Momentary Software Update Today

Just today, there was an update to several of the packages on this server, that provide PHP5. This triggered an automatic restart of my Apache server, due to which the site might have momentarily been unavailable from 19h06 until 19h07 this afternoon.

There appears to have been no deterioration in how the site works, and because my caching daemon is a separate process, the site should also be as quick to view, as it was at any time the computer has been up for a few days.

Dirk

 

Unattended Upgrades were already performed on this Blog.

Since I started this blog, my Linux O/S has already installed Unattended Upgrades, to packages that are needed to display the blog correctly. This includes upgrades to the Apache server, as well as to the MySQL database engine. In each case, the blog would have been unable to load properly for up to two minutes. Yet, I have not allowed this for any WordPress.org plugins.

 

I’ve Upgraded my Permalinks.

There was a subject in Web-hosting, which I was not even aware of until recently. Often, when a site offers URLs to the browser, those URLs contain a question-mark, followed by variables and values, such as Posting Numbers. Those question-marks explicitly invoke a CGI script on the server, which in this case is written in PHP.

Well as long as that’s happening, the URLs are not fully ‘permalinks’. Full permalinks are URLs which seem to extend beyond the real file system with slashes, and which the Web site rewrites in-place, when the browser requests them, to translate them into CGI-calls. This requires a server module to be loaded, which in the case of Apache is named ‘mod_rewrite.c’ , and of course it requires that the rules for doing so be defined, before the CGI script is even invoked.

Until very recently it was not really necessary for the links on my blog to be of that type. But what I’ve just done in the past few days, was make the site multilingual. And since this relies on machine translations, this can look very ugly to search engines. So with my new rewrite rules, the German translation of my site is virtually at

dirkmittler.homeip.net/blog/de

And the French version is at

dirkmittler.homeip.net/blog/fr

That way the search engines can keep them all nice and tidy, even though those are the derived ones.

And naturally, from about 14h30 through 15h00 today, clicking on the actual, new permalinks also caused some 404 Errors, until I got all that sorted out, which it should be by now. If people are having later problems with the new permalinks, please leave me a Comment about it…

Dirk

 

My Site mainly Requires Web-Sockets.

The origins of HTTP were essentially ‘sessionless’. This meant that with a server always listening on Port 80, a client could request one URL at a time, in response to which the server would return the page in question directly to the client’s port number. This included the CGI-scripts’ FORM data. But as the early Internet evolved, Web-sites started to become ‘session-aware’. I explained this to my friends in the past as follows:

The client connects to the assigned port number 80 on the server, and requests a session, which causes the server to start listening on another port number, this forming a ‘session socket’. The one listening on port 80 was the ‘server socket’. The server’s session socket was dedicated to one client and to one session.

My friends did not acknowledge this description of how TCP works, I think mainly, because I did not use the right terminology. What I had referred to as a ‘session socket’, is officially termed a “Web-Socket” in the case of HTTP. It turns out that with an Apache server, many sub-processes can bear these Web-Sockets. They don’t exclusively exist in order to output Web-pages at a faster rate, in response to individual requests made by the clients, to the process still listening on port 80.

One fact to know about my site, is that for such purposes as viewing this blog, the use of Web-Sockets is required. In the case of certain other sections of my site, such as http://dirkmittler.homeip.net/GallIndex.htm, the use of Web-Sockets is not required, because those Web-pages exist mainly in a sessionless way – they can be fetched one at a time without error.

Certain proxy-servers will not allow a Web-Socket to get forwarded. These are logically also proxies which don’t allow SSL connections to be forwarded, because the encrypted SSL data is also sent via Web-Sockets or their equivalent. If you are connecting to the Internet via such a proxy, I’m afraid you won’t be able to navigate my blog correctly. I apologize for this, but there is little I can do about that. I think that you should still be able to fetch a single posting of mine, that comes up through a search engine.

Dirk

(Edit: ) This may also apply if you’re trying to connect to my IPv6 address, because my IPv6 is being provided by a Teredo proxy, which might have just assigned reduced privileges to my client:

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