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gzip compression support #6

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62 changes: 46 additions & 16 deletions lib/prerenderRedisCache.js
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Original file line number Diff line number Diff line change
Expand Up @@ -7,10 +7,14 @@ var redis_url = process.env.REDISTOGO_URL || process.env.REDISCLOUD_URL || proce
url = require('url'),
ttl = process.env.PAGE_TTL || 86400;

var zlib = require('zlib'),
gzip_level = parseInt(process.env.GZIP_LEVEL) || 0;


// Parse out the connection vars from the env string.
var connection = url.parse(redis_url),
redis = require('redis'),
client = redis.createClient(connection.port, connection.hostname),
client = redis.createClient(connection.port, connection.hostname, {'return_buffers': true}),
redis_online = false,
last_error = "",
last_end_message = ""; // Make redis connection
Expand All @@ -22,9 +26,9 @@ if (connection.auth) {

// Catch all error handler. If redis breaks for any reason it will be reported here.
client.on("error", function (err) {
if(last_error === err.toString()) {
if(last_error === err.toString()) {
// Swallow the error for now
} else {
} else {
last_error = err.toString();
console.log("Redis Cache Error: " + err);
}
Expand All @@ -38,27 +42,51 @@ client.on("ready", function () {
client.on("end", function (err) {
if(err) {
err = err.toString();
if(last_end_message == err) {
if(last_end_message == err) {
// Swallow the error for now
} else {
} else {
last_end_message = err;
redis_online = false;
console.log("Redis Cache Conncetion Closed. Will now bypass redis until it's back.");
}
}
});

function redisSet(key, val) {
client.set(key, val, function (err, reply) {
// If library set to cache set an expiry on the key.
if (!err && reply && ttl && ttl != 0) {
client.expire(key, ttl, function (err, didSetExpiry) {
console.warn(!!didSetExpiry);
});
}
});
}

module.exports = {
beforePhantomRequest: function (req, res, next) {
//
//
if (req.method !== 'GET' || redis_online !== true) {
return next();
}

client.get(req.prerender.url, function (err, result) {

// Page found - return to prerender and 200
if (!err && result) {
res.send(200, result);
if (gzip_level > 0) {
zlib.gunzip(result, function (gzip_err, gunzip_result) {
if (!gzip_err && gunzip_result) {
res.send(200, gunzip_result);
}
else {
console.log("Failed to decompress key value, maybe you should flush your cache?");
next();
}
});
} else {
res.send(200, result);
}
} else {
next();
}
Expand All @@ -71,15 +99,17 @@ module.exports = {
}
// Don't cache anything that didn't result in a 200. This is to stop caching of 3xx/4xx/5xx status codes
if (req.prerender.statusCode === 200) {
client.set(req.prerender.url, req.prerender.documentHTML, function (err, reply) {
// If library set to cache set an expiry on the key.
if (!err && reply && ttl && ttl != 0) {
client.expire(req.prerender.url, ttl, function (err, didSetExpiry) {
console.warn(!!didSetExpiry);
});
}
});
if (gzip_level > 0) {
zlib.gzip(req.prerender.documentHTML, {'level': gzip_level}, function (gzip_err, gzip_result) {
if (!gzip_err) {
redisSet(req.prerender.url, gzip_result);
}
});
} else {
redisSet(req.prerender.url, req.prerender.documentHTML);
}

}
next();
}
};
};