All Internet applications developed in the SAP@Web Studio are known to the Internet Transaction Server (ITS) as services.

An ITS service is the set of files required by the ITS to run an Internet application from a Web browser. Each service can consist of up to five ITS file types:

• A service file
• HTML^Business templates
• Flow files
• Language resources
• Multipurpose Internet Mail Extension (MIME) files

The service file contains the service description, which is the set of parameters that determines how a service runs. If this information is incomplete at runtime, the ITS may derive some details from the global service file (see below), or require the user to enter logon information. In any case, there must be one service file for each application.

Each service can be divided into one or more themes. Themes are instances of services that differ only in look and feel (appearance, graphics, layout or language). Each theme has its own set of HTML^Business templates, flow files (if applicable), language resources, and Multipurpose Internet Mail Extension (MIME) files, but the functionality of the service is identical. In the SAP@Web Studio, themes are stored in subdirectories of the service directory.

HTML^Business templates are the means used by the ITS to display application screens in a Web browser when running a service.

For each screen, there must be one HTML^Business template. Each template contains standard HTML code, and HTML ^Business statements.
HTML^Business is an SAP-specific macro language, which allows you to merge R/3 data dynamically into HTML ^Business templates.

Flow files contain the dialog flow logic that defines logical transitions between application states, depending on what the user chooses to do in the course of running an application.

When you are developing applications with the flow file implementation model, you need to generate one flow file for each HTML^Business template. Each flow file contains Extensible Markup Language (XML) statements, using a predefined subset of XML elements.

Language resources are language-independent texts used by the ITS to run a service in a particular language.

Instead of hard-coding language-specific texts in HTML^Business templates, you specify placeholders and store the texts in the relevant language resource file. At runtime, the ITS looks for placeholders in the templates and replaces them with texts from the language resource file.

For ease of maintenance alone, it makes sense to keep HTML^Business templates for a service language-independent by creating language resources. However, not all templates use language resource files, and they are not mandatory.

MIME files contain the image, sound, and video elements you may want to include in services to enhance the visual appearance and effectiveness of your Internet applications. Like language resources, MIME files are optional.

The following table summarizes the ITS file types used to develop Internet applications in the SAP@Web Studio, together with their name format and file extenson. The table also specifies whether each file type is required or optional.