Network performance optimizations for node.js (#5436)

core/language/en-GB/Help/listen.tid

@@ -30,6 +30,7 @@ All parameters are optional with safe defaults, and can be specified in any orde
 * ''tls-key'' - pathname of TLS key file (relative to wiki folder)
 * ''debug-level'' - optional debug level; set to "debug" to view request details (defaults to "none")
 * ''gzip'' - set to "yes" to enable gzip compression for some http endpoints (defaults to "no")
+* ''use-browser-cache'' - set to "yes" to allow the browser to cache responses to save bandwith (defaults to "no")
 
 For information on opening up your instance to the entire local network, and possible security concerns, see the WebServer tiddler at TiddlyWiki.com.
 

core/modules/server/routes/get-favicon.js

@@ -17,9 +17,8 @@ exports.method = "GET";
 exports.path = /^\/favicon.ico$/;
 
 exports.handler = function(request,response,state) {
-	response.writeHead(200, {"Content-Type": "image/x-icon"});
 	var buffer = state.wiki.getTiddlerText("$:/favicon.ico","");
-	response.end(buffer,"base64");
+	state.sendResponse(200,{"Content-Type": "image/x-icon"},buffer,"base64");
 };
 
 }());

core/modules/server/routes/get-file.js

@@ -34,10 +34,7 @@ exports.handler = function(request,response,state) {
 			content = content;
 			type = ($tw.config.fileExtensionInfo[extension] ? $tw.config.fileExtensionInfo[extension].type : "application/octet-stream");
 		}
-		response.writeHead(status,{
-			"Content-Type": type
-		});
-		response.end(content);
+		state.sendResponse(status,{"Content-Type": type},content);
 	});
 };
 

core/modules/server/routes/get-index.js

@@ -12,38 +12,16 @@ GET /
 /*global $tw: false */
 "use strict";
 
-var zlib = require("zlib");
-
 exports.method = "GET";
 
 exports.path = /^\/$/;
 
 exports.handler = function(request,response,state) {
-	var acceptEncoding = request.headers["accept-encoding"];
-	if(!acceptEncoding) {
-		acceptEncoding = "";
-	}
 	var text = state.wiki.renderTiddler(state.server.get("root-render-type"),state.server.get("root-tiddler")),
 		responseHeaders = {
 		"Content-Type": state.server.get("root-serve-type")
 	};
-	/*
-	If the gzip=yes flag for `listen` is set, check if the user agent permits
-	compression. If so, compress our response. Note that we use the synchronous
-	functions from zlib to stay in the imperative style. The current `Server`
-	doesn't depend on this, and we may just as well use the async versions.
-	*/
-	if(state.server.enableGzip) {
-		if (/\bdeflate\b/.test(acceptEncoding)) {
-			responseHeaders["Content-Encoding"] = "deflate";
-			text = zlib.deflateSync(text);
-		} else if (/\bgzip\b/.test(acceptEncoding)) {
-			responseHeaders["Content-Encoding"] = "gzip";
-			text = zlib.gzipSync(text);
-		}
-	}
-	response.writeHead(200,responseHeaders);
-	response.end(text);
+	state.sendResponse(200,responseHeaders,text);
 };
 
 }());

core/modules/server/routes/get-status.js

@@ -17,7 +17,6 @@ exports.method = "GET";
 exports.path = /^\/status$/;
 
 exports.handler = function(request,response,state) {
-	response.writeHead(200, {"Content-Type": "application/json"});
 	var text = JSON.stringify({
 		username: state.authenticatedUsername || state.server.get("anon-username") || "",
 		anonymous: !state.authenticatedUsername,
@@ -28,7 +27,7 @@ exports.handler = function(request,response,state) {
 		},
 		tiddlywiki_version: $tw.version
 	});
-	response.end(text,"utf8");
+	state.sendResponse(200,{"Content-Type": "application/json"},text,"utf8");
 };
 
 }());

core/modules/server/routes/get-tiddler-html.js

@@ -32,9 +32,9 @@ exports.handler = function(request,response,state) {
 			renderTemplate = renderTemplate || state.server.get("tiddler-render-template");
 		}
 		var text = state.wiki.renderTiddler(renderType,renderTemplate,{parseAsInline: true, variables: {currentTiddler: title}});
+
 		// Naughty not to set a content-type, but it's the easiest way to ensure the browser will see HTML pages as HTML, and accept plain text tiddlers as CSS or JS
-		response.writeHead(200);
-		response.end(text,"utf8");
+		state.sendResponse(200,{},text,"utf8");
 	} else {
 		response.writeHead(404);
 		response.end();

core/modules/server/routes/get-tiddler.js

@@ -36,8 +36,7 @@ exports.handler = function(request,response,state) {
 		tiddlerFields.revision = state.wiki.getChangeCount(title);
 		tiddlerFields.bag = "default";
 		tiddlerFields.type = tiddlerFields.type || "text/vnd.tiddlywiki";
-		response.writeHead(200, {"Content-Type": "application/json"});
-		response.end(JSON.stringify(tiddlerFields),"utf8");
+		state.sendResponse(200,{"Content-Type": "application/json"},JSON.stringify(tiddlerFields),"utf8");
 	} else {
 		response.writeHead(404);
 		response.end();

core/modules/server/routes/get-tiddlers-json.js

@@ -33,7 +33,6 @@ exports.handler = function(request,response,state) {
 	}
 	var excludeFields = (state.queryParameters.exclude || "text").split(","),
 		titles = state.wiki.filterTiddlers(filter);
-	response.writeHead(200, {"Content-Type": "application/json"});
 	var tiddlers = [];
 	$tw.utils.each(titles,function(title) {
 		var tiddler = state.wiki.getTiddler(title);
@@ -45,7 +44,7 @@ exports.handler = function(request,response,state) {
 		}
 	});
 	var text = JSON.stringify(tiddlers);
-	response.end(text,"utf8");
+	state.sendResponse(200,{"Content-Type": "application/json"},text,"utf8");
 };
 
 }());

core/modules/server/server.js

@@ -17,7 +17,9 @@ if($tw.node) {
 		fs = require("fs"),
 		url = require("url"),
 		path = require("path"),
-		querystring = require("querystring");
+		querystring = require("querystring"),
+		crypto = require("crypto"),
+		zlib = require("zlib");
 }
 
 /*
@@ -47,6 +49,8 @@ function Server(options) {
 	this.csrfDisable = this.get("csrf-disable") === "yes";
 	// Initialize Gzip compression
 	this.enableGzip = this.get("gzip") === "yes";
+	// Initialize browser-caching
+	this.enableBrowserCache = this.get("use-browser-cache") === "yes";
 	// Initialise authorization
 	var authorizedUserName = (this.get("username") && this.get("password")) ? this.get("username") : "(anon)";
 	this.authorizationPrincipals = {
@@ -78,6 +82,71 @@ function Server(options) {
 	this.transport = require(this.protocol);
 }
 
+/*
+Send a response to the client. This method checks if the response must be sent
+or if the client alrady has the data cached. If that's the case only a 304
+response will be transmitted and the browser will use the cached data.
+Only requests with status code 200 are considdered for caching.
+request: request instance passed to the handler
+response: response instance passed to the handler
+statusCode: stauts code to send to the browser
+headers: response headers (they will be augmented with an `Etag` header)
+data: the data to send (passed to the end method of the response instance)
+encoding: the encoding of the data to send (passed to the end method of the response instance)
+*/
+function sendResponse(request,response,statusCode,headers,data,encoding) {
+	if(this.enableBrowserCache && (statusCode == 200)) {
+		var hash = crypto.createHash('md5');
+		// Put everything into the hash that could change and invalidate the data that
+		// the browser already stored. The headers the data and the encoding.
+		hash.update(data);
+		hash.update(JSON.stringify(headers));
+		if(encoding) {
+			hash.update(encoding);
+		}
+		var contentDigest = hash.digest("hex");
+		// RFC 7232 section 2.3 mandates for the etag to be enclosed in quotes
+		headers["Etag"] = '"' + contentDigest + '"';
+		headers["Cache-Control"] = "max-age=0, must-revalidate";
+		// Check if any of the hashes contained within the if-none-match header
+		// matches the current hash.
+		// If one matches, do not send the data but tell the browser to use the
+		// cached data.
+		// We do not implement "*" as it makes no sense here.
+		var ifNoneMatch = request.headers["if-none-match"];
+		if(ifNoneMatch) {
+			var matchParts = ifNoneMatch.split(",").map(function(etag) {
+				return etag.replace(/^[ "]+|[ "]+$/g, "");
+			});
+			if(matchParts.indexOf(contentDigest) != -1) {
+				response.writeHead(304,headers);
+				response.end();
+				return;
+			}
+		}
+	}
+	/*
+	If the gzip=yes is set, check if the user agent permits compression. If so,
+	compress our response if the raw data is bigger than 2k. Compressing less
+	data is inefficient. Note that we use the synchronous functions from zlib
+	to stay in the imperative style. The current `Server` doesn't depend on
+	this, and we may just as well use the async versions.
+	*/
+	if(this.enableGzip && (data.length > 2048)) {
+		var acceptEncoding = request.headers["accept-encoding"] || "";
+		if(/\bdeflate\b/.test(acceptEncoding)) {
+			headers["Content-Encoding"] = "deflate";
+			data = zlib.deflateSync(data);
+		} else if(/\bgzip\b/.test(acceptEncoding)) {
+			headers["Content-Encoding"] = "gzip";
+			data = zlib.gzipSync(data);
+		}
+	}
+
+	response.writeHead(statusCode,headers);
+	response.end(data,encoding);
+}
+
 Server.prototype.defaultVariables = {
 	port: "8080",
 	host: "127.0.0.1",
@@ -89,7 +158,8 @@ Server.prototype.defaultVariables = {
 	"system-tiddler-render-type": "text/plain",
 	"system-tiddler-render-template": "$:/core/templates/wikified-tiddler",
 	"debug-level": "none",
-	"gzip": "no"
+	"gzip": "no",
+	"use-browser-cache": "no"
 };
 
 Server.prototype.get = function(name) {
@@ -167,6 +237,7 @@ Server.prototype.requestHandler = function(request,response,options) {
 	state.urlInfo = url.parse(request.url);
 	state.queryParameters = querystring.parse(state.urlInfo.query);
 	state.pathPrefix = options.pathPrefix || this.get("path-prefix") || "";
+	state.sendResponse = sendResponse.bind(self,request,response);
 	// Get the principals authorized to access this resource
 	var authorizationType = this.methodMappings[request.method] || "readers";
 	// Check for the CSRF header if this is a write

languages/de-DE/Help/listen.tid

@@ -31,5 +31,6 @@ Mögliche Parameter:
 * ''tls-key'' - Pfad zur "TLS key" Datei (relativ zum Wiki Verzeichnis)
 * ''debug-level'' - "debug" bewikt eine detailierte Anzeige der HTTP Anfrage-Parameter. (Standard: "none")
 * ''gzip'' - Wenn auf "yes" gesetzt, dann wird gzip Kompression aktiviert. (Standard: "no")
+* ''use-browser-cache'' - Ist dieser Parameter auf "yes" gesetzt kann der Browser Inhalte zwischenspeichern um Übertragungsbandbreite zu sparen. (Standard: "no")
 
 Für weitere Sicherheitshinweise und Informationen für die Verwendung in lokalen Netzwerken siehe: WebServer auf TiddlyWiki.com