Sessions and Session Variables

Sessions allow server-side and UI components to exchange data specific to a single current system user, e.g. operator or third-party application working via API.

Communications within a session are implemented via session variables those life time is bound to session duration.

A special set of functions and events inside the root context can be used for reading and writing session variables.

sessionSet() function sets the value of the session variable. Variable is available while the current user session is open. You can request its value from a widget or a dashboard.

You can use this expression, for example.

callFunction({:}, "sessionSet", "test1", array("strTest","newStr1", "newStr2"))

sessionGet() function gets value of the mentioned session variable.

Expression sample:

callFunction({:}, "sessionGet", "test1")

sessionVariableUpdated event fires on every session variable update. So it can be used for activator of widget or model binding for further data processing.

There are several standard session variables that are available without prior definition:

Variable Name

Description

type

Stores type of the connection, for example, if user is connected through the Web UI or Iotellect Client.

username

The variable contains the Iotellect username used for authentication in the current session.

login

Stores what data was entered on the logon screen. Its value may differ from the username variable. This can happen if an external authentication method is being used.

displayName

Shows the preferred name for an object to be used when displaying entries. This is usually а combination of the user’s first name, middle initial, and last name.

company

Stores the user's company or organization name.

department

Contains the name of the department in which the user works.

title

Indicates the user's job title. Typically used to display the formal job title, such as Senior Programmer, rather than occupational class, such as programmer. It is not typically used for suffix titles such as Esq. or DDS.

cookies

Stores a data table with HTTP cookies related to the user's interaction with the page. There are two fields in this table indicating the cookie name and value, respectively.

headers

Stores a data table with HTTP header information, typically consisting of the following header fields:

  • host

  • user-agent

  • accept

  • accept-language

  • accept-encoding

  • sec-websocket-version

  • origin

  • sec-websocket-extensions

  • sec-websocket-key

  • dnt

  • connection

  • cookie

  • pragma

  • cache-control

  • upgrade

For example, standard session variables can help you show different interfaces for different user connection types if you use them inside the dashboard validity expression.

Here is a sample Validity Expression that analyzes user’s connection type:

cell(callFunction({:}, "sessionGet", "type"), "value") == "Web"

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