Setting up a dynamic HDML service

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Current chapter: Creating a Dynamic HDML Service
Section 22 out of 67 total sections , Section 2 out of 8 sections in this chapter

Setting up a dynamic HDML service

The examples so far in this manual focus on using static HDML decks. Static decks are useful for providing menus and nonvolatile information. However, if you want to take full advantage of the UP.Link platform's unique ability to deliver timely information, you probably need to implement your service as a CGI or Web server application that generates content dynamically. A dynamic HDML service can deliver not only HDML content to a UP.Phone; it can also broadcast alerts, modify the UP.Phone cache, and send faxes on behalf of the subscriber.

To implement a dynamic service, be sure to:

Generate message entities that are acceptable to the UP.Link server
Use the appropriate HTTP post and response headers
Identify your service to the UP.Link server

The following sections discuss these topics in more detail.

Valid content types

An HDML service can send the following content types (or message entities) to the UP.Link server.

Content	MIME type	Description
HDML	`text/x-hdml`	An HDML deck.
Cache operation	`application/x-up-cacheop`	A command that invalidates an individual deck or an entire service in the UP.Phone cache.
Alert	`application/x-up-alert`	A command that instructs the UP.Phone to beep or display a visual signal to notify the subscriber that information has been pushed to the phone.
Digest	`multipart/mixed`	A combination message containing at least one HDML deck and zero or more content entities of any of the other types listed above.

These message entities all leverage the MIME message format. Each entity consists of a header and a body as specified in:

http://www.internic.net/rfc/rfc822.txt

http://www.internic.net/rfc/rfc1521.txt

The digest format, in particular, is simply a standard MIME multipart/mixed message.

For example, the following is a valid HTTP response containing a single uncompiled HDML deck:

Content-type: text/x-hdml

<HDML VERSION=3.0>

<DISPLAY>

Hello Unwired World! <DISPLAY> <HDML>

IMPORTANT The UP.Link server requires that you include at least one blank line between the content type and the rest of your HDML deck (as shown above).

The UP.SDK Getting Started Guide manual provides an example of how to generate an HTTP response like this with a CGI script.

The following sections in this chapter describe how to write your service to generate digests and conduct cache operations. For information on generating alerts, see Creating HDML Services that "Push" Information.

The UP.SDK provides sample Perl and C libraries that insulate you from the detail of generating HDML decks, digests, and other MIME types supported by the UP.Link platform. It is strongly recommended that you use these libraries instead of generating these types from scratch. The Perl class libraries are in sdk_installdir/examples/apputils¹. The sample Perl scripts in sdk_installdir/examples/scripts demonstrate how to use them. The C libraries and header files are in sdk_installdir/examples/source/digests. The test1.c file in that directory provides examples of how to use them.

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Current chapter: Creating a Dynamic HDML Service
Section 22 out of 67 total sections , Section 2 out of 8 sections in this chapter