Posted by Doug
Fri, 08 Jul 2005 15:58:00 GMT
A friend of mine is still stuck in .Net land. We have discussions about
Ruby on Rails from time to time. That’s why I was pretty interested to find
this thread on the mailing list about a “Rails in .Net”.
There are several “Rails in Foo” projects to implement the ideas of Rails in various languages. All in all, I like to see environments try to learn from each other and all grow. After all, Rails is “just” a good implementation of some solid design patterns for web development. It has some nice helper methods thrown in to improve testing and also
HTML/AJAX generation. Theoretically, you could implement Rails in almost any language.
Don’t be misled though. It’s called
RUBY on Rails for a reason. The strengths of Ruby really shine in Rails. I was once asked, “Could you implement Rails in Perl?” The answer is yes. In fact, prior to picking up Rails I had attempted to do just that. It was hard work and very complicated code though. Ruby makes this stuff a lot simpler.
Posted in Ruby on Rails | 4 comments
Posted by Doug
Tue, 05 Jul 2005 14:00:00 GMT
Leave it to my good friend,
MarkWindholtz, to lift my spirits. After my
post on
http://RubyOnRails.org speed he had this to say. I was paraphrasing the
original post about switching from ColdFusion to RoR. I had said Michael Buffington claimed it took him 10 hours to do
http://wordPhoto.org and then another 30 to “polish” it.
Mark: “Polishing” is an interesting term, I’m hearing it more latlely. I’ve even used it. It means getting the app to actually work. Am I wrong?
Me: Hmm, I guess so. Maybe “polishing” is claiming to finish in N hours of working functionality, and then polishing for 3 – 5 x N to get it to where someone can actually use it.
Mark: To paraphrase Yoda: Done or not Done there is no polish.
How’s that for a rash of Ruby on Rails posts for today?
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Posted by Doug
Tue, 05 Jul 2005 13:54:00 GMT
Speaking of images, I’ve been doing more image work on my commercial Ruby on Rails project.
I had some experience with imaging from my
RailsDay project. The bad news is that because of how old my server is (running Debian Woody), I was unable to get the Ruby bindings for Image Magick installed (which is what nearly everyone seems to be using for imaging). So, I ended up using the
ruby bindings for
Imlib2.
My main problem came from how to cleanly test the image handling. Uploading and saving images isn’t very hard. Tracking the images and the various scaled versions gets a little tricky.
After several false starts and finally pairing with
MarkWindholtz, here’s what I’ve come up with:
I have an Image class based on ActiveRecord. This pretty much just stores the filename of where the image is on the filesystem.
I have an ImageFiler object that is responsible for taking either the StringIO or File object from Ruby’s
CGI and writing it out to the disk. It also deletes the file when appropriate. Its purpose is to be the interface between the Image and the Filesystem.
I also have an Imager object. This is a wrapper around the Imlib2 functions. It does things like scale the image appropriately and returns the image’s size.
The containing Image object has pass through functions to a contained Imager and ImageFiler object. Overall, that works pretty well. It was easy to test all three objects independent of each other. My test fixtures were very simple.
The second wrinkle came when I tried to create and cache scaled versions of the images. I wanted the thumbnail (and other scaled versions) to be actual Image objects, but I didn’t want them stored in the database as saved ActiveRecords. So, I made creation functions off of Image to create new Image objects, but just never saved them. These “sub-Images” are created on the fly or loaded from disk.
It was a little tricky to get all the cached versions deleted when the Image object is deleted. I ended up having a flag on the Image determine what type of Image it is: normal, thumbnail, scaled medium, etc. This keeps me from going into a recursive loop and not deleting the thumbnail of the thumbnail Image.
The whole thing was kind of tricky. I’d have thought image handling would be easier. It could be that I’m just a
sub-standard programmer and my code is more complicated than it needs to be.
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