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Report Server | Architecture

ReportBuilder Services
ReportBuilder Services is a Windows service designed to act as a host to a report server application. This two-piece architecture isolates a report server application in its own process, allowing it to be started and stopped from the service. By default, the service is configured to start automatically each time the server machine boots. Once the service is started, it launches the report server application. The service is also configured to automatically restart the report server application in the event of a crash.

To install ReportBuilder Services, you simply run the included RBWinService.exe installation program. The program installs and starts the Windows service and deploys a server management application, accessible from both a system tray icon and a Start menu item. You can then access the management application and point the Windows service to the location of your report server application.

Report Server Component
The Report Server component implements a multi-threaded report server that can execute reports and deliver report pages to clients. You build a report server application by dropping a ReportServer component on a Delphi form, creating data modules which contain ReportVolume components (explained next) and compiling the application. And that's it; you can build an entire server application without writing any code. Once the application is built you can then use ReportBuilder Services to quickly and easily designate it as the official report server. The Report Server is implemented using an I/O completion port/worker thread architecture that optimally manages persistent report sessions to maximize performance and throughput. The server can generate reports incrementally (that is, page-by-page) in order to optimize response time. Pages are cached on the server and on the client to minimize network traffic. The amount of time that passes before a session expires (and the cache is cleared) can be controlled via the TimeOut property.

Report Volume Components
Report Volume components are used to register a collection of reports with the server. The server uses a report catalog to build and store the tree structure which forms as the various reports are registered.

There are several types of report volume components, one for each of the ways that reports are most commonly deployed. For report templates stored in file directories or database tables, there is the ReportTemplateVolume. For reports stored in the Explorer database structure (i.e. RB end-user reports), there is the ReportExplorerVolume. For report archives stored in file directories or database tables, there is the ReportArchiveVolume. For reports stored on a Delphi form, there is the "behind-the-scenes" report volume object. The bottom-line: wherever or however your reports are deployed, there is a simple way to register them with the server, usually without writing a single-line of code.

Report volumes are also dynamic; as you add reports to a designated file directory or database storage medium, the report server will automatically add or remove those reports from the catalog. Yes, this does mean that you can deploy reports to the server without bringing the server down.

Windows Rich Client Components
With one ClientReportExplorer, one ClientReport, and one line of code, you can build a full-featured Delphi reporting application which provides access to reports on a remote server. The ClientReportExplorer uses a Windows Explorer style interface to display a folder tree structure of available reports. The ClientReport makes it easy to preview and print. When previewing a report that requires search criteria, the AutoSearch dialog is automatically displayed and any search values entered are returned to the server. The report is then generated and pages are returned.

WebTier Component
When compiled as part of a web application, the web tier acts as a middle tier, providing access to a report server application from a web browser. A user may select reports from a folder tree structure, enter search criteria when applicable and preview report pages from the web browser. All of these capabilities are made possible via a zero-client application (100% JavaScript/XHTML) generated by the web tier. The zero-client is compatible with Netscape 4, Netscape 6, and Internet Explorer (5 and 6.)

Designed to integrate seamlessly with Delphi's various web technologies, the web tier requires only a single line of code to compile successfully as part of an ISAPI DLL or Apache Shared Module. ASP is also a snap, as a single COM interface (easily generated with the help of Delphi's ActiveX support) is all that is needed to deploy the web tier as part of an Active Server Page.

The web tier implements a sophisticated concept of "session", grouping all of the communications received from a single web browser under a single session object. In order to optimize performance, both the state of the session, and any report output generated for the session are cached. For example, assume a user previews report A, then report B, then returns again to report A. The web tier would manage all of this activity as a single session, and whenever possible, would return pages from the session cache, instead of re-requesting them from the report server application. The amount of caching which occurs, the TimeOut for a session and the frequency with which garbage collection is performed on expired sessions are just a few of the configuration options available on the web tier.

Implemented as a set of Delphi classes, the WebTier consists primarily of objects which descend from TrsWebContentProvider. Web content providers communicate with the report server application, converting the response from SOAP/XML to native Delphi objects to XHTML/JavaScript, suitable for consumption by a web browser. The content providers included in the Server Edition make it easy to provide a complete, robust, and professional web reporting solution right out of the box. You can customize the HTML created by the web tier by creating your own content provider descendants.

ReportBuilder ISAPI Thread Pool
The Server Edition includes a custom ISAPI thread pool, implemented using an I/O completion port/worker thread architecture designed to optimally manage incoming requests. The thread pool queues requests based on session, and can eliminate redundant requests. This greatly improves both throughput and performance, as the web tier passes only relevant requests through to the report server application.

Server Farm
The web tier can be configured to utilize any number of report servers to maximize scalability. This allows the web tier to scale gracefully as a greater number of users access reports. There are two load balancing options provided: Round Robin and Minimum Load. Round Robin simply steps through a list of servers, each time returning the next server in the list. Minimum Load checks the CPU usage of each server (based on a sixty second moving average), and returns the server with the minimum usage.

Documentation, Help & Examples
The Server Edition Developer's Guide is provided in PDF format. The concepts behind the web server are covered, along with numerous step-by-step tutorials that guide you through everything from creating a report server application to deploying the web tier with a server farm. The online help is a reference for all of the components and major classes which make up the product. The help is integrated with the Delphi help and is accessible via the help menu or the F1 key. Numerous examples of report server applications, web applications and client applications are also provided.

The following components appear on the RBServer tab of the Delphi component palette when you install ReportBuilder Server:

Component

Icon

Description

Report Server Used to create a report server application. Encapsulates all of the functionality required to communicate with remote clients and execute reports on their behalf.
Web Tier Used to build web based reporting solutions. The web tier acts as a middle tier between web browser clients and the report server. It enables web browser clients to request and view reports generated by a report server application.
Report Archive Volume Represents a collection of report archives on the server.  Used in a server application to enable clients to preview and print a collection of report archives. Dynamically generates catalog items for archives stored in a file directory structure or database table.
Report Template Volume Represents a collection of report templates on the server. The report templates may be stored in .rtm files or a database table.  Used in a server application to enable clients to preview and print a collection of report templates.
Report Explorer Volume Represents a collection of reports stored in the report explorer database tables.  Used in a server application to enable clients to preview and print a collection of reports stored in report explorer database tables.
Client Report A report component that communicates with a report server. Contains many of the same properties and methods that are used to print and preview via a standard TppReport component.
Client Report Explorer Provides a user-interface that enables client applications to browse, preview, and print reports residing on a report server. The interface is very similar to the Windows Explorer and to the TppReportExplorer used to build end-user applications.