From 1bced5737a74678b6dd3ed8e73cf14871701ec92 Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Sat, 8 Nov 2014 15:27:51 +0100
Subject: [PATCH] Add support for gzip in serve-analysis.js.

---
 www/serve-analysis.js | 44 +++++++++++++++++++++++++++++++++----------
 1 file changed, 34 insertions(+), 10 deletions(-)

diff --git a/www/serve-analysis.js b/www/serve-analysis.js
index 80f969e..d1f0bae 100644
--- a/www/serve-analysis.js
+++ b/www/serve-analysis.js
@@ -7,12 +7,14 @@ var fs = require('fs');
 var url = require('url');
 var querystring = require('querystring');
 var path = require('path');
+var zlib = require('zlib');
 
 // Constants.
 var json_filename = '/srv/analysis.sesse.net/www/analysis.json';
 
 // The current contents of the file to hand out, and its last modified time.
 var json_contents = undefined;
+var json_contents_gz = undefined;
 var json_last_modified = undefined;
 
 // The list of clients that are waiting for new data to show up,
@@ -38,9 +40,14 @@ var reread_file = function(event, filename) {
 			fs.read(fd, buffer, 0, 1048576, 0, function(err, bytesRead, buffer) {
 				if (err) throw err;
 				fs.close(fd, function() {
-					json_contents = buffer.toString('utf8', 0, bytesRead);
-					json_last_modified = st.mtime.getTime();
-					possibly_wakeup_clients();
+					var new_json_contents = buffer.toString('utf8', 0, bytesRead);
+					zlib.gzip(new_json_contents, function(err, buffer) {
+						if (err) throw err;
+						json_contents = new_json_contents;
+						json_contents_gz = buffer;
+						json_last_modified = st.mtime.getTime();
+						possibly_wakeup_clients();
+					});
 				});
 			});
 		});
@@ -49,7 +56,7 @@ var reread_file = function(event, filename) {
 var possibly_wakeup_clients = function() {
 	for (var i in sleeping_clients) {
 		clearTimeout(sleeping_clients[i].timer);
-		send_json(sleeping_clients[i].response);
+		send_json(sleeping_clients[i].response, sleeping_clients[i].accept_gzip);
 	}
 	sleeping_clients = {};
 }
@@ -60,20 +67,28 @@ var send_404 = function(response) {
 	response.write('Something went wrong. Sorry.');
 	response.end();
 }
-var send_json = function(response) {
-	response.writeHead(200, {
+var send_json = function(response, accept_gzip) {
+	var headers = {
 		'Content-Type': 'text/json',
 		'X-Remoteglot-Last-Modified': json_last_modified,
 		'X-Remoteglot-Num-Viewers': count_viewers(),
 		'Access-Control-Allow-Origin': 'http://analysis.sesse.net',
 		'Access-Control-Expose-Headers': 'X-Remoteglot-Last-Modified, X-Remoteglot-Num-Viewers',
 		'Expires': 'Mon, 01 Jan 1970 00:00:00 UTC',
-	});
-	response.write(json_contents);
+	};
+
+	if (accept_gzip) {
+		headers['Content-Encoding'] = 'gzip';
+		response.writeHead(200, headers);
+		response.write(json_contents_gz);
+	} else {
+		response.writeHead(200, headers);
+		response.write(json_contents);
+	}
 	response.end();
 }
 var timeout_client = function(client) {
-	send_json(client.response);
+	send_json(client.response, client.accept_gzip);
 	delete sleeping_clients[client.request_id];
 }
 var count_viewers = function() {
@@ -114,10 +129,18 @@ http.createServer(function(request, response) {
 		last_seen_clients[unique] = (new Date).getTime();
 	}
 
+	var accept_encoding = request.headers['accept-encoding'];
+	var accept_gzip;
+	if (accept_encoding !== undefined && accept_encoding.match(/\bgzip\b/)) {
+		accept_gzip = true;
+	} else {
+		accept_gzip = false;
+	}
+
 	// If we already have something newer than what the user has,
 	// just send it out and be done with it.
 	if (json_last_modified !== undefined && (!ims || json_last_modified > ims)) {
-		send_json(response);
+		send_json(response, accept_gzip);
 		return;
 	}
 
@@ -128,5 +151,6 @@ http.createServer(function(request, response) {
 	client.response = response;
 	client.timer = setTimeout(function() { timeout_client(client); }, 30000);
 	client.request_id = request_id;
+	client.accept_gzip = accept_gzip;
 	sleeping_clients[request_id++] = client;
 }).listen(5000);
-- 
2.39.2