/Users/sho/src/nodejs/semirara/node_modules/socket.io/lib/namespace.js:116:11)
    at Namespace.run (/Users/sho/src/nodejs/semirara/node_modules/socket.io/lib/namespace.js:128:3)
    at Namespace.add (/Users/sho/src/nodejs/semirara/node_modules/socket.io/lib/namespace.js:157:8)
    at Client.connect (/Users/sho/src/nodejs/semirara/node_modules/socket.io/lib/client.js:75:20)
    at Server.onconnection (/Users/sho/src/nodejs/semirara/node_modules/socket.io/lib/index.js:317:10)
    at emitOne (events.js:90:13)
    at Server.emit (events.js:182:7)