28.03.08
Posted in Tips, vim at 11:26 pm by Guy
I started developing Google Gadgets for LabPixies, so one of the first thing I looked for was syntax highlighting. Vim recognized the gadgets’ code as XML file (which is correct), but I wanted also HTML syntax highlighting for the HTML part. So after searching a bit for some existing solution, I found one, but I didn’t like as it required me to wrap the HTML code with a specific comment. As I don’t like this kind of solution, I’ve decided to create my own syntax highlighting file for Vim.
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19.03.08
Posted in Projects, biscan at 1:08 am by Guy
After writing the post on converting PNMs to DjVu I’ve ran into some trouble scanning documents written in blue ink. The problem: XSane didn’t allow me to set the threshold for converting the scanned image to line-art (B&W). So, I tried scanning the document in grayscale and in color and convert it afterwards to bitonal using imagemagick. This ended up with two results. When I used the -monochrome command line switch, the conversion looked good, but it used halftones (dithering), when I tried to convert it to DjVu it resulted in a document size twice as large as normal B&W would. The other thing that I tried is using the -threshold switch. The DjVu compressed document size was much better now, but the document was awful looking, either it was too dark, or some of the text disappeared. After giving it some thought I knew I can find a better solution.
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11.03.08
Posted in Bash, Projects at 11:47 pm by Guy
I’ve decided to scan some notebooks. After researching a bit, I’ve decided to use DjVu (instead of PDF which I normally use). I’ve chose to use DjVu because it offered great quality with very good compression rate (~26KB per page) in lineart (black and white).
While XSane can natively save a multipage project into PDF it can’t do so for DjVu. So, the solution is to use the PNMs generated by XSane and convert them using the command line tools offered by DjVuLibre to bundle them together to a DjVu file. As you can guess doing this manually is pretty hard work. To make this task easier I’ve written a small bash script to automate the process.
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08.03.08
Posted in PHP at 1:36 am by Guy
While working on a new project using CakePHP, I’ve came across a weird problem. In one of the controllers the the session always came out as invalid, as
always returned false. I tried debugging this weird stuff, and it looked like all the session variables are unset. Using
to get the last error returned “Config doesn’t exist”. After further debugging “Config” turned out to be an internal array that is saved by CakePHP to the session and holds various internal data (some of it is used for validation like user-agent hash). I kept printing more and more debugging data as well as looking at CakePHP’s trac system.
I found an interesting bug (ticket #4217) and it looked very promising, as it almost fully described my problem. Unfortunately, the solution offered didn’t seem to work for me. But it inspired me to try and start the session manually using session_start() instead of using Cake’s startup and activate methods of the Session Component.
I found out that the session_id() returned empty string. Luckily calling session_start() directly from the controller, gave me a lead. The session seemed to work well but a nasty error about headers already been sent showed up.
I little more investigation lead up that I had a trailing newline after my closing PHP tag in that controller file. Deleting this trailing whitespace completely solved the problem. No need anymore to manually start the session. It’s pretty annoying that such a small thing like trailing new line can cause such seemingly unrelated problems in CakePHP’s session handling.
Maybe CakePHP should add a little debug notice when the session doesn’t start because header were already sent. This can be done by modifying the else statement in the __startSession() method in cake/lib/session.php (line 557 in version 1.2.0.6311). I wonder what the reason they had not to inform the developer when such event happens, as I don’t see why someone will deliberately try to start the session after sending the headers, I think it only happens by mistake (at least most of the time).
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01.03.08
Posted in Bash, Linux, Projects, Tips at 11:12 pm by Guy
This is a small script I wrote today, to automate my backups, which I do on Amazon S3. This is fairly short, yet useful bash script that utilize the s3cmd to do the actual sending of the files.
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