brain tags Je Maintiendrai

Friend Of A Friend

FOAF provides an execellent vocabulary for describing people and the relation between people. It is a way to describe yourself — your name, email address, and the people you’re friends with — using XML and RDF. This allows software to process these descriptions, perhaps as part of an automated search engine, to discover information about your and the communities of which you’re a member.

Of course I created a FOAF description of myself, using the FOAF-a-Matic. You can find my FOAF at http://braintags.com/foaf.rdf. If you link your FOAF to mine, please let me know, so I can update my file.

[Update 03.08.2003]: After seeing 23 404-errors in my logfile, I came to the conclusion that I must have saved the FOAF file with the wrong name. It is now fixed, so it should work alright.

For those people who are too lazy to look into the file, my FOAF description looks as follows:

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
  xmlns:foaf="http://xmlns.com/foaf/0.1/">
  <foaf:Person>
    <foaf:name>Jeroen Sangers</foaf:name>
    <foaf:title>Mr</foaf:title>
    <foaf:firstName>Jeroen</foaf:firstName>
    <foaf:surname>Sangers</foaf:surname>
    <foaf:nick>Beltza</foaf:nick>
    <foaf:mbox_sha1sum>6fe5a1c9a2f3ce9d6a53d4f82d0e4a92254bba2b</foaf:mbox_sha1sum>
    <foaf:homepage rdf:resource="http://braintags.com/"/>
    <foaf:phone rdf:resource="tel:+34-6-19204630"/>
    <foaf:workplaceHomepage rdf:resource="http://www.icg.es/"/>
    <foaf:schoolHomepage rdf:resource="http://www.uu.nl/"/>
  </foaf:Person>
</rdf:RDF>

Changing hosting provider #4

It has been three days ago since I switched my site to the new server. Little by little the visitors switched as DNS servers synchronised all over the world. And little by little I noticed some problems on my site.

These problems were related the two changes I made in the set-up of my site: I moved my photo gallery from its subdirectory /photos to its own sub-domain photos.braintags.com and I changed all URLs of the individual archives from entry_name.html to entry_name/index.shtml.

The first change broke all links to the photos — and what is a photo gallery without photos? — which I corrected by editing all 51 entries. Furthermore I still have to create a symbolic link to some files from my main site, like robots.txt.

The second change broke nothing on my site, but some links to my pages on other sites (Google!) broke terribly. Therefore I decided to us my good friend mod_rewrite to serve people the right page. All I had to do was to create a rule to redirect requests for /archives/yyyy/mm/entry_name.html to /archives/yyyy/mm/entry_name/. So I created the following rule:

# Redirect old URI's to future-proof directories
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule (archives/[0-9]{4}/[0-9]{2}/.*)\.html$ $1/ [R=permanent]

This did a good job, except for two problems: it also redirected the URI of my monthly archives to archives/yyyy/mm/index/ and it added a slash in front of the URI, so the URL would look like http://jeroensangers.com//archives/…. The first problem was easily solved:

# Redirect old URI's to future-proof directories
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !index.s?html$
RewriteRule (archives/[0-9]{4}/[0-9]{2}/.*)\.html$ $1/ [R=permanent]

For the second problem I am still looking for a solution.

Viruses

Most viruses that replicate themselves through e-mail forge the from: field of their messages. Usually they take a random address, or pick one from your address book or web cache. Therefore, a virus appearing to come from jeroen@example.com, rarely really originates from this address.

I can image that some users don’t know this, and when they receive a virus from me they send me a reply with a warning that I have a virus. Usually I explain these people the story above and tell them — of course after checking that my anti-virus software is up-to-date — that I don’t have a virus. No problem for me.

What I don’t understand is that some people who are responsible for really big mail servers also don’t understand that viruses forge headers, and have their servers configured in such a way that they reply to me. Of course they have the right to block a message with a virus to protect their customers. But please don’t bother me with these messages. I can assure you that I am not the one sending these messages; just check the mail headers and you will see that they originate from a completely different server.

This morning somebody who apparently had visited my site cached a virus and started sending out the virus in my name. Luckily for him, his provider scans all incoming SMTP mail and intercepted all messages. Instead of simply not accepting these messages, they had configured procmail to send a warning to the address mentioned in the from-field (me) including the virus!!!!! As a result, my inbox is flooded with viruses from this server (mail.infosys.tuwien.ac.at).

Once again, none of my computers is infected with a virus.

Copy protection

First a question for the music industry: “What the heck are you doing?”

Yesterday MJ gave me a present; the CD Fleshwounds from Skin. Of course I was really happy with it, but I immediately noticed a big label on both sides with the words COPY CONTROLLED. In the specifications I read that this CD would work in any CD-player, the latest Macs and PCs with minimal Pentium II, 233 MHz and 64MB RAM. I am perfectly happy with my Cyrix P133+ with 48MB RAM, and until now I was able to play any CD I liked. Of course I tried to play the CD, but my computer could not find the CD. :-(

I really like buying CD’s; I prefer to buy one to using a copied CD. Because for me the CD is more than just the disk with the bits and bytes. I like to look at the artwork in the booklet, and no inkjet printed paper gives me the same feeling as the original CD. And because I usually buy older CD’s, I never feel that I pay a lot — of course I wouldn’t complain if they became cheaper. So I buy the original CD’s because of the better quality of the total product.

But now the record companies are throwing in their own windows, because they decrease the quality of their product. And why would I want to pay a lot for something that is broken? I don’t have any problem yet, since there are so many old CD’s out there that I still want to buy. But I can assure that I am never ever going to buy a copy protected CD anymore. Not because I want to copy it — which I feel is my right — but because it is essentially a broken product.

You can read more about copy-protected CD’s at Kuro5hin or if you truely want to know everything you can go to the UK campain for Digital Rights.

Pentagrama

I just found a small list on my desk, and remembered that I wrote it last Friday — or better: Saturday morning — to publish it later on this site. The aim was to make it clear that I had a great night, visiting my favourite club Pentagrama again. These are the titles and artists of some songs they played, and people who know me and these songs can imaging that I was enjoying a lot.

• London calling — Clash
• Personal Jesus — Depeche Mode
• Black Betty — Ram Jam
• Tunnel of love — Dire Straits
• Should I stay or should I go — Clash
• Entre dos tierras — Héroes del Silencio

I have been thinking about making this list into a small contest, but I have no idea what to give to the person who knows all corresponding artists. Maybe I can come up with something later, so go ahead and tell me who you think the performers are.

[Update 2003.08.28]: Coen van Kuijk sent me a list which contained only one mistake. After a small hint he was able to give me all the names of the artists. Somebody wants to try to solve it in a single try????

[Update 2003.09.03]: Since I haven’t received any other messages, I decided to fill in the artists and close the competition.

Advertisements

You might already have noticed it: I added some advertisements to this site. Since now I am paying a hosting provider to host this site, I thought that I might try to get back at least some of the money I spend for it. The advertisements are related to the contents of the page, so I only added them the pages of the individual items. This makes the chance bigger that they may actually be useful for my visitors as well. I decided to give it a try for about two months; if I notice at that moment that they are not working, I will remove them.

People using a modern browser won’t see the advertisements, since the advertisement script does not work when the page is processed ad XML.

Work to do

When I designed this site, I of course tested the layout on my Windows computer. I know that it looks alright with IE6 and Mozilla, and I suspect that it looks acceptable in most other OS/browser combinations. If I would be a professional designer, I would run it through the famous BrowserCam, but my little site is not worth the money.

Of course there are some emulators available, which might give you an idea of how your site looks — but remember that if something looks wrong you never know for sure whether it is your code or the emulator. A new emulator I found today, shows how this site looks on an iPaq PDA.

Mmmm. Header to big, no skip navigation link, useless side column, font too big, … But still readable. I also loaded the Fimcap site, which still has a tables based layout, and that looked way worse. To read the text you have to keep on scrolling.

I guess I will have to make a new stylesheet, or maybe serve PDA’s the print stylesheet. But the print stylesheet removes all the navigational elements… Anyway, the coming days I will tweak this site so it will look better for my mobile readers — do I have any?

application/xhtml+xml

The moment I changed the looks of this site, I also changed the version of the code used for these pages. My site is now made up in XHTML version 1.1. I only forgot to change one thing. I did change some tags elements to their new variants, and of course I included the right DTD. But my pages were still served to your browser with the text/html MIME type, while the specification tells me that I should serve my pages as application/xhtml+xml.

The specification is quite clear in this, but as usual the reality is more complicated. I could simple change the file extensions to .xhtml, which are automatically send with the right MIME type. But at this moment a lot of browsers (including IE6) are not able to handle this kind of documents. So I need to distinguish browsers that can handle application/xhtml+xml from those that cannot handle it. Fortunately, most browsers send a list of MIME types they can handle each time they request a file from the server; so all I have to do is look at this list, and change the MIME type for modern browsers. Therefore I added the following lines to my .htaccess file:

RewriteCond %{HTTP_ACCEPT} application/xhtml\+xml  
RewriteCond %{HTTP_ACCEPT} !application/xhtml\+xml\s*;\s*q=0  
RewriteCond %{REQUEST_URI} \.html$  
RewriteCond %{THE_REQUEST} HTTP/1\.1  
RewriteCond %{HTTP_HOST} !photos.braintags.com  
RewriteRule .* - [T=application/xhtml+xml]

The first line looks whether the MIME type is in the accepted list of the browser.
The second lines looks whether it does not have q=0 (q stands for quality), which means that the browser does not want to use this MIME type.
The third line limits the requests to .html files only, since we do not want to change the MIME type for images, stylesheets and other files.
The fourth line limits the requests to HTTP version 1.1.
The fifth line excludes my photo pages, since I haven’t updated them to XHTML1.1 yet.
And the last line finally specifies the right MIME type for requests that satisfy all conditions above.

Holidays in the Netherlands

One more week to go, and we have our second short vacation of this year!!! After going to Croatia in July, we will visit the good ol’ Netherlands this time. From September 9 until 16 you will have a bigger than normal chance of seeing us in the north of Europe. We didn’t make an exact planning of what we are going to do, but we have made two short lists. One with some practical things I have to arrange, and one with some places we want to visit. The first list has to be followed, and the second list will almost surely change on a day-by-day basis.

HTTP Error 411: Length required

Today I noticed something strange in the access report of this site. In the error codes list I found error 411. Since I haven’t seen this error code before, I googled on internet for some more information.

The official RFC 2616 says the following: The server refuses to accept the request without a defined Content-Length. The client MAY repeat the request if it adds a valid Content-Length header field containing the length of the message-body in the request message.

It appears that a server is returning code 411 when a client (=browser) tries to send data to the server without specifying the size of the data. Normally a client only receives data from the server (reading pages), and all common modern browsers are programmed in such a way that they include the data length when sending data. Therefore I suspected that somebody with a home-grown application had tried to mess with my site.

I did a quick grep in my Apache log files and found out that somebody had accessed the file mt-xmlrpc.cgi with an application that identified itself as Java/1.4.1_01. This file is a XML-RPC interface to Movable Type, allowing other applications to interact with MT, for example to publish entries on this site from a special desktop client. Since I am the only responsible for this site, nobody but me has any reason to use this file. This visitor also triggered my Spam trap, and was already blocked from my system, but if not, his badly programmed application did ring the alarm bell.

CD List

Throught the wonderful Internet Archive Wayback Machine, I was able to visit my old site again. My biggest proud of that site was the big list of all the CD’s I own. So here it is, the list of March 12, 2001!