iTP Active Transaction Pages (iTP ATP) Programmer's Guide

ATP Web Page and Script Structure

iTP Active Transaction Pages (iTP ATP) Programmer’s Guide—522292-002

3-9

Using Pathway TS/MP Servers from JavaScript

Accepting the Request from the Browser

To identify the kind of request received from the browser, the script

(/examples/pathway/homebank/Webpages/address.atp) examines the

atp.request object. Specifically, it tests the REQUEST_METHOD environment

variable, which is a property of the atp.request object. A value of POST indicates

that the user submitted a transaction.

So far this example is like the SQL example.

Performing the Requested Transaction

To send a request to a server class, the script

(/examples/pathway/homebank/Webpages/address.atp) creates an

instance of the atp.dictionary object. This object represents a Data Definition

Language (DDL) dictionary that defines the message layouts meaningful to the server

class. (Alternatively, a script author could use output from the dview tool, which

allows passive use of the DDL dictionary.)

Next the script creates an atp.buffer object to hold the request and later the reply.

The setData method fills the buffer, using data from the request as represented by the

atp.request object. To place values in multiple fields, a script must invoke the

setData method once for each field; for example, a script could use a loop to fill rows

of a table.

To update the database, the script calls the send_to_server function, which

1. Creates an atp.transaction object to protect the database update.

2. Uses the send method of the atp.buffer object to send the buffer to the server

class specified in the function call.

3. Checks the Pathsend error code, stored in the error property of the atp.buffer

object.

4. Commits or rolls back the transaction, using methods of the atp.transaction

object.

The reply to the request is in the reply property of the atp.buffer object. The

reply property is itself a buffer object, named replyBuf in this example. To extract