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Forms That Initiate Interactions with Servers
This chapter describes the behavior of event objects that interact with servers. Such event objects allow
you to implement forms with a range of Web behavior.
In a simpler Web-interactive form, event objects can cause part or all of the XFA form to be submitted to a
server, as though the user is committing the form. In some situations, data submission is followed by the
the server processing the data as specified in the template and returning the result to the client. These
simpler cases of submission are described in
“Submitting Data and Other Form Content to a Server” on
page 324.
In a more complex Web-interactive form, event objects can dynamically request a server to provide
additional information and then populate the form with the delivered information. Further, the form may
select from multiple servers depending on the data view. Such more complex interactions are described in
“Structure of a Web Service Message” on page 331
“Using Web Services” on page 329.
Forms can also interact with a external data, where the platform supports it, using ActiveX® Data Objects.
This Microsoft®-specific interface is closely coupled to the ADO Application Program Interface, as
described in
[ADO].
This is a record-oriented interface which is most often used for accessing databases. It
does not have Web-strength security features and hence is most suitable for use within a corporate LAN or
WAN. The use of this interface is discussed in
“Invoking ADO APIs Through the Source Set DOM” on
page 341.
Submitting Data and Other Form Content to a Server
This section describes content submission performed by event objects having a submit action (henceforth
called
submitting events).
More specifically, it describes the tasks that occur when such an event is
activated, the types of content included in the submission, packaging of that content, and the encoding of
those packages.
Submitting events use the HTTP POST operation to submit content to a server. Such events request the
origin server to accept the submitted content as a new subordinate of the resource identified by the
Request-URI in the Request-Line. [HTTP] describes HTTP POST operations as follows:
POST is designed to allow a uniform method to cover the following functions:
❚
❚
❚
❚
Annotating an existing resource
Posting a message to a bulletin board, newsgroup, mailing list, or similar group of articles
Providing a block of data, such as the result of submitting a form, to a data-handling process
Extending a database through an append operation
About
Content submission is specified using an event object that specifies the
submit
property as the action to
perform when the event is activated. (See also the
syntax description for the
element.)
The object that describes content submission may be a property of any type of event; however, it is
typically associated with a click event that has a button appearance, as shown in the following example.
Users would click such a button to indicate they have finished filling out the form and wish to submit it for
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