First pass at SSE support

plugins/tiddlywiki/multiwikiclient/multiwikiclientadaptor.js

@@ -108,6 +108,38 @@ Get details of changed tiddlers from the server
 */
 MultiWikiClientAdaptor.prototype.getUpdatedTiddlers = function(syncer,callback) {
 	var self = this;
+	const eventSource = new EventSource("/recipes/" + this.recipe + "/events?last_known_tiddler_id=" + this.last_known_tiddler_id);
+	eventSource.onerror = function(event) {
+		console.log("SSE connection error",event);
+	}
+	eventSource.onopen = function(event) {
+		console.log("SSE connection opened",event);
+	}
+	eventSource.onmessage = function(event) {
+	  console.log("SSE Event",event);
+	};
+	eventSource.addEventListener("change", function(event) {
+		const data = $tw.utils.parseJSONSafe(event.data);
+		if(data) {
+			console.log("SSE data",data)
+			if(data.is_deleted) {
+				self.removeTiddlerInfo(data.title);
+				delete syncer.tiddlerInfo[data.title];
+				syncer.logger.log("Deleting tiddler missing from server:",data.title);
+				syncer.wiki.deleteTiddler(data.title);
+				syncer.processTaskQueue();
+			} else {
+				syncer.titlesToBeLoaded[data.title] = true;
+				syncer.processTaskQueue();
+			}
+		}
+	});
+
+	return callback(null,{
+		modifications: [],
+		deletions: []
+	});
+	
 	$tw.utils.httpRequest({
 		url: this.host + "recipes/" + this.recipe + "/tiddlers.json",
 		data: {

plugins/tiddlywiki/multiwikiserver/modules/routes/handlers/get-recipe-events.js

@@ -0,0 +1,88 @@
+/*\
+title: $:/plugins/tiddlywiki/multiwikiserver/routes/handlers/get-recipe-events.js
+type: application/javascript
+module-type: mws-route
+
+GET /recipes/:recipe_name/events
+
+headers:
+
+Last-Event-ID: 
+
+\*/
+(function() {
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+const SSE_HEARTBEAT_INTERVAL_MS = 10 * 1000;
+
+exports.method = "GET";
+
+exports.path = /^\/recipes\/([^\/]+)\/events$/;
+
+exports.handler = function(request,response,state) {
+	// Get the  parameters
+	const recipe_name = $tw.utils.decodeURIComponentSafe(state.params[0]);
+	let last_known_tiddler_id = 0;
+	if(request.headers["Last-Event-ID"]) {
+		last_known_tiddler_id = $tw.utils.parseNumber(request.headers["Last-Event-ID"]);
+	} else if(state.queryParameters.last_known_tiddler_id) {
+		last_known_tiddler_id = $tw.utils.parseNumber(state.queryParameters.last_known_tiddler_id);
+	}
+	if(recipe_name) {
+		// Start streaming the response
+		response.writeHead(200, {
+			"Content-Type": "text/event-stream",
+			"Cache-Control": "no-cache",
+			"Connection": "keep-alive"
+		});
+		// Setup the heartbeat timer
+		var heartbeatTimer = setInterval(function() {
+			response.write(':keep-alive\n\n');
+		},SSE_HEARTBEAT_INTERVAL_MS);
+		// Method to get changed tiddler events and send to the client
+		function sendUpdates() {
+			// Get the tiddlers in the recipe since the last known tiddler_id
+			var recipeTiddlers = $tw.mws.store.getRecipeTiddlers(recipe_name,{
+				include_deleted: true,
+				last_known_tiddler_id: last_known_tiddler_id
+			});
+			// Send to the client
+			if(recipeTiddlers) {
+				for(let index = recipeTiddlers.length-1; index>=0; index--) {
+					const tiddlerInfo = recipeTiddlers[index];
+					if(tiddlerInfo.tiddler_id > last_known_tiddler_id) {
+						last_known_tiddler_id = tiddlerInfo.tiddler_id;
+					}
+					response.write(`event: change\n`)
+					let data = tiddlerInfo;
+					if(!tiddlerInfo.is_deleted) {
+						const tiddler = $tw.mws.store.getRecipeTiddler(tiddlerInfo.title,recipe_name);
+						if(tiddler) {
+							data = $tw.utils.extend({},data,{tiddler: tiddler.tiddler})
+						}	
+					}
+					response.write(`data: ${JSON.stringify(data)}\n`);
+					response.write(`id: ${tiddlerInfo.tiddler_id}\n`)
+					response.write(`\n`);
+				}
+			}
+		}
+		// Send current and future changes
+		sendUpdates();
+		$tw.mws.store.addEventListener("change",sendUpdates);
+		// Clean up when the connection closes
+		response.on("close",function () {
+			clearInterval(heartbeatTimer);
+			$tw.mws.store.removeEventListener("change",sendUpdates);
+		});
+		return;
+	}
+	// Fail if something went wrong
+	response.writeHead(404);
+	response.end();
+};
+
+}());

plugins/tiddlywiki/multiwikiserver/modules/store/sql-tiddler-store.js

@@ -27,6 +27,8 @@ function SqlTiddlerStore(options) {
 	options = options || {};
 	this.attachmentStore = options.attachmentStore;
 	this.adminWiki = options.adminWiki || $tw.wiki;
+	this.eventListeners = {}; // Hashmap by type of array of event listener functions
+	this.eventOutstanding = {}; // Hashmap by type of boolean true of outstanding events
 	// Create the database
 	this.databasePath = options.databasePath || ":memory:";
 	var SqlTiddlerDatabase = require("$:/plugins/tiddlywiki/multiwikiserver/store/sql-tiddler-database.js").SqlTiddlerDatabase;
@@ -37,6 +39,39 @@ function SqlTiddlerStore(options) {
 	this.sqlTiddlerDatabase.createTables();
 }
 
+SqlTiddlerStore.prototype.addEventListener = function(type,listener) {
+	this.eventListeners[type] = this.eventListeners[type]  || [];
+	this.eventListeners[type].push(listener);
+};
+
+SqlTiddlerStore.prototype.removeEventListener = function(type,listener) {
+	const listeners = this.eventListeners[type];
+	if(listeners) {
+		var p = listeners.indexOf(listener);
+		if(p !== -1) {
+			listeners.splice(p,1);
+		}
+	}
+};
+
+SqlTiddlerStore.prototype.dispatchEvent = function(type /*, args */) {
+	const self = this;
+	if(!this.eventOutstanding[type]) {
+		$tw.utils.nextTick(function() {
+			self.eventOutstanding[type] = false;
+			const args = Array.prototype.slice.call(arguments,1),
+				listeners = self.eventListeners[type];
+			if(listeners) {
+				for(var p=0; p<listeners.length; p++) {
+					var listener = listeners[p];
+					listener.apply(listener,args);
+				}
+			}
+			});
+		this.eventOutstanding[type] = true;
+	}
+};
+
 /*
 Returns null if a bag/recipe name is valid, or a string error message if not
 */
@@ -142,6 +177,7 @@ SqlTiddlerStore.prototype.saveTiddlersFromPath = function(tiddler_files_path,bag
 			}
 		}
 	});
+	self.dispatchEvent("change");
 };
 
 SqlTiddlerStore.prototype.listBags = function() {
@@ -156,6 +192,7 @@ SqlTiddlerStore.prototype.createBag = function(bag_name,description) {
 			return {message: validationBagName};
 		}
 		self.sqlTiddlerDatabase.createBag(bag_name,description);
+		self.dispatchEvent("change");
 		return null;
 	});
 };
@@ -184,6 +221,7 @@ SqlTiddlerStore.prototype.createRecipe = function(recipe_name,bag_names,descript
 	var self = this;
 	return this.sqlTiddlerDatabase.transaction(function() {
 		self.sqlTiddlerDatabase.createRecipe(recipe_name,bag_names,description);
+		self.dispatchEvent("change");
 		return null;
 	});
 };
@@ -193,7 +231,9 @@ Returns {tiddler_id:}
 */
 SqlTiddlerStore.prototype.saveBagTiddler = function(incomingTiddlerFields,bag_name) {
 	const {tiddlerFields, attachment_blob} = this.processIncomingTiddler(incomingTiddlerFields);
-	return this.sqlTiddlerDatabase.saveBagTiddler(tiddlerFields,bag_name,attachment_blob);
+	const result = this.sqlTiddlerDatabase.saveBagTiddler(tiddlerFields,bag_name,attachment_blob);
+	this.dispatchEvent("change");
+	return result;
 };
 
 /*
@@ -209,7 +249,9 @@ Returns {tiddler_id:}
 SqlTiddlerStore.prototype.saveBagTiddlerWithAttachment = function(incomingTiddlerFields,bag_name,options) {
 	const attachment_blob = this.attachmentStore.adoptAttachment(options.filepath,options.type,options.hash);
 	if(attachment_blob) {
-		return this.sqlTiddlerDatabase.saveBagTiddler(incomingTiddlerFields,bag_name,attachment_blob);
+		const result = this.sqlTiddlerDatabase.saveBagTiddler(incomingTiddlerFields,bag_name,attachment_blob);
+		this.dispatchEvent("change");
+		return result;
 	} else {
 		return null;
 	}
@@ -220,11 +262,15 @@ Returns {tiddler_id:,bag_name:}
 */
 SqlTiddlerStore.prototype.saveRecipeTiddler = function(incomingTiddlerFields,recipe_name) {
 	const {tiddlerFields, attachment_blob} = this.processIncomingTiddler(incomingTiddlerFields);
-	return this.sqlTiddlerDatabase.saveRecipeTiddler(tiddlerFields,recipe_name,attachment_blob);
+	const result = this.sqlTiddlerDatabase.saveRecipeTiddler(tiddlerFields,recipe_name,attachment_blob);
+	this.dispatchEvent("change");
+	return result;
 };
 
 SqlTiddlerStore.prototype.deleteTiddler = function(title,bag_name) {
-	return this.sqlTiddlerDatabase.deleteTiddler(title,bag_name);
+	const result = this.sqlTiddlerDatabase.deleteTiddler(title,bag_name);
+	this.dispatchEvent("change");
+	return result;
 };
 
 /*
@@ -332,7 +378,9 @@ SqlTiddlerStore.prototype.getRecipeLastTiddlerId = function(recipe_name) {
 SqlTiddlerStore.prototype.deleteAllTiddlersInBag = function(bag_name) {
 	var self = this;
 	return this.sqlTiddlerDatabase.transaction(function() {
-		return self.sqlTiddlerDatabase.deleteAllTiddlersInBag(bag_name);
+		const result = self.sqlTiddlerDatabase.deleteAllTiddlersInBag(bag_name);
+		self.dispatchEvent("change");
+		return result;
 	});
 };