What happens when you view a report?

This section describes the viewing mechanisms that are implemented in the Crystal Enterprise web desktop. The description of processing flow covers both the case where the web desktop is implemented with Crystal Server Pages and uses the Web Component Server (WCS) as its application server, and the case where the web desktop is implemented in Java Server Pages and runs in a generic application server. The processing flow for custom ASP, JSP, and ASP.NET applications may differ.

When you view a Crystal report (.rpt file) through Crystal Enterprise, the processing flow varies depending upon your default report viewer, the type of report, and the rights you have to the report. In all cases, however, the request that begins at the web server must be forwarded to the application server.

The actual request is constructed as a URL that includes the report's unique ID. This ID is passed as a parameter to a server-side script that, when evaluated by the application server, verifies the user's session and retrieves the logon token from the browser. The script then checks the user's Crystal Enterprise web desktop preferences and redirects the request to the viewing mechanism that corresponds to the user's default viewer.

Different report viewers require different viewing mechanisms:

• The zero-client DHTML viewer is implemented through viewreport.csp or viewreport.jsp.

  When evaluated by the application server, this script communicates with the framework (through the published SDK interfaces) in order to create a viewer object and retrieve a report source from the Cache Server and Page Server.

• The zero-client Advanced DHTML viewer is implemented through viewreport_ia.csp or viewreport_ia.jsp.

  When evaluated by the application server, this script communicates with the framework (through the published SDK interfaces) in order to create a viewer object and retrieve a report source from the Report Application Server.

• The client-side report viewers (the ActiveX and Java viewers) are implemented through viewrpt.cwr, hosted by the WCA or WCS.

  The Crystal Web Request is executed internally through viewer code on the application server. The viewer code communicates with the framework in order to retrieve a report page in .epf format from the Cache Server and Page Server.

  If they haven't already done so, users are prompted to download and install the appropriate viewer software.

Click the appropriate link to jump to that section:

• Report viewing with the Cache Server and Page Server
• Report viewing with the Report Application Server