Creating tags on posts RAILS

I am making something that's like that autocomplete tags field for the posts on stackoverflow.com

I want to make it so that when you make a blog post, you can tag it with words in a database, similar to SO.

For the posts, it belongs_to_and_has_many tags For the tags, it belongs_to_and_has_many posts

However it is a problem for me to do it on the same page because @post would be nil.

How can I implement this?

(If someone can give me the code开发者_开发百科 for the stackoverflow ask question page that would be AWESOME)

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I think the problem here is that it seems like you are asking two different questions. Please correct me if I'm wrong on this.

The first question is how you would implement the autocomplete feature to allow users to easily select from a pre-populated list of tags. To answer this, you might refer to spncrgr's answer above.

The second question is how to deal with associating these retrieved tags to the current post. For this you can add additional javascript functionality to your autocomplete solution. When a user selects which tag they want from the autocomplete field, you can do like StackOverflow does and add the tag to a list of tags in a single text field. These can be either space or comma delimited. When you submit the form to create the new post, you can parse this field into it's separate tags:

tags = params[:tags].split(' ')

You can then associate these tags to the model in the Post#create action.

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This may not help you at all (or you may have already seen it), but here's a link to a Railscasts' episode on auto-complete:

http://railscasts.com/episodes/102-auto-complete-association

I know it helped me when trying to do something similar.

HTH

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It looks for me like you want to generate tags automatically.

You could create

class Post
before_save :create_tags

private
def create_tags
# get your tags somehow
self.tags << Tag.new(:text=>"...")
end
end

method in models/post.rb and build them there.

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If you want to search among existing tags for your auto-suggest, you should have it match from Tag.all, as that won't be nil, just as you would collect a group of objects in a select drop down. Not sure about the code for auto-complete, but the tags should be in the Tag table.