1 files changed, 481 insertions, 0 deletions
diff --git a/static/js/ext/ws.js b/static/js/ext/ws.js
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--- /dev/null
+++ b/static/js/ext/ws.js
@@ -0,0 +1,481 @@
+/*
+WebSockets Extension
+============================
+This extension adds support for WebSockets to htmx.  See /www/extensions/ws.md for usage instructions.
+*/
+
+(function () {
+
+	if (htmx.version && !htmx.version.startsWith("1.")) {
+		console.warn("WARNING: You are using an htmx 1 extension with htmx " + htmx.version +
+			".  It is recommended that you move to the version of this extension found on https://htmx.org/extensions")
+	}
+
+	/** @type {import("../htmx").HtmxInternalApi} */
+	var api;
+
+	htmx.defineExtension("ws", {
+
+		/**
+		 * init is called once, when this extension is first registered.
+		 * @param {import("../htmx").HtmxInternalApi} apiRef
+		 */
+		init: function (apiRef) {
+
+			// Store reference to internal API
+			api = apiRef;
+
+			// Default function for creating new EventSource objects
+			if (!htmx.createWebSocket) {
+				htmx.createWebSocket = createWebSocket;
+			}
+
+			// Default setting for reconnect delay
+			if (!htmx.config.wsReconnectDelay) {
+				htmx.config.wsReconnectDelay = "full-jitter";
+			}
+		},
+
+		/**
+		 * onEvent handles all events passed to this extension.
+		 *
+		 * @param {string} name
+		 * @param {Event} evt
+		 */
+		onEvent: function (name, evt) {
+			var parent = evt.target || evt.detail.elt;
+
+			switch (name) {
+
+				// Try to close the socket when elements are removed
+				case "htmx:beforeCleanupElement":
+
+					var internalData = api.getInternalData(parent)
+
+					if (internalData.webSocket) {
+						internalData.webSocket.close();
+					}
+					return;
+
+				// Try to create websockets when elements are processed
+				case "htmx:beforeProcessNode":
+					forEach(queryAttributeOnThisOrChildren(parent, "ws-connect"), function (child) {
+						ensureWebSocket(child)
+					});
+					forEach(queryAttributeOnThisOrChildren(parent, "ws-send"), function (child) {
+						ensureWebSocketSend(child)
+					});
+			}
+		}
+	});
+
+	function splitOnWhitespace(trigger) {
+		return trigger.trim().split(/\s+/);
+	}
+
+	function getLegacyWebsocketURL(elt) {
+		var legacySSEValue = api.getAttributeValue(elt, "hx-ws");
+		if (legacySSEValue) {
+			var values = splitOnWhitespace(legacySSEValue);
+			for (var i = 0; i < values.length; i++) {
+				var value = values[i].split(/:(.+)/);
+				if (value[0] === "connect") {
+					return value[1];
+				}
+			}
+		}
+	}
+
+	/**
+	 * ensureWebSocket creates a new WebSocket on the designated element, using
+	 * the element's "ws-connect" attribute.
+	 * @param {HTMLElement} socketElt
+	 * @returns
+	 */
+	function ensureWebSocket(socketElt) {
+
+		// If the element containing the WebSocket connection no longer exists, then
+		// do not connect/reconnect the WebSocket.
+		if (!api.bodyContains(socketElt)) {
+			return;
+		}
+
+		// Get the source straight from the element's value
+		var wssSource = api.getAttributeValue(socketElt, "ws-connect")
+
+		if (wssSource == null || wssSource === "") {
+			var legacySource = getLegacyWebsocketURL(socketElt);
+			if (legacySource == null) {
+				return;
+			} else {
+				wssSource = legacySource;
+			}
+		}
+
+		// Guarantee that the wssSource value is a fully qualified URL
+		if (wssSource.indexOf("/") === 0) {
+			var base_part = location.hostname + (location.port ? ':' + location.port : '');
+			if (location.protocol === 'https:') {
+				wssSource = "wss://" + base_part + wssSource;
+			} else if (location.protocol === 'http:') {
+				wssSource = "ws://" + base_part + wssSource;
+			}
+		}
+
+		var socketWrapper = createWebsocketWrapper(socketElt, function () {
+			return htmx.createWebSocket(wssSource)
+		});
+
+		socketWrapper.addEventListener('message', function (event) {
+			if (maybeCloseWebSocketSource(socketElt)) {
+				return;
+			}
+
+			var response = event.data;
+			if (!api.triggerEvent(socketElt, "htmx:wsBeforeMessage", {
+				message: response,
+				socketWrapper: socketWrapper.publicInterface
+			})) {
+				return;
+			}
+
+			api.withExtensions(socketElt, function (extension) {
+				response = extension.transformResponse(response, null, socketElt);
+			});
+
+			var settleInfo = api.makeSettleInfo(socketElt);
+			var fragment = api.makeFragment(response);
+
+			if (fragment.children.length) {
+				var children = Array.from(fragment.children);
+				for (var i = 0; i < children.length; i++) {
+					api.oobSwap(api.getAttributeValue(children[i], "hx-swap-oob") || "true", children[i], settleInfo);
+				}
+			}
+
+			api.settleImmediately(settleInfo.tasks);
+			api.triggerEvent(socketElt, "htmx:wsAfterMessage", { message: response, socketWrapper: socketWrapper.publicInterface })
+		});
+
+		// Put the WebSocket into the HTML Element's custom data.
+		api.getInternalData(socketElt).webSocket = socketWrapper;
+	}
+
+	/**
+	 * @typedef {Object} WebSocketWrapper
+	 * @property {WebSocket} socket
+	 * @property {Array<{message: string, sendElt: Element}>} messageQueue
+	 * @property {number} retryCount
+	 * @property {(message: string, sendElt: Element) => void} sendImmediately sendImmediately sends message regardless of websocket connection state
+	 * @property {(message: string, sendElt: Element) => void} send
+	 * @property {(event: string, handler: Function) => void} addEventListener
+	 * @property {() => void} handleQueuedMessages
+	 * @property {() => void} init
+	 * @property {() => void} close
+	 */
+	/**
+	 *
+	 * @param socketElt
+	 * @param socketFunc
+	 * @returns {WebSocketWrapper}
+	 */
+	function createWebsocketWrapper(socketElt, socketFunc) {
+		var wrapper = {
+			socket: null,
+			messageQueue: [],
+			retryCount: 0,
+
+			/** @type {Object<string, Function[]>} */
+			events: {},
+
+			addEventListener: function (event, handler) {
+				if (this.socket) {
+					this.socket.addEventListener(event, handler);
+				}
+
+				if (!this.events[event]) {
+					this.events[event] = [];
+				}
+
+				this.events[event].push(handler);
+			},
+
+			sendImmediately: function (message, sendElt) {
+				if (!this.socket) {
+					api.triggerErrorEvent()
+				}
+				if (!sendElt || api.triggerEvent(sendElt, 'htmx:wsBeforeSend', {
+					message: message,
+					socketWrapper: this.publicInterface
+				})) {
+					this.socket.send(message);
+					sendElt && api.triggerEvent(sendElt, 'htmx:wsAfterSend', {
+						message: message,
+						socketWrapper: this.publicInterface
+					})
+				}
+			},
+
+			send: function (message, sendElt) {
+				if (this.socket.readyState !== this.socket.OPEN) {
+					this.messageQueue.push({ message: message, sendElt: sendElt });
+				} else {
+					this.sendImmediately(message, sendElt);
+				}
+			},
+
+			handleQueuedMessages: function () {
+				while (this.messageQueue.length > 0) {
+					var queuedItem = this.messageQueue[0]
+					if (this.socket.readyState === this.socket.OPEN) {
+						this.sendImmediately(queuedItem.message, queuedItem.sendElt);
+						this.messageQueue.shift();
+					} else {
+						break;
+					}
+				}
+			},
+
+			init: function () {
+				if (this.socket && this.socket.readyState === this.socket.OPEN) {
+					// Close discarded socket
+					this.socket.close()
+				}
+
+				// Create a new WebSocket and event handlers
+				/** @type {WebSocket} */
+				var socket = socketFunc();
+
+				// The event.type detail is added for interface conformance with the
+				// other two lifecycle events (open and close) so a single handler method
+				// can handle them polymorphically, if required.
+				api.triggerEvent(socketElt, "htmx:wsConnecting", { event: { type: 'connecting' } });
+
+				this.socket = socket;
+
+				socket.onopen = function (e) {
+					wrapper.retryCount = 0;
+					api.triggerEvent(socketElt, "htmx:wsOpen", { event: e, socketWrapper: wrapper.publicInterface });
+					wrapper.handleQueuedMessages();
+				}
+
+				socket.onclose = function (e) {
+					// If socket should not be connected, stop further attempts to establish connection
+					// If Abnormal Closure/Service Restart/Try Again Later, then set a timer to reconnect after a pause.
+					if (!maybeCloseWebSocketSource(socketElt) && [1006, 1012, 1013].indexOf(e.code) >= 0) {
+						var delay = getWebSocketReconnectDelay(wrapper.retryCount);
+						setTimeout(function () {
+							wrapper.retryCount += 1;
+							wrapper.init();
+						}, delay);
+					}
+
+					// Notify client code that connection has been closed. Client code can inspect `event` field
+					// to determine whether closure has been valid or abnormal
+					api.triggerEvent(socketElt, "htmx:wsClose", { event: e, socketWrapper: wrapper.publicInterface })
+				};
+
+				socket.onerror = function (e) {
+					api.triggerErrorEvent(socketElt, "htmx:wsError", { error: e, socketWrapper: wrapper });
+					maybeCloseWebSocketSource(socketElt);
+				};
+
+				var events = this.events;
+				Object.keys(events).forEach(function (k) {
+					events[k].forEach(function (e) {
+						socket.addEventListener(k, e);
+					})
+				});
+			},
+
+			close: function () {
+				this.socket.close()
+			}
+		}
+
+		wrapper.init();
+
+		wrapper.publicInterface = {
+			send: wrapper.send.bind(wrapper),
+			sendImmediately: wrapper.sendImmediately.bind(wrapper),
+			queue: wrapper.messageQueue
+		};
+
+		return wrapper;
+	}
+
+	/**
+	 * ensureWebSocketSend attaches trigger handles to elements with
+	 * "ws-send" attribute
+	 * @param {HTMLElement} elt
+	 */
+	function ensureWebSocketSend(elt) {
+		var legacyAttribute = api.getAttributeValue(elt, "hx-ws");
+		if (legacyAttribute && legacyAttribute !== 'send') {
+			return;
+		}
+
+		var webSocketParent = api.getClosestMatch(elt, hasWebSocket)
+		processWebSocketSend(webSocketParent, elt);
+	}
+
+	/**
+	 * hasWebSocket function checks if a node has webSocket instance attached
+	 * @param {HTMLElement} node
+	 * @returns {boolean}
+	 */
+	function hasWebSocket(node) {
+		return api.getInternalData(node).webSocket != null;
+	}
+
+	/**
+	 * processWebSocketSend adds event listeners to the <form> element so that
+	 * messages can be sent to the WebSocket server when the form is submitted.
+	 * @param {HTMLElement} socketElt
+	 * @param {HTMLElement} sendElt
+	 */
+	function processWebSocketSend(socketElt, sendElt) {
+		var nodeData = api.getInternalData(sendElt);
+		var triggerSpecs = api.getTriggerSpecs(sendElt);
+		triggerSpecs.forEach(function (ts) {
+			api.addTriggerHandler(sendElt, ts, nodeData, function (elt, evt) {
+				if (maybeCloseWebSocketSource(socketElt)) {
+					return;
+				}
+
+				/** @type {WebSocketWrapper} */
+				var socketWrapper = api.getInternalData(socketElt).webSocket;
+				var headers = api.getHeaders(sendElt, api.getTarget(sendElt));
+				var results = api.getInputValues(sendElt, 'post');
+				var errors = results.errors;
+				var rawParameters = results.values;
+				var expressionVars = api.getExpressionVars(sendElt);
+				var allParameters = api.mergeObjects(rawParameters, expressionVars);
+				var filteredParameters = api.filterValues(allParameters, sendElt);
+
+				var sendConfig = {
+					parameters: filteredParameters,
+					unfilteredParameters: allParameters,
+					headers: headers,
+					errors: errors,
+
+					triggeringEvent: evt,
+					messageBody: undefined,
+					socketWrapper: socketWrapper.publicInterface
+				};
+
+				if (!api.triggerEvent(elt, 'htmx:wsConfigSend', sendConfig)) {
+					return;
+				}
+
+				if (errors && errors.length > 0) {
+					api.triggerEvent(elt, 'htmx:validation:halted', errors);
+					return;
+				}
+
+				var body = sendConfig.messageBody;
+				if (body === undefined) {
+					var toSend = Object.assign({}, sendConfig.parameters);
+					if (sendConfig.headers)
+						toSend['HEADERS'] = headers;
+					body = JSON.stringify(toSend);
+				}
+
+				socketWrapper.send(body, elt);
+
+				if (evt && api.shouldCancel(evt, elt)) {
+					evt.preventDefault();
+				}
+			});
+		});
+	}
+
+	/**
+	 * getWebSocketReconnectDelay is the default easing function for WebSocket reconnects.
+	 * @param {number} retryCount // The number of retries that have already taken place
+	 * @returns {number}
+	 */
+	function getWebSocketReconnectDelay(retryCount) {
+
+		/** @type {"full-jitter" | ((retryCount:number) => number)} */
+		var delay = htmx.config.wsReconnectDelay;
+		if (typeof delay === 'function') {
+			return delay(retryCount);
+		}
+		if (delay === 'full-jitter') {
+			var exp = Math.min(retryCount, 6);
+			var maxDelay = 1000 * Math.pow(2, exp);
+			return maxDelay * Math.random();
+		}
+
+		logError('htmx.config.wsReconnectDelay must either be a function or the string "full-jitter"');
+	}
+
+	/**
+	 * maybeCloseWebSocketSource checks to the if the element that created the WebSocket
+	 * still exists in the DOM.  If NOT, then the WebSocket is closed and this function
+	 * returns TRUE.  If the element DOES EXIST, then no action is taken, and this function
+	 * returns FALSE.
+	 *
+	 * @param {*} elt
+	 * @returns
+	 */
+	function maybeCloseWebSocketSource(elt) {
+		if (!api.bodyContains(elt)) {
+			api.getInternalData(elt).webSocket.close();
+			return true;
+		}
+		return false;
+	}
+
+	/**
+	 * createWebSocket is the default method for creating new WebSocket objects.
+	 * it is hoisted into htmx.createWebSocket to be overridden by the user, if needed.
+	 *
+	 * @param {string} url
+	 * @returns WebSocket
+	 */
+	function createWebSocket(url) {
+		var sock = new WebSocket(url, []);
+		sock.binaryType = htmx.config.wsBinaryType;
+		return sock;
+	}
+
+	/**
+	 * queryAttributeOnThisOrChildren returns all nodes that contain the requested attributeName, INCLUDING THE PROVIDED ROOT ELEMENT.
+	 *
+	 * @param {HTMLElement} elt
+	 * @param {string} attributeName
+	 */
+	function queryAttributeOnThisOrChildren(elt, attributeName) {
+
+		var result = []
+
+		// If the parent element also contains the requested attribute, then add it to the results too.
+		if (api.hasAttribute(elt, attributeName) || api.hasAttribute(elt, "hx-ws")) {
+			result.push(elt);
+		}
+
+		// Search all child nodes that match the requested attribute
+		elt.querySelectorAll("[" + attributeName + "], [data-" + attributeName + "], [data-hx-ws], [hx-ws]").forEach(function (node) {
+			result.push(node)
+		})
+
+		return result
+	}
+
+	/**
+	 * @template T
+	 * @param {T[]} arr
+	 * @param {(T) => void} func
+	 */
+	function forEach(arr, func) {
+		if (arr) {
+			for (var i = 0; i < arr.length; i++) {
+				func(arr[i]);
+			}
+		}
+	}
+
+})();
+