I’m currently trying to track down an ActiveRecord 3.2.* bug related to generating a count query, and thought it might be useful see a visualization of the ARel object that this query generates.
It turns out this is pretty easy!
ARel already implements a method called “to_dot” that converts your ARel into DOT, which is readable by Graphviz.
I’ve been pretty impressed with the Grape Rack library for building an API, but I was curious how it stacks up against Rails 3, now that Rails has been Rack-ified and has steadily become more hospitable to APIs.
Using an existing Rails app with a Grape API mounted as middleware, I ran a benchmark against a vanilla API with this environment:
And it looks like Grape wins in this particular environment:
Here’s how I implemented both scenarios:
Upon migrating from Rails 2 to 3, one might happen across some “gotchas”. I present a few such that you may heed caution.
ActiveSupport::Callbacks#run_callbacks
This method takes a &block parameter. In Rails 2, &block will run after each callback, and halt the chain if it returns false. In Rails 3, &block will run after the :before/:around callbacks and before the :after callbacks. More has changed about callbacks, so please read the docs.
Mail#header
ActionMailer in Rails 3 uses a different underlying library than 2: mail instead of tmail. Setting headers in the new library will accumulate headers rather than replacing them:
m['X-Something'] = 1
m['X-Something'] = 2
m.header['X-Something'] = 3
Now m has 3 values for the X-Something header: 1, 2 and 3.
ActiveRecord::Base#touch
In Rails 2, touch() ultimately calls save!() and runs through all the validation and callbacks. In Rails 3, touch() saves the record using update_all(), so no validations are performed and only the new after_touch() callback is run.
ActiveRecord#order
In Rails 2, queries are ordered like this:
User.first(:order => "name")In Rails 3, AREL gives us a new method for queries called order(), but remember that it will accumulate order values instead of replacing them:
User.order("name").order("id").first
# ... ORDER BY name, id .... #Remember to use reorder() to reset the value:
User.order("name").reorder("id")
# ... ORDER BY id ... #One thing lacking from ActiveSupport::Callbacks, imo, is a way to reorder callbacks.
For instance, it would be nice if you could define the order in which Authlogic (which uses ActiveSupport::Callbacks) tries to persist a session (ie ‘remember’ cookie, then ‘session’ cookie, then ‘http_auth’, and so on).
Here’s some code to put at the end of your session models to prioritize their callback chains…
For Rails 2:
For Rails 3:
(link)
If you need to move your information from Runner’s World into RunKeeper, but like me have run into the problem that RunKeeper doesn’t have an api (yet?) and doesn’t let you import data, then fear not!
If you like living “on the edge”, try running my script by following these steps:
sudo gem install active_support hpricot jsonruby run_hacker.rb rwFile.xml (where ‘rwFile.xml’ is the file you downloaded from Runner’s World)CATCHES:
This script has worked for me so far; let me know if you try it and encounter any problems! I’d love to abstract this into a real api wrapper, but I am on the verge of wasting too much time.
Enjoy.
I found some tonight to return to Similar Stories Different Take and make a few changes:
(visit the site to install)
And if you happen to be in Utah tomorrow (Apr. 27), check out the Kynetx Impact Conference!
NAME: Similar News Stories
DESCRIPTION
When the user is on a major news site, this app will attempt to provide up to 20 links to similar news stories from other sources.
BACKGROUND:
This is a contest entry for the Kynetx App Contest. Go check out Kynetx if you haven’t yet— it’s a really nice platform for building context-based applications. Sort of like what hoodwink.d was for commenting, but you can do a lot more than just comments.
USE CASE
User reads a news article; User wants to see how other news sources are reporting the same story; User clicks the “Similar News Stories” bookmarklet and they’re given a list of links to matching news stories.
WORKING?
This is mostly working for me, although I have a few kinks to iron out. The current news sources it is targeted for are: CNN, NYtimes, LATimes, WSJ, DailyKos, FOXNews, Yahoo, Reuters, HuffingtonPost, and MSNBC (I’m having issues with a few of these currently).
When I have time I’d like to iron out the search algorithm, try to weed out links that point back to the same article, etc.
HOW TO INSTALL
EXAMPLE ARTICLES
Once you’ve installed, here is a sample NYTimes article, here’s one for WSJ, and here’s one for HuffingtonPost.
Finally finished my PC festival mashup… and it’s at pc.muviluv.com
It has the screening dates, event dates and venue information for Sundance, Slamdance and X-DANCE (an “action sports film festival”).
There are a couple bugs I’d like to fix, but I’m also looking for some feedback for anyone who uses it ^_^
When setting your site’s file cache settings, there are 2 common ways to properly save bandwidth with HTTP headers.
First method: compare the browser cache’s current versions
Set an http header such as ETag or Last-Modified that allows a client (browser) to compare its cached version of a file with the one on the server. With ETag, for example, the client checks the ETag of its cached file against the server’s version of the file, and a 304 Not Modified is sent back to the client without the actual file contents.
This method saves bandwidth, but it also requires a GET or HEAD request to the server to find out if the browser needs a new version of the file.
Second method: give the file a lifetime in the cache
To avoid the lightweight GET/HEAD request, we can also set the Expires or Cache-Control: max-age headers. Expires will tell the browser the date that the file expires (so it can make a new request to the server), and max-age will tell the browser how long the file is good for (compared to the Date header returned in the response).
Accent theme by Handsome Code
tiegz: me on twitter
wherewedowhatwedo: a gallery of workspaces
say it ☎: SMS pronunciation tool
different take ⚖: browser extension for balanced news
muviluv: database of film festivals
effects of space: a space blog
