Why you should be at conf.kde.in

conf.kde.in is happening in Bangalore from 9th-13th March. This is a golden opportunity for students to have fun and learn some really interesting things that no college or class can teach. It is also a chance to form friendships that last forever.

If you don’t like long posts: here is the gist.

• Short term benefits – a great time and a cool t-shirt.
• Long term benefits – create something awesome, lots of friends and an impressive CV that recruiters will notice.

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Remember that feeling you had the first time you made a paper boat all by yourself and set it on the water? Or the time when you sang really well on stage and a hundred people gave you a standing ovation? With KDE, its possible to create beauty everyday!

When I first started using Linux in 2004, KDE 3.2 was an eye-opener about what truly functional and powerful computing could be. It was liberating. But the real magic of KDE is in its people, highly talented, motivated and very warm individuals with a lot of free hugs. So come and join the community. You don’t have to be a top-grade programmer, a really great designer or a Indian language expert to enter. At KDE we welcome everybody who has the passion to improve the computing experience for millions of people.

If you are a programmer, at conf.kde.in you have a chance to take away intimate knowledge about working with technologies like Qt, a cross-platform library which allows you to create high-quality applications on Linux, Windows, Mac OS, Symbian and even Android. With so much web and social and information, you might want to make use of KDE’s excellent Nepomuk framework to create semantically aware apps that can look at things like humans. Or the lab sessions will have you get started with submitting bug fixes for KDE in no time.

If drawing and painting is your forte, we have sessions to get you contributing your skills to open source applications and improving the KDE look and feel. You could create the next UI paradigm and dominate the world! :)

A billion people are waiting to use computers, and one of the things stopping them from having cheap, affordable machines is the lack of English literacy. So if you know more than one language, you could jump in and translate applications to Indian languages and bring a smile to some kid, and make his future!

Don’t think that as a student you lack the qualifications to attend. A HUGE chunk of KDE is made of students, with even teenage contributors! I myself am just a 3rd year undergraduate. We encourage students through programs like Google Summer of Code, Season of KDE and Google Code-In for high-school students. conf.kde.in is here to guide you even if you have never programmed before. We have excellent talks for all levels, by notable members of the KDE community. We also have interactive lab sessions where you will get to hack and explore more code than you will ever do in your college courses :P

Make sure you drag along your teachers too. They can be introduced to the educational tools that make KDE such a great platform to learn new things on. Whether its astronomy or jigsaw puzzles or Ph. D. level computer courses, KDE has applications for them to make their teaching more tangible!

Student passes are Rs. 500 (for all 3 days, including lunch), teachers can register for Rs. 700. For others its Rs. 900. Register online before 25th February to attend conf.kde.in. Although you can register after that, even on the spot at the day of the conference, it will be more expensive later (Students: Rs. 700, Teachers: Rs. 900, Normal: Rs. 1200). Remember to enter discount codes to get a discount, and get your college ID card to the event.

• Student discount: KDEIN_DIS_STU
• Teacher discount: KDEIN_DIS_TCR

If you need a letter to get permission from your college, we can arrange that.

PS. If you can get a laptop with Linux on it to conf.kde.in, you can have twice the fun :)

Posted via email from nikhil's posterous

QHttpServer: Web Apps in Qt

Qt is a great GUI toolkit, but it is also an entire C++ standard library waiting to be used for other tasks. In addition the network module is really powerful. I’ve been playing around with node.js for a while now, and realized that Qt’s default asynchronous nature maps over perfectly to create a event-based web server. To make things better, Ryan Dahl’s small and fast http-parser is freely available. So I just combined the two, and here is QHttpServer.

Here is a ‘web-application’ written completely in C++/Qt. You can even try it out.

#!cpp
#include "greeting.h"

#include <QCoreApplication>
#include <QRegExp>
#include <QStringList>

#include <qhttpserver.h>
#include <qhttprequest.h>
#include <qhttpresponse.h>

Greeting::Greeting()
{
    QHttpServer *server = new QHttpServer;
    server->listen(QHostAddress::Any, 5000);
    connect(server, SIGNAL(newRequest(QHttpRequest*, QHttpResponse*)),
            this, SLOT(handle(QHttpRequest*, QHttpResponse*)));
}

void Greeting::handle(QHttpRequest *req, QHttpResponse *resp)
{
    QRegExp exp("^/user/([a-z]+)$");
    if( exp.indexIn(req->path()) != -1 )
    {
        resp->setHeader("Content-Type", "text/html");
        resp->writeHead(200);
        QString name = exp.capturedTexts()[1];

        QString reply = tr("<html><head><title>Greeting App</title></head><body><h1>Hello  %1!</h1></body></html>");
        resp->end(reply.arg(name).toAscii());
    }
    else
    {
        resp->writeHead(403);
        resp->end("You aren't allowed here!");
    }
}

int main(int argc, char **argv)
{
    QCoreApplication app(argc, argv);

    Greeting hello;
    
    app.exec();
}

Awesome isn’t it? You launch an instance of QHttpServer, it emits a signal whenever a new request comes in, you can handle and respond to it. The code is fully documented, so you can do a git clone and run doxygen in the docs/ folder to get API documentation. For now it doesn’t deal with everything that can happen in HTTP, but it does know about keep-alives (no chunked encoding though). QHttpServer is streaming, see the body data example.

Here is a simple ApacheBench run comparing qhttpserver and node.

QHttpServer Greeting app:

> ab -n 1000 -c 100 http://localhost:5000/user/nikhil
This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking localhost (be patient)


Server Software:        
Server Hostname:        localhost
Server Port:            5000

Document Path:          /user/nikhil
Document Length:        88 bytes

Concurrency Level:      100
Time taken for tests:   0.467 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      151000 bytes
HTML transferred:       88000 bytes
Requests per second:    2142.47 [#/sec] (mean)
Time per request:       46.675 [ms] (mean)
Time per request:       0.467 [ms] (mean, across all concurrent requests)
Transfer rate:          315.93 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    2   4.7      0      23
Processing:    14   43  18.9     40     123
Waiting:       13   43  18.9     40     123
Total:         14   45  18.9     41     130

Percentage of the requests served within a certain time (ms)
  50%     41
  66%     48
  75%     53
  80%     58
  90%     69
  95%     80
  98%     98
  99%    117
 100%    130 (longest request)

node.js greeting app:

> ab -n 1000 -c 100 http://localhost:5000/user/nikhil
This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking localhost (be patient)


Server Software:        
Server Hostname:        localhost
Server Port:            5000

Document Path:          /user/nikhil
Document Length:        88 bytes

Concurrency Level:      100
Time taken for tests:   0.441 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      151000 bytes
HTML transferred:       88000 bytes
Requests per second:    2267.94 [#/sec] (mean)
Time per request:       44.093 [ms] (mean)
Time per request:       0.441 [ms] (mean, across all concurrent requests)
Transfer rate:          334.43 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    2   4.4      0      18
Processing:     4   40  22.7     37     101
Waiting:        4   40  22.9     37     101
Total:          4   42  21.7     39     101

Percentage of the requests served within a certain time (ms)
  50%     39
  66%     50
  75%     57
  80%     63
  90%     73
  95%     83
  98%     91
  99%     95
 100%    101 (longest request)

While not a very scientific benchmark, this does show them pretty close. C++ is compiled, but I believe node has less ‘layers’ and a particularly efficient I/O infrastructure which allows it to be better even with an interpreted language.

I would really like to see this being used in Qt apps that need a web interface for remote control, or for simple delivery of files.

In addition, if you will be attending conf.kde.in in Bangalore, India on March 9th-13th, my talk on Qt Scripting will involve writing a thin JavaScript wrapper over this and doing some other cool stuff! So be there.