Talk:API:EPrints

I'm going to use this page to get my thoughts in order. Cjg 16:58, 2 September 2009 (BST)

Current 3.1 System

Unsessioned Classes

These classes don't store a session internally resulting in methods like $foo->render( $session, ARGS ).

• Repository
• DataSet
• MetaField
• Language

Sessioned Classes

These classes store a session internally resulting in methods like $foo->render( ARGS ).

• Session
• DataObj
• Plugin
• List
• Search
• Database
• Workflow
• ScreenProcessor

API

New Plan(!)

• Merge Session and Repository into a single class.
• Move XML functions into their own class.
• Move Page functions into their own class.
• Add a link to repository for dataset and metafield.
• Ensure cleanup when repository object goes out of scope.
• Make EPrints->new() return an eprints object which can pass out repository objects.
  • repository objects don't have a link to the EPrints object EVER.
  • When the eprints object is DESTROY'd it takes out the repositories, datasets and metafields etc.

EPrints

$ep = EPrints->new();
$repo = $ep->repository( "devel", noise=>1 );
$repo = $ep->current_repository(); # from Apache::Request URI
EPrints->abort( $message );

repo

Yes:

$xml = $repo->xml;
$dataset = $repo->dataset( "user" );
$user = $repo->current_user;
$query = $repo->query;
$current_page_url = $repo->current_url; 
$config_element = $repo->config( $key, [@subkeys] );
$repository->log( $message ); 
$string = $repo->query->param( "X" );
$repo->redirect( $url );

Maybe:

• tdb: language accessors
  • cjg: I think thses don't belong in the API - why do people need access to them? If I'm wrong we add them in API 1.1?

$lang = $repo->language( $langid );
$lang = $repo->default_language; # needed? nee ->language( undef )
$lang = $repo->current_language;

• cjg: I think these would be very useful but they are inconsistent.

$eprint = $repo->eprint( 23 );
$user = $repo->user( 23 );
$user = $repo->user_by_username( "cjg" );
$user = $repo->user_by_email( 'cjg@ecs.soton.ac.uk' );

dataset

$string = $dataset->base_id; # eprint
$string = $dataset->id; # inbox
$dataobj = $datasset->create_dataobj( $data );
$user = $dataset->dataobj( 23 );

$search = $dataset->prepare_search( %options );
$list = $dataset->search( %options ); # prepare_search( %options )->execute
$list = $dataset->search; # match ALL

$metafield = $dataset->field( $fieldname );
$metafield = $dataset->key_field;
@metafields = $dataset->fields; 

$dataset->search->map( sub {}, $ctx );
$n = $dataset->search->count; 
$ids = $dataset->search->ids;

Maybe:

• tdb: is this common enough to replace EPrints::List->new()?
  • cjg: part of the API goal IMO is to get away from classnames if at all possible, so this would become the proper way to create a list object.

$list = $dataset->list( \@ids ); 

Maybe not:

• pm5 why not this one? i think thats handy
  • cjg: because we could use (defined $dataset->field( $fieldname ))

$bool = $dataset->has_field( $fieldname );

list

$n = $list->count;
$list->map( sub {}, $ctx );
$dataobj = $list->item( offset );
@dataobjs = $list->slice( offset, length ); 
# tdb: consistent with creating a list: unbounded returns should use array ref?
\@ids = $list->ids;

search

$search = $dataset->prepare_search( order => "-date", satisfy_all=>1 );
$search = $dataset->prepare_search( query => [], filters => [], ... );

$list = $search->execute;

# the below call needs replacing with something less sucky.
$search->add_term( %opts ); # better name needed?
$search->add_term( $ds->field( "type" ), qw/ article book /, "EQ", "ANY" );

Alternatives

I would like to make the value argument not automagically-split on ANY but explicitly use an array ref of values to match.

my $s = $dataset->prepare_search( order => "-date", satisfy_all => 1, query => [
 { fields => ["type"], values => [qw/article book/], merge => EPrints::Search::ANY },
 { fields => [qw( title abstract )], values => ["dogbert dilbert"], match => EPrints::Search::INDEX, merge => EPrints::Search::ALL },
 { fields => ["userid"], values => ["52"], match => EPrints::Search::EXACT },
] );
my $s = $dataset->prepare_search( order => "-date", satisfy_all => 1 );
$s->add_query( ["type"], [qw/article book/], merge => EPrints::Search::ANY );
$s->add_query( [qw( title abstract )], ["dogbert dilbert"], match => EPrints::Search::INDEX, merge => EPrints::Search::ALL );
$s->add_query( ["userid"], ["52"], match => EPrints::Search::EXACT );
my $list = $s->execute;

$s->add_query( [$dataset->field( "type" )], [qw/ article book/], merge => EPrints::Search::ANY );

print $list->count, "\n";

• Cjg 18:27, 16 September 2009 (BST) : I kinda like where this is going but don't like the ugly constants. Also, it'd be much cleaner if you could allow array ref or scalar as the field list and value list.

XML

$doc = $xml->parse_string( $string );
$doc = $xml->parse_file( $filename );
$doc = $xml->parse_url( $url );

$utf8_string = $xml->to_string( $dom_node, %opts );
# tdb: to_text needs a better name
$utf8_string = $xml->to_text( $dom_node, %opts ); # nee tree_to_utf8

$dom_node = $xml->clone( $dom_node ); # deep
$dom_node = $xml->clone_node( $dom_node ); # shallow

$dom_node = $xml->contents_of( $dom_node ); # clone and return child nodes
$utf8_string = $xml->text_contents_of( $dom_node ); # clone and return text child nodes

$dom_node = $xml->create_element( $name, %attr );
$dom_node = $xml->create_text_node( $value );
$dom_node = $xml->create_comment_node( $value );
$dom_node = $xml->create_document_fragment;

$xml->dispose( $dom_node );

• • • • pm5 firstly most of this looks good so well done. is there a reason why we have create_element but appendChild? i know the camel casing is sort of a hand me down from the various xml libraries might it be worth wrapping those or camel casing everything in this class (just for consistancy). Also im not sure about render_ what about create_ the result being createLink, createInputField etc
        • cjg: because appendChild is a DOM method, not part of the EPrints API. All EPrints API methods use the "foo_bar" style of method name. DOM is a defined standard we can't alter.

XHTML

$xhtml = $repo->xhtml;

$utf8_string = $xhtml->to_xhtml( $dom_node, %opts ); # remove NS prefixes, fix <script> etc.

• tdb: Any circumstances where input_field won't have a type, name and value?
  • cjg: could have an undef value. Also, 3 values starts to get too long to keep track of. type should maybe default to "text" and have the type=> as an option? Also then matches text_area and hidden for consistency.

$xhtml_dom_node = $xhtml->input_field( $type, $name, $value, %opts ); # nb. noenter are now options.
$xhtml_dom_node = $xhtml->hidden_field( $name, $value, %opts ); # tdb: this is used *a lot* and is well defined
$xhtml_dom_node = $xhtml->text_area_field( $name, $value, %opts ); # tdb: value becomes a child text node 
$xhtml_dom_node = $xhtml->form( $method, $url );

$page = $xhtml->build_page( %opts );

# $repo->xhtml->phrase( $phrase_id )
$xhtml_dom_node = $xhtml->phrase( $phrase_id, %pins );

# is this an XHTML function or move to Repository?
$utf8string = $xhtml->text_phrase( $phrase_id, %pins );

# Maybe not (due to making Patrick sad, and just as easy to do with create_element( "a", href=>... )
$xhtml_dom_node = $xhtml->link( $url, %opts ); #nb will require clever hack if scalar @opts = 1;

• tdb: these are really not useful - nbsp is a kludge, ruler should be done by CSS
  • Cjg: nbsp is just a convenient way of inserting a unicode character which is frequently used, so I vote to keep it in, name() is also useful IMO. Ruler can be easily replaced with a phrase call, and isn't used much in EP3+ so I can happily see that go into the west and diminish.

$xhtml_dom_node = $xhtml->ruler;
$xhtml_dom_node = $xhtml->nbsp;
$xhtml_dom_node = $xhtml->name( $namehash, render_order=>"gf" ); # or fg

Page

$page->send( %options ); 
$page->write_to_file( $filename );

DataObj

$dataobj = $dataset->dataobj( $id );
$dataobj->delete;
$dataobj->commit( $force );
$dataobj->set_value( $fieldname, $value );
$value = $dataobj->value( $fieldname );
$boolean = $dataobj->is_set( $fieldname );
$id = $dataobj->id;
$xhtml = $dataobj->render_value( $fieldname );
$xhtml = $dataobj->render_citation( $style, %opts );
($xhtml, $title, $head_elements) = $dataobj->render;
$uri = $dataobj->uri;
$url = $dataobj->url;
$string = $dataobj->export( $plugin_id, %opts );

• cjg: would render() be better replaced with something which returns a hash not an array?

EPrint

@documents = $eprint->documents;
$eprint->set_status( "inbox" );
$document = $eprint->add_document( $doc_data );

User

$user = $repository->dataset( "user" )->dataobj( 23 );
$user->send_email( .... ) ?? # tdb: is this accessor or action? c.f. send_page()

Subject

$subject = $repository->dataset("subject")->dataobj( "FOO" );
@subjects = $subject->children;
@subjects = $subject->parents; 

• CJG: issue with confusion with subobjects like document, or are these really subobjects? Maybe child_subjects parent_subjects to avoid overlapping names?

Document

• tdb: consistency - all unbounded lists are array refs

my $document = $repo->dataset( "document" )->dataobj( 23 );
my $docs = $eprint->documents( %opts ); # isVolatileVersionOf => 0 ?
foreach my $document ( @$docs ) { .. }

# create a new document on $eprint 
$doc_data = { ... };
$doc = $eprint->create_subobject( "documents", $doc_data ); 
# eprint to which this document belongs
$eprint = $doc->parent;

# delete a document object *forever*:
$ok = $doc->delete;

$url = $doc->url( [$file] );

• tdb: is $file ^^ a file object or filename?

# change the file which is used as the URL for the document.
$doc->set_value( "main", "foo.html" );

# dealing with files
$file = $doc->file_by_filename( $filename ); # nee get_stored_file
\@files = $doc->value( "files" );
$file->value( "filename" );
$file->value( "filesize" );

# delete a file
$doc->file_by_filename( $filename )->delete;

# delete all files
$files = $doc->value( "files" );
foreach my $file (@$files) { $file->delete; } 

# icons and previews???? These need work!
$xhtml = $doc->render_icon_link( %opts );
$xhtml = $doc->render_preview_link( %opts );

Maybe

# Add files to the document
# tdb: these should be deprecated from Document and moved to Import/Screen plugins
$success = $doc->upload( $filehandle, $filename [, $preserve_path [, $filesize ] ] );
$success = $doc->upload_archive( $filehandle, $filename, $archive_format );
$success = $doc->add_archive( $file, $archive_format );
$success = $doc->add_directory( $directory );
$success = $doc->upload_url( $url );

File

$file = $history->file_by_filename( "dataobj.xml" );
$file->retrieve( sub { ... }, $info ); # callback-based file content retrieval

• I don't know enough about this method to know what we *must* have in. Less is better IMO, though. Cjg 01:23, 17 September 2009 (BST)
• tdb: files should probably be only created via a parent object

MetaField

Now has a handle on both it's repository/session AND dataset.

my $field = $dataset->field( $fieldname );
$field->set_property( $property, $value );

$name = $field->name;
$type = $field->type;
$value = $field->property( $property );

$xhtml = $field->render_name;
$xhtml = $field->render_help;
$xhtml = $field->render_value_label( $value );

$values = $field->values( %opts );
$sorted_list = $field->sort_values( $unsorted_list );