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a9cbc43 @binarylogic Add v2 files
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1 = Searchlogic
2
3 <b>Searchlogic has been <em>completely</em> rewritten for v2. It is much simpler and has taken an entirely new approach. To give you an idea, v1 had ~2300 lines of code, v2 has ~350 lines of code.</b>
4
5 Searchlogic is a library that leverages named scopes to make searching in your application simple.
6
7 Instead of explaining what Searchlogic can do, let me show you. Let's start at the top:
8
9 # We have the following model
10 User(id: integer, created_at: datetime, username: string, age: integer)
11
12 # Searchlogic gives you a bunch of named scopes for free:
13 User.username_equals("bjohnson")
14 User.username_does_not_equal("bjohnson")
15 User.username_begins_with("bjohnson")
16 User.username_like("bjohnson")
17 User.username_ends_with("bjohnson")
18 User.age_greater_than(20)
19 User.age_greater_than_or_equal_to(20)
20 User.age_less_than(20)
21 User.age_less_than_or_equal_to(20)
22 User.username_null
23 User.username_blank
24
25 # You can also order by columns
26 User.ascend_by_username
27 User.descend_by_username
28 User.order("ascend_by_username")
29
30 Keep in mind, these are just named scopes, you can chain them, call methods off of them, etc:
31
32 scope = User.username_like("bjohnson").age_greater_than(20).ascend_by_username
33 scope.all
34 scope.first
35 scope.count
36 # etc...
37
38 == Named scopes for associations
39
40 You also get named scopes for any of your associations:
41
42 # We have the following relationships
43 User.has_many :orders
44 Order.has_many :line_items
45 LineItem
46
47 # Set conditions on association columns
48 User.orders_total_greater_than(20)
49 User.orders_line_items_price_greater_than(20)
50
51 # Order by association columns
52 User.ascend_by_order_total
53 User.descend_by_orders_line_items_price
54
55 Again these are just named scopes. You can chain them together, call methods off of them, etc. What's great about these named scopes is that they do NOT use the :include option, making them much faster. Instead they create a LEFT OUTER JOIN and pass it to the :joins option, which is great for performance. If you want to use the :include option, just specify it:
56
57 User.orders_line_items_price_greater_than(20).all(:include => {:orders => :line_items})
58
59 Now all of Searchlogic's goodness fits nicely into your app and you can use it with your custom named scopes. Nice and clean.
60
61 == Make searching in your application trivial
62
63 The above is great, but what about tying all of this in with a search form in your application? Just do this...
64
65 User.search(:username_like => "bjohnson", :age_less_than => 20)
66
67 The above is equivalent to:
68
69 User.username_like("bjohnson").age_less_than(20)
70
71 All that the search method does is chain named scopes together for you. What's so great about that? It keeps your controllers extremely simple:
72
73 class UsersController < ApplicationController
74 def index
75 @search = User.search(params[:search])
76 @users = @search.all
77 end
78 end
79
80 It doesn't get any simpler than that. Adding a search condition is as simple as adding a condition to your form. Remember all of those named scopes above? Just create fields with the same names:
81
82 - form_for @search do |f|
83 = f.text_field :username_like
84 = f.select :age_greater_than, (0..100)
85 = f.text_field :orders_total_greater_than
86 = f.submit
87
88 == Use your existing named scopes
89
90 This is one of the big differences between Searchlogic v1 and v2. What about your existing named scopes? Let's say you have this:
91
92 User.named_scope :four_year_olds, :conditions => {:age => 4}
93
94 Again, these are all just named scopes, use it in the same way:
95
96 User.search(:four_year_olds => true, :username_like => "bjohnson")
97
98 Notice we pass true as the value. If a named scope does not accept any parameters (arity == 0) you can simply pass it true or false. If you pass false, the named scope will be ignored. If your named scope accepts a parameter, the value will be passed right to the named scope regardless of the value.
99
100 Now just throw it in your form:
101
102 - form_for @search do |f|
103 = f.text_field :username_like
104 = f.check_box :four_year_olds
105 = f.submit
106
107 What's great about this is that you can do just about anything you want. If Searchlogic doesn't provide a named scope for that crazy searching edge case that you need, just create your own named scope. The sky is the limit.
108
109 == Pagination (leverage will_paginate)
110
111 Instead of recreating the wheel with pagination, Searchlogic works great with will_paginate. All that Searchlogic is doing is creating named scopes, and will_paginate works great with named scopes:
112
113 User.username_like("bjohnson").age_less_than(20).paginate(:page => params[:page])
114
115 If you don't like will_paginate, use another solution, or roll your own. Pagination really has nothing to do with searching, and the main goal for Searchlogic v2 was to keep it lean and simple. No reason to recreate the wheel and bloat the library.
116
117 == Under the hood
118
119 Before I use a library in my application I like to glance at the source and try to at least understand the basics of how it works. If you are like me, a nice little explanation from the author is always helpful:
120
121 Searchlogic utilizes method_missing to create all of these named scopes. When it hits method_missing it creates a named scope to ensure it will never hit method missing for that named scope again. Sort of a caching mechanism. It works in the same fashion as ActiveRecord's "find_by_*" methods. This way only the named scopes you need are created and nothing more.
122
123 That's about it, the named scope options are pretty bare bones and created just like you would manually.
124
125 == Copyright
126
127 Copyright (c) 2009 {Ben Johnson of Binary Logic}[http://www.binarylogic.com], released under the MIT license
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