Class: BentoSearch::ScopusEngine

Inherits:
Object
  • Object
show all
Extended by:
HTTPClientPatch::IncludeClient
Includes:
SearchEngine
Defined in:
app/search_engines/bento_search/scopus_engine.rb

Overview

Supports fielded searching, sorting, pagination.

Required configuration:

  • api_key

Defaults to ‘relevance’ sort, rather than scopus’s default of date desc.

Uses the Scopus SciVerse REST API. You need to be a Scopus customer to access. api.elsevier.com www.developers.elsevier.com/action/devprojects

ToS: www.developers.elsevier.com/devcms/content-policies “Federated Search” use case. Also: www.developers.elsevier.com/cms/apiserviceagreement

Note that ToS applying to you probably means you must restrict access to search functionality to authenticated affiliated users only.

Register for an API key at “Register New Site” at developers.elsevier.com/action/devnewsite You will then need to get server IP addresses registered with Scopus too, apparently by emailing directly to dave.santucci at elsevier dot com.

Scopus API Docs:

Some more docs on response elements and query elements:

Other API’s in the suite not being used by this code at present:

Support: [email protected]

TODO: Mention to Scopus: Only one author? Paging of 50 gets an error, but docs say I should be able to request 200. q

Scopus response does not seem to include language of hit, even though api allows you to restrict by language. ask scopus if we’re missing something?

Constant Summary

Constants included from SearchEngine

BentoSearch::SearchEngine::DefaultPerPage

Class Method Summary collapse

Instance Method Summary collapse

Methods included from HTTPClientPatch::IncludeClient

include_http_client

Methods included from SearchEngine

#fill_in_search_metadata_for, #initialize, #normalized_search_arguments, #public_settable_search_args, #search

Methods included from BentoSearch::SearchEngine::Capabilities

#search_keys, #semantic_search_keys, #semantic_search_map, #sort_keys

Class Method Details

.default_configuration ⇒ Object 



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# File 'app/search_engines/bento_search/scopus_engine.rb', line 179

def self.default_configuration
  { 
    :base_url => "http://api.elsevier.com/",
    :cluster => "SCOPUS"
  }
end

.required_configuration ⇒ Object 



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# File 'app/search_engines/bento_search/scopus_engine.rb', line 175

def self.required_configuration
  ["api_key"]
end

Instance Method Details

#escape_query(query) ⇒ Object

The escaping rules are not entirely clear for the API. We know colons and parens are special chars. It’s unclear how or if we can escape them, we’ll just remove them.



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# File 'app/search_engines/bento_search/scopus_engine.rb', line 166

def escape_query(query)
  # backslash escape doesn't seem to work
  #query.gsub(/([\\\(\)\:])/) do |match|
  #  "\\#{$1}"
  #end
  query.gsub(/([\\\(\)\:])/, ' ')      
end

#max_per_page ⇒ Object

Max per-page is 200, as per www.developers.elsevier.com/devcms/content-apis, bottom of page.



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# File 'app/search_engines/bento_search/scopus_engine.rb', line 187

def max_per_page
  200
end

#search_field_definitions ⇒ Object 



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# File 'app/search_engines/bento_search/scopus_engine.rb', line 191

def search_field_definitions
  {
    nil           => {:semantic => :general},
    "AUTH"        => {:semantic => :author},
    "TITLE"       => {:semantic => :title},
    # controlled and author-assigned keywords
    "KEY"         => {:semantic => :subject},
    "ISBN"        => {:semantic => :isbn},
    "ISSN"        => {:semantic => :issn},              
  }
end

#search_implementation(args) ⇒ Object 



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# File 'app/search_engines/bento_search/scopus_engine.rb', line 53

def search_implementation(args)         
  results = Results.new
  
  xml, response, exception = nil, nil, nil
  
  url = scopus_url(args) 

  begin
    response = http_client.get( url , nil,
      # HTTP headers. 
      {"X-ELS-APIKey" => configuration.api_key, 
      "X-ELS-ResourceVersion" => "XOCS",
      "Accept" => "application/atom+xml"}
    )

    xml = Nokogiri::XML(response.body)
  rescue TimeoutError, HTTPClient::ConfigurationError, HTTPClient::BadResponseError, Nokogiri::SyntaxError  => e
    exception = e        
  end
  
  
  # handle errors
  if (response.nil? || xml.nil? || exception || 
      (! HTTP::Status.successful? response.status) ||
      xml.at_xpath("service-error")
      )
  
    # UGH. Scopus reports 0 hits as an error, not entirely distinguishable
    # from an actual error. Oh well, we have to go with it. 
    if ( 
        (response.status == 400) &&
        xml &&
        (error_xml = xml.at_xpath("./service-error/status")) &&
        (node_text(error_xml.at_xpath("./statusCode")) == "INVALID_INPUT") &&
        (node_text(error_xml.at_xpath("./statusText")).starts_with? "Result set was empty")
      )
      # PROBABLY 0 hit count, although could be something else I'm afraid. 
      results.total_items = 0
      return results
    else
      # real error              
      results.error ||= {}
      results.error[:exception] = e
      results.error[:status] = response.status if response
      # keep from storing the entire possibly huge response as error
      # but sometimes it's an error message. 
      results.error[:error_info] = xml.at_xpath("service_error") if xml
      return results
    end
  end                  
  
  
  results.total_items = (node_text xml.at_xpath("//opensearch:totalResults", xml_ns)).to_i
  
  xml.xpath("//atom:entry", xml_ns).each do | entry |

    results << (item = ResultItem.new)  
    if scopus_link = entry.at_xpath("atom:link[@ref='scopus']", xml_ns)
      item.link = scopus_link["href"]
    end
    
    item.unique_id             = node_text entry.at_xpath("dc:identifier", xml_ns)
    
    item.title          = node_text entry.at_xpath("dc:title", xml_ns)
    item.journal_title  = node_text entry.at_xpath("prism:publicationName", xml_ns)
    item.issn           = node_text entry.at_xpath("prism:issn", xml_ns)
    item.volume         = node_text entry.at_xpath("prism:volume", xml_ns)
    item.issue          = node_text entry.at_xpath("prism:issueIdentifier", xml_ns)
    item.doi            = node_text entry.at_xpath("prism:doi", xml_ns)
    
    # pages might be in startingPage/endingPage OR in pageRange
    if (start = entry.at_xpath("prism:startingPage", xml_ns))
      item.start_page = start.text.to_i
      if ( epage = entry.at_xpath("prism:endingPage", xml_ns))
        item.end_page = epage.text.to_i
      end
    elsif (range = entry.at_xpath("prism:pageRange", xml_ns))
      (spage, epage) = *range.text().split("-")
      item.start_page = spage
      item.end_page = epage
    end
    
    # get the year out of the date
    if date = entry.at_xpath("prism:coverDate", xml_ns)
      date.text =~ /^(\d\d\d\d)/
      item.year = $1.to_i if $1
    end
    
    # Authors might be in atom:authors seperated by |, or just
    # a single one in dc:creator
    if (authors = entry.at_xpath("atom:authors", xml_ns))
      authors.text.split("|").each do |author|
        item.authors << Author.new(:display => author.strip)
      end
    elsif (author = entry.at_xpath("dc:creator", xml_ns))
      item.authors << Author.new(:display => author.text.strip)
    end
    
    # Format we're still trying to figure out how Scopus API
    # delivers it. Here is at at least one way.
    if (doctype = entry.at_xpath("atom:subtype", xml_ns))
      item.format     = doctype_to_format(doctype.text)
      item.format_str = doctype_to_string(doctype.text) 
    end
    
  end
  
  return results
end

#sort_definitions ⇒ Object 



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# File 'app/search_engines/bento_search/scopus_engine.rb', line 203

def sort_definitions
  # scopus &sort= values, not yet URI-escaped, later code will do that.  
  #
  # 'refeid' key is currently undocumented on Scopus site, but
  # was given to me in email by scopus. 
  {
    "title_asc"     => {:implementation => "+itemtitle"},
    "date_desc"     => {:implementation => "-datesort,+auth"},
    "relevance"     => {:implementation => "refeid" }, 
    "author_asc"    => {:implementation => "+auth"},        
    "num_cite_desc" => {:implementation => "-numcitedby"}
  }
end