Blag o' dkam

New post on Daemons over on the Booko blog.

Just posted on the Booko Blogo an article about implementing Users and Passwords.

Over on the Booko Blog.

I’ve taken Phil’s advice and removed the Javascript from the body’s onload event handler, replacing it with Prototype’s event handler.

    <script type="text/javascript">
    Event.observe(
             window,
             "load",
         <%=  remote_function :url => { :action => "get_prices", :isbn13 => @book.isbn13  },:method => :get %>
        );
    </script>

I spent several hours yesterday fighting with RubyGems – I’d even written a vitriolic post about it – but I … did something … and bam, like that it was gone. RubyGem is Ruby’s version of Perl’s CPAN. It’s got a very annoying trait – its prodigious use of memory. For each gem ( a gem is a Ruby module – like rails or hpricot for example ) RubyGem would load the spec into memory in order ( I’m guessing after reading a bunch of forum posts ) to build a dependency tree. On a 256MB slice host, this pushes you into swap hell. On a 512MB host it would use up to 68% of memory.

So what can you do but rent a bigger slicehost? Moe Sizlack said it best: “I’m choking on my own rage over here!”

Naturally, it’s been fixed. Today.

If only I’d done something more constructive yesterday. Like played COD.

This Simple XMPP client for Ruby looks like a great way to get some IM loving into an application. I’d love a monitoring system which used IM to alert me to failures. Since IM is not exactly a perfect medium, sending a copy of the message via Email for critical alerts is probably a good idea too.

Could be fun to ask your monitoring IM buddy “Status?” and get a status report. X Emails delivered, Y Emails rejected, Z books looked up on Booko.

Fun.

Well, apparently I’ve not been consistent enough – an important quality when one bags out others for being inconsistent. So – I’ve updated all references to “Bookie” to the now correct “Booko”.

While I was at it I updated the scraping code for Fishpond who have again updated their site. At least they’ve updated it for the better. Compare and contrast the old and new Hpricot XPath code for grabbing the book title and author.

The Old:

book.title     = (doc/"table/tr/td/div/h1").inner_html
book.author    = (doc/"table/tr/td/p[2]/a/font/u").inner_html

The New:

book.title     = (doc/"h1#product_title").first.inner_html
book.author    = (doc/"p#product_author/a").first.inner_html

Much nicer!

I added fragment caching to Booko the other day. I’ve added caching to four sections, the Recent Searchs, Most Popular, Shopping Cart and the section which displays the prices of a book.

Now, instead of calculating the most popular books every time someone views a page, we look to see if that part of the site has been created recently – if it has, use it again. The Shopping cart is another good example – it only changes when you add or remove a book from it. Now Booko avoids having to calculate the cost of your shopping trolley at all shops every time you view a page – it regenerates that part of the page only when you add or remove a book.

Kinda wishing I’d bench marked it before and after. I think it’s faster now – but that’s because I’m looking for it. It feels snappier. Anyway – let me know what you think, faster or slower?

Well, I’ve added another feature. You can now add books to a cart, which will calculate the price to buy all books in your cart at the various online book stores, including calculating shipping.

It might be slightly problematic for collecting referrer fees as people will probably not be clicking on each of the book links. I’ll have to have a think on that.

Next job is to make it look better.

Well, it’s been a while, but it looks like someone (Tim you’re the only person who looks at cooking books) found a bug. Searching for a book which has an ISBN which is only available via Fishpond and not Amazon, means that you could find the book, but that it didn’t have a title, author or image. Well, I’ve fixed that now.

Also, you can now click on the book cover image to take you to the price lookup page.

Lastly, shipping price can now be more than just a single number – I can define rules for shipping. So, for example ( the only one I’ve found so far ) Fishpond have free shipping for books over $50 – this is now correctly accounted for.