Dashboard Variables
Variables in QPR UI are for storing session time information and communicating between different user interface elements, such as views, panels and presentation objects. Variables can only contain textual (string) values. If other types of values are provided, they are converted into strings.
Variable Behaviors
Variables can be defined for views and presentation objects which form a scope for the defined variables. Variables are visible and accessible in the scope where they have been defined and also in all sub scopes in the hierarchy of UI elements. For example, a variable defined in a view scope is visible in all panels and presentation objects in the view. Also a variable defined in a panel is visible in all presentation objects in the panel, but not in presentation objects in other panels. In addition to UI elements (view, panel and presentation object), variables can exist in session scope. The session scope is visible in all views, i.e. session variables are preserved when opening another view. Thus the visibility hierarchy for variables is (starting from the top):
- Session
- View
- Panel
- Presentation object
When setting or getting variable values and two variables with same names exist in different scopes, the variable in the lower scope takes priority over the variable in the upper scope, i.e. the lower scope variable hides the upper scope variable within the scope of the lower scope variable.
Each defined variable have a behavior which determine how the variables work when setting and getting their values. The following behaviors are available:
| Variable behavior | Description |
|---|---|
| Local variable | Local variables are visible in the scope where the variable is defined and also in all its sub scopes. When initialized, the local variable gets a value that is set in its definition (in the Variables tab). When a local variable value is changed by logic in a presentation object (e.g. data grid action), the change is made to the variable in the nearest scope of the presentation object in the UI element hierarchy where the variable has been defined as Local variable. |
| Optional parameter | Optional parameters work like the local variables, except that the optional parameters get their initial values from the upper scope when the variables are initialized. For example, optional parameters in view scope get their values from the session scope when a view is opened, and optional parameters in the panel scope get their values from the view scope when the panel is initialized. If a variable having the same name doesn't exist in any of the upper scope, the optional parameter will have the value that is set in its definition (in the Variables tab). After the optional parameter value is initialized, any changes in the upper scope variables don't affect the optional parameter value. |
| Stored variable | Stored variables work like Local variables, except that when the view is saved, the current value of the Stored variable is saved to the view at the level where the Stored variable is defined. |
| Default value | Unlike local variables and optional parameters, Default value variables are not independent variables but they are just default values for non-existing variables. Thus, if a variable with the same name exists in the upper scope, the defined default value variable doesn't have any effect. Only if no upper scope variable exists, the value defined for the default value variable (in the Variables tab) is used in the default value variables' scope when referring to a variable with that name. Default value variable values cannot be set by presentation objects, so when trying to set an default value variable value, the value is set to the session scope variable. |
Note that variables in the session scope cannot be defined like the UI element variables, but session scope variables are created when they are set for the first time during a user session.
When presentation objects set variable values, either the nearest UI element scope variable or the session scope variable can be set. In a data grid actions the setting is called scope with alternatives local and global, and in HTML presentation object functions, it's done using a parameter named presentation object runtime id. When setting a UI element variable, always the nearest variable value in the hierarchy is set. For example, when setting a value from a data grid, the data grid presentation object is the nearest scope, the panel is the next and the view scope is after the panel. If there is no variable in any UI element scope defined, the value is set to the session scope.
When creating bookmarks, currently only the session scope variables are stored to the bookmark.
Setting Variable Values in URL
It's possible to set variable values in the url pointing to QPR UI. To do this, for each variable add "&<variable name>=<variable value>" in the end of the URL. For example: http(s)://SERVERNAME/ui/#/dashboard?sys:dashboard=24026&myvariable1=myvalue1&myvariable2=myvalue2
Note that when using variables a url, variable values need to be url encoded (more information: https://www.w3schools.com/tags/ref_urlencode.asp).
System Variables
QPR UI has the system variables defined in the table below. System variables have a special functionality in the system. All system variables start with sys: prefix, and thus it's a good practice not to name other variables to start with that to avoid accidental use of system variables.
When using variables a url pointing to QPR UI, variable values need to be url encoded (more information: https://www.w3schools.com/tags/ref_urlencode.asp).
| Variable name | Description |
|---|---|
| sys:dashboard | Id of the currently open view. Another view can be opened by changing this variable value. |
| sys:dashboardIdentifier | Use this variable when you want to open another view using a path the target view. The path can be defined as:
Absolute paths always starts with the slash (/), whereas relative paths don't start with slash. sys:dashboardIdentifier variable can only be used in the session variables. Setting the sys:dashboardIdentifier variable value will automatically set the corresponding value to sys:dashboard variable. sys:dashboardIdentifier will be removed automatically after. |
| sys:hideViewHeader | Defines whether the top main toolbar in the view is hidden (true) or visible (false). |
| sys:password | Use this parameter to provide password to login automatically to QPR UI without going to the login screen. You also need to provide the sys:username parameter. sys:username and sys:password parameters are removed from the URL after the login, and thus they won't be stored as QPR UI variables. Note however, that the username and password can be stored in the browser history. See url examples in the description of the sys:username parameter. |
| sys:settingsPanel | View level variable defining whether the right side settings page is open and which tab in the pane is active. sys:settingsPanel is defined as a JSON object with following properties:
Example: {"isOpen":true,"activePage":"settings"} |
| sys:username | Use this parameter to provide username to login automatically to QPR UI without visiting the login screen. To be able to authenticate, you also need to provide the sys:password parameter. sys:username and sys:password parameters are removed from the URL after the login, and so that they won't be stored as QPR UI variables. Note however, that the username and password can be stored in the browser history. sys:username and sys:password parameters only work when authenticating using QPR Suite or QPR ProcessAnalyzer; credentials for the federated authentication identity provider cannot be used here.
Example url's:
|
Variables and Web Browser History
Any time the session variables are modified, a new browser history entry is created. The preceding values in the session variables can be restored via the browser's Back button. Left-clicking the Back button will restore the previous session variables values, whereas right-clicking the Back button will show a list of session variables changes to select from. Selecting an entry on the list will restore the session variables from that entry.
File:BrowserHistory.png
