Class: BbEPUB::Transform::Metadata

Inherits:
Bookbinder::Transform
  • Object
show all
Defined in:
lib/bb-epub/transform/metadata.rb

Overview

Takes all the elements in the <metadata> tag of the OPF file and generates a clean hash of the data. Other transforms will pick and choose from this hash. What’s left over is mostly just for preserving EPUB’s guff.

So this:

<metadata>
  <dc:identifier id="isbn-id">
    urn:isbn:9780101010101
  </dc:identifier>
  <meta
    refines="#isbn-id"
    property="identifier-type"
    scheme="onix:codelist5"
  >
    15
  </meta>
  <dc:source id="src-id">
    urn:isbn:9780375704024
  </dc:source>
  <meta
    refines="#src-id"
    property="identifier-type"
    scheme="onix:codelist5"
  >
    15
  </meta>
</metadata>

… becomes this:

"metadata": {
  "identifier": [{
    "@": "urn:isbn:9780101010101",
    "identifier-type": {
      "@": 15,
      "scheme": {
        "@": "onix-codelist5"
      }
    }
  }],
  "source": [{
    "@": "urn:isbn:9780375704024",
    "identifier-type": {
      "@": 15,
      "scheme": {
        "@": "onix-codelist5"
      }
    }
  }]
}

You can nest properties arbitrarily deep in the map’s “metadata” structure.

"metadata": {
  "some-property": [{
    "@": "value-of-some-property",
    "some-property-property": {
      "@": "value-of-some-property-property",
      "some-property-property-property": {
        "@": "value-of-etc"
      }
    }
  }],
  "other-property": [
    { "@": "other-property-first-value" },
    { "@": "other-property-second-value" }
  ]
}

Instance Method Summary collapse

Instance Method Details

#dependencies ⇒ Object 



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# File 'lib/bb-epub/transform/metadata.rb', line 75

def dependencies
  [BbEPUB::Transform::OPF]
end

#from_map(package) ⇒ Object 



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# File 'lib/bb-epub/transform/metadata.rb', line 133

def from_map(package)
end

#to_map(package) ⇒ Object 



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# File 'lib/bb-epub/transform/metadata.rb', line 80

def to_map(package)
  opf_doc = package.file(:opf).document('r')
  md = {}
  opf_doc.each('opf|metadata > *') { |tag|
    # If this tag refines another metadata tag, we can skip it
    if refines = tag['refines']
      refines = "opf|metadata > *[id=\"#{refines.sub(/^#/,'')}\"]"
      next if opf_doc.find(refines)
    end

    # Find the basic name and value of the meta tag
    name = tag.node_name
    value = { '@' => tag.content.strip }
    # If the meta tag has attributes, add them to the value
    # (but note that these are deprecated in EPUB3 in favor
    # of refinements).
    tag.attributes.each_pair { |key, attr|
      value[key] = { '@' => attr.value }
      value[key]['deprecated'] = true  unless key == 'id' || key == 'refines'
    }
    if name == 'meta'
      if tag['property']
        name = tag['property']
        value.delete('property')
      elsif tag['name']
        # Note that <meta name="" content=""> is deprecated in EPUB3.
        name = tag['name']
        value['@'] = tag['content']
        value['deprecated'] = true
        value.delete('name')
      end
    end
    # If the meta tag is refined by another meta tag, add the
    # refinements to our value hash.
    if tag['id']
      refines = opf_doc.search(
        'opf|metadata > opf|meta[refines="#'+tag['id']+'"]'
      )
      refines.each { |refinement|
        refine_value = { '@' => refinement.content.strip }
        refinement.attributes.each_pair { |key, attr|
          refine_value[key] = attr.value
        }
        value[refinement['property']] = refine_value
      }
    end
    # Add the name and value to our metadata hash
    add_to_hash(md, name, value)
  }
  package.map['metadata'] = md
end