In previous blogs I have introduced the new "Unified Extension/Package Installer", particularly with respect to how it is used. In this blog I will start to introduce developers to the new system.
The concept of the new Installer can be summed up as follows:
- Provide a manifest driven installation - in this case configuration over convention
- Provide a single "unified" manifest applicable to all extension types - modules/skins/languages
- Provide a "component" based installer - a files component for modules can be reused in installing skins or languages files
- Provide extension points for developers to take advantage of the new system.
So lets dive in to the new manifest and see what is going on.
This is the basic outline of an extension manifest. In this example we see the outline for the manifest for the Broadcast Polling Caching Provider.
The first line identifies this as a "Package" manifest, and it is a version 5.0 manifest. This is used by the Installer to identify it as a "new" manifest, and process it accordingly. The installer, will also recognize legacy manifests, and translate the manifests to the new system.
The architecture of the installer (and the manifest) allows for the installation of multiple packages in one zip archive and this is shown by the use of the packages and package nodes. A package node has a number of attributes and child nodes. While these may be fairly obvious, I will briefly explain each one:
- package - the parent node for a "package"
- name - a Unique name for the package
- type - the type of package/extension - eg Module, Skin, Container, Provider, SkinObject etc
- version - the version of the package
- friendlyName - a friendly name for the package
- description - a description of the package
- owner - the owner of the package
- name - the name of the owner
- organization - the organization that owns/created the package
- url - A url to the owner's website
- email - A support email address for communicating with the owner
- license - the license for the package - the license text can either be embedded in the manifest - or in an external file
- src - the location of the license text - if in an external file
- releaseNotes - release Notes for this version of the package (as with the license the text can be embedded in the manifest - or in an external file)
- src - the location of the release notes - if in an external file
- dependencies - this section describes dependencies that the package expects - I will go into more detain on this in a future blog - but dependencies can be core version, another package (for example a German Language Pack for the Links module has a dependency on the Links module being installed AND a depenency on the German core language being installed)
- components - a list of components that are in this package. As with dependenices I will go into this in a future blog - but as an example this package actually contains 5 components - An assembly component, a files component, a database script comonent, a config component for updating web.config and a file cleanup component.
The benefit of this common approach is that all extensions can benefit from the same kind of features we have come to expect from modules. In addition, we have added a number of new features, definition of the owner/author of the package, inclusion of a license - that the user must explicitly agree to on installation, inclusion of release notes, an extensible dependency framework and an extensible component architecture.
In my next blog on this subject I will delve into the common "components" that make up an Extension package.