Handover
I like lighthouses. For me as a sailor their pin sharp little light in a sea of darkness always represent orientation and safety.
I was in open source hell
Originally I wanted to convert some TIFFs to JPEG and rename them at the same time by some naming convention. I am no imaging expert when it comes to coding but hey, there are cool libraries that do such sort of things - uhuh, I thought at least.
Home networking finally really made easy
Yesterday I installed two Devolo dLAN 200 AV adapter and they work like a charm. For the first time I can do full audio and video streaming reliably without interrupts.
The Friday Shift
I walked around in Hirtshals. I considered myself to be alone when I was surprised by a group of cyclists
The World Outside
Arriving at a big airport, hurrying through windowless walkways along endless aisles finding your way out.
Nowhere Man In Nowhere Land
Hirtshals, a city in the northernmost part of Jutland, Denmark, hosts a notable fishing harbour as well as a ferry harbour to Norway (Bergen, Kristiansand, Larvik, Oslo). Located at the southern bounds of the Skagerrak it could well be regarded as the last post of civilization at the edge of what goes 700 m deep into the north sea.
Visitors driving beyond the ferry harbour and from there turing left into the eastern part of the industrial harbour are led to a street that literally ends nowhere all of a sudden. The long roadway goes straight down to a seemingly endless lonesome beach. Already from far away an almost displaced sign in alarming flashy yellow can be seen at the end of the road which upon getting closer turns out to be a warning of quicksand looking somewhat bizarre so near to an industrial harbour complex.
Coming to a stop in front of the sign just where the road ends seems as if one came to the end of the entire european continent, marked by a flashy yellow quicksand sign.
After I made the photograph when I walked beyond the sign towards the beach I felt a little like nowhere man being in nowhere land.
Setting the default Java runtime environment on SuSE Linux
SuSE Linux is distributed with a comparably old Java runtime environment (JRE) but most up to date applications require a later JRE. Therefore it is necessary to install a newer JRE after intial setup of SuSE Linux.
Installation of a JRE is comparably simple. The latest JRE at http://java.sun.com is downloaded, the archive is unpacked and the binary is started. The result is a new directory such as /usr/lib/java-1.6.0_2 or the like. The new JRE can be used from out of that new directory instantly.
However, SuSE Linux still points to its default JRE, the one that was to be replaced and not our new one. I.e. applications not automatically use our new JRE just by installing it as described above.
Normally it would be necessary to set all kinds of environment variables to let an application pick up Java from the new JRE directory instead of the old default JRE that came with SuSE Linux. And in addition to that comparably big effort it also is never clear which setting is taken by which application to pick the correct JRE with that many settings.
A workaround is to place the default JRE into the JRE default directory of SuSE Linux instead of changing all path settings. SuSE Linux typically is set to look for Java in directory /usr/lib/java. To replace the older JRE with our new one, simply take the following three steps:
1. Create a new directory such as /usr/lib/java_old_linux_default
2. move all contents of /usr/lib/java to /usr/lib/java_old_linux_default
3. move all contents of /usr/lib/java-1.6.0_2 to /usr/lib/java
Now any Java application will start using the latest version of the JRE by default and without additional configuration.
Installation of a JRE is comparably simple. The latest JRE at http://java.sun.com is downloaded, the archive is unpacked and the binary is started. The result is a new directory such as /usr/lib/java-1.6.0_2 or the like. The new JRE can be used from out of that new directory instantly.
However, SuSE Linux still points to its default JRE, the one that was to be replaced and not our new one. I.e. applications not automatically use our new JRE just by installing it as described above.
Normally it would be necessary to set all kinds of environment variables to let an application pick up Java from the new JRE directory instead of the old default JRE that came with SuSE Linux. And in addition to that comparably big effort it also is never clear which setting is taken by which application to pick the correct JRE with that many settings.
A workaround is to place the default JRE into the JRE default directory of SuSE Linux instead of changing all path settings. SuSE Linux typically is set to look for Java in directory /usr/lib/java. To replace the older JRE with our new one, simply take the following three steps:
1. Create a new directory such as /usr/lib/java_old_linux_default
2. move all contents of /usr/lib/java to /usr/lib/java_old_linux_default
3. move all contents of /usr/lib/java-1.6.0_2 to /usr/lib/java
Now any Java application will start using the latest version of the JRE by default and without additional configuration.
A glimpse of autumn light
I was glad to have my camera with me after we were at the toys yesterday. The entire day was dull grey but in late afternoon the sun came out under the clouds to let us have a glimpse of lovely autumn light. I did not wait and quickly went out to catch some of the magic. Shortly after, the sun was gone for the day.
Domain names on Tomcat
In another blog entry I gave a step by step explanation about how to install and start a Tomcat application server on Linux. Today I would like to add to this post by looking at how domain names are set up with Tomcat.
What are domain names?
A domain name is something like uhilger.de or photochrome.de and the first step to own such a domain is to register it at the network information center (NIC) where it is hosted (i.e. DENIC for .de-domains, INTERNIC for .com/.net/.org-domains, etc.). Domain registration is typically done by a registrar and I personally have made best experiences with providers that act as registrars and offer to host a domain name only, without any webspace etc. (often referred to as DNS domain hosting).
Tomcat can operate many domain names on one instance simply by mapping a given web application to a domain name. But before we get to how to do that let us have a look at how Tomcat is configured 'out of the box'.
Tomcat default configuration
A Tomcat server is configured with a file named server.xml located in directory [tomcat_installdir]/conf. After installation it is preconfigured to have one <Connector> entry that is set to listen to port 8080. This way when Tomcat is started it reacts to all HTTP requests to that machine only when they are addressed to port 8080 explicitly. This is a nice setting for tests as it does not conflict with the default HTTP port 80.
Another default setting is to have one default host set to the name of localhost and a respective <Host> entry that maps name localhost to directory webapps.
Consequently, the first step to go into production with a Tomcat server is to change that port setting in file server.xml to 80 once all other parts of the server have been set accordingly. With the change to port 80 in respective <Connector> of file server.xml the machine Tomcat is running on will direct all requests received via port 80 to Tomcat thus making Tomcat the handler for all HTTP requests, i.e. a web server.
Web applications on Tomcat
To allow Tomcat to handle HTTP requests in a meaningful way it needs at least one web application that actually handles HTTP requests. By default Tomcat has a set of information and example pages preinstalled in directory [tomcat_installdir]/webapps which is displayed upon requests when the server is started.
So, with above mentioned default setting a HTTP request to http://[IPaddress] will be directed to the samples web application in the webapps directory.
To change this default behaviour an own web application is deployed onto Tomcat remotely using the Tomcat manager web application at URL http://[IPadress]/manager/html. I will tell about how to create a web application in a separate blog post. If we assume an own web application is deployed using a web archive file (.war file) named myapp.war Tomcat will unpack this web archive upon deployment and place it in a new subdirectory [tomcat_installdir]/webapps/myapp.
The new web application can then be used instantly using URL http://[IPaddress]/myapp.
Domain name configuration
In above example URLs always have the IP address of a server machine in their path so any change of that address would mean to have to change all URLs referring to that server. As this is not very viable domain names are used instead. Let us assume we have registered domain name uhilger.de and we have mapped our domain name uhilger.de to the IP address of our Tomcat server in the domain name system (DNS).
To let Tomcat know which web application it should direct requests for uhilger.de to, an entry in file server.xml in directory [tomcat_installdir]/conf is necessary. To map web application myapp to domain name uhilger.de a new <Host> entry is created in file server.xml:
<Host name="www.uhilger.de" appBase="webapps/myapp"
unpackWARs="true" autoDeploy="true"
xmlValidation="false" xmlNamespaceAware="false">
<Context path="" docBase="."/>
<Alias>uhilger.de</Alias>
</Host>
Note that the new <Host> element has a <Context> and an <Alias> element. It is important to include the <Context> element in the way shown so that Tomcat does not require a ROOT directory inside directory [tomcat_installdir]/webapps/myapp. Element <Alias> makes sure that requests to http://uhilger.de are handled in the same way as requests to http://www.uhilger.de.
Conclusion
To configure domain names on Tomcat only requires a <Host> entry in file server.xml. By mapping different domain names to different web applications as shown above it is simple to let one instance of Tomcat host multiple domains.
Ready made web applications such as Pebble can be deployed on an existing instance of Tomcat and operated under an own domain name aside other applications and domain names.
In my case for instance Pebble and other web applications such as the photochrome gallery are operated this way on the same Tomcat server under different domain names and after having set up my server I wanted to share above information with other Tomcat users.
What are domain names?
A domain name is something like uhilger.de or photochrome.de and the first step to own such a domain is to register it at the network information center (NIC) where it is hosted (i.e. DENIC for .de-domains, INTERNIC for .com/.net/.org-domains, etc.). Domain registration is typically done by a registrar and I personally have made best experiences with providers that act as registrars and offer to host a domain name only, without any webspace etc. (often referred to as DNS domain hosting).
Tomcat can operate many domain names on one instance simply by mapping a given web application to a domain name. But before we get to how to do that let us have a look at how Tomcat is configured 'out of the box'.
Tomcat default configuration
A Tomcat server is configured with a file named server.xml located in directory [tomcat_installdir]/conf. After installation it is preconfigured to have one <Connector> entry that is set to listen to port 8080. This way when Tomcat is started it reacts to all HTTP requests to that machine only when they are addressed to port 8080 explicitly. This is a nice setting for tests as it does not conflict with the default HTTP port 80.
Another default setting is to have one default host set to the name of localhost and a respective <Host> entry that maps name localhost to directory webapps.
Consequently, the first step to go into production with a Tomcat server is to change that port setting in file server.xml to 80 once all other parts of the server have been set accordingly. With the change to port 80 in respective <Connector> of file server.xml the machine Tomcat is running on will direct all requests received via port 80 to Tomcat thus making Tomcat the handler for all HTTP requests, i.e. a web server.
Web applications on Tomcat
To allow Tomcat to handle HTTP requests in a meaningful way it needs at least one web application that actually handles HTTP requests. By default Tomcat has a set of information and example pages preinstalled in directory [tomcat_installdir]/webapps which is displayed upon requests when the server is started.
So, with above mentioned default setting a HTTP request to http://[IPaddress] will be directed to the samples web application in the webapps directory.
To change this default behaviour an own web application is deployed onto Tomcat remotely using the Tomcat manager web application at URL http://[IPadress]/manager/html. I will tell about how to create a web application in a separate blog post. If we assume an own web application is deployed using a web archive file (.war file) named myapp.war Tomcat will unpack this web archive upon deployment and place it in a new subdirectory [tomcat_installdir]/webapps/myapp.
The new web application can then be used instantly using URL http://[IPaddress]/myapp.
Domain name configuration
In above example URLs always have the IP address of a server machine in their path so any change of that address would mean to have to change all URLs referring to that server. As this is not very viable domain names are used instead. Let us assume we have registered domain name uhilger.de and we have mapped our domain name uhilger.de to the IP address of our Tomcat server in the domain name system (DNS).
To let Tomcat know which web application it should direct requests for uhilger.de to, an entry in file server.xml in directory [tomcat_installdir]/conf is necessary. To map web application myapp to domain name uhilger.de a new <Host> entry is created in file server.xml:
<Host name="www.uhilger.de" appBase="webapps/myapp"
unpackWARs="true" autoDeploy="true"
xmlValidation="false" xmlNamespaceAware="false">
<Context path="" docBase="."/>
<Alias>uhilger.de</Alias>
</Host>
Note that the new <Host> element has a <Context> and an <Alias> element. It is important to include the <Context> element in the way shown so that Tomcat does not require a ROOT directory inside directory [tomcat_installdir]/webapps/myapp. Element <Alias> makes sure that requests to http://uhilger.de are handled in the same way as requests to http://www.uhilger.de.
Conclusion
To configure domain names on Tomcat only requires a <Host> entry in file server.xml. By mapping different domain names to different web applications as shown above it is simple to let one instance of Tomcat host multiple domains.
Ready made web applications such as Pebble can be deployed on an existing instance of Tomcat and operated under an own domain name aside other applications and domain names.
In my case for instance Pebble and other web applications such as the photochrome gallery are operated this way on the same Tomcat server under different domain names and after having set up my server I wanted to share above information with other Tomcat users.
A day at the toys
We took the boys to the annual meeting of local model railway builders and players today.
It is not only fun for them to look at the many details of models shown there. I had my share too watching the deep dedication of adult men to what is one of their major interests since they were children:
As well as to see the fascination in the faces of visitors old and young:
And the lovely fun everyone shared mutually:
Last but not least seeing original toys more than 70 years old and still going as if brand new:
It was a wonderful and lovely feeling to find so many different people old and young coming together like this and play as children do.
It is not only fun for them to look at the many details of models shown there. I had my share too watching the deep dedication of adult men to what is one of their major interests since they were children:
As well as to see the fascination in the faces of visitors old and young:
And the lovely fun everyone shared mutually:
Last but not least seeing original toys more than 70 years old and still going as if brand new:
It was a wonderful and lovely feeling to find so many different people old and young coming together like this and play as children do.
Greetings from the other side
I mentioned in a previous post that I have left Ipernity recently which in turn was after having left flickr some months before. While I left both platforms for different reasons I now find out that I most probably would have left flickr also if it would not have been for the censorship issue anyway.
Nonetheless I enjoy to look at photos there still, I just do not participate there anymore. Now when I looked at a photo of one of my former contacts today I found a comment which referred to - me (!). It was surprisingly funny to see people making fun of me and my moves at flickr and ipernity here.
It is true, I am a reflective and critical character, so who would I be without commenting on it? Still, the absolute certainty to make a statement about me from a person whom I met personally only comparably shortly for a few times makes me wonder about where people take their wisdom from.
Let me tell you folks, you don't know me and you never will. I am quite happy with the state I'm in actually. But you're right, Uli, my dear namesake, there is always something to improve.
Greetings from the other side!
Segementing the web with photo sharing sites
I spend quite some time with looking at other photoblogs and photo streams at various individual blogs and sharing sites because I like to look at what others do in photography and because I like to find inspirations by good photographers that share their work online. It is difficult to find photographers that I like and therefore I welcome as many sources as I can find.
In that context seeing so many interesting photographers at different photo sharing sites is a problem, as every photo sharing site requires to have an account and to log in inorder to leave comments (some at least require to log in using OpenID).
This is a limitation of all those communities in my eyes and a pity because not only on flickr I do not maintain an account (anymore). I think there should be the functionality to be able to comment without the need to open an account. At least for me it is impossible otherwise to comment :-(
I do leave comments in photo blogs where it is not necessary to log in first because I think an outstanding photo deserves feedback to let the photographer know and to probably let him gain confidence in his work too.
I subscribed to a number of photo stream feeds at flickr, ipernity, zooomr, 23hq, smugmug, webshots, view, etc. and really enjoy following what is uploaded. As well I enjoy not needing to adapt to all kinds of different user interfaces when I am only interested in new photos of certain people. Here the feed reader really simplyfies recognition of new posts through a common simple interface regardless of the underlying platform.
I think with the mentioned limitiation photo sharing sites create an annoying segmentation of the web and I regret that I can not comment without an account, when I especially like a certain photo. And while I continue to enjoy all the work published as described I definitely do not want to open an account all and everywhere just to leave a comment here or then :-(
In that context seeing so many interesting photographers at different photo sharing sites is a problem, as every photo sharing site requires to have an account and to log in inorder to leave comments (some at least require to log in using OpenID).
This is a limitation of all those communities in my eyes and a pity because not only on flickr I do not maintain an account (anymore). I think there should be the functionality to be able to comment without the need to open an account. At least for me it is impossible otherwise to comment :-(
I do leave comments in photo blogs where it is not necessary to log in first because I think an outstanding photo deserves feedback to let the photographer know and to probably let him gain confidence in his work too.
I subscribed to a number of photo stream feeds at flickr, ipernity, zooomr, 23hq, smugmug, webshots, view, etc. and really enjoy following what is uploaded. As well I enjoy not needing to adapt to all kinds of different user interfaces when I am only interested in new photos of certain people. Here the feed reader really simplyfies recognition of new posts through a common simple interface regardless of the underlying platform.
I think with the mentioned limitiation photo sharing sites create an annoying segmentation of the web and I regret that I can not comment without an account, when I especially like a certain photo. And while I continue to enjoy all the work published as described I definitely do not want to open an account all and everywhere just to leave a comment here or then :-(
The Streets of Hirtshals
The streets of Hirtshals, Denmark had some lovely light and moments to offer one day this October. I'll post some street shots from that photo walk now for the next days after the many recent idyllic and nature shots from the region.
Especially the area around the city center towards harbour and the harbour itself - here the industrial part in particular - always attract me again so stay tuned for some urban impressions.
Back in the global village
I just recently initiated my new blog here after having used a blog over at Ipernity for some time. While it has been convenient to see all new blog entries from my contacts neatly ordered, this functionality is limited to Ipernity members only.
Having now left Ipernity I use a feed reader, Awasu in my case, to keep track of new entries. I can use it to subscribe to any newsfeed, photo blog, blog, etc. including Ipernity or flickr. Btw. if anyone who reads this can recommend another feed reader ideally with stating why you like the receommended software this would be quite interesting too.
People claimed without using a photo sharing community it would be more difficult to oversee new content over multiple different sources but I have to admit that I can not confirm such experience. In fact, once subscribed to a certain feed it is simple to identify new posts over ones I already saw and regardless of number of subscriptions I do not have to visit many different places because all is automatically collected into one place for me.
So, given a feed reader that fits your needs it is quite a relief from the dependency and limitations of a certain site or community.
At Ipernity I posted the question of why it is necessary to use a photo sharing site to form a community. I still think - and the above somehow confirms to me - that it actually are the people who actually form a community and that they typically do it across boundaries. Sites such as flickr or Ipernity and all the many other 'closed shops' limit a community rather than to foster individual freedom and openmindedness (is this a word?) in my opinion.
Apart of that, what I like with photo blogs vs. photo communities is that you don't need to have an account with them to comment. At Ipernity at least they now allow to log in using OpenID as does Zooomr, while flickr still requires an account (I guess?). But having to log in first or having to creat an account locks out potential commenters who are not interested in opening, say, a flickr account just to leave a comment, even if it is free.
Photo sharing sites might be ok for having a place with online storage and for not having to set up an own internet presence of any type. But especially anyone who uses a web server already (maybe for other purposes as well), might not need a photo sharing site in addition.
The web is the community, the global village.
Having now left Ipernity I use a feed reader, Awasu in my case, to keep track of new entries. I can use it to subscribe to any newsfeed, photo blog, blog, etc. including Ipernity or flickr. Btw. if anyone who reads this can recommend another feed reader ideally with stating why you like the receommended software this would be quite interesting too.
People claimed without using a photo sharing community it would be more difficult to oversee new content over multiple different sources but I have to admit that I can not confirm such experience. In fact, once subscribed to a certain feed it is simple to identify new posts over ones I already saw and regardless of number of subscriptions I do not have to visit many different places because all is automatically collected into one place for me.
So, given a feed reader that fits your needs it is quite a relief from the dependency and limitations of a certain site or community.
At Ipernity I posted the question of why it is necessary to use a photo sharing site to form a community. I still think - and the above somehow confirms to me - that it actually are the people who actually form a community and that they typically do it across boundaries. Sites such as flickr or Ipernity and all the many other 'closed shops' limit a community rather than to foster individual freedom and openmindedness (is this a word?) in my opinion.
Apart of that, what I like with photo blogs vs. photo communities is that you don't need to have an account with them to comment. At Ipernity at least they now allow to log in using OpenID as does Zooomr, while flickr still requires an account (I guess?). But having to log in first or having to creat an account locks out potential commenters who are not interested in opening, say, a flickr account just to leave a comment, even if it is free.
Photo sharing sites might be ok for having a place with online storage and for not having to set up an own internet presence of any type. But especially anyone who uses a web server already (maybe for other purposes as well), might not need a photo sharing site in addition.
The web is the community, the global village.
E-Mail notifications now work
With the help of a blog entry which I found via Google the e-mail notifications were put to work now. It was not obvious to me that there were some plugins to be activated through uncommenting them in the plugins configuration of Pebble.
In the context of such server administration topics I often find that such issues are documentation issues rather than bugs. In this case the documentation of Pebble could well afford an end to end description of how to set up e-mail notifications such as the one linked above.
Still I have to thank Simon Brown, the creator of Pebble, for such a great piece of software.
In the context of such server administration topics I often find that such issues are documentation issues rather than bugs. In this case the documentation of Pebble could well afford an end to end description of how to set up e-mail notifications such as the one linked above.
Still I have to thank Simon Brown, the creator of Pebble, for such a great piece of software.
Open air performance
When I walked around Rubjerg Knude Fyr for photos, this group of tourists stood at the edge of the cliff line staring at the sea.
It was a somewhat surreal encounter because of their stoic torpor as well as lack of target to look at in ther direction of view. They did not move for the entire time it took to change my lens and still stood there when I moved on.
The scene appeared like some kind of performance.
New Toys, New Challenges
Whoopee, now that this thing is live I still struggle with setup of E-Mail notifications so bear with me while this is being sorted out. Other than that I really like what this open source blogging software features. Should anyone use Tomcat or another J2EE application server, check out Pebble
This guy Simon Brown, the creator of Pebble, did a heluva job here. Keep it up, Simon!
This guy Simon Brown, the creator of Pebble, did a heluva job here. Keep it up, Simon!
Hello World!
This is my new public diary where I intend to publish thoughts and information around computing and photography among other themes. I had blogged for a while at Ipernity but find that I prefer to maintain my blog on my own server just as the photo blog I operate there already.
I hope the world will find interesting stuff in my new blog here and then, so for now...Hello World!
I hope the world will find interesting stuff in my new blog here and then, so for now...Hello World!