Topper's blog about ruby on rails and javascript

Sep 4 09

Fix string memory leaks in Ruby 1.8.6

by Topper

UPDATE: This is rails-incompatible... which sucks.

Ruby 1.8.6 leaks memory in some surprising places. Even gsub and split on the String class cause some bad headaches. If you're using Haml and 1.8.6 - you are probably in a bit of trouble.
Read more: http://blog.edhickey.com/2008/12/03/memory-leak-in-ruby-186-string-class/

However, simply overwriting the offending methods fixes this memory leak at least. With a weird caveat that you may not use $ variables (eg $1) in any blocks passed to gsub.

Re-read that last sentence... "boom".gsub(/b(.)/) {|m| $1.upcase} will NO LONGER work. Unfortunately... rails uses that syntax, making this blog post probably moot

PLAIN TEXT

RUBY:

class ::String
# This below fixes a bad memory leak in ruby 1.8.6
# http://blog.edhickey.com/2008/12/03/memory-leak-in-ruby-186-string-class/
alias :non_garbage_split :split
alias :non_garbage_gsub :gsub
alias :non_garbage_gsub! :gsub!
def split(char)
holder = char
non_garbage_split(holder)
end
def gsub(*args, &block)
if args.size == 1
non_garbage_gsub(args[0], &block)
else
non_garbage_gsub(args[0], args[1], &block)
end
end
def gsub!(*args, &block)
holder = args[0]
args[0] = holder
non_garbage_gsub!(*args, &block)
end
#end memory leak fixes
end

Aug 13 09

Fast RFC 3339 date processing in javascript

by Topper

At Motionbox, we use a RFC 3339 time format in some data we return. Javascript doesn't natively handle this format with Date.parse. The only other blog post I've seen on the subject is this:

http://dansnetwork.com/2008/11/01/javascript-iso8601rfc3339-date-parser/

However, since that's a regular expression that's parsing on the string, it can sometimes be slower (but not toooo bad... 1000 iterations on the code from the blog post above took < 100 miliseconds in IE7 (~40 miliseconds in Firefox on a macbook pro).

I knew we could do better with splits. With my code below I got it operating 60% faster (so operations take 40% of the time from the code above).

PLAIN TEXT

JavaScript:

Date.prototype.setRFC3339 = function(dString){
var utcOffset, offsetSplitChar;
var offsetMultiplier = 1;
var dateTime = dString.split("T");
var date = dateTime[0].split("-");
var time = dateTime[1].split(":");
var offsetField = time[time.length - 1];
var offsetString;
offsetFieldIdentifier = offsetField.charAt(offsetField.length - 1);
if (offsetFieldIdentifier == "Z") {
utcOffset = 0;
time[time.length - 1] = offsetField.substr(0, offsetField.length - 2);
} else {
if (offsetField[offsetField.length - 1].indexOf("+") != -1) {
offsetSplitChar = "+";
offsetMultiplier = 1;
} else {
offsetSplitChar = "-";
offsetMultiplier = -1;
}
offsetString = offsetField.split(offsetSplitChar);
time[time.length - 1] == offsetString[0];
offsetString = offsetString[1].split(":");
utcOffset = (offsetString[0] * 60) + offsetString[1];
utcOffset = utcOffset * 60 * 1000;
}
this.setTime(Date.UTC(date[0], date[1] - 1, date[2], time[0], time[1], time[2]) + (utcOffset * offsetMultiplier ));
return this;
};

Mar 15 09

Mamoo released as open source

by Topper

I just put the Motionbox Advanced Model Observer Observer (Mamoo) up on Github. It's a light-weight (13k), but fairly powerful framework for javascript built on top of Prototype and the Motionbox EventHandler.

It's fairly well documented and has a full suite of specs written in ScrewUnit.

Mamoo let's you stop thinking about the "glue code" you need on a client-side app - and start thinking like "when this happens, I want this to happen." - Event driven architecture in JS.

Checkout the readme for a romp through most of the features.

To whet your appetite, here's a really small, but useful app written with Mamoo.

PLAIN TEXT

JavaScript:

Message = MBX.JsModel.create("Message");
MBX.MessageView = MBX.JsView.create({
model: Message,
onInstanceCreate: function (message) {
var li = this.buildLi(message);
$("message_list").insert(li);
},
buildLi: function (message) {
var li = new Element("li", { id: message.primaryKey() });
li.update(message.get('body'));
li.updatesOn(message, "body");
return li;
}
});
// This will add the ui element
var message = Message.create({ body: "this is my body!" });
// and if you change body, the ui will automatically update as well
message.set('body', "some other body");

Assuming you have an ol with the id of "message_list" in your html page, now everytime you create a message, it'll get populated into the DOM.

I also put together a 15minute screencast that gives you a quick demo of a bunch of the features of Mamoo.

Nifty?

Mar 2 09

Boxes and Arrows: Bringing Holistic Awareness to Your Design

by Topper

Bringing Holistic Awareness to Your Design - Boxes and Arrows

We did not find any correlation with user satisfaction and those teams with the most specialized team members, one way or the other: some teams with the most specialization did well, and some teams did poorly. What we did consistently observe among teams that had high user satisfaction scores, was one characteristic that stood out above all the othersâ€”what we began to call shared, holistic understanding. Those teams that achieved the highest degree of shared, holistic understanding consistently designed the best web applications. The more each team member understood the business goals, the user needs, and the capabilities and limitations of the IT environmentâ€”a holistic viewâ€”the more successful the project. In contrast, the more each team member was â€œsiloedâ€ into knowing just their piece of the whole, the less successful the project.

Yes, yes yes. I now work for a company that believes in top-down and bottom-up understanding. I didn't always. I've always said that even the full-time janitor needs to understand the business goals in order to most-effectively do their job.

Mar 1 09

Free git training course

by Topper

h/t to Ruby Flow:

Rubylearning.com is offering a free git and github training course. I don't have any personal experience with RubyLearning, but I hear good things and it might be a good introductory course for anyone that is just getting used to git.

http://rubylearning.com/blog/2009/02/10/git-and-github-a-free-course/

Topper’s Blog

Fix string memory leaks in Ruby 1.8.6

Fast RFC 3339 date processing in javascript

Mamoo released as open source

Boxes and Arrows: Bringing Holistic Awareness to Your Design

Free git training course

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