Class: Scopus

Inherits:
Service show all
Includes:
MetadataHelper, UmlautHttp
Defined in:
lib/service_adaptors/scopus.rb

Overview

Service adapter plug-in.

PURPOSE: Includes "cited by", "similar articles" and "more by these authors" links from scopus. Also will throw in an abstract from Scopus if found.

LIMTATIONS: You must be a Scopus customer for these links generated to work for your users at all! Off-campus users should be going through ezproxy, see the EZProxy plug-in. Must find a match in scopus, naturally. "cited by" will only be included if Scopus has non-0 "cited by" links. But there's no good way to precheck similar/more-by for this, so they are provided blind and may result in 0 hits. You can turn them off if you like, with @include_similar, and @include_more_by_authors.

REGISTERING: This plug in actually has to use two seperate Scopus APIs. For the first, the scopus 'json' search api, you must regsiter and get an api key from scopus, which you can do here: searchapi.scopus.com Then include as @json_api_key in service config.

For the second Scopus API, you theoretically need a Scopus "PartnerID" and corresponding "release number", in @partner_id and @scopus_release There's no real easy way to get one. Scopus says:

"To obtain a partner ID or release number, contact your nearest regional
Scopus office. A list of Scopus contacts is available at
http://www.info.scopus.com/contactus/index.shtml"

Bah! But fortunately, using the "partnerID" assigned to the Scopus Json API, 65, seems to work, and is coded here as the default. You could try going with that. When you register a partnerID, you also get a 'salt key', which is currently not used by this code, but @link_salt_key is reserved for it in case added functionality does later.

Constant Summary

Constant Summary

Constants inherited from Service

Service::LinkOutFilterTask, Service::StandardTask

Instance Attribute Summary

Attributes inherited from Service

#name, #priority, #request, #service_id, #session_id, #status, #task, #url

Instance Method Summary (collapse)

Methods included from UmlautHttp

#http_fetch, #proxy_like_headers

Methods inherited from Service

#display_name, #handle_wrapper, #link_out_filter, #preempted_by, required_config_params, #response_to_view_data, #response_url, #session, #update_session, #view_data_from_service_type

Constructor Details

- (Scopus) initialize(config)

A new instance of Scopus



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# File 'lib/service_adaptors/scopus.rb', line 52

def initialize(config)
  #defaults
  @display_name = "Scopus"
  @registered_referer
  @scopus_search_base = 'http://www.scopus.com/scsearchapi/search.url'
  
  @include_abstract = true
  @include_cited_by = true
  @include_similar = true
  @include_more_by_authors = true
  @more_by_authors_type = "similar"

  @inward_cited_by_url = "http://www.scopus.com/scopus/inward/citedby.url"
  #@partner_id = "E5wmcMWC"
  @partner_id = 65
  @link_salt_key = nil
  @scopus_release = "R6.0.0"

  # Scopus offers to algorithms for finding similar items.
  # This variable can be:
  # "key" => keyword based similarity 
  # "ref" => reference based similiarity (cites similar refs?) Seems to offer 0 hits quite often, so we use keyword instead. 
  # "aut" => author. More docs by same authors. Incorporate this latter as
  # an additional link?
  @more_like_this_type = "key"
  @inward_more_like_url = "http://www.scopus.com/scopus/inward/mlt.url"
  
  super(config)
end

Instance Method Details

- (Object) add_abstract(first_hit, request) 



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# File 'lib/service_adaptors/scopus.rb', line 222

def add_abstract(first_hit, request)

  return if first_hit["abstract"].blank?
  
  request.add_service_response( :service=>self, :display_text => "Abstract from #{@display_name}", :content => first_hit["abstract"], :url => detail_url(first_hit), :service_type_value => :abstract)
end

- (Object) add_cited_by_response(result, request)

Input is a ruby hash that came from the scopus JSON, representing a single hit. We're going to add this as a result.



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# File 'lib/service_adaptors/scopus.rb', line 201

def add_cited_by_response(result, request)
  # While scopus provides an "inwardurl" in the results, this just takes
  # us to the record detail page. We actually want to go RIGHT to the
  # list of cited-by items. So we create our own, based on Scopus's
  # reversed engineered predictable URLs. 

  count = result["citedbycount"]
  label = ServiceTypeValue[:cited_by].display_name_pluralize.downcase.capitalize    
    if count && count == 1
      label = ServiceTypeValue[:cited_by].display_name.downcase.capitalize
    end
  cited_by_url = cited_by_url( result )
  
  request.add_service_response(:service=>self, 
    :display_text => "#{count} #{label}", 
    :count=> count, 
    :url => cited_by_url, 
    :service_type_value => :cited_by)

end

- (Object) check_for_hits(url)

NOT currently working. Scopus doesn't make this easy. Takes a scopus direct url for which we're not sure if there will be results or not, and requests it and html screen-scrapes to get hit count. (We can conveniently find this just in the html <title> at least). Works for cited_by and more_like_this searches at present. May break if Scopus changes their html title!



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# File 'lib/service_adaptors/scopus.rb', line 259

def check_for_hits(url)

  response = http_fetch(url).body

  hpricot = Hpricot(response)

  title = hpricot.at('title').inner_text
  # title is "X documents" (or 'Documents') if there are hits.
  # It's annoyingly "Search Error" if there are either 0 hits, or
  # if there was an actual error. So we can't easily log actual
  # errors, sorry.
  title.downcase =~ /^\s*(\d+)?\s+document/
  if ( hits = $1)
    return hits.to_i
  else
    return 0
  end    
end

- (Object) cited_by_url(result) 



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# File 'lib/service_adaptors/scopus.rb', line 238

def cited_by_url(result)
  eid = CGI.escape(result["eid"])    
  #return "#{@scopus_cited_by_base}?eid=#{eid}&src=s&origin=recordpage"
  # Use the new scopus direct link format!
  return "#{@inward_cited_by_url}?partnerID=#{@partner_id}&rel=#{@scopus_release}&eid=#{eid}"
  return 
end

- (Object) detail_url(hash) 



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# File 'lib/service_adaptors/scopus.rb', line 229

def detail_url(hash)
  url = hash["inwardurl"]
  # for some reason ampersand's in query string have wound up double escaped
  # and need to be fixed.
  url = url.gsub(/\&amp\;/, '&')

  return url
end

- (Object) handle(request) 



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# File 'lib/service_adaptors/scopus.rb', line 82

def handle(request)
  scopus_search = scopus_search(request)

  # we can't make a good query, nevermind. 
  return request.dispatched(self, true) if scopus_search.blank? 

  
  # The default fields returned dont' include the eid (Scopus unique id) that we need, so we'll supply our own exhaustive list of &fields=
  url = 
  "#{@scopus_search_base}?devId=#{@json_api_key}&search=#{scopus_search}&callback=findit_callback&fields=title,doctype,citedbycount,inwardurl,sourcetitle,issn,vol,issue,page,pubdate,eid,scp,doi,firstAuth,authlist,affiliations,abstract";
  
  # Make the call.
  headers = {}
  headers["Referer"] = @registered_referer if @registered_referer 

  response = open(url, headers).read    
  
  # Okay, Scopus insists on using a jsonp technique to embed the json array in
  # a procedure call. We don't want that, take the actual content out of it's
  # jsonp wrapper. 
  response =~ /^\w*findit_callback\((.*)\);?$/
  response = $1;
  
  # Take the first hit from scopus's results, hope they relevancy ranked it
  # well. For DOI/pmid search, there should ordinarly be only one hit!
  results = JSON.parse(response)

  if ( results["ERROR"])
    RAILS_DEFAULT_LOGGER.error("Error from Scopus API: #{results["ERROR"].inspect}   openurl: ?#{request.referent.to_context_object.kev}")
    return request.dispatched(self, false)
  end

  # For reasons not clear to me, the JSON data structures vary.
  first_hit = nil
  if ( results["PartOK"])
    first_hit = results["PartOK"]["Results"][0]
  elsif ( results["OK"] )
    first_hit = results["OK"]["Results"][0]
  else
    # error. 
  end

  if ( first_hit )
  
    if (@include_cited_by && first_hit["citedbycount"].to_i > 0)
      add_cited_by_response(first_hit, request)
    end

    if (@include_abstract && first_hit["abstract"])
      add_abstract(first_hit, request)
    end

    if (@include_similar)
      url = more_like_this_url(first_hit)
      # Pre-checking for actual hits not currently working, disabled.
      if (true || ( hits = check_for_hits(url) ) > 0 )
        request.add_service_response( :service=>self, :display_text => "#{hits} #{ServiceTypeValue[:similar].display_name_pluralize.downcase.capitalize}", :url => url, :service_type_value => :similar)          
      end                
    end

    if ( @include_more_by_authors)
      url = more_like_this_url(first_hit, :type => "aut")
      # Pre-checking for actual hits not currently working, disabled. 
      if (true || ( hits = check_for_hits(url) ) > 0 )
        request.add_service_response( :service=>self, :display_text => "#{hits} More from these authors", :url => url, :service_type_value => :similar)          
      end        
    end

  end

  return request.dispatched(self, true)
end

- (Object) more_like_this_url(result, options = {}) 



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# File 'lib/service_adaptors/scopus.rb', line 246

def more_like_this_url(result, options = {})
  options[:type] ||= @more_like_this_type
  
  eid = CGI.escape(result["eid"])
  return "#{@inward_more_like_url}?partnerID=#{@partner_id}&rel=#{@scopus_release}&eid=#{eid}&mltType=#{options[:type]}"
end

- (Object) phrase(str)

backslash escapes any double quotes, and embeds string in scopus phrase search double quotes. Does NOT uri-escape.



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# File 'lib/service_adaptors/scopus.rb', line 195

def phrase(str)
  '"' + str.gsub('"', '\\"') + '"'
end

- (Object) scopus_search(request)

Comes up with a scopus advanced search query intended to find the exact known item identified by this citation.

Will try to use DOI or PMID if available. Otherwise will use issn/year/vol/iss/start page if available. In some cases may resort to author/title.



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# File 'lib/service_adaptors/scopus.rb', line 161

def scopus_search(request)
  
  if (doi = get_doi(request.referent))
    return CGI.escape( "DOI(#{phrase(doi)})" )
  elsif (pmid = get_pmid(request.referent))
    return CGI.escape( "PMID(#{phrase(pmid)})" )
  elsif (isbn = get_isbn(request.referent))
    # I don't think scopus has a lot of ISBN-holding citations, but
    # it allows search so we might as well try. 
    return CGI.escape( "ISBN(#{phrase(isbn)})" )
  else            
    # Okay, we're going to try to do it on issn/vol/issue/page.
    # If we don't have issn, we'll reluctantly use journal title
    # (damn you google scholar).
    metadata = request.referent.metadata
    issn = request.referent.issn
    if ( (issn || ! metadata['jtitle'].blank? ) &&
         ! metadata['volume'].blank? &&
         ! metadata['issue'].blank? &&
         ! metadata['spage'].blank? )
      query = "VOLUME(#{phrase(metadata['volume'])}) AND ISSUE(#{phrase(metadata['issue'])}) AND PAGEFIRST(#{phrase(metadata['spage'])}) "
      if ( issn )
        query += " AND (ISSN(#{phrase(issn)}) OR EISSN(#{phrase(issn)}))"
      else
        query += " AND EXACTSRCTITLE(#{phrase(metadata['jtitle'])})"
      end
      return CGI.escape(query)
    end
    
  end
end

- (Object) service_types_generated 



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# File 'lib/service_adaptors/scopus.rb', line 41

def service_types_generated
  types = []
  types.push( ServiceTypeValue[:abstract]) if @include_abstract
  types.push( ServiceTypeValue[:cited_by] ) if @include_cited_by
  types.push( ServiceTypeValue[:abstract] ) if @include_abstract
  types.push( ServiceTypeValue[:similar] ) if @include_similar
  types.push( ServiceTypeValue[@more_by_authors_type] ) if @include_more_by_authors

  return types
end