Module: RelatonDoi::Crossref

Extended by:
Crossref
Included in:
Crossref
Defined in:
lib/relaton_doi/crossref.rb

Constant Summary collapse

HEADER = 
{
  "User-Agent" => "Relaton/RelatonDoi (https://www.relaton.org/guides/doi/; mailto:open.source@ribose.com)"
}.freeze
MAX_REDIRECTS = 
5

Instance Method Summary collapse

Instance Method Details

#get(doi) ⇒ RelatonBib::BibliographicItem, ...

Get a document by DOI from the CrossRef API.

Parameters:

  • doi (String) —

    The DOI.

Returns:

  • (RelatonBib::BibliographicItem, RelatonIetf::IetfBibliographicItem, RelatonBipm::BipmBibliographicItem, RelatonIeee::IeeeBibliographicItem, RelatonNist::NistBibliographicItem) —

    The bibitem.



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# File 'lib/relaton_doi/crossref.rb', line 23

def get(doi)
  Util.info "Fetching from search.crossref.org ...", key: doi
  id = doi.sub(%r{^doi:}, "")
  message = get_by_id id
  if message
    Util.info "Found: `#{message['DOI']}`", key: doi
    Parser.parse message
  else
    Util.info "Not found.", key: doi
    nil
  end
end

#get_by_id(id) ⇒ Hash

Get a document by DOI from the CrossRef API.

Parameters:

  • id (String) —

    The DOI.

Returns:

  • (Hash) —

    The document.



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# File 'lib/relaton_doi/crossref.rb', line 43

def get_by_id(id) # rubocop:disable Metrics/AbcSize,Metrics/MethodLength,Metrics/CyclomaticComplexity,Metrics/PerceivedComplexity
  n = 0
  redirects = 0
  url = "https://api.crossref.org/works/#{CGI.escape(id)}"
  loop do
    resp = Faraday.get url, nil, HEADER
    case resp.status
    when 200
      work = JSON.parse resp.body
      return work["message"] if work["status"] == "ok"
    when 404 then return nil
    when 301, 302
      raise RelatonBib::RequestError, "Crossref error: too many redirects" if redirects >= MAX_REDIRECTS

      location = resp.headers["location"] || resp.headers["Location"]
      raise RelatonBib::RequestError, "Crossref error: redirect without Location" if location.nil? || location.empty?

      url = URI.join(url, location).to_s
      redirects += 1
      next
    end

    if n > 1
      raise RelatonBib::RequestError, "Crossref error: #{resp.body}"
    end

    n += 1
    sleep resp.headers["x-rate-limit-interval"].to_i * n
  end
end