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Working with the 5250 Bridge API

Introduction

The 5250 Bridge API is a more flexible implementation of the Emulator's capabilities which allows you to access and customize the PHP/CSS and JavaScript code (also used by the emulator) to create additional functionality.
This is suitable for users who want to make cosmetic changes to their application and apply some additional display logic. In addition, users can choose to remove or filter out content/data for a subset of end-users (e.g. redundant fields) or even pipeline the data coming from the bridge for usage in other, non browser applications (Java, Web Services, others.). Also suitable for users who expect to continue significant development of their RPG 5250 applications and want to minimize their Parallel Maintenance considerations.

The 5250 Bridge API offers a number of functions/classes for PHP developers to grab fields and strings from an interactive (5250) program and wrap them into real web applications. This way you can seamlessly integrate output of green screen applications into your PHP Web application without the need to rewrite the business logic and directly access the database. Alternatively you can use the 5250 Bridge API to directly access the database and create completely new Web applications (e.g. omit certain fields or integrate fields from different screens into one).

The 5250 Bridge APIs have two interfaces: object oriented and procedural functions. If a developer is not comfortable using object oriented (class access) methods in PHP he can use regular procedural functions to access the same APIs.

The 5250 Bridge API accessed information in your 5250 application's input/output fields and allows you to use this information to 'transform' your application in PHP and HTML, while still using your 5250 back-end logic.

The Zend 5250 Bridge API has the following purposes:

Starting an interactive job or 5250 session.
Running IBM i interactive program or menu in an interactive job..
Accessing 5250 screen data such as screen size, input/output field values, size, location and attributes.
Updating input-field value content.
Sending updated input-fields to an interactive job.
Sending a function-key action to an interactive job.

Examples

To see examples of how the 5250 Bridge API can be used to web-enable your 5250 application, see the Working with the Demo Applications.

Using the 5250 Bridge API

There are three ways of discovering the field ID's used in your application:

Using the 'hover' function in the emulator demo.
Run the Zend 5250 Emulator. Hovering over the fields will display the field ID.
Using the 'Show XML code' option in the Emulator demo.
Clicking the Show XML button will display... containing the field array structure.
Using 5250 Bridge API functions such as 'zend_5250_get_input_fields' and 'zend_5250_get_output_fields' in your PHP program.
This will perform a 'screen dump' of the XML information for a screen, which can then be used to write code for the next screen.

When writing a PHP application, you must first include the 5250 Bridge PHP API library in your code in order to be able to use the 5250 API functions.

This example shows the include code for 5250 Bridge PHP API procedural functions:

set_include_path ('/usr/local/zendsvr/5250/API/' );

require_once ('Zend/ProceduralApi.php');

This example shows the include code for 5250 Bridge PHP API classes:

set_include_path ('/usr/local/zendsvr/5250/API/' );

require_once ('Zend/5250.php');

Developing using the Zend 5250 Bridge API then involves using the input and output field data from your 5250 application screens and setting an appropriate function-key action. Each field has an id number and certain characteristics such as row column and attributes.

In order to use this screen information in your PHP Program, you must first examine the fields by using 5250 Bridge API functions such as 'zend_5250_get_input_fields' and 'zend_5250_get_output_fields' in your PHP program.

For example, start with code which:

Connects to your IBM i server and starts a 5250 session by using the zend_5250_open and zend_5250_connect functions.
Sends a command to the system to display the input and output field array structure information for that screen.

<?php

set_include_path('/usr/local/zendsvr/5250/API/');

require_once('Zend/ProceduralApi.php');

// Opens a 5250 session

$bridge = Zend_5250_open ( 'simple' );

$response = @zend_5250_connect($bridge);

// Get the 5250 screen output fields for the IBM i login screen

$outputFields = zend_5250_get_output_fields($response);

// Print the output fields information

echo "<pre>";

print_r($outputFields);

echo "<pre>";

// End the 5250 session

zend_5250_disconnect($bridge);

Notes:

The Zend 5250 Bridge without a valid Zend Server for IBMi license will enable a single connection at a time. Therefore, ensure you close the 5250 Bridge connection at the end of a program by using the zend_5250_disconnect() function.

Running this code will launch your IBM i connection screen and display the array structure information for this screen as follows (the following information is only partial):

Array

(

[0] => Array

(

[id] => 0

[row] => 1

[column] => 23

[length] => 33

[value] => Sign On

[color] => 3

)

[1] => Array

(

[id] => 1

[row] => 2

[column] => 48

[length] => 19

[value] => System . . . . . :

[color] => 1

)

[2] => Array

(

[id] => 2

[row] => 2

[column] => 70

[length] => 8

[value] => I5QA2

[color] => 1

)

[3] => Array

(

[id] => 3

[row] => 3

[column] => 48

[length] => 19

[value] => Subsystem . . . . :

[color] => 1

)

[4] => Array

(

[id] => 4

[row] => 3

[column] => 70

[length] => 10

[value] => QINTER

[color] => 1

)

[5] => Array

(

[id] => 5

[row] => 4

[column] => 48

[length] => 19

[value] => Display . . . . . :

[color] => 1

)

[6] => Array

(

[id] => 6

[row] => 4

[column] => 70

[length] => 10

[value] => QQF048FE62

[color] => 1

)

[7] => Array

(

[id] => 7

[row] => 6

[column] => 17

[length] => 33

[value] => User . . . . . . . . . . . . . .

[color] => 1

)

[8] => Array

(

[id] => 8

[row] => 7

[column] => 17

[length] => 33

[value] => Password . . . . . . . . . . . .

[color] => 1

)

[9] => Array

(

[id] => 9

[row] => 8

[column] => 17

[length] => 33

[value] => Program/procedure . . . . . . . .

[color] => 1

)

[10] => Array

(

[id] => 10

[row] => 9

[column] => 17

[length] => 33

[value] => Menu . . . . . . . . . . . . . .

[color] => 1

)

[11] => Array

(

[id] => 11

[row] => 10

[column] => 17

[length] => 33

[value] => Current library . . . . . . . . .

[color] => 1

)

[12] => Array

(

[id] => 12

[row] => 24

[column] => 40

[length] => 40

[color] => 3

)

Using the array structure information displayed for the input and output fields, you can then write further code utilizing the Zend 5250 Bridge API. You can either create HTML browser based screens for user input, or automatically continue running the 5250 application by setting input field values and sending the function key actions.

You must then get array structure information for the next screen in order to continue developing.

For example, the following code will start a 5250 sess5sion, log you in to the IBM i system and display array structure information for the next screen:

<?php

set_include_path('/usr/local/zendsvr/5250/API/');

require_once('Zend/ProceduralApi.php');

// Opens a 5250 session

$bridge = Zend_5250_open ( 'simple' );

$response = @zend_5250_connect($bridge);

// Sets and submits username and password for the IBM i login screen

zend_5250_set_input_field ( $bridge, 0, 'Z5250DEMO' );

zend_5250_set_input_field ( $bridge, 1, 'Z5250DEMO' );

$response = zend_5250_submit ( $bridge );

// Get the 5250 screen output fields for the IBM i login screen

// Gets arrays structure information from the next screen

$outputFields = zend_5250_get_output_fields($response);

$inputFields = zend_5250_get_input_fields($response);

// Print the output fields information

echo "<pre>";

print_r($outputFields);

echo "<pre>";

// Print the input fields information

echo "<pre>";

print_r($inputFields);

echo "<pre>";

// End the 5250 session

zend_5250_disconnect($bridge);

You will need to repeat this process to get and use field array structure information for each 5250 screen in your PHP application.

There is an additional way a developer can identify the 5250 screen field type (input/output) and field id.
Run an interactive (5250) application using the 5250 Bridge Emulator program. Place the cursor on a screen location where you want to know the screen type and screen id.

For example, in the screen below the cursor is placed on '2.Office tasks' location and the 5250 Bridge emulator program shows that this is an output field and its id is 7.

FLD_06_007. where 06 is a field row and 007 is a field starting colum7.

Identifying 5250 Screen Field Types

See the 5250 Demo Applications included with the 5250 Bridge for further examples on writing applications using the 5250 Bridge API. For example, to see the code for the 'subfile' demo application go to: /usr/local/zend/5250/demos/subfile/index.php. For more sample code, refer to Zend 5250 Bridge Use Case Examples.

Note:

The 5250 Bridge installation includes two Java Script files to catch function key clicks. You can find more information in the Zend installation folder: /usr/local/zendsvr/5250/demos/ JSfunctionKeyListener on your System i server.