The Web Client block enables opening application screens by commands provided in the URL. If the browser does not have an active session with a logged in user, the application will show the login screen first, and then, after successful authentication, proceed to the main application window with the requested screen.

The list of supported commands is defined by the cuba.web.linkHandlerActions application property. By default, these are open and o. When the HTTP request is being processed, the last part of the URL is analyzed, and if it matches a registered command, control is passed to an appropriate processor, which is a bean implementing the LinkHandlerProcessor interface.

The platform provides a processor that accepts the following request parameters:

  • screen – name of the screen defined in screens.xml, for example:

    http://localhost:8080/app/open?screen=sec$User.browse

  • item – an entity instance to be passed to the edit screen, encoded according to conventions of the EntityLoadInfo class, i.e. entityName-instanceId or entityName-instanceId-viewName. Examples:

    http://localhost:8080/app/open?screen=sec$User.edit&item=sec$User-60885987-1b61-4247-94c7-dff348347f93

http://localhost:8080/app/open?screen=sec$User.edit&item=sec$User-60885987-1b61-4247-94c7-dff348347f93-user.edit

    In order to create a new entity instance directly in the opened editor screen, add the NEW- prefix before the entity class name, for example:

    http://localhost:8080/app/open?screen=sec$User.edit&item=NEW-sec$User

  • params – parameters passed to the screen controller’s init() method. Parameters are encoded as name1:value1,name2:value2. Parameter values may include entity instances encoded according to the conventions of the EntityLoadInfo class. Examples:

    http://localhost:8080/app/open?screen=sales$Customer.lookup&params=p1:v1,p2:v2

http://localhost:8080/app/open?screen=sales$Customer.lookup&params=p1:sales$Customer-01e37691-1a9b-11de-b900-da881aea47a6

If you want to provide additional URL commands, do the following:

  • Create a bean implementing the LinkHandlerProcessor interface in the web module of your project.

  • The canHandle() method of your bean must return true if the current URL, which parameters are passed in the ExternalLinkContext object, should be processed by your bean.

  • In the handle() method, perform required actions.

Your bean can optionally implement Spring’s Ordered interface or contain the Order annotation. Then you can specify the order of your bean in the chain of processors. Use the HIGHEST_PLATFORM_PRECEDENCE and LOWEST_PLATFORM_PRECEDENCE constants of the LinkHandlerProcessor interface to put your bean before or after processors defined in the platform. So if you specify the order lesser than HIGHEST_PLATFORM_PRECEDENCE, your bean will be requested earlier and you can override actions defined by a platform processor if needed.