Acts As Commentable Plugin

18
Jun
47

I am happy to announce that I have released the acts_as_commentable plugin, my first Ruby on Rails plugin. The Acts As Commentable plugin allows for comments to be added to your Rails ActiveRecord classes.

To install the Acts As Commentable plugin run the following command:

script/plugin install http://juixe.com/svn/acts_as_commentable

The installation process will add several ruby scripts in the vendor/plugins directory. Create a new rails migration and cut and past the following self.up and self.down methods:

def self.up
  create_table :comments, :force => true do |t|
    t.column :title, :string, :limit => 50, :default => ""
    t.column :comment, :string, :default => ""
    t.column :created_at, :datetime, :null => false
    t.column :commentable_id, :integer, :default => 0, :null => false
    t.column :commentable_type, :string, :limit => 15,
      :default => "", :null => false
    t.column :user_id, :integer, :default => 0, :null => false
  end

  add_index :comments, ["user_id"], :name => "fk_comments_user"
end

def self.down
  drop_table :comments
end

Once you have installed the plugin you can start using it in your ActiveRecord class simply by calling the acts_as_commentable method.

class Post < ActiveRecord::Base
  acts_as_commentable
end

To add a comment to a post object you can do the following:

comment = Comment.new(:title => titleStr, :comment => commentStr)
logger << "COMMENT #{comment.comment}\n"
post.comments << comment

Or you could have use the add_comment method on post.

post.add_comment comment

You can also use the post’s comments property to read all comments for the given post. Once a comment has been added to a post you can always reference the post object using the comment’s commentable property.

comment.commentable # references the post

One note, the default implementation of Acts As Commentable requires you to use a user model to link all comments to a user. This requirement can easily be removed or enhanced in the Comment class. But if you have a user model you can retrieve all comments for a user by executing the following statement:

comments = Comment.find_comments_by_user(userInstance)

If you want to retrieve only the comments for a user for a particular model you can do something like:

postComments = Post.find_comments_by_user(userInstance)

If you have any comments, questions, and/or suggestions please don’t hesitate to drop me a line.

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Filed under: Ruby, TechKnow
47 Comments

47 Comments

  1. Bryan
    3:28 pm on January 29th, 2007

    Just thought you might want to know: we’re using this on likebetter.com for photo commenting. thanks!

  2. famoseagle
    6:00 pm on February 6th, 2007

    I think something happened to this plugin with the newest version of rails. Basically, every time I reload the comment model it’s not picking up the belongs_to relationship. So:

    belongs_to :user

    Causes an ActiveRecord::AssociationTypeMismatch error. Says:

    User expected, got User

    That doesn’t make much sense. I know it’s probably a rails issue, but I thought you might have some insight. There are some other loading issues that are a bit too complex to explain in this little form.

  3. TechKnow
    2:05 am on February 7th, 2007

    @Bryan
    Did I see you give a presentation on likebetter at the January SV RoR meeting here in the Yay Area!? I was there! Thats a great application you have there…

    @famoseagle
    I think the issue that you are dealing with is that you don’t have a user model. The plugin comes with a comment model and this requires a user. If you don’t have users just feel free to comment the belongs_to :user line in the comment.rb file.

    I did test this with Rails 1.2.2 on two separate machines and ‘it is working on my machine…’ :)

  4. carlivar
    9:51 pm on February 19th, 2007

    How can I do counter caching with acts_as_commentable? Not sure how that works with polymorphic relationships. Currently I am summarizing comment counts quite often which is leading to a lot of extra db queries. Thanks!

  5. bmctigue
    10:56 am on February 20th, 2007

    Just wanted to let you know that I was getting feedback from my users that comment text was being cutting off. I changed the comment field to be type text and the issue is fixed. Otherwise, a great plugin. Thanks!

  6. TechKnow
    5:22 pm on February 20th, 2007

    @carlivar - You can have a summary table for you model which might have a count of the comment for that model. The summary table is not part of the plugin, so at this time you would need to manage that…

    @bmctigue - The migration in the README used to have comment as a string type this has been modified to describe the comment as a text for a while now. Sorry for any inconvenience that might have caused.

  7. carlivar
    3:44 pm on February 21st, 2007

    Thank you. Small feature request? It would be nice to be able to turn built-in rails counter caching on? Something like:

    acts_as_commentable, :counter_cache => true

  8. Anand
    6:28 pm on March 2nd, 2007

    Hi

    Many thanks for this neat plugin. I needed comments on comments [multi level].

    I changed Comment itself to be acts_as_commentable and it works just fine. Do you see any problems with this approach?

    anand

  9. matthibcn
    5:35 am on March 27th, 2007

    I do get => undefined method ‘find_commentable’ for Comment:Class following this example from Comments on Acts as Commentable found via SWik.

    In my model.rb I do have added acts_as_commentable, also the values commentable / commentable_id are set and post correctly reflecting the model in question…

  10. matthibcn
    5:45 am on March 27th, 2007

    Never mind, in my enthusiasm I added an CommentModel to my app before reading further yesterday night and then forgot about it at all..so it was overwriting the plugins modelClass..it works as promised ;)

    Thx and regards

  11. matthibcn
    3:10 pm on March 27th, 2007

    Ok, now I do have an issue.

    Where do you get the property “comments” from for a given model ??

    reading on this page and the forumentry I posted above I understand I would get all comments belonging to an ég. item just by doing:

    @comments = @item.comments

    This method isnt veen executed looking at the logfile, nor I dont see any method in your plugin called “comments” so I just wonder where it should come from

    on the other side, I also dont get a “method not found “exception” what makes me wonder also

  12. Jan
    4:15 pm on April 17th, 2007

    @famoseagle: I was thrown back by the same bug as you today and I think I found the problem: Since plugin code doesn’t get reloaded on every request, the comment model saves the object type of the user model at “load time”, but the user model gets reloaded at every request (at least in development mode) and so the user model gets a new object_id every time and this is not reflected in the comments model association.

    The error message is funny, but User and User are really two different things, then. One solution is to move comment.rb to app/models/, since then it will be reloaded, too and all is synchronized.

    A more complete description can be found at

    http://localhost3000.de/2007/04/17/acts_as_commentable-reload-fubar/

    Hope it helps.

  13. Casey Helbling
    8:08 pm on April 17th, 2007

    Jan,
    Thank you very much. That is exactly what I did … Stripped out all the extra garbage and moved it into my app. Very interesting issue though… I will have to keep that one in my back pocket. Thanks for the heads up.
    Casey

  14. Mark
    5:36 pm on April 28th, 2007

    After upgrading to rails 1.2.3 I am occasionally getting the following error when accessing the comments for a model that acts_as_commentable.

    undefined method `table_name’ for REXML::Comment:Class

    It appears that the wrong Comment class is being referenced. Has anybody else seen this? Does anybody know how to fix it?

    Thanks,
    Mark

  15. herval
    11:17 am on May 13th, 2007

    My dirty little hack to use counter_cache while you guys don’t come up with a new release:

    http://www.hervalfreire.com/blog/2007/05/13/caching-comments-with-acts_as_commentable/

  16. Avi
    3:15 pm on May 19th, 2007

    I sexy’d up that migration for Rails 2.0 or the Sexy_Migration plugin:

    def self.up
      create_table :comments, :force => true do
        string :title, :limit => 50, :default => ""
        string :comment, :default => ""
        timestamps!
        polymorphic :commentable
        foreign_key :user
      end
    
      add_index :comments, ["user_id"], :name => "fk_comments_user"
    end
    
    def self.down
      drop_table :comments
    end
    
  17. Lance Carlson
    10:54 am on July 8th, 2007

    Hey I love the plugin. Was just wondering if you or I could make a generator for the migrations and stick them inside the repo. I think it will make the installation just that much easier :)

  18. Andrew Gordon
    4:05 am on July 12th, 2007

    Great plugin thanks

  19. Andrew Gordon
    2:23 pm on July 17th, 2007

    [new to rails] and being stupid, but how do i get the name of the user who added the comment, i have a partial that displays the comment and thought i would enter somthing like but this dont work.

    I am using acts_as_authenticated, can anyone help me?

  20. Evan
    1:01 pm on August 2nd, 2007

    Andrew -

    You should be able to make use of the model associations (ie, has_many: , belongs_to:, etc) to pull in the name of the user from another table. An example:

    ” class=”comment_bar”>
    ” class=”comment_header”> ()
    ” class=”comment_body”>

  21. Evan
    4:46 pm on August 2nd, 2007

    Hmm. The cut and paste didn’t translate well.

    Lets say that I have a photo model using acts_as_commentable, which is associated to the user model with belongs_to: / has_many:

    I would do something to this effect in the view:

    for p in @photo.comments
    … p.user.realname
    … p.user.email

    (etc)

  22. Soleone
    12:35 am on January 3rd, 2008

    Very good plugin, because it’s easy to install and use, and also easy to change since it’s so small.

    Note: The sexy migration (Rails 2.0 style) posted here does not work and needs some changes first.

  23. morgajel
    8:30 pm on January 25th, 2008

    Nice plugin, I plan on using it for a project I’m working on. One thing you could add with little effort is a fixture. acts_as_taggable_on_steroids has a good example- it’d be like 1 line in your test file and yaml file with some default data.

    either way, nice job, keep up the good work.

  24. Jason
    10:55 am on February 12th, 2008

    Awesome plugin! If you’d like to map the comments table to a non-standard user foreign key but aren’t sure where to start, I wrote up a short blog post about it: Using acts_as_commentable with a non-standard user foreign key

    Hope this helps somebody!

  25. Vipin
    3:48 am on February 18th, 2008

    Hey guys,
    Is there any way to integrate attachment_fu plugin with in Acts As Commentable Plugin? i want to add more than 1 image for a comment. how can i do it?
    thanks in advance
    Vipin

  26. Ivan Storck
    5:44 pm on March 4th, 2008

    This is the migration I used for Rails 2.0 (mostly sexy migrations)

      def self.up
        create_table :comments, :force => true do |t|
          t.string :title, :default => ""
          t.text :comment, :default => ""
          t.timestamps
          t.integer :user_id, :default => 0, :null => false
          t.string :web_site
          t.string :email
          t.string :name
          t.references :commentable, :polymorphic => true
        end
        add_index :comments, ["user_id"], :name => "fk_comments_user"
      end
    
  27. Randy
    1:56 pm on April 29th, 2008

    Is there a way to incorporate this with paperclip?

    I added has_attached_file to the comment.rb and followed directions but its not saving the file. It keeps coming up blank.

  28. Keith Carter
    10:54 am on November 14th, 2008

    Is there a way to eager load the objects associated with comments?

  29. Alexey
    8:37 am on November 18th, 2008

    2 years of superior plugin ! :)

  30. Alexey
    9:39 am on November 18th, 2008

    I just remember year ago i put this plugin in rails 1.2.6 .. now in 2.1.2 :)

  31. Fran
    4:21 am on February 12th, 2009

    Herval’s dirty little hack to use counter_cache (site is down):

    #comments.rb
    
    def after_create
     if commentable.attributes['comments_count']
      commentable.increment!(”comments_count”)
     end
    end
    
    def before_destroy
     if commentable.attributes['comments_count']
      commentable.class.decrement_counter(”comments_count”, commentable.id)
     end
    end
    
  32. Auraelius
    11:37 am on April 16th, 2009

    Hi,
    I’m having trouble when using acts_as_commentable with restful_authentication: The user_id field in the comment table is never getting set — all the values are NULL.

    I have a “users” table as supplied by that plugin. Is acts_as_commentable looking for a “user” table? I’m still trying to understand all of Rails’ pluralization.

    Where in the code does the user_id get set? I’m stepping through the process with a debugger and can’t see it happening. Is this something ActiveRecord does?

    Thanks for helping a newbie figure things out!

  33. Jeff Tucker
    1:59 pm on June 24th, 2009

    Thanks for the plugin! One issue I had when installing though — I grabbed the gem from your most recent commit (19 May 2009) and had the error:

    Expects acts_as_commentable.rb to define ActsAsCommentable (LoadError).
    

    I had to add

    require 'comment_methods'
    

    to the top of lib/acts_as_commentable.rb to get everything running.

  34. TechKnow
    3:39 pm on June 24th, 2009

    @Jeff - Thanks for that info, I test this on a more recent Rails version. I can’t believe it, but this plugin was originally written in Rails 1.2 and now there is talk of Rails 3.0.

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