When doing integration testing or fixing a bug in a piece of Java code that uses Oracle as a database, being able to do quick exports and imports of your schema can be a big help. Sometimes just calling Oracle’s imp/exp commandline tools from your code can be of help, but I was looking for something a bit more portable and less demanding on my local development machine. I found that Oracle’s datapump functionality can be called from stored procedures, which in turn can be called from a normal JDBC statement.
Category: Software
Arduino and the QVGA 2.2″ TFT SPI screen
I went through all the struggles everybody else seems to be going through to get this screen connected to my Arduino Nano. I had the 5V to 3.3V voltage conversion problem, and the “only works with software interrupts” problem which makes the display run slow. The solutions are not complicated but not very wel documented. Until now.
Open a port in OSX Mavericks’ Firewall
The new firewall in Mavericks is great. For the common user. For a developer, not so much. If you are a Java developer like me, and you just need to open one port (say, 8080) so that the web application you’re working on is accessable from another computer, you can’t. I disabled the Firewall altogether for a few days, but it didn’t feel right.
I googled around and to make a long story short, here’s how to open port 8080 on any interface to any application on your OSX Mavericks installation in 3 steps:
sudo vim /etc/pf.conf
Then add the following lines at the end of the file:
# Open port 8080 for TCP on all interfaces
pass in proto tcp from any to any port 8080
Test (and, according to the documentation, load) your edits with:
sudo pfctl -vnf /etc/pf.conf
Reboot.
(I have found at least 5 pieces of voodoo to make the Firewall restart and reload, but none of them seemed to work reliably, so pardon the reboot)
You can close it by commenting out the lines in pf.conf and reboot again. If anybody knows of an easier way to do this, preferably in one terminal command, and without rebooting, let me know.
Hope this helps.
There’s life without Google. Or iCloud. Or Facebook.
Regular readers of this blog already know that I am not using dropbox, and I was an Evernote user, but recently decided it became to dangerous and replaced it with my own scripts. I had an interesting discussion on Twitter which made me decide to show you how I run my digital life without the help of Google, Facebook, Dropbox, Whatsapp or iCloud, and still be able to have all the functionality these services offer.
The search was hard and sometimes I need to reconsider some of the choices, but the last few years the selection of products was very stable and the setup has worked flawlessly. Searching for a secure replacement for Whatsapp or Google? It’s in here.
Read More “There’s life without Google. Or iCloud. Or Facebook.” »
Replace Evernote with Spidernote
In the past I have used Evernote extensively, it really helped me in my research for this blog and keeping track of meeting notes, todo lists and even making pictures of whiteboards at work searchable. As a product, there is no note taking app that can beat Evernote. But there is a little problem that has become a deal breaker for me, and that is basically the NSA and the way Americans, and particularly the American government seems to think about people’s privacy and online security.
Evernote is an American company, which sadly has to comply with whatever ridiculous request by the U.S. government to turn over data of innocent people all over the world (yes, even outside the U.S. border, I know, it’s amazing). This, combined with the fact that Evernote clearly can not use zero-knowledge encryption because of the services it provides, makes that all the data you and I put into Evernote are at NSA’s fingertips at all times. If you find that as scary as I do, and you have a Mac, there is a way to solve this.
From the Finder to the Shell (and back)
A quick tip for OSX users out there who frequently need to open a Terminal window for the current location in the finder, or the other way around:
Install the free application from the App Store: Go2Shell. It will give you an icon on the toolbar of your Finder, and pressing it will open a Terminal window and automatically change it’s directory to match the Finder’s location.
The other way around is easier; you can already do that on any Mac. Simply type “open .” (that’s the word “open”, followed by a space and a period). This command will open a Finder window for the directory location your Terminal window is in.
Bonus tip: Also check the “open -t [filename]” command, it will open your system’s default text editor with the given file.
Anonimatron: Quick Start
After reading my last blogpost on Anonimatron, you must have asked yourself “Great, but how do I actually use Anonimatron to de-personalize my database”? I tried my best to make basic Anonimatron configuration as self-explanatory as possible, just start it without any command line arguments and it will tell you.
Less adventurous or in a big hurry? This blogpost will show how simple it is to install and configure Anonimatron on an example MySQL database.
Anonimatron: Overview
In every software project, there comes a time where a bug pops up, nobody knows how to reproduce it, and somebody says “I know, let’s test this against a copy of the production database”. Even with the best intentions, once production data leaves the production machine with all its safeguards it becomes really hard to do access control on that data.
Most of the time, it’s not even needed to have that data. Developers just need a data set which resembles the production scenario close enough. Some brave souls have mixed succes with data generators, but those generators usually are tedious to maintain and die a slow death under the pressure of the daily grind.
In some ambitious projects automated integration testcases are built on top of the data which was inserted by the data generators. As the generators die, so die the tests. If you recognize this pattern, Anonimatron might be the answer for you.
Non-Java Binary Dependencies in Maven
Suppose you have a Java Server application, and some of the runtime binaries in that application are external to your application. Generated image files, compiled Silverlight components in your pages, or resource files which are managed by an external team.
Much like the jar files used by your application, these external binaries can be seen as dependencies, with versions. This blogpost assumes your project is built with Maven 2, because the real world isn’t always a greenfield project.
Because Maven is designed around jar file dependencies, and a lot of it’s internal decisions are based on file extensions, it looks like this problem can not be tackled with Maven. But there is a way to do this. It will decouple your sub-projects and make version and dependency management much better.
BaseCamp Import problem [fixed]
On Mac OSX, when installing Garmin BaseCamp 4.1.2 from the Appstore, there is a chance that importing downloaded routes in gdb or gpx files from your local machine will not work. The error you’ll get is “[filename].gdb not found”, in a popup much like the one shown here. If you open the console app, you’ll see the following error in the logfile:
sandboxd[28092]: ([27931]) Garmin BaseCamp(27931) deny file-read-data /Users/rolf/Desktop
This means that the OSX Sandbox mechanism does not allow Garmin BaseCamp to read files in that folder. I have briefly searched documentation on how to grant BaseCamp the rights to read files there, but I couldn’t find anything that would work. I did find a way to work around this problem though: Garmin BaseCamp does have rights to read your Garmin device. So here we go:
- Temporarily copy the files you want to import in Garmin BaseCamp onto your device (or in my case: the extra SD card in the device).
- Start Garmin BaseCamp, and select “File” -> “Import…”.
- Browse to the Garmin SD card and select the gdb file to import. Voila. That will get it into BaseCamp.
- Delete the gdb file from the Garmin. We don’t need it anymore, the Garmin was just a place where BaseCamp could read the file.
From here on, everything should work as normal. This is just a workaround. If anybody finds out how to really fix this problem let me know.