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[EP-tech] Re: EP_TRIGGER_URL_REWRITE and redirecting to a screen

Hola,

I think you can pass on the ScreenProcessor / a Screen from your trigger.

Something like:
$c->add_trigger( EP_TRIGGER_URL_REWRITE, sub
{
	my( %args ) = @_;

	my( $repository, $uri, $return_code, $request ) = @args{ qw( repository uri return_code request ) };
	if( defined $uri && ($uri =~ m# ^/(\d+)/$ #x ) )
	{
		my $eprintid = $1;
		my $eprint = $repository->dataset( "eprint" )->dataobj( $eprintid );
		# this is an overridden 'permit' that does some new things, but still returns a '1' or '0'.
		my $can_view = $eprint->permit( "eprint/view", $repository->current_user ); #NB current_user may be undef
		if( $can_view ){

			$r->set_handlers( PerlResponseHandler => sub {

				my( $r ) = @_;						# if needed
				my $repository = $EPrints::HANDLE->current_repository;	# if needed
				EPrints::ScreenProcessor->process(
			        	repository => $repository,
				        screenid => "YourScreenID",
	
					# ... whatever other params your Screen needs ....
				);

				return HTTP_OK;

			} );

			$$return_code = EPrints::Const::OK;
			return EP_TRIGGER_DONE;

		 }
	}
	return EP_TRIGGER_OK;

}, priority => 100 ); 


      

      Alternatively, you can have an actual Perl Response Handler, you
      can use as templates:

      

      -
      http://bazaar.eprints.org/325/1/epm/meprints/cfg/cfg.d/z_meprints.pl
      (search for
      
      EP_TRIGGER_URL_REWRITE)

      -
      http://bazaar.eprints.org/325/1/plugins/EPrints/Plugin/MePrints/MePrintsHandler.pm
      (the handler can do whatever you want, you can print the page to
      STDOUT, or let the ScreenProcessor do that for you).

      

      And just, as a small add-on, on some ACL work I was looking at, my
      main method was called permit_action (on DataObj) and you pass the
      action as a param so that it looks like:

      

      my $rc = $dataobj->permit_action( "view", $current_user );   
          # current_user may be undef too

      

      Hope this helps,

      Seb.

      

      

      

      On 17/07/14 13:45, Enio Carboni wrote:

    

    

      
      
Hi John,

         I think you must use something like this in your
        EP_TRIGGER_URL_REWRITE (this trigger, i think, can't control
        direct "render a screen"):

        

        
my
$url="";

          EPrints::Apache::AnApache::send_status_line( $args{request},
          307, "Temporary Redirect" );

          EPrints::Apache::AnApache::header_out( $args{request},
          "Location", $url );

          EPrints::Apache::AnApache::send_http_header( $args{request} );

          ${$args{return_code}} = EPrints::Apache::AnApache::DONE;

          return EP_TRIGGER_DONE;

        

        

          Enio

        

        

        Il 17/07/2014 13:43, John Salter ha scritto:

      

      

        
Hi Seb,
Thanks for the reply, sorry for the delay in getting back to you.

I'm still not sure I understand how to get where I need to be - here's what I'm trying to do:
 - intercept a request for an EPrint - the rewrite trigger matches a URL e.g. http://repo/123/ with '^/(\d+)/$'.  *
 - check (with the new Access Control stuff we're working on :o) whether the request can view the item**
 - if the request is permitted to view, render a variant of the EPrint::Summary screen, EPrint::SecureSummary
 - if it can't, let EPrints do it's normal thing - which in this case will direct to a summary page with minimal metadata.

* I don’t want to redirect from http://repo/123/ to http://repo/cgi/[something],
**There may not be a 'user' at this point in time - there could be an IP-based 'allow'.

Below is what I've got so far for my trigger - I've tried various things - either resulting in a login page, a 404 error or a smoking server...

$c->add_trigger( EP_TRIGGER_URL_REWRITE, sub
{
	my( %args ) = @_;

	my( $repository, $uri, $return_code, $request ) = @args{ qw( repository uri return_code request ) };
	if( defined $uri && ($uri =~ m# ^/(\d+)/$ #x ) )
	{
		my $eprintid = $1;
		my $eprint = $repository->dataset( "eprint" )->dataobj( $eprintid );
		# this is an overridden 'permit' that does some new things, but still returns a '1' or '0'.
		my $can_view = $eprint->permit( "eprint/view", $repository->current_user ); #NB current_user may be undef
		if( $can_view ){
			#render the EPrint::SecureSummary screen
			#and set the return code?
			# ${$return_code} = EPrints::Const::OK;
			#return EP_TRIGGER_DONE;
		}
	}
	return EP_TRIGGER_OK;

}, priority => 100 ); 

Any (further) thoughts welcomed!
Cheers,
John


-----Original Message-----
From: eprints-tech-bounces@ecs.soton.ac.uk [mailto:eprints-tech-bounces@ecs.soton.ac.uk] On Behalf Of Sebastien Francois
Sent: 11 July 2014 11:37
To: eprints-tech@ecs.soton.ac.uk
Subject: [EP-tech] Re: EP_TRIGGER_URL_REWRITE and redirecting to a screen

Hi John,

I don't think that case (1) redirects - see eprints3/cgi/users/home. It 
just passes on the request to the ScreenProcessor. You could achieve the 
same with a trigger in fact.

Since your screen already has a url 
(http://repo/cgi/users/home?screen=MyScreen), I guess what you want to 
do is a rewrite as in mod_rewrite.

Seb.

On 11/07/14 11:16, John Salter wrote:


        

          
Hi,
What's the *best/intended* way to go from an  EP_TRIGGER_URL_REWRITE trigger to a screen?

>From searching the Bazaar, is seems like most things like this either:
(1) use a cgi/... script that does the screen selection/processing, or
(2) register a handler that does the work (e.g.  $request->set_handlers(PerlResponseHandler => [ 'EPrints::Plugin::MePrints::MePrintsHandler' ] ); )

Both seem not-quite-right: (1) requires the trigger to do a redirect (another HTTP call), (2) would duplicate a lot of stuff that EPrints does 'normally' (the screen I want to use is a normal EPrints screen).

Should the trigger should be able to do the work?
Have I missed some magic way of doing this?

Cheers,
John



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