If you are interested in becoming the maintainer of this project, please let me know.
Automatically store a version of a MongoMapper document every time it's updated. Configure a maximum number of versions you'd like to keep, or even the amount of time a particular document should keep versions around.
Add the gem to your Gemfile. Add the necessary Mongo indexes: run
Version.create_indexes in your console, or if you are using Rails run the
rake versioned:create_indexes command.
versioned declaration to the MongoMapper document models you want to keep versions of. When you update a versioned document, a new version will be stored. Deleting a stored document will delete all the associated versions.
class User versioned key :name, String key :email, String end
Every versioned document model has an association called
versions that contains all past versions of a document. It's a plain old MongoMapper one-to-many association with the
Version model, sorted in reverse chronological order. You can query for versions using MongoMapper's standard query criteria:
@user.versions.where(:created_at.lt > 1.day.ago)
Pruning old versions
max option to specifiy the maximum number of versions you want to keep. When the document is updated, the oldest versions will be pruned away to keep no more than the maximum number you specify.
class User versioned max: 10 key :name, String key :email, String end
If you'd rather specify the amount of time the versions of a doc should be kept, implement
keep_versions_for. It must return the number of seconds to keep each revision. Every time a new version is created, versions will be purged based on their age.
This doesn't work with the
max option. Use one or the other.
class User versioned key :name, String key :email, String def keep_versions_for 90.days end end
Handling version conflicts
Attempting to update a document with an old
version_id will result in a
Versioned::ConflictingVersionError. Use the error's
version_id accessor to get the version of the currently stored document.
This feature is meant to prevent you from over-writing someone else's changes and give you the option of resolving the conflict gracefully:
@user = User.first @user.name = "Bobby" begin @user.save rescue Versioned::ConflictingVersionError => e # Keep your changes @user.version_id = e.version_id @user.save # Or keep other person's changes # @user.reload end
When a versioned document is saved, you can pass the
updater option to the save method. The associated version will keep a reference to the document passed. This allows you to keep track of who made a change to a versioned document.
@reginold = User.find_by_email('email@example.com') @user.name = "Bob" @user.save(:updater => @reginold) @user.versions.first.updater => @reginold
Version contains a copy of the document as it existed at a point in time. You can roll back to a particular version by calling the
rollback method on the document, passing the version.
@user.versions.count => 9 version = @user.versions @user.rollback(version) => true @user.versions.count => 10 @user.version_id == @user.versions.version_id => true
What happens to the versions collection on rollback?
Rolling back a document will create a new version representing its persisted state just prior to rollback. When you rollback a document, then make changes on top of the rolled back document, the
versions collection contains two Version instances with the same
versions collection contains all the previous versions of a document. The document itself represents the "current version." The document has a
version_id key and when the document is updated its version id is stored with the Version. Then the document gets a new
Rolling back to a previous revision will also roll back the
version_id value of the document.
This mechanism allows you to easily undo changes to a document:
version_id = @user.version_id @user.name => "Roger" # change some stuff @user.name = "Frank" @user.save @user.name = "Bob" @user.save # rollback version = @user.versions.find(version_id) @user.rollback(version) # document is restored @user.name => "Roger" @user.version_id == version_id => true