我想提高 signalR 客户端的客户端实现的弹性。
目前,我这样做:
hub.server.sendClientNotification(string, appSettings.username());
然而,偶尔会引发与连接相关的异常,因为服务器没有响应或客户端的互联网连接变得不可用。
我想通过排队请求然后执行以下操作来解决此问题:
try {
// pop from queue
hub.server.sendClientNotification(string, appSettings.username());
// success - discard element
} catch (e) {
// requeue element
}
通过这种实现,我是否需要使用重新初始化我的 signalR 连接$.connection.hub.start
在断开连接之间,或者我可以在一段时间内继续尝试集线器传输吗?
这就是我的建议:
var hub = null;
const internalQueue = [];
const states = {
connecting: 0, connected: 1, reconnecting: 2, disconnected: 4
}
const signalrModule = {};
var isInitialized = false;
const connectSignalR = function () {
return new Promise(function (resolve, reject) {
if ($.connection.hub.state == states.connected) {
resolve();
} else {
window.hubReady = $.connection.hub.start({ transport: ["serverSentEvents", "foreverFrame", "longPolling"] });
window.hubReady.done(function () {
isInitialized = true;
resolve();
});
window.onbeforeunload = function (e) {
$.connection.hub.stop();
};
}
})
}
signalrModule.init = function (handleNotification) {
hub = $.connection.appHub;
hub.client.clientNotification = handleNotification;
$.connection.hub.qs = {
"username": appSettings.username()
};
connectSignalR();
}
const tryEmptyQueue = function () {
connectSignalR().then(function() {
if (isInitialized) {
var continueTrying = true;
while (internalQueue.length && continueTrying) {
const nextMessage = internalQueue.shift();
try {
hub.server.sendClientNotification(nextMessage, appSettings.username());
} catch (e) {
internalQueue.push(nextMessage);
continueTrying = false;
}
}
}
})
}
signalrModule.sendClientNotification = function (message) {
if (typeof message != "string") {
message = JSON.stringify(message);
}
if (isInitialized) {
try {
hub.server.sendClientNotification(message, appSettings.username());
tryEmptyQueue();
} catch (e) {
logger.log("SignalR disconnected; queuing request", logger.logLevels.warning);
internalQueue.push(message);
}
} else {
internalQueue.push(message);
};
}
const internalQueueInterval = setInterval(function () {
tryEmptyQueue();
}, 5000);
return signalrModule;