add geolocation search for public channels

app/controllers/channels_controller.rb

@@ -6,6 +6,7 @@ class ChannelsController < ApplicationController
   layout 'application', :except => [:social_show, :social_feed]
   protect_from_forgery :except => [:realtime, :realtime_update, :post_data, :create, :destroy, :clear]
   require 'csv'
+  require 'will_paginate/array'
 
   # get list of all realtime channels
   def realtime
@@ -55,6 +56,10 @@ class ChannelsController < ApplicationController
     elsif params[:tag].present?
       @header = "#{t(:tag).capitalize}: #{params[:tag]}"
       @channels = Channel.public_viewable.active.order('ranking desc, updated_at DESC').with_tag(params[:tag]).paginate :page => params[:page]
+    # get channels by location
+    elsif params[:latitude].present? && params[:longitude].present? && params[:distance].present?
+      @header = "#{t(:channels_near)}: [#{params[:latitude]}, #{params[:longitude]}]"
+      @channels = Channel.location_search(params).paginate :page => params[:page]
     # normal channel list
     else
       @header = t(:featured_channels)

app/models/channel.rb

@@ -52,6 +52,11 @@
 
 class Channel < ActiveRecord::Base
   include KeyUtilities
+  # geolocation search: Channel.within(miles, :origin => [latitude, longitude]).to_a
+  # example: channels = Channel.within(4000, :origin => [4, 6]).to_a
+  # channels.sort_by{|s| s.distance_to([4, 6])}
+  acts_as_mappable :default_units => :kms, :default_formula => :sphere,
+    :distance_field_name => :distance, :lat_column_name => :latitude, :lng_column_name => :longitude
 
   belongs_to :user
   has_many :feeds
@@ -85,6 +90,18 @@ class Channel < ActiveRecord::Base
   cattr_reader :per_page
   @@per_page = 15
 
+  # search for public channels within a certain distance from the origin
+  # requires latitude, longitude, and distance to be present as options keys
+  # distance is in kilometers
+  def self.location_search(options = {})
+    # set the origin
+    origin = [options[:latitude].to_f, options[:longitude].to_f]
+    # query the database
+    channels = Channel.public_viewable.within(options[:distance].to_f, :origin => origin)
+    # sort channels by distance
+    return channels.sort_by{|c| c.distance_to(origin)}
+  end
+
   # how often the channel is updated
   def update_rate
     last_feeds = self.feeds.order('entry_id desc').limit(2)

app/views/docs/channels/_index.html.erb

@@ -16,6 +16,14 @@ Valid parameters:
   <li><b>username</b> (string) Person's username that you want to search Channels for (optional)</li>
 </ul>
 
+<br>
+You can also search for Channels within a certain distance of a location by including the following location parameters:
+<ul>
+  <li><b>latitude</b> (decimal) - Latitude of location in degrees. (optional)</li>
+  <li><b>longitude</b> (decimal) - Longitude of location in degrees. (optional)</li>
+  <li><b>distance</b> (decimal) - Distance in kilometers from location. (optional)</li>
+</ul>
+
 <br>
 Example GET:
 
@@ -163,6 +171,7 @@ Valid parameters:
   <li><b>api_key</b> (string) - Your Account API Key (this is different from a Channel API Key, and can be found in your Account settings). (required)</li>
 </ul>
 
+
 <br>
 Example GET: