Extending Reporting Services - Professional SQL Server 2005 Reporting Services - page 538

Delivery extensions allow you to deliver reports to users or groups of users according to a
schedule. E-mail and network file shares are the delivery mechanisms currently built into the
product.

Creating a delivery extension is really a two-part process. You must create the extension itself,
as well as a UI tool to manage the extension if you want it to be usable from the SSRS Report
Manager. The difficulty in creating a delivery extension is primarily a function of the delivery
mechanism.

❑ Rendering Extensions: Rendering extensions control the type of document/media that gets

created when a report is processed. Theoretically, you could have Report Services create any
type of media given the ability to extend the product in this area. Microsoft provides the following
rendering extensions out of the box:

❑ HTML: The HTML extension will generate HTML 3.2 for use with older browsers and

HTML 4.0 for browsers that support the dynamic HTML standard.

❑ MHTML: MHTML is another HTML standard that was created to allow disconnected

viewing of HTML documents. All the images in the page are encoded into the document,
which increases its size but allows it to be viewed both online and offline.

❑ Excel: The Excel extension creates Excel-specific MHTML.

❑ CSV: The Comma Separated Values emit the data fields separated by a comma. The

first row of the CSV results contains the field names for the data.

❑ Image: The image extension allows you to export reports as images in the EMF, GIF,

JPEG, PNG, TIFF, and WMF formats.

❑ PDF: This extension allows the generation of reports in the PDF format.

❑ Security Extensions: In its first release, Reporting Services only supported Integrated Windows

Security for report access. This was a pretty big problem for some enterprise players. Most
companies have heterogeneous networks with multiple operating systems and products. In a
perfect world, all of our networks, applications, and resources would support some form of
“ single sign-on, ” or at least would allow us to build this ourselves. If Microsoft wanted SQL
Server to be a key part of an Enterprise Business Intelligence platform, it had to play nice with
others.

Microsoft fixed this problem in service release one. The release contained full documented security
extension interfaces and an example using forms-based security. You may now implement your
security model using SSRS.

Extension through Interfaces
Reporting Services uses common interfaces or “extension points” to allow expanding the product in a
standard way. Enforcing the requirement that RS extension objects must implement certain interfaces
allows Reporting Services to interact with different object types without knowledge of their specific
implementation. This is a common object-oriented programming technique used to abstract the design
from the implementation.

For an in-depth study of this topic, look at the “Creational Patterns” section of Design Patterns
(Addison Wesley).