calling a method in a model from another controller in rails 3 - ruby-on-rails

Question

In my rails application I need to call a method defined in one table from another controller. There are two tables named coordinates and tweets. The condition for the tweets table is decided by the coordinates table. In my final view I need to display the attributes of the tweets table for which the condition is decided by the coordinates table.
My Coordinates table code
class Coordinates<ActiveRecord::Base
def self.query()
a = Coordinates.where("city=?", params[:show])
b = a.first
if a.count == 1
latitude = b.latitude
longitude= b.longitude
if(latitude=0 && longitude=0) then
return sql="Select * from tweets where tweet_text LIKE '%text%' AND user_loc LIKE '%show%' order by id desc"
else if (latitude!=0 && longitude!=0)
min_lat = latitude - 1.0
max_lat = latitude + 1.0
min_lng = longitude - 1.0
max_lng = longitude + 1.0
return sql = "Select * from tweets where tweet_text LIKE '%text%' AND ( ((longitude BETWEEN min_lng and max_lng) AND (latitude BETWEEN min_lat and max_lat)) OR (user_loc LIKE '%show%') ) order by id desc"
else
return sql="Select * from tweets where tweet_text LIKE '%text%'"
end
end
end
My tweets table
class Tweets<ActiveRecord::Base
attr_accessible :id, :tweet_created_at, :tweet_id, :tweet_text, :tweet_source, :user_id, :user_name, :user_sc_name, :user_loc, :user_img, :longitude, :latitude, :place, :country
end
I need to call the query definition from my tweets_controller so that it decides what query to fetch from the tweets table and display in the final view . But the params function is not working in the model.rb file . I want something like this
My tweets_controller.rb
class TweetsController<ApplicationController
def index
Coordinates.query()
end
end
My final view code
<%= #tweets.each do |tweets| %>
<ul>
<li><%= tweets.id %></li>
<li><%= tweets.tweet_created_at %></li>
<li><%= tweets.tweet_source %></li>
<li><%= tweets.tweet_text %></li>
<li><%= tweets.user_id %></li>
<li><%= tweets.user_name %></li>
<li><%= tweets.user_sc_name %></li>
<li><%= tweets.user_loc %></li>
<li><%= tweets.user_img %></li>
<li><%= tweets.longitude %></li>
<li><%= tweets.latitude %></li>
<li><%= tweets.place %></li>
<li><%= tweets.country %></li>
</ul>
<% end %>
I am not able to call the query function defined in coordinates table from tweetscontroller. Also I tried using helper methods but that does not seem to help and sounds very complicated. Anybody kindly help me with this

Answer 1

Actually, I see a few issues with your code.
First off: use meaningful names. You are retrieving tweets pertaining to a certain city. Secondly, in your query method, most of what you are trying to do is retrieving tweets, which should be in the tweet model.
What your code does wrong:
it just builds the sql?
it searches for tweets containing the fixed text %text%, I am assuming that should be a given search-term
it searches for a given user-location %show%, I am assuming that should be the city-name (your params[:show]
What I would suggest:
finding tweets should be in Tweet model
use more smaller methods
for simplicity I assume your search-term is params[:text]
So I would write your code as follows:
class TweetsController < ApplicationController
def index
city = params[:show]
search_term = params[:text]
city_coordinates = Coordinates.where('city=?', city)
#tweets = if city_coordinates.count == 1 && city_coordinates.first.valid_location?
Tweet.for_coordinate(city_coordinates.first)
else
Tweet.for_user_location(city)
end
#tweets = #tweets.where("tweet_text like ?", "%#{search_term}%")
end
end
Do not build the sql yourself, let activerecord do that for you. Also: where is lazy, so you can easily chain them.
Then in your Coordinate model add
class Coordinate < ActiveRecord::Base
def valid_location?
self.latitude != 0 && self.longitude != 0
end
end
and in your Tweet model
class Tweet < ActiveRecord::Base
def self.for_coordinate(coordinate)
bbox = { min_lat: coordinate.latitude - 1.0, max_lat: coordinate.latitude + 1.0,
min_lng: coordinate.latitude - 1.0, max_lng: coordinate.latitude + 1.0
}
Tweet.where("(longitude BETWEEN ? and ?) AND (latitude BETWEEN ? and ?)) OR (user_loc LIKE ?)",
bbox[:min_lng], bbox[:max_lng], bbox[:min_lat], bbox[:max_lat], "%#{coordinate.city}%")
end
def self.for_user_location(city)
Tweet.where("user_loc like ?", "%#{city}%")
end
end

Answer 2

In your self.query method in model, set an argument like this :
class Coordinates<ActiveRecord::Base
def self.query(something)
a = Coordinates.where("city=?", something)
b = a.first
if a.count == 1
latitude = b.latitude
longitude= b.longitude
if(latitude=0 && longitude=0) then
return sql="Select * from tweets where tweet_text LIKE '%text%' AND user_loc LIKE '%show%' order by id desc"
else if (latitude!=0 && longitude!=0)
min_lat = latitude - 1.0
max_lat = latitude + 1.0
min_lng = longitude - 1.0
max_lng = longitude + 1.0
return sql = "Select * from tweets where tweet_text LIKE '%text%' AND ( ((longitude BETWEEN min_lng and max_lng) AND (latitude BETWEEN min_lat and max_lat)) OR (user_loc LIKE '%show%') ) order by id desc"
else
return sql="Select * from tweets where tweet_text LIKE '%text%'"
end
end
end
In your controller, pass your params[:show] as as parameter :
class TweetsController<ApplicationController
def index
#tweets = Coordinates.query(params[:show])
end
end
Now it should work. Thanks

Answer 3

You call Coordinates.query() but you don't actually store the return value.
Try this:
#tweets = Coordinates.query()