API:EPrints/Plugin/Screen - Revision history

Tdb01r at 09:47, 29 July 2013

2013-07-29T09:47:22Z

Tdb01r at 16:17, 25 July 2013

2013-07-25T16:17:58Z

Tdb01r at 15:57, 25 July 2013

2013-07-25T15:57:59Z

Tdb01r: Created page with '

@@ Line 37: / Line 37: @@
 The reason for using a redirect is that the user will end up on a page that can be reloaded without re-submitting the form. This is particularly important where submitting the action twice may result in an error, for example when deleting an object (can't delete twice!).
 <!-- Edit below this comment -->
@@ Line 254: / Line 315: @@
 <!-- Pod2Wiki=head_copyright -->
 ==COPYRIGHT==
-Copyright 2000-2011 University of Southampton.
+Copyright 2000-2013 University of Southampton.
 This file is part of EPrints http://www.eprints.org/.

@@ Line 16: / Line 16: @@
 Screen plugins provide the CGI user interface to EPrints. Only "static" pages (summary pages, browse views) are not rendered via screens.
-Screens generate elements of the page that are then rendered using the [[API:EPrints/Apache/Template|EPrints::Apache::Template]]. This includes the page title, header elements and page body.
+Screens generate elements of the page that are then rendered using the [[API:EPrints/Apache/Template|EPrints::Apache::Template]]. These elements include the page title, header elements and page body. Screens can also '''export''' (depending on [[API:EPrints/Plugin/Screen#wishes_to_export|wishes_to_export]]) which allows complete control over the HTTP response.
 Most screens have an interactive element that follow this pattern:
@@ Line 34: / Line 34: @@
 third request ... back to step 1.
-Given the server-client nature of Web pages a user interaction will occur over several requests. This can either be in two or three steps in a Screen, depending on whether server-side state is changed. Its important to note, especially for three-step, that any state information needed for the screen to render needs to be persisted in the form submission and the resulting redirect.
+The exception to this is where [[API:EPrints/Plugin/Screen#redirect_to_me_url|redirect_to_me_url]] is sub-classed to return undef, in which case the screen is expected to render in addition to processing the form request.
 <!-- Edit below this comment -->
@@ Line 40: / Line 72: @@
 <!-- Pod2Wiki= -->
-<!-- Pod2Wiki=head_two_requests -->
+<!-- Pod2Wiki=head_render -->
-===Two Requests===
+===render===
-The screen renders a link or GET-method form. When the user follows the link or submits the form the screen renders something different but does not change the state of an object on the server. i.e. if the user were to reload the page they would receive the same response.
 <!-- Edit below this comment -->
@@ Line 48: / Line 84: @@
 <!-- Pod2Wiki= -->
-<!-- Pod2Wiki=head_three_requests -->
+<!-- Pod2Wiki=head_render_links -->
-===Three Requests===
+===render_links===
-The redirect turns the request from a POST into a GET, which implicitly allows the user to reload the page without causing the change to happen again. This is important where, for example a user might be deleting an object. Attempting to re-submit the form would result in an error.
+<source lang="perl">$xhtml = $screen->render_links()
-Some screens override this behaviour and instead will render in response to a POST request.
+</source>
 <!-- Edit below this comment -->
@@ Line 60: / Line 96: @@
 <!-- Pod2Wiki= -->
 <!-- Pod2Wiki=head_hidden_bits -->
 ===hidden_bits===
@@ Line 71: / Line 105: @@
 At the top-level this is just the 'screen' id.
 <!-- Edit below this comment -->
@@ Line 85: / Line 175: @@
 If the CSRF check fails no action should be taken as this may be an attempt to forge a request.
 <!-- Edit below this comment -->

@@ Line 6: / Line 6: @@
 <!-- Pod2Wiki=_private_ --><!-- Pod2Wiki=head_name -->
 ==NAME==
-EPrints::Plugin::Screen
+EPrints::Plugin::Screen - dynamic user interface web pages
 <!-- Edit below this comment -->
@@ Line 12: / Line 12: @@
 <!-- Pod2Wiki= -->
- @params = $screen-&gt;hidden_bits()
+<!-- Pod2Wiki=head_description -->
 Returns a key-value list of values that must be set when referring to this screen.
 At the top-level this is just the 'screen' id.
- $ok = $screen-&gt;verify_csrf()
+<!-- Edit below this comment -->
 Verify that the CSRF token in the user agent's cookie matches the token passed in the form value.
 If the CSRF check fails no action should be taken as this may be an attempt to forge a request.
- @screen_opts = $screen-&gt;list_items( $list_id, %opts )
+<!-- Edit below this comment -->
 Returns a list of screens that appear in list $list_id ordered by their position.
@@ Line 37: / Line 110: @@
    params =&gt; {}</pre>
- $ok = $screen-&gt;has_action( $action_id )
+<!-- Edit below this comment -->
 Returns true if this screen has an action $action_id.
- $url = $screen-&gt;action_icon_url( $action )
+<!-- Edit below this comment -->
 Returns the relative URL to the $action icon for this screen.
- $frag = $screen-&gt;render_action_link()
+<!-- Edit below this comment -->
 Returns a link to this screen.
 <!-- Pod2Wiki=head_copyright -->
 ==COPYRIGHT==