While the next release of Rails appears to be coming up, there’s still plenty of small, useful features from previous releases that aren’t widely used.
A few of my favorites:- query_attribute
- polymorphic_path
- debug
- rake -T `query` ( Not Rails specific, but still handy! )
- extract_options!
1. ActiveRecord’s query_attribute
Query methods are available for each of a record’s attributes, providing for a cleaner way to check for the presence of an attribute.
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# == Schema Information # Schema version: 17 # # Table name: users # # id :integer(11) not null, primary key # first_name :string(255) # last_name :string(255) # Original class User < ActiveRecord::Base def named? !first_name.blank? && !last_name.blank? end end # Refactored to use query_attribute class User < ActiveRecord::Base def named? first_name? && last_name? end end |
2. Indifferent links with polymorphic paths.
Rails has polymorphic edit/new/formatted path routing available out of the box. Providing an array will namespace the path with those array parameters. Available Methods: (edit|new|formatted|)polymorphic_path(record_or_hash_or_array)
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# Before: <% if @record.is_a?(User) %> <%= user_path(@record) %> <% elsif @record.is_a?(Friend) <%= friend_path(@record) %> ... etc. # After: <%= polymorphic_path(@record) %> |
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# Paths can be namespaced: #=> admin/users/5/edit edit_polymorphic_path([:admin, @record]) # Polymorphic urls are also internally used by helpers: # redirects to store_path(@store) redirect_to @store # builds a form with an action to 'new_admin_stores_path' #=> <form action="admin/stores/new" ... /> form_for([:admin, Store.new]) # <a href="/stores/5">A store in Minneapolis, MN</a> link_to @store.name, @store |
3. debug
Especially useful when starting out a project, this is quick way to understand what objects are being used in the view.
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<%= debug @user %>
# Yields this in the view:
# - !ruby/object:User
# attributes:
# salt: 7be4287a1b27426fa6e5b6d733c707dd66425e82
# updated_at: 2008-04-22 19:01:23
# crypted_password: abb611def895dac923ba8ea59a78451f77473d5e
# id: "1"
# first_name: Eric
# last_name: Chapweske
# created_at: 2008-04-06 01:45:33
# attributes_cache: {}
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4. rake -T task
This is a handy Rake feature, and not limited to Rails. Can’t remember the exact syntax for a particular rake task? Trim the results generated with `rake -T` with an optional search parameter.
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$rake -T rake annotate_models # Add schema information (as comments)... rake audit:purge # Removes Audit records older than 2 m... rake db:abort_if_pending_migrations # Raises an error if there are pending... ... etc. rake tmp:sockets:clear # Clears all files in tmp/sockets // Searching by the task's name $rake -T db:migrate:r rake db:migrate:redo # Rollbacks the database one migration and re migrat... rake db:migrate:reset # Resets your database using your migrations for the... |
5. extract_options!
While not needed very often, Rails comes bundled with a method to extract the options from methods that utilize the splat operator. This method removes the last object from an array if it’s a Hash, otherwise an empty hash is returned.
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class Story < ActiveRecord::Base # Example: # Story.published_and_tagged_with('deep', 'thoughts', :order => 'created_at desc') # The generated options for this method look like this: #=> { :include => :tags, :order => 'created_at desc' } def self.published_and_tagged_with(*tag_names) options = tag_names.extract_options! options[:include] ||= :tags ... end end |
References
I wasn’t able to find any write ups on the above methods, so reading the source code may be the best path if you’re curious about their exact implementations.
I dunno where to put this, since there is no contact form…
i subscribed using google reader, and i get duplicate items A LOT, please have a look if you are sending valid RSS, or bookmark your feed yourself, it really starts to get annoying…
mg
Thanks, mg – we’ve investigated a bit. It looks like our feed is valid, but it could be a few other things (regarding ids/guids or edits). And it only happens in some RSS readers. We’ll see what we can do.
Anyone have expertise with this sort of thing?
polymorphic_path is a huge time saver. thanks for the heads up.
Howdy!
Just wondering if you manually pasted the schema info comments above your model in section 1 or if you know of a way to make Rails do that itself. I always find myself checking schema.rb often when returning to models I haven’t worked on in awhile.
Thanks for these tips, I’m sure I’ll find uses for them!
Jerod:
Checkout the annotate_models plugin, a must have of mine.
Regarding #4, even more useful than -T is -D. rake -T really does print ”...” at column 75, no matter how wide the terminal is (why oh why?). rake -D prints the whole description.
Thansk! No more $ rake
-tasks | grep whaetever :)Thanks for this post—polymorphic_path is real handy.
polymorphic_path is awesome, I cleaned up a bunch of my views. I also found #1 to be useful. Thanks a lot.
@Jerod It is output from Annotate Models plugin
These are not heavily used methods, but it’s good to remember them!
Good post!
Felipe Giotto ;-)
well done, man