Question

I have a rails app with a Backbone.js front-end. In my Backbone model/collection definition, I have the following for a model (in project.js.coffee.erb)

#############################
##  MODEL
#############################
class window.Project extends Backbone.Model

  urlRoot: '/projects'

#############################
##  COLLECTION
#############################
class window.Projects extends Backbone.Collection

  model: Project

  url: '/projects'


# initialize new collection
window.projects = new Projects
projects.reset(<%= Project.all.to_json %>)

The last line is where ERB loads in all the projects in JSON.

When I load my application, this bootstraping results in a collection that contains old data. I know it’s old because I’ve gone as far as to:

• delete my development database (sqlite3)
• alter my database.yml to rename my development database name
• re-run rake db:migrate to create a brand new .sqlite3 database file

I can run sqlite3 and see that the projects table contains no rows, and yet, even after restarting the server, project.js is compiled to contain a collection full of now non-existent data.

Rails correctly boots into development mode when I run rails s:

=> Booting WEBrick
=> Rails 3.2.5 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2012-07-02 21:24:08] INFO  WEBrick 1.3.1
[2012-07-02 21:24:08] INFO  ruby 1.9.3 (2012-04-20) [x86_64-darwin11.4.0]
[2012-07-02 21:24:08] INFO  WEBrick::HTTPServer#start: pid=11607 port=3000

If I create new projects, they even save to the database. They also get added to the Backbone collection just fine. But, again, if I reload the page or even restart the server, the collection is again populated with the old data.

Can someone help me figure out what I’m doing wrong here?

Answer 1

Ok, turns out I figured out what’s going on.

Assets in rails are cached so long as the file itself doesn’t change. So once project.js.coffee.erb was compiled into project.js, the data being bootstrapped into the collection would remain static until I made a change to project.js.coffee.erb, at which point rails would re-compile the file, only then re-fetching the data from the database.

I realized that if I want new data to be bootstrapped into the collection on each page load, I’d need to add the projects.reset() javascript as an inline script in the main app/views/layouts/application.html.haml. Adding this code to the end of my body tag did the trick.

:javascript
  projects.reset(#{Project.all.to_json})
  groups.reset(#{Group.all.to_json})
  users.reset(#{User.all.to_json})

Now, each time the page is reloaded, the current data is loaded into the appropriate collections.