/ 
SeeAlso-Source-BeaconAggregator-0.2_50
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/ SeeAlso::Source::BeaconAggregator

NAME

SeeAlso::Source::BeaconAggregator - Beacon files as source for SeeAlso::Server

SYNOPSIS

 use CGI;
 use SeeAlso::Identifier::ISSN;
 use SeeAlso::Server;
 use SeeAlso::Source::BeaconAggregator;

 my $srcdescription = {
       "ShortName" => "TestService",                               # 16 Characters
        "LongName" => "Sample SeeAlso Beacon Aggregator",          # 48 characters
#     "Description" => "The following services are contained: ...", # 1024 Characters
     "DateModfied" => "...",
   _dont_advertise => 1,
 };

 my $CGI = CGI->new(); binmode(STDOUT, ":utf8");

 my $source = SeeAlso::Source::BeaconAggregator->new(
           'file' => "/path/to/existing/database",
'identifierClass' => SeeAlso::Identifier::ISSN->new(),
        'verbose' => 1,
    'description' => $srcdescription,
 );

 my $server = SeeAlso::Server->new (
       'cgi' => $CGI,
        xslt => "/client/showservice.xsl",    # => <?xml-stylesheet?> + <?seealso-query-base?>
  clientbase => "/client/",      # => <?seealso-client-base?>
     expires => "+2d",
 );

 my $rawid = $CGI->param('id') || "";
 my $identifier = $rawid ? SeeAlso::Identifier::ISSN->new($rawid) : "";
 my $result = $server->query($source, $identifier ? $identifier->value() : undef);
 print $result;

DESCRIPTION

This Module allows a collection of BEACON files (cf. http://de.wikipedia.org/wiki/Wikipedia:PND/BEACON) to be used as SeeAlso::Source (probably in the context of an SeeAlso::Server application). Therefore it implements the four methods documented in SeeAlso::Source

The BEACON files (lists of non-local identifiers of a certain type documenting the coverage of a given online database plus means for access) are imported by the methods provided by SeeAlso::Source::BeaconAggregator::Maintenance.pm, usually by employing the script sasbactrl.pl as command line client.

Serving other formats than SeeAlso or providing a BEACON file with respect to this SeeAlso service is achieved by using SeeAlso::Source::BeaconAggregator::Publisher.

USAGE

Class methods

beaconfields ( [ $what ] )

(Class method) Called without parameter returns an array of all valid field names for meta headers

@meta_supported = SeeAlso::Source::BeaconAggregator->beaconfields();

With given parameter $what in scalar context returns the column name of the database for the abstract field name. In array context additionally the column type and optional flag designating a mandatory entry are returned.

$internal_col = SeeAlso::Source::BeaconAggregator->beaconfields('FORMAT');

($internal_col, $specs, $mandatory)
    = SeeAlso::Source::BeaconAggregator->beaconfields('FORMAT');

Fields are:

 # mandatory
FORMAT, TARGET
 # as of PND/BEACON spec
VERSION, FEED, TIMESTAMP, REVISIT, UPDATE
CONTACT, INSTITUTION, ISIL, 
 # from the experimental BEACON spec
MESSAGE, ONEMESSAGE, SOMEMESSAGE
PREFIX, EXAMPLES
 # later additions
COUNT, REMARK
 # current practise
NAME
 # experimental extension "Konkordanzformat"
ALTTARGET, IMGTARGET

osdKeys ( [ $what ] )

(Class method) Called without parameter returns an array of all valid element names for the OpenSearchDescription:

@meta_names = SeeAlso::Source::BeaconAggregator->osdKeys();

With given parameter $what returns the value for the given OpenSearchDescription element:

$osd_value = SeeAlso::Source::BeaconAggregator->beaconfields('LongName');

OSD elements are

ShortName, Description
Contact, Tags, LongName, Developer, Attribution, SyndicationRight, AdultContent
Language, InputEncoding, OutputEncoding
 # special for SeeAlso::Family
Example, Examples, BaseURL, DateModified, Source

SeeAlso::Source methods

new( %accessor [, %options ] )

Creates the SeeAlso::Source::BeaconAggregator object and connects to an existing database previously created with the methods from SeeAlso::Source::BeaconAggregator::Maintenance (currently SQLlite)

Accessor options:

dbh

handle of a database already connected to

dbroot

optional path to prepend to dsn or file

dsn

directory name (directory contains the database file "<dsn>-db"

file

full path of the database

Other options:

identifierClass

contains an already instantiated object of that class

verbose (0|1)
description

Hashref with options to be piped through to SeeAlso::Source

Returns undef if unable to DBI->connect() to the database.

description ()

Inherited from SeeAlso::Source.

about ()

Inherited from SeeAlso::Source.

query( [ $identifier] )

Returns a SeeAlso::Response listing all matches to the given string or SeeAlso::Identifier $identifier.

Auxiliary Methods

Sequence numbers (Seqnos) are primary keys to the database table where each row contains the meta fields of one BEACON file

Seqnos ( $colname , $query )

Return Seqnos from querying the table with all beacon headers in column (field name) $colname for a $query (which may contain SQL placeholders '%').

RepoCols ( [ $colname [, $seqno_or_alias ]] )

Return a hashref indexed by seqence number of all values of column (header field) $colname [alias] optionally constrained by a SeqNo or Alias.

Default for $colname is '_alias'.

OSDValues ( [ $key ] )

Returns a hashref containing the OpenSearchDescription keywords an their respective values.

findExample ( $goal, $offset, [ $sth ])

Returns a hashref

{       id => identier,
  response => Number of beacon files matching "/" Sum of individual hit counts
}

for the $offset'th identifier with at least $goal hits.

$sth will be initialized by a statement handle to pass to subsequent calls if defined but false.

BUGS

SUPPORT

Send mail to the author

AUTHOR

Thomas Berger <ThB@gymel.com>

COPYRIGHT

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

The full text of the license can be found in the LICENSE file included with this module.

SEE ALSO

perl(1).