OpenAjaxPublishSync

 

 

Purpose

.OpenAjaxPublishSync Client method publishes messages to the OpenAjax Hub in the Open Client browser. Subscribers to the message as defined in the $topic parameter receive the message payload as contained in the $data parameter. If the kernel tries to call the method when connected to an older Open Client, a rollback run-time error occurs and the current function terminates.

Note: When using the OpenAjaxPublishSync Client method, the kernel waits for a response from the method before continuing and a value is returned in the $return parameter.

Click here for more information about the OpenAjax Hub.

Object Type

Client

Syntax

variable=Client.OpenAjaxPublishSync ($topic, $data, $return)

Operation

variable is a numeric variable that captures the return code.

$topic defines a message in the OpenAjax Hub.

$data contains the message payload that is sent to subscribers of the $topic parameter in the hub. The maximum payload length is 2000 bytes.

$return accepts the return string from the Client.

Remarks

If using this feature, it is recommended that the TP_ROLLBACK setting is set to 'Y' in the pro4v[n].ini file.

Example

The following is an example that demonstrates OpenAjaxPublishSync:

$topic = “Weather�?

$data = "{'town': 'Luton', 'TempMin': '4C',  'TempMax':'11C', 'Outlook':'Rain & Wind', 'WindSpeedMax':'35mph', 'Tomorrow': 'Sunny'}"

 

Client.OpenAjaxPublishSync($topic, $data, $Result)

 

The html document below shows the contents of a Template page (the Template page defined in an Open Client Session Definition) that subscribe to and handle the published event from the logic example.

Example Template Page

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">

<html>

<head>

</head>

<body>

<div id="proiv_panel">

</div>

<script language="javascript">

OpenAjax.hub.subscribe("Weather ", function(event, obj){         obj.returnValue = "Weather received.�?      });

</script>

</body>

</html>

If you then publish the weather using 'sync' method the “Weather received.�? message is the $result parameter.

 

  • The OpenAjaxPublishSync method waits for a return value from the browser before continuing.

  • The data to be returned from the browser is set using the 'returnValue' property of the supplied published object.

  • In the Javascript example, this is referenced by the 'obj' parameter. This data is passed to the '$return' parameter of the Client.OpenAjaxPublishSync method call.

  • The 'publishData' supplied by the Client.OpenAjaxPublishSync method call is passed in as the 'publisherData' property of the 'obj' object.

 

 

Note: This method applies to PROIV Open Client only.

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Topic ID: 510173

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