CODEWITHSUNDEEP
javascriptjqueryvb.netsignalr
Lajos Arpad
Lajos Arpad

Reputation: 76631

How can we determine the group which initiated SignalR extended method?

I have created a Javascript function to make SignalR even more magical:

//Initializable
function Initializable(params) {
    this.initialize = function (key, def, private) {
        if (def !== undefined) {
            (!!private ? params : this)[key] = (params[key] !== undefined) ? params[key] : def;
        }
    };
}
/*SignalR Updater*/
function SignalRUpdater(params) {
    Initializable.call(this, params);
    var self = this;
    this.initialize("RawHubs", [], true);
    this.initialize("RawGroups", {}, true);
    this.initialize("Connection", $.connection, true);
    this.initialize("Extend", {});
    this.Hubs = {};
    this.addHub = function (name, extend) {
        if (self.Hubs[name]) {
            return false;
        }
        self.Hubs[name] = params.Connection[name];
        self.Hubs[name].Groups = {};
        params.RawHubs.push(name);
        if (!params.RawGroups[name]) {
            params.RawGroups[name] = [];
        }
        if (extend) {
            if ((!self.Extend) || (!extend.append)) {
                self.Extend = extend;
            } else {
                if (!self.Extend) {
                    self.Extend = {};
                }
                if (extend.append) {
                    for (var extendIndex in extend) {
                        if (extendIndex !== "append") {
                            self.Extend = extend[extendIndex];
                        }
                    }
                } else {
                    self.Extend = extend;
                }
            }
            $.extend(params.Connection[name].client, self.Extend);
        } else if (self.Extend) {
            $.extend(params.Connection[name].client, self.Extend);
        }
        return true;
    };
    this.removeHub = function (name) {
        if (!self.Hubs[name]) {
            return false;
        }
        for (var groupIndex in self.Hubs[name].Groups) {
            self.Hubs[name].Groups[groupIndex].unsubscribe();
        }
        delete self.Hubs[name];
        delete params.RawGroups[name];
        params.RawHubs.splice(params.RawHubs.indexOf(name), 1);
        return true;
    };
    this.addGroupToHub = function (hubName, groupName) {
        if ((self.Hubs[hubName]) && (self.Hubs[hubName].Groups[groupName])) {
            return false;
        }
        self.Hubs[hubName].server.subscribe(groupName);
        self.Hubs[hubName].Groups[groupName] = {}; //Here we can hold group-related data
        if (params.RawGroups[hubName].indexOf(groupName) < 0) {
            params.RawGroups[hubName].push(groupName);
        }
        return true;
    };
    this.removeGroupFromHub = function (hubName, groupName) {
        if ((!self.Hubs[hubName]) || (!self.Hubs[hubName].Groups[groupName])) {
            return false;
        }
        self.Hubs[hubName].server.unsubscribe(groupName);
        delete self.Hubs[hubName].Groups[groupName];
        if (params.RawGroups[hubName].indexOf(groupName) >= 0) {
            params.RawGroups[hubName].splice(params.RawGroups[hubName].indexOf(groupName), 1);
        }
        return true;
    };
    for (var hubIndex in params.RawHubs) {
        self.addHub(params.RawHubs[hubIndex]);
    }
    params.Connection.hub.start().done(function () {
        for (var hubIndex in params.RawGroups) {
            for (var groupIndex in params.RawGroups[hubIndex]) {
                self.addGroupToHub(hubIndex, params.RawGroups[hubIndex][groupIndex]);
            }
        }
    });
}

I am using it like this, for example:

    function statusUpdate(status) {
        alert(status);
    }
    var signalRUpdater = new SignalRUpdater({
        RawHubs: ["statusUpdates"],
        Extend: {
            statusUpdate: statusUpdate
        }
    });

So far, so good. However, I may have several groups in the same hub and at the point of statusUpdate I do not seem to know about the group. I can send it from server-side as a parameter to statusUpdate, but I wonder whether this is an overkill and whether it is possible out of the box with SignalR.

Upvotes: 0

Views: 43

Answers (1)

Pawel
Pawel

Reputation: 31610

When sending a group message to clients the server does not send the name of the group the message was sent to. The server selects clients that are members of the group and just sends them the message. If you want to understand the protocol SignalR is using you can find a description I wrote some time ago here.

Upvotes: 1

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