dm-is-checksumed
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- [Email](mailto:postmodern.mod3 at gmail.com)
Description
A DataMapper plugin which adds checksum properties to a Model, referencing other properties.
Features
- Uses sha256
- Allows unique and non-unique checksums.
- Automatically substitutes in checksums in queries to avoid expensive queries.
- Works with
first_or_createandfirst_or_new.
Examples
require 'dm-is-checksumed'
class Url
include DataMapper::Resource
is :checksumed
property :id, Serial
# The property to be checksumed
property :url, Text
# Defines the `url_checksum` property, referencing `url`
checksum :url
end
# Checksums are automatically calculated
url = Url.create(:url => 'http://example.com/extremely/long/url....')
url.url_checksum
# => "b74d7288b86817dea55bd044d3cedc013e83518b461cd6f202be85e33d95715b"
# Checksums are automatically substituted into queries
url = Url.first(:url => 'http://example.com/same/huge/url')
# ~ (0.000116) SELECT "id", "url_checksum" FROM "urls" WHERE "url_checksum" = 'b74d7288b86817dea55bd044d3cedc013e83518b461cd6f202be85e33d95715b' ORDER BY "id" LIMIT 1
# Works with first_or_create and first_or_new
url = Url.first_or_create(:url => 'http://example.com/same/huge/url')
url.url_checksum
# => "b74d7288b86817dea55bd044d3cedc013e83518b461cd6f202be85e33d95715b"
url = Url.first_or_create(:url => 'http://example.com/different/url')
url.url_checksum
# => "09a27797a33153b005871b61675a920fa6bedbb034a3b283bbe5803a1d31ac42"
Requirements
- dm-core ~> 1.0
Install
$ gem install dm-is-checksumed
Copyright
Copyright (c) 2011 Hal Brodigan
See {file:LICENSE.txt} for details.