Nicolas Steenlant > Dancer-Plugin-Catmandu-OAI > Dancer::Plugin::Catmandu::OAI

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Module Version: 0.0308   Source  

NAME ^

Dancer::Plugin::Catmandu::OAI - OAI-PMH provider backed by a searchable Catmandu::Store

SYNOPSIS ^

    #!/usr/bin/env perl

    use Dancer;
    use Catmandu;
    use Dancer::Plugin::Catmandu::OAI;

    Catmandu->load;
    Catmandu->config;

    my $options = {};

    oai_provider '/oai' , %$options;

    dance;

DESCRIPTION ^

Dancer::Plugin::Catmandu::OAI is a Dancer plugin to provide OAI-PMH services for Catmandu::Store-s that support CQL (such as Catmandu::Store::ElasticSearch). Follow the installation steps below to setup your own OAI-PMH server.

REQUIREMENTS ^

In the examples below an ElasticSearch 1.7.2 https://www.elastic.co/downloads/past-releases/elasticsearch-1-7-2 server will be used.

Follow the instructions below for a demonstration installation:

    $ cpanm Dancer Catmandu::OAI Catmandu::Store::ElasticSearch

    $ wget https://download.elastic.co/elasticsearch/elasticsearch/elasticsearch-1.7.2.zip
    $ unzip elasticsearch-1.7.2.zip
    $ cd elasticsearch-1.7.2
    $ bin/elasticsearch

RECORDS ^

Records stored in the Catmandu::Store can be in any format. Preferably the format should be easy to convert into the mandatory OAI-DC format. At a minimum each record contains an identifier '_id' and a field containing a datestamp.

    $ cat sample.yml
    ---
    _id: oai:my.server.org:123456
    datestamp: 2016-05-17T13:37:18Z
    creator:
     - Musterman, Max
     - Jansen, Jan
     - Svenson, Sven
    title:
     - Test record
    ...

CATMANDU CONFIGURATION ^

ElasticSearch requires a configuration file to map record fields to CQL terms. Below is a minimal configuration required to query for identifiers and datastamps in the ElasticSearch collection:

    $ cat catmandu.yml
    ---
    store:
      oai:
        package: ElasticSearch
        options:
          index_name: oai
          bags:
            data:
              cql_mapping:
                default_index: basic
                indexes:
                  _id:
                    op:
                      'any': true
                      'all': true
                      '=': true
                      'exact': true
                    field: '_id'
                  datestamp:
                    op:
                      '=': true
                      '<': true
                      '<=': true
                      '>=': true
                      '>': true
                      'exact': true
                    field: 'datestamp'
          index_mappings:
            publication:
              properties:
                datestamp: {type: date, format: date_time_no_millis}

IMPORT RECORDS ^

With the Catmandu configuration files in place records can be imported with the catmandu command:

    # Drop the existing ElasticSearch 'oai' collection
    $ catmandu drop oai

    # Import the sample record
    $ catmandu import YAML to oai < sample.yml

    # Test if the records are available in the 'oai' collection
    $ catmandu export oai

DANCER CONFIGURATION ^

The Dancer configuration file 'config.yml' contains basic information for the OAI-PMH plugin to work:

    * store - In which Catmandu::Store are the metadata records stored
    * bag   - In which Catmandu::Bag are the records of this 'store' (use: 'data' as default)
    * datestamp_field - Which field in the record contains a datestamp ('datestamp' in our example above)
    * repositoryName - The name of the repository
    * uri_base - The base URL of the repository
    * adminEmail - An administrative email
    * earliestDatestamp - The earliest datestamp available in the dataset an YYYY-MM-DDTHH:MM:SSZ
    * deletedRecord - The policy for deleted records. See also: L<https://www.openarchives.org/OAI/openarchivesprotocol.html#DeletedRecords>
    * repositoryIdentifier - A prefix to use in OAI-PMH identifiers
    * cql_filter -  A CQL query to find all records in the database that should be made available to OAI-PMH
    * limit - The maximum number of records to be returned in each OAI-PMH request
    * delimiter - Delimiters used in prefixing a record identifier with a repositoryIdentifier (use: ':' as default)
    * sampleIdentifier - A sample identifier
    * metadata_formats - An array of metadataFormats that are supported
        * metadataPrefix - A short string for the name of the format
        * schema - An URL to the XSD schema of this format
        * metadataNamespace - A XML namespace for this format
        * template - The path to a Template Toolkit file to transform your records into this format
        * fix - Optionally an array of one or more L<Catmandu::Fix>-es or Fix files
    * sets - Optional an array of OAI-PMH sets and the CQL query to retrieve records in this set from the Catmandu::Store
        * setSpec - A short string for the same of the set
        * setName - A longer description of the set
        * cql - The CQL command to find records in this set in the L<Catmandu::Store>

Below is a sample minimal configuration for the 'sample.yml' demo above:

    $ cat config.yml
    charset: "UTF-8"
    plugins:
      'Catmandu::OAI':
        store: oai
        bag: data
        datestamp_field: datestamp
        repositoryName: "My OAI DataProvider"
        uri_base: "http://oai.service.com/oai"
        adminEmail: me@example.com
        earliestDatestamp: "1970-01-01T00:00:01Z"
        cql_filter: "datestamp>1970-01-01T00:00:01Z"
        deletedRecord: persistent
        repositoryIdentifier: oai.service.com
        limit: 200
        delimiter: ":"
        sampleIdentifier: "oai:oai.service.com:1585315"
        metadata_formats:
          -
            metadataPrefix: oai_dc
            schema: "http://www.openarchives.org/OAI/2.0/oai_dc.xsd"
            metadataNamespace: "http://www.openarchives.org/OAI/2.0/oai_dc/"
            template: oai_dc.tt

METADATAPREFIX TEMPLATE ^

For each metadataPrefix a Template Toolkit file needs to exist which translate Catmandu::Store records into XML records. At least one Template Toolkit file should be made available to transform stored records into Dublin Core. The example below contains an example file to transform 'sample.yml' type records into Dublin Core:

    $ cat oai_dc.tt
    <oai_dc:dc xmlns="http://www.openarchives.org/OAI/2.0/oai_dc/"
               xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/"
               xmlns:dc="http://purl.org/dc/elements/1.1/"
               xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
               xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
    [%- FOREACH var IN ['title' 'creator' 'subject' 'description' 'publisher' 'contributor' 'date' 'type' 'format' 'identifier' 'source' 'language' 'relation' 'coverage' 'rights'] %]
        [%- FOREACH val IN $var %]
        <dc:[% var %]>[% val | html %]</dc:[% var %]>
        [%- END %]
    [%- END %]
    </oai_dc:dc>

START DANCER ^

If all the required files are available, then a Dancer application can be started. See the 'demo' directory of this distribution for a complete example:

    $ ls 
    app.pl  catmandu.yml  config.yml  oai_dc.tt
    $ cat app.pl
    #!/usr/bin/env perl

    use Dancer;
    use Catmandu;
    use Dancer::Plugin::Catmandu::OAI;

    Catmandu->load;
    Catmandu->config;

    my $options = {};

    oai_provider '/oai' , %$options;

    dance;

    # Start Dancer
    $ perl ./app.pl
  
    # Test queries:

    $ curl "http://localhost:3000/oai?verb=Identify"
    $ curl "http://localhost:3000/oai?verb=ListSets"
    $ curl "http://localhost:3000/oai?verb=ListMetadataFormats"
    $ curl "http://localhost:3000/oai?verb=ListIdentifiers&metadataPrefix=oai_dc"
    $ curl "http://localhost:3000/oai?verb=ListRecords&metadataPrefix=oai_dc"

SEE ALSO ^

Dancer, Catmandu, Catmandu::Store

AUTHOR ^

Nicolas Steenlant, <nicolas.steenlant at ugent.be>

CONTRIBUTORS ^

Nicolas Franck, <nicolas.franck at ugent.be>

Vitali Peil, <vitali.peil at uni-bielefeld.de>

Patrick Hochstenbach, <patric.hochstenbach at ugent.be>

LICENSE ^

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

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