Using Environment Variables

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Overview. 1

Specifying environment variables 1

Referring to environment variables 1

References from Ebase elements 1

References from FPL scripts 2

Overview

There are many occasions where it is desirable to refer to some sort of external variable e.g. to define a file path or external URL. To meet this requirement, Ebase provides support for environment variables which can be specified outside the Ebase designer environment and then referenced by the Ebase runtime system.

Specifying environment variables

Environment variables are specified in the web deployment descriptor file web.xml for the Ebase application. This file is located in the WEB-INF directory of the Ebase web application (for Tomcat systems, this will normally be UfsServer/tomcat/webapps/ufs/WEB-INF). Each environment variable is specified as shown in the following example:

<env-entry>

<env-entry-name>XML_DOCS_PATH</env-entry-name>

<env-entry-value>C:/Prod/XML/Documents</env-entry-value>

<env-entry-type>java.lang.String</env-entry-type>

</env-entry>

where..

env-entry-name is the name of the environment variable. This name is case sensitive and should not contain spaces.

env-entry-value is the value for the environment variable

env-entry-type is the type for the environment variable. Only java.lang.String is currently supported.

Environment variable definitions should be added to the bottom of the web.xml file, immediately preceding the final </web-app> tag. Any number of environment variables can be defined.

Referring to environment variables

Environment variables can be used with a number of Ebase elements e.g. Print resources, XML resources, Web Services resources. In each case the variable name should be prefixed with &&$ENV_. For example, the variable XML_DOCS_PATH shown above should be entered as:

&&$ENV_XML_DOCS_PATH

Please note that all references to environment variables must use the same case as the definitions in the web.xml file i.e. MY_VAR is not the same as my_var.

References from Ebase elements

Environment variables can be used in any location where substitution with a && variable is possible. This includes:

· All SQL fields in database resources

· All SQL fields in dynamic lists

· All fields in email resources

· The image URL for a button

· Within all texts

In addition, the following elements in the Ebase Designer provide specific support for environment variables:

Element type	Field
Print Resources	Full document path on server
XML and Web Services Resources	Most adapter parameters e.g. file path and URL specifications
Custom resources using XMLCustomResource	All parameters
Custom resources using WebServicesCustomResource	All parameters

It is also possible to use the syntax &&{$ENV_XML_DOCS_PATH} which can be useful when additional characters are required immediately after the variable

e.g. &&{$ENV_XML_DOCS_PATH}/orders

If an environment variable cannot be found, no substitution will take place.

References from scripts

Environment variables are read only and can be referred to using the $ENV_ prefix as shown below. e.g.

FPL

set F1 = $ENV_XML_DOCS_PATH;

goto url $ENV_PAYMENT_ENGINE_URL;

If an environment variable cannot be found, a null value is returned.

API based language

Environment variables are referenced in the same way as system variables e.g.

var abc = system.variables.$ENV_XML_DOCS_PATH.value;