Thanks Martin...I'll be sure to add a mutex lock and unlock either side of the map call...probably shouldn't have chosen a networked multi-player game as my first project but I sure am learning a lot !! It's a very fun language too.
On Sat, 12 Sep 2020 at 17:03, Martin Schnabel <m...@mb0.org> wrote: > > Hi Andy, > > a global map is the way to go, however writing an reading the map from > multiple go routines will fail (in your case different handle calls for > connections) because the map data structure is not safe for concurrent use > and must be coordinated. the way it is usually solved is by adding another > sync.Mutex (mutually exclusive) variable to ensure only one go routine at a > has access to the map. > > https://godoc.org/sync#Mutex > > just a heads up, have fun! > > On 9/12/20 2:46 PM, Andy Hall wrote: > > OK so I just moved the declaration of the map to the package itself which > makes it universal...all working as expected. Thanks. > > On Saturday, September 12, 2020 at 1:35:49 PM UTC+1 Andy Hall wrote: >> >> So this works fine... >> >> func handleConnection(c net.Conn) { >> // get user details >> username := createUser(c, "Please enter you username (new users will be >> created / existing users will be loaded): ") >> // map username to connection >> var m = make(map[string]net.Conn) >> m[username] = c >> n := len(m) >> fmt.Println(strconv.Itoa(n)) >> >> But due to the concurrent nature of the function ( I can't have player 1 >> blocking player 2 ) the map only ever has details of your own >> connection...as seen from the output of len on the server... >> >> $ go run game-server.go 6666 >> 1 >> 1 >> >> I guess I need to handle this outside of a goroutine... >> On Saturday, September 12, 2020 at 7:55:34 AM UTC+1 Andy Hall wrote: >>> >>> I think this is exactly what I need to do...thanks very much. I'm looking >>> forward to implementing it. >>> >>> On Saturday, September 12, 2020 at 5:43:09 AM UTC+1 Shulhan wrote: >>>> >>>> >>>> >>>> Pada tanggal Sab, 12 Sep 2020 02.54, Andy Hall <andyjo...@gmail.com> >>>> menulis: >>>>> >>>>> if I have multiple clients connected to a tcp server and I wish to write >>>>> back to specific connections I can record the net.Conn value and then use >>>>> the Write method on it...but when using Println I get the following for >>>>> two clients... >>>>> >>>>> &{{0xc000094000}} >>>>> &{{0xc000094080}} >>>>> >>>>> which when testing with a simple write doesn't work... >>>>> >>>>> package main >>>>> import "net" >>>>> var c net.Conn = "&{{0xc000094000}}" >>>>> func writeConn(c net.Conn) { >>>>> c.Write([]byte(string("Hello\n"))) >>>>> } >>>>> func main() { >>>>> writeConn(c) >>>>> } >>>>> >>>>> ...and results in the following... >>>>> >>>>> cannot use "&{{0xc000094000}}" (type string) as type net.Conn in >>>>> assignment >>>>> >>>>> clearly using Println to output the net.Conn is not a viable var to use >>>>> so how could I do this ? I intend to record each users net.Conn in a >>>>> database which can then be queried as required. >>>>> >>>>> any help would be most greatly appreciated. >>>> >>>> >>>> >>>> Either I miss something or Go has different socket concept, but last time >>>> I learn this is not how the network socket works in general. >>>> >>>> First, &{{0xc000094000}} is the address of a variable. You can't convert >>>> an address from string back to variable, because that would be security >>>> issue. Usually socket connection is signed integer, in C you can assign >>>> integer value to variable let other process write into it. But in Go, >>>> connection is an interface/structure. >>>> >>>> If you want to record each users, you have two options: >>>> >>>> 1) Let the user send unique ID (for example their user ID or email or >>>> username) on first accept. >>>> >>>> 2) Get unique ID from connection IP address (beware that two or more >>>> connection may come from the same IP address). >>>> >>>> You then must have a map that store unique ID as key and net.Conn as >>>> value. So, if you want to send some value to specific user, you query the >>>> map first and if exist then you can proceeds. >>>> >>>> I hope that helps. > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/eff5d382-7bc5-4f2e-9752-a3c850318c0fn%40googlegroups.com. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAOp5WB43tBJyNzgHxhrg_PWAE3DikRJcVL9sHA2xhHEkJ4F8sA%40mail.gmail.com.
