sven.buschbeck » code

First GWT Steps

Sven Buschbeck — Wed, 25 Aug 2010 09:41:44 +0000

Just started to work with GWT – a pretty interesting approach for web development compared to PHP or JSF. The whole Application engine is quite impressive especially allowing you to quickly test your applications locally by supporting automatic hot deployment after each code update.
One thing that took me a while was one of that “[ERROR] Unable to find ’[some-file].xml’ on your classpath; could be a typo, or maybe you forgot to include a classpath entry for source?” errors. If you are sure the file is in place I found restarting the App Engine or Eclipse mostly solves that problem.

How to make Jquerymenu for Drupal Keeping its State on Page Reload

Sven Buschbeck — Tue, 02 Feb 2010 18:13:32 +0000

While setting up the website for my new project “Glocal” www.glocal-project.eu), I came across the problem of finding a proper menu module. Something easy to use, stable and efficient in the same time for the complex intranet structure (therefore, sorry, but you will not be able to see my solution there unless you are a project member). Something with a high usability in the end. Activemenu is still quite buggy and DHTML Menue requires a double click to actually open a page — unbearable in a non-doulbe-click environment like the Internet — who is supposed to guess, that this menu requires a double click?? Leaving me with JQuerymenu.

First impression: perfect! Open and close branches by clicking (+) or (-) — view page by clicking menu item label. Even the few styling issues could be fixed easily by using CSS. But as soon, as someone clicks a label, the menu collapses to its default status. It does not remember its last status after loading a different page with the same menu.

Is this it? All module have critical downsides like this? I was quite disappointed!

But I taught JQuerymenu to remember!

As it is quite some code, I will not post it here directly, but added it to the tracker page for this “feature request” or you can download the two updated files (jquerymenu.js and jquerymenu.module) here and replace the once in your /sites/all/modules/jquerymenu folder.

But please be careful, it should be considered an alpha version, there are quite some weaknesses (see tracker page). Any feedback or suggestions are very welcome!

Simple redirection using PHP and HTML meta tag

Sven Buschbeck — Wed, 05 Aug 2009 12:12:49 +0000

Something everyone needs once in a while… maybe you moved a file on your server or you did not install wordpress in the root folder of your webserver – like I did neither – a redirection or forwarding can be an easy answer.

The script is rather simple – it redirects in three ways to provide a reasonable fall back if any of the automatic redirecting fails. To use it on your server, just enter the URL/address/file name/folder you would like the user to be redirected to in the second line of the page/script.

Put the whole code and markup in a file with file extension “.php”.

In my case, every user ending up at “www.svenbuschbeck.net” should to be forwarded to “www.svenbuschbeck.net/wordpress/home”. So I adjusted the script below like “$url = ‘wordpress/home’”, named the file “index.php” and put it in the root folder. Done .







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fixing flex VideoDisplay CuePointManager

Sven Buschbeck — Wed, 24 Jun 2009 14:03:31 +0000

I was creating a Flex application to show slides and a presentation video of previously recorded presentations. Accordingly, each slide should appear at a certain point of time in the video – calls for cue points!

As all slides and there appearance are stored in a text file in my case, I started adding cue points with ActionScript. But as soon as the video can be controlled with a slider, allowing to shift for- and backwards, the event handler “cuePoint” was not triggered any more. Thus, the slides where not changed correctly as the user jumps ahead, as the cue points between the previous and the new position did not cause and cue point event.

Finally I wrote AdvCuePointManager, inheriting from CuePointManager, but which can deal with jumping back- and forward.

Copy it to “/net/svenbuschbeck/flex/video” and use it as follows:

how to install memchached 1.2.2 from source

Sven Buschbeck — Thu, 16 Apr 2009 16:46:49 +0000

I have installed an instance of memchached version 1.2.2 on one of our servers (Debian etch) today and to keep you from spending a whole afternoon, see my everything-step-by-step instruction below.

Memchached is a distributed hash map, which can be used for example to speed up any kind of web application, see website for details. In our case, we want to use it as temporary data store. I will report about the experiences in a latter post.

introduction

Always refer to this page for details, but I created a version with less text but including steps to really start from scratch.

All lines starting with # are command lines, i.e. you need to type into a linux shell.
Output of any kind is always surrounded by ” even if it is multiline output.

content

a. get libevent (needed to install memcached)
b. get memcached and verify installation
c. use and test memcached within Java with junit/ant

a. installing libevent 1.3

a.1. check for current version of libevent

a.1a.

# updatedb
# locate libevent

If there is output including “libevent1″ and/or “libevent-1″ (ignore package files like *.deb) -> a.1b, otherwise a.2

a.1b. removing old libevent version

# apt-get remove –purge libevent1
# Y

# updatedb
# locate libevent
Should now return nothing or package files only, i.e. you are ready for installation

a.2. installing libevent 1.3

a.2a downloading and unpacking

# cd /usr/local/src
# wget http://monkey.org/~provos/libevent-1.3b.tar.gz
# tar zxvf libevent-1.3b.tar.gz
# cd libevent-1.3b

a.2b. configuring

# ./configure
check the output, if it contains something like “configure: error: no acceptable C compiler found in $PATH” -> a.2c. otherwise a.2d.

a.2c. compiling

# apt-get install gcc

Redo a.2b.
I got output like “C compiler cannot create executables”, reading file ‘config.log’ did not help me at all. Googling finally did, as I found a forum entry, pointing out a missing lib.
So try this:

# apt-get install libc-dev

Redo a.2b.
If that did not solve it… sorry … google on, there is no sense in going on without solving this issue. :-/

a.2d. make it!

# make && make install

If you get something like “-bash: make: command not found” -> A.2e, otherwise A.3.

a.2e.

# apt-get install make

Redo a.2d.

a.3. configuration

Press the Esc key as you read [esc] in the commands below.

# vim /etc/ld.so.conf.d/libevent-i386.conf
# i/usr/local/lib/[esc]:wq
# ldconfig

b. install memchached and verify installation

b.1. download, unpack and install memchached

# cd /usr/local/src
# wget http://danga.com/memcached/dist/memcached-1.2.2.tar.gz
# tar zxvf memcached-1.2.2.tar.gz
# cd memcached-1.2.2
# ./configure
# make && make install

After installing gcc and libc-dev in section a, this one went easily for me – if you skipped section a and run in problems here, please install gcc and libc-dev (see a.2c).

b.2. verify installation of memchached

b.2a. start memchached server

# memcached -u www-data -vv

Output should end with line “<3 server listening”. Perfect!

b.2b test server

I will refer to this shell in front of you as server shell below. Now, open another shell on the same machine, I will refer to it a client shell.

# telnet localhost 11211

You should see something like “<7 new client connection” on the server shell, switch back to client shell.

# set test1 1 10000 1
# a

You should see “STORED” on client shell and the two following lines on server shell
“<7 set test1 1 10000 1
>7 STORED”

Perfect!
You did it, your memcached is up and running

c. memcached and Java

I wrote a little test package using a Java client library for memcached from here, together with junit and ant. You can download it to have a look how simple using memcache is and to verify your installation with an included junit test, automated with an ant build file.