This week I improved the Amazon wishlist support in PriceChirp. One of the cool features of PriceChirp from the beginning has been how easy it is to import an Amazon wishlist into PriceChirp. The only problem with this feature is it was an all or nothing proposition. Now, we have the ability to view our wishlists in PriceChirp and select which items we wish to import. The old feature of importing everything is still thee, but now we have options.

To see this feature in action, log into your PriceChirp account and do a wishlist search. This is done by searching for the email address associated to your Amazon wishlist. Once your wishlists are displayed, you can select "view wishlist" to get a listing of your items. From this page you can easily select which item to import into your personalized tracker.

Have fun!

PriceChirp is growing. This week I added support to allow people to track prices and be alerted of changes for all the international Amazon sites. This includes Amazon US, Canada, France, Germany, Japan, and the UK. Just select the location of Amazon you are interested in searching, and use PriceChirp like normal. It was designed to make it easy to manage products from multiple sites at once. I'm hoping this design decision will pay off if in the future I add more vendors to PriceChirp.

Gravatar is the globally recognized avatar run by the folks who run Wordpress.com.

Your Gravatar is an image that follows you from site to site appearing beside your name when you do things like comment or post on a blog. This is done by associating an image to the users email address. Adding Gravatar to PriceChirp seemed like a fun thing to do.

The API is very simple, so adding it to a Ruby on Rails site is easy.

First, add a few lines to your application-helper.rb:

  def gravatar_url_for(email, options = {})
    url_for({
      :gravatar_id => Digest::MD5.hexdigest(email),
      :host => 'www.gravatar.com',
      :protocol => 'http://',
      :only_path => false,
      :skip_relative_url_root => true,
      :controller => '/avatar'
    }.merge(options)
    )
  end

You may also need to add:

Today I updated PriceChirp from rails 2.2.2 to rails 2.3.3. It was easier than expected, but I ran into several gotchas along the way. Here's an outline of the major issues I encountered and how I addressed them.  Depending on your code, this may or may not be any any use.  Note: Several of these steps had to be performed on both the development and production boxes.

1) Updating gems

To upgrade the base system gems, as root I ran:

gem update

This upgraded the system gems such as rails, mysql, passenger, etc. The gems built into PriceChirp in the /vendor/gems directory had to be updated separately. I'll get to those in a few minutes.

2) Updating passenger

Last year I had an excellent time at Barcamp NOLA. This year's Barcamp NOLA 2 was twice as large and more than twice as fun. Many thanks to all to the good people of New Orleans for making me feel at home. @cSchultz, @tritico, @NewJess, @LizMoney, @ev3rywh3re, @hartmyst, @CallMeAlva, @plainprogrammer (And many more who's twitter accounts I don't know)

Although they had four rooms open for panels, somehow, every session I was interested in was held in the main room. I attended panels on:

• Unit Testing
• Design patterns you can learn from a professional kitchen
• The history of SMS
  -- The average American sends 347 text messages a month yet only make 243 phone calls a month.
• Design patterns for mobile devices
• Four apps that turn the iPhone camera into a point and shoot replacement
  -- Night Camera, iFlash Ready, Photo Jen, and Autostitch
• Bringing social networking skills to realestate agents
• Application and Network secuity
  -- I need to check out Burp Suite, OWASP, WebGoat, Paros, and, cain oxid.it

I gave a talk on Cloud Computing and how it can be used by startups.  The talk went well.  At the end of the talk, I was pleased Chris asked me to demo PriceChirp for the group as a real world example of a project running in the cloud.

Code updated 9/18/2009

This week I added sitemap files to my rails site PriceChirp. Sitemaps are used to help search engines to find all your content. They are especially helpful in enumerating pages that are difficult for web crawlers to discover, such as content from database searches.

The web is full of instructions on how to generate sitemaps on the fly using rxml templates. This does not scale well if your site has thousands of links. A better method is to periodically generate site maps and serve these cached files when requested.

www.fortytwo.gr has a good example for generating sitemaps with rails. I've taken his code and fixed/extended it to fit my needs.

Understanding Sitemaps

Google's sitemap howto.

Basically, there are two types of sitemap files: