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Add Relation#find_by and Relation#find_by!

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1 parent 3a8c543 commit 13b3c77e393b8fb02588f39e6bfa10c832e251ff @jonleighton jonleighton committed Mar 30, 2012
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@@ -1,5 +1,15 @@
## Rails 4.0.0 (unreleased) ##
+* Added `#find_by` and `#find_by!` to mirror the functionality
+ provided by dynamic finders in a way that allows dynamic input more
+ easily:
+
+ Post.find_by name: 'Spartacus', rating: 4
+ Post.find_by "published_at < ?", 2.weeks.ago
+ Post.find_by! name: 'Spartacus'
+
+ *Jon Leighton*
+
* Added ActiveRecord::Base#slice to return a hash of the given methods with
their names as keys and returned values as values.
@@ -5,6 +5,7 @@ module ActiveRecord
module Querying
delegate :find, :first, :first!, :last, :last!, :all, :exists?, :any?, :many?, :to => :scoped
delegate :first_or_create, :first_or_create!, :first_or_initialize, :to => :scoped
+ delegate :find_by, :find_by!, :to => :scoped
delegate :destroy, :destroy_all, :delete, :delete_all, :update, :update_all, :to => :scoped
delegate :find_each, :find_in_batches, :to => :scoped
delegate :select, :group, :order, :except, :reorder, :limit, :offset, :joins,
@@ -109,6 +109,25 @@ def find(*args)
end
end
+ # Finds the first record matching the specified conditions. There
+ # is no implied ording so if order matters, you should specify it
+ # yourself.
+ #
+ # If no record is found, returns <tt>nil</tt>.
+ #
+ # Post.find_by name: 'Spartacus', rating: 4
+ # Post.find_by "published_at < ?", 2.weeks.ago
+ #
+ def find_by(*args)
+ where(*args).first
+ end
+
+ # Like <tt>find_by</tt>, except that if no record is found, raises
+ # an <tt>ActiveRecord::RecordNotFound</tt> error.
+ def find_by!(*args)
+ where(*args).first!
+ end
+
# A convenience wrapper for <tt>find(:first, *args)</tt>. You can pass in all the
# same arguments to this method as you can to <tt>find(:first)</tt>.
def first(*args)
@@ -2069,4 +2069,18 @@ def test_slice
assert_nil hash[:firm_name]
assert_nil hash['firm_name']
end
+
+ ["find_by", "find_by!"].each do |meth|
+ test "#{meth} delegates to scoped" do
+ record = stub
+
+ scope = mock
+ scope.expects(meth).with(:foo, :bar).returns(record)
@tenderlove

tenderlove Feb 17, 2014

Owner

find_by and find_by! fail IRL when you pass two parameters. Is passing two parameters important to this test?

@tenderlove

tenderlove Feb 17, 2014

Owner

I guess I was wrong about the multi arg thing o_O

+
+ klass = Class.new(ActiveRecord::Base)
+ klass.stubs(:scoped => scope)
+
+ assert_equal record, klass.public_send(meth, :foo, :bar)
+ end
+ end
@tenderlove

tenderlove Feb 17, 2014

Owner

Is there a way to write this test without mocking everything out? It forces us to call scope inside the implementation, when maybe we don't want to.

@jonleighton

jonleighton Feb 18, 2014

Member

I'm not entirely sure what you mean, but in general I don't know why I wrote such an over-complicated test, feel free to change it to one that just calls the method on an AR class.

end
@@ -1256,4 +1256,38 @@ def test_presence
assert topics.loaded?
end
+
+ test "find_by with hash conditions returns the first matching record" do
+ assert_equal posts(:eager_other), Post.order(:id).find_by(author_id: 2)
+ end
+
+ test "find_by with non-hash conditions returns the first matching record" do
+ assert_equal posts(:eager_other), Post.order(:id).find_by("author_id = 2")
+ end
+
+ test "find_by with multi-arg conditions returns the first matching record" do
+ assert_equal posts(:eager_other), Post.order(:id).find_by('author_id = ?', 2)
+ end
+
+ test "find_by returns nil if the record is missing" do
+ assert_equal nil, Post.scoped.find_by("1 = 0")
+ end
+
+ test "find_by! with hash conditions returns the first matching record" do
+ assert_equal posts(:eager_other), Post.order(:id).find_by!(author_id: 2)
+ end
+
+ test "find_by! with non-hash conditions returns the first matching record" do
+ assert_equal posts(:eager_other), Post.order(:id).find_by!("author_id = 2")
+ end
+
+ test "find_by! with multi-arg conditions returns the first matching record" do
+ assert_equal posts(:eager_other), Post.order(:id).find_by!('author_id = ?', 2)
+ end
+
+ test "find_by! raises RecordNotFound if the record is missing" do
+ assert_raises(ActiveRecord::RecordNotFound) do
+ Post.scoped.find_by!("1 = 0")
+ end
+ end
end
@@ -133,6 +133,24 @@ SELECT * FROM clients ORDER BY clients.id DESC LIMIT 1
<tt>Model.last</tt> returns +nil+ if no matching record is found. No exception will be raised.
+h5. +find_by+
+
+<tt>Model.find_by</tt> finds the first record matching some conditions. For example:
+
+<ruby>
+Client.find_by first_name: 'Lifo'
+# => #<Client id: 1, first_name: "Lifo">
+
+Client.find_by first_name: 'Jon'
+# => nil
+</ruby>
+
+It is equivalent to writing:
+
+<ruby>
+Client.where(first_name: 'Lifo').first
+</ruby>
+
h5(#first_1). +first!+
<tt>Model.first!</tt> finds the first record. For example:
@@ -167,6 +185,24 @@ SELECT * FROM clients ORDER BY clients.id DESC LIMIT 1
<tt>Model.last!</tt> raises +RecordNotFound+ if no matching record is found.
+h5(#find_by_1). +find_by!+
+
+<tt>Model.find_by!</tt> finds the first record matching some conditions. It raises +RecordNotFound+ if no matching record is found. For example:
+
+<ruby>
+Client.find_by! first_name: 'Lifo'
+# => #<Client id: 1, first_name: "Lifo">
+
+Client.find_by! first_name: 'Jon'
+# => RecordNotFound
+</ruby>
+
+It is equivalent to writing:
+
+<ruby>
+Client.where(first_name: 'Lifo').first!
+</ruby>
+
h4. Retrieving Multiple Objects
h5. Using Multiple Primary Keys

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