httpserver

A zero-dependency implementation of the JDK com.sun.net.httpserver.HttpServer specification with a few significant enhancements.

It adds websocket support using modified source from nanohttpd.

It has basic server-side proxy support using ProxyHandler.

ProxyHandler also supports tunneling proxies using CONNECT for https.

All async functionality has been removed. All synchronized blocks were removed in favor of other Java concurrency concepts.

The end result is an implementation that easily integrates with Virtual Threads available in JDK 21 - simply set a virtual thread based ExecutorService.

Improved performance by more than 3x over the JDK implementation, using http pipelining, optimized String parsing, etc.

Designed for embedding with only a 90kb jar and zero dependencies.

background

The JDK httpserver implementation has no support for connection upgrades, so it is not possible to add websocket support.

Additionally, the code still has a lot of async - e.g. using SSLEngine to provide SSL support - which makes it more difficult to understand and enhance.

The streams based processing and thread per connection design simplifies the code substantially.

testing

Nearly all of the tests were included from the JDK so this version should be highly compliant and reliable.

using

Set the default HttpServer provider when starting the jvm:

-Dcom.sun.net.httpserver.HttpServerProvider=robaho.net.httpserver.DefaultHttpServerProvider

or instantiate the server directly using this.

or the service loader will automatically find it when the jar is placed on the class path when using the standard HttpServer service provider.

performance

This version performs more than 3x better than the JDK version when tested using the Tech Empower Benchmarks on an identical hardware/work setup with the same JDK 21 version.¹ Early results with JDK-24 and the improved virtual threads scheduling shows even greater performance improvement.

The frameworks were also tested using go-wrk²

¹Currently working on submitting the robaho version to the Tech Empower benchmarks project for 3-party confirmation.
²go-wrk does not use http pipelining so, the large number of connections is the limiting factor. go-wrk was tested using the Tech Empower server process.

robaho tech empower

robertengels@macmini go-wrk % wrk -H 'Host: imac' -H 'Accept: text/plain,text/html;q=0.9,application/xhtml+xml;q=0.9,application/xml;q=0.8,*/*;q=0.7' -H 'Connection: keep-alive' --latency -d 60 -c 64 --timeout 8 -t 2 http://imac:8080/plaintext -s ~/pipeline.lua -- 16
Running 1m test @ http://imac:8080/plaintext
  2 threads and 64 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency   658.83us  665.90us  19.01ms   16.14%
    Req/Sec   294.57k    28.40k  329.21k    85.67%
  Latency Distribution
     50%    0.00us
     75%    0.00us
     90%    0.00us
     99%    0.00us
  35179762 requests in 1.00m, 4.65GB read
Requests/sec: 586136.93
Transfer/sec:     79.38MB

jdk 21 tech empower

robertengels@macmini go-wrk % wrk -H 'Host: imac' -H 'Accept: text/plain,text/html;q=0.9,application/xhtml+xml;q=0.9,application/xml;q=0.8,*/*;q=0.7' -H 'Connection: keep-alive' --latency -d 60 -c 64 --timeout 8 -t 2 http://imac:8080/plaintext -s ~/pipeline.lua -- 16
Running 1m test @ http://imac:8080/plaintext
  2 threads and 64 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency     3.10ms    6.16ms 407.66ms   65.94%
    Req/Sec    86.84k    10.05k  119.40k    71.00%
  Latency Distribution
     50%    5.17ms
     75%    0.00us
     90%    0.00us
     99%    0.00us
  10371476 requests in 1.00m, 1.30GB read
Requests/sec: 172781.10
Transfer/sec:     22.24MB

robaho go-wrk

robertengels@macmini go-wrk % ./go-wrk -c=1024 -d=30 -T=100000 http://imac:8080/plaintext
Running 30s test @ http://imac:8080/plaintext
  1024 goroutine(s) running concurrently
3194361 requests in 30.105607793s, 380.80MB read
Requests/sec:		106105.18
Transfer/sec:		12.65MB
Overall Requests/sec:	104132.86
Overall Transfer/sec:	12.41MB
Fastest Request:	104µs
Avg Req Time:		9.65ms
Slowest Request:	2.414591s
Number of Errors:	0
10%:			2.554ms
50%:			3.123ms
75%:			3.29ms
99%:			3.395ms
99.9%:			3.399ms
99.9999%:		3.399ms
99.99999%:		3.399ms
stddev:			36.233m

jdk 21 go-wrk³

robertengels@macmini go-wrk % ./go-wrk -c=1024 -d=30 -T=100000 http://imac:8080/plaintext
Running 30s test @ http://imac:8080/plaintext
  1024 goroutine(s) running concurrently
2046367 requests in 15.233001979s, 230.28MB read
Requests/sec:		134337.74
Transfer/sec:		15.12MB
Overall Requests/sec:	59207.56
Overall Transfer/sec:	6.66MB
Fastest Request:	317µs
Avg Req Time:		7.622ms
Slowest Request:	20.820991s
Number of Errors:	651
Error Counts:		operation timed out=651
10%:			1.007ms
50%:			1.321ms
75%:			1.422ms
99%:			1.498ms
99.9%:			1.501ms
99.9999%:		1.501ms
99.99999%:		1.501ms
stddev:			207.565ms

³Note the failures/timeouts when using the JDK version which affects the overall statistics.

server statistics

The server tracks some basic statistics. To enable the access endpoint /__stats, set the system property robaho.net.httpserver.EnableStatistics=true.

Sample usage:

$ curl http://localhost:8080/__stats
Connections: 4264
Active Connections: 2049
Requests: 2669256
Requests/sec: 73719
Handler Exceptions: 0
Socket Exceptions: 0
Mac Connections Exceeded: 0
Idle Closes: 0
Reply Errors: 0

The counts can be reset using /__stats?reset. The requests/sec is calculated from the previous statistics request.

maven

<dependency>
  <groupId>io.github.robaho</groupId>
  <artifactId>httpserver</artifactId>
  <version>1.0.8</version>
</dependency>

future work

There is no http2 support.

robaho/httpserver