How to design a simple keyword content delivery mechanism that functions like Adwords

I'm have application that allows users to store food diary entries of approximately 140 characters in length. I am looking for a solution that will allow me to tie content modules (think tips for healthy eating) to the user's diary entries based on keywords in the entry similar to what Google does with adwords. Are there any out-of-the-box solutions that can do that in Rails?

Here are the specific requirements:

• User logs food diary entry
• In the user's food diary, if there's a specific tip that matches a keyword for the entry, then the tip is displayed next to the entry
• Tips would be defined through an admin tool where the admin specifies the tip content and keywords that would make it appear in the diary

Trying to figure out a) if there's a pre-build solution I could use for something like this or b) what the best approach would be for performance since the users's food diary might have 20 entries per page, and each entry would have to be evaluated to see if there are any corresponding tips that match entry keywords.

For designing a home-grown solution, one idea I had was to make the tip associations when a new food entry is stored like this:

1. user adds a food entry
2. after_save a callback method breaks apart the entry into keywords and searches the tips model for matches
3. if there's a match, it's stored in an association table when new entries are created rather then when the user's food diary is rendered in the web page.

There's a performance hit on stori开发者_如何转开发ng new entries, but it might allow the user's diary to load faster then doing all those look-ups when the diary is rendered.

Does that make sense, or is there a better way? better yet, are there tools that can accomplish what I'm trying to do?

Thanks!

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This is not an AdWords API question, but I'll take a shot:

1. I would move the association table building into an offline task / cronjob. That would take care of the performance overhead when creating new entries, and users would be generally okay with a message like "Tips are being generated, please be patient" if they happen to view the topic too soon.

2. I'm not aware of any existing solutions, but this sounds like a hashtag system to me. Basically you have two lists (food dairy entries, tips), you want to assign hashtags to both lists and then pair entries with same hashtags. Googling for a hashtag system / library might be a good starting point.

Cheers, Anash