CMS migration to AEM

There are several available APIs/approaches to getting content into the AEM repository. Some of the available documentation is:

• Sling RESTful API - http://sling.apache.org/documentation/bundles/manipulating-content-the-slingpostservlet-servlets-post.html - that's generic Sling documentation not AEM specific so you will have to understand the AEM page content structure in order to pages that will work properly.
• AEM Package Manager - http://dev.day.com/docs/en/crx/current/using_crx/content_import_and.html - this documentation is largely focused on how moving content between AEM instances, however this interface is one effective way to get content in so understanding it is useful. 

Generally there are some analysis tasks you need to complete in order to effectively migrate your content in an automated way:

1. You need to complete your Template and Component design. In order to understand how to migrate your content you need to have completed you template and component design so you understand you target content model. You should keep the fact that you want to do automated migration in mind when doing your template and component design so that you don't create a content model that can not be mapped to your existing model (so for example if you current content model has a single rich text editor field for the body of you page, and you create a template/component design that requires splitting that content into two columns it will be difficult to automatically migrate the content). Don't lock your self into automatically migrating however. If you just do a one to one mapping you may lose the ability leverage much of the capability and flexibility that AEM provides you. 
2. Once you complete you template and component design you need to map your existing content model to your new template and component design to understand which templates and components you will be migrating content into. 
3. This process will help determine what content can realistically be automatically migrated. 

Conceptually there are a couple of viable automated approaches that will work

• Use the package manager to import content as XML. This works well in your system supports exporting as XML. A few steps are required to leverage this approach:
  • Enter some example content into your target templates and components and then create a package with this content and export it. Packages are just zip files in a specific format with what is essentially a manifest telling the package manager what to import, and a a set of XML files in a specific format holding the content. This will be your target format. 
  • Design a process to transform your current system's XML into the CQ package format. This involves not just mapping to specific XML elements, but also creating the right directory structure and filter/configuration files to ensure that the content is properly import. 
  • This works well if the XML output you have is already page focused and the mapping is relatively easy. 
• Create a scripting process that accesses the content on your current system and uses the Sling POST servlet to store the content. This works well if your current system does not have a good export mechanism and you need to do a lot of API calls to your current system to get content. 
• Write Java code in an OSGI bundle that accesses your current system directly, or accesses a export format and then uses the AEM/Sling/JCR Java APIs to store content in the appropriate locations in AEM. 
• Finally there are some commercial products out there for content migration that will assist in this, however those require significant investment and consulting and so may not be cost effective for small amounts of content.