给 connect 的 static 模块加上url路径前缀
估计我们使用 connect 都会很自然地按照官方的例子使用静态文件模块 static:
var connect = require('connect');
connect(
connect.static(__dirname),
function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
}
).listen(8124);
console.log('Server running at http://127.0.0.1:8124/');
基准性能
为了评测 static 的性能，我们需要又一个基准对比。
官方最纯洁的 helloworld
我们使用 nodejs 官方文档给出的 helloworld 做最基础的参照：
var http = require('http');
http.createServer(function (request, response) {
response.writeHead(200, {'Content-Type': 'text/plain'});
response.end('Hello World\n');
}).listen(8124);
console.log('Server running at http://127.0.0.1:8124/');
最纯洁的 connect helloworld
不使用任何中间件模块
var connect = require('connect');
connect(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
}).listen(8124);
console.log('Server running at http://127.0.0.1:8124/');
结合 domain 模块的 connect helloworld
var connect = require('connect');
var createDomain = require('domain').create;
connect(
function (req, res, next) {
var domain = createDomain();
domain.on('error', function (err) {
console.log('errrrrr', err);
res.statusCode = 500;
res.end(err.message + '\n');
domain.dispose();
});
domain.run(next);
},
function (req, res, next) {
if (req.url === '/error') {
process.nextTick(function () {
res.end('params: ' + req.query.abc);
});
return;
}
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
}
).listen(8124);
console.log('Server running at http://127.0.0.1:8124/');
测试结果
官方最纯洁的 helloworld: 7851.56 qps
$ siege -b -c10 -t10S http://127.0.0.1:8124/
** SIEGE 2.72
** Preparing 10 concurrent users for battle.
The server is now under siege...
Lifting the server siege... done.
Transactions: 78123 hits
Availability: 100.00 %
Elapsed time: 9.95 secs
Data transferred: 0.89 MB
Response time: 0.00 secs
Transaction rate: 7851.56 trans/sec
Throughput: 0.09 MB/sec
Concurrency: 9.93
Successful transactions: 78123
Failed transactions: 0
Longest transaction: 0.09
Shortest transaction: 0.00
最纯洁的 connect helloworld: 6808.19 qps
$ siege -b -c10 -t10S http://127.0.0.1:8124/
** SIEGE 2.72
** Preparing 10 concurrent users for battle.
The server is now under siege...
Lifting the server siege... done.
Transactions: 65699 hits
Availability: 100.00 %
Elapsed time: 9.65 secs
Data transferred: 0.75 MB
Response time: 0.00 secs
Transaction rate: 6808.19 trans/sec
Throughput: 0.08 MB/sec
Concurrency: 9.96
Successful transactions: 65699
Failed transactions: 0
Longest transaction: 0.05
Shortest transaction: 0.00
使用 domain 模块的 connect helloworld: 5601.35 qps
** SIEGE 2.72
** Preparing 50 concurrent users for battle.
The server is now under siege...
Lifting the server siege... done.
Transactions: 53885 hits
Availability: 100.00 %
Elapsed time: 9.62 secs
Data transferred: 0.62 MB
Response time: 0.01 secs
Transaction rate: 5601.35 trans/sec
Throughput: 0.06 MB/sec
Concurrency: 49.62
Successful transactions: 53885
Failed transactions: 0
Longest transaction: 0.05
Shortest transaction: 0.00
带 static 的 connect helloworld: 3636.98 qps
$ siege -b -c10 -t10S http://127.0.0.1:8124/
** SIEGE 2.72
** Preparing 10 concurrent users for battle.
The server is now under siege...
Lifting the server siege... done.
Transactions: 34915 hits
Availability: 100.00 %
Elapsed time: 9.60 secs
Data transferred: 0.40 MB
Response time: 0.00 secs
Transaction rate: 3636.98 trans/sec
Throughput: 0.04 MB/sec
Concurrency: 9.97
Successful transactions: 34915
Failed transactions: 0
Longest transaction: 0.06
Shortest transaction: 0.00
为什么性能降低了50%
晕，为什么加上了 static 模块，性能会降低了50％这么多？
查看 static.send() 源代码:
// "hidden" file
if (!hidden && '.' == basename(path)[0]) return next();
fs.stat(path, function(err, stat){
// mime type
type = mime.lookup(path);
// ignore ENOENT
if (err) {
if (fn) return fn(err);
return ('ENOENT' == err.code || 'ENAMETOOLONG' == err.code)
? next()
: next(err);
// redirect directory in case index.html is present
} else if (stat.isDirectory()) {
if (!redirect) return next();
res.statusCode = 301;
res.setHeader('Location', url.pathname + '/');
res.end('Redirecting to ' + url.pathname + '/');
return;
}
static 模块每次都需要一次文件IO，判断文件是否存在，这是多么损耗性能啊。
增加静态文件url路径前缀
既然找到性能问题所在，就可以解决此问题了。对症下药，无需让所有请求都经过 static 处理即可。
给 static 增加一个url前缀判断，例如 /public/images/logo.jpg 只有前缀是 /public 的 url 请求才需要进入 static 模块处理。
那么我们改进后的代码应该是这样的:
var connect = require('connect');
var app = connect();
app.use('/public', connect.static(__dirname));
app.use(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
}).listen(8124);
console.log('Server running at http://127.0.0.1:8124/');
性能如何？ wow 6749.03 qps, 几乎和 connect hellowrold 一致。done!
$ siege -b -c10 -t10S http://127.0.0.1:8124/
** SIEGE 2.72
** Preparing 10 concurrent users for battle.
The server is now under siege...
Lifting the server siege... done.
Transactions: 66073 hits
Availability: 100.00 %
Elapsed time: 9.79 secs
Data transferred: 0.76 MB
Response time: 0.00 secs
Transaction rate: 6749.03 trans/sec
Throughput: 0.08 MB/sec
Concurrency: 9.97
Successful transactions: 66073
Failed transactions: 0
Longest transaction: 0.03
Shortest transaction: 0.00
重现一下之前的性能问题，访问 /public/foo 即可重现。
$ siege -b -c10 -t10S http://127.0.0.1:8124/public/foo
** SIEGE 2.72
** Preparing 10 concurrent users for battle.
The server is now under siege...
Lifting the server siege... done.
Transactions: 37773 hits
Availability: 100.00 %
Elapsed time: 9.59 secs
Data transferred: 0.43 MB
Response time: 0.00 secs
Transaction rate: 3938.79 trans/sec
Throughput: 0.05 MB/sec
Concurrency: 9.97
Successful transactions: 37773
Failed transactions: 0
Longest transaction: 0.05
Shortest transaction: 0.00
有爱
记得给 connect.static 加上一个url路径前缀喔!
^_^ 希望本文对你有用.
