环境
golang 1.9
websocket包采用的是github.com/gorilla/websocket
在小程序H5页面与websocket联调的时候出现了如下错误，Sec-Websocket-Protocol参数应该是小程序中自己添加进去的，后端要做一些处理。
问题
image
Error during Websocket handshake: Sent non-empty 'Sec-Websocket-Protocol'header but no response was received
处理
一般而言，websocket出现这种问题只要获取请求头的Sec-Websocket-Protocol参数，随后将参数添加到response的请求头中即可。但我在尝试之后，问题并没有解决。
在部门大佬的指导下，去看了github.com/gorilla/websocket包的源代码，发现包里对于这个参数已经做了处理
//源码
// Subprotocols specifies the server's supported protocols in order of
// preference. If this field is not nil, then the Upgrade method negotiates a
// subprotocol by selecting the first match in this list with a protocol
// requested by the client. If there's no match, then no protocol is
// negotiated (the Sec-Websocket-Protocol header is not included in the
// handshake response).
Subprotocols []string
func (u *Upgrader) selectSubprotocol(r *http.Request, responseHeader http.Header) string {
if u.Subprotocols != nil {
clientProtocols := Subprotocols(r)
for _, serverProtocol := range u.Subprotocols {
for _, clientProtocol := range clientProtocols {
if clientProtocol == serverProtocol {
return clientProtocol
}
}
}
} else if responseHeader != nil {
return responseHeader.Get("Sec-Websocket-Protocol")
}
return ""
}
所以我们只需要将获取的参数放进Subprotocols即可
var upgrade = websocket.Upgrader{
// cross origin domain
CheckOrigin: func(r *http.Request) bool { //这个是解决跨域问题
return true
},
Subprotocols:[]string{s.Ctx.Input.Header("Sec-WebSocket-Protocol")},
//将获取的参数放进这个数组，问题解决
}
在引用第三方包的时候，遇到问题，多读源码
