How to make a Screen perform Actions

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Works in EPrints 3.2+

Please read the page on How_to_make_a_Screen_for_the_Admin_Section as this extends that information.

What's happening

The process has four parts:

  1. Some action buttons
  2. Some action routines
    1. A allow routine
    2. An action routine
      1. These routines could all be contained in the one package
      2. These routines could be spread out over several packages
  3. Where to go after the action completes

Making the buttons

The action buttons are the functionality that make the work... well, flow.

You need to define the "screen" (perl package) that contains the actions, and what the actions are.

The $s->render_action_buttons function takes a hash, which describes the set of buttons to display:

    my %buttons = (
		    cancel   => $self->phrase( "action:cancel:title" ), # Is defined as "Cancel"
                    update   => $self->phrase( "action:update:title" ), # Is defined as "Update"
                    _order   => [ "update", "cancel" ],
                    _class   => "ep_form_button_bar"
	          );
    $f->appendChild( $s->render_action_buttons( %buttons ) );
  • cancel => $self->phrase( "action:cancel:title" ) describe one action button: the internal name for the action and the text to be used for that button. You may have any number of buttons.
  • _order is a reference to a list defining the order for the buttons. With nothing defined, the order will be random.
  • _class defines the css class to give to the div that contains the buttons.

The above code would produce the following (x)html:

<div class="ep_form_button_bar">
 <input type="submit" class="ep_form_action_button"
        onclick="return EPJS_button_pushed( '_action_update' )"
        name="_action_update" value="Update">
 <input type="submit" class="ep_form_action_button"
        onclick="return EPJS_button_pushed( '_action_cancel' )"
        name="_action_cancel" value="Cancel">
 </div>

Where the actions are processed

The actions are processed in a "Screen", a perl package. The form being submitted therefor needs to contain a reference to that package:

   $f->appendChild( $s->render_hidden_field( "screen", "Orgs"));

This would call the package EPrints::Plugin::Screen::Orgs, and try to process the selected action in there

(Yes, this means that one can have the same action in multiple Screens, as well as multiple action in the same Screen)

Processing the actions

The EPrints processor system calls a specified action in a named package (as detailed above)

There are two functions needed: allow_action and action_action.