D-Net

import {Injectable} from '@angular/core';

import {Http, Response} from '@angular/http';

import {Observable}     from 'rxjs/Observable';

import {OpenaireProperties} from '../../../utils/properties/openaireProperties';

import 'rxjs/add/observable/of';

import 'rxjs/add/operator/do';

import 'rxjs/add/operator/share';

@Injectable()

export class SearchCrossrefService {

  constructor( private http: Http ) {}

  searchCrossrefResults (term: string, size : number, page : number):any {

     let url = OpenaireProperties.getSearchCrossrefAPIURL()+'?query='+term+'&rows='+size+'&offset='+(size*(page-1));

     let key = url;

     return this.http.get( (OpenaireProperties.isCacheEnabled())? (OpenaireProperties.getCacheUrl()+encodeURIComponent(url)): url)

                     .map(request => <any> request.json().message)

                     .do(items => console.log("Crossref Results: total results = "+items['total-results']+" keyword = "+term));

                     //.catch(this.handleError);

    }

    searchCrossrefByDOIs(DOIs: string[]):any {

      /*

      $request ="http://api.crossref.org/works"."?filter=";

                      foreach($dois as $doi){

                          $request.="doi:".urlencode( trim($doi)).",";

                      }

      */

      var doisParams = "";

      for(var i =0 ;i < DOIs.length; i++){

        doisParams+=(doisParams.length > 0?",":"")+'doi:'+DOIs[i];

      }

       let url = OpenaireProperties.getSearchCrossrefAPIURL()+'?filter='+doisParams;

       let key = url;

       return this.http.get( (OpenaireProperties.isCacheEnabled())? (OpenaireProperties.getCacheUrl()+encodeURIComponent(url)): url)

                       .map(request => <any> request.json().message)

                       .do(items => console.log("Crossref Results: total results = "+items['total-results']+" for doi = "+doisParams));

                       //.catch(this.handleError);

      }

      searchCrossrefByMultipleDOIs(dois: string[]):any {

        let url = OpenaireProperties.getSearchCrossrefAPIURL()+'?filter=doi:';

        for(var i=0; i<dois.length; i++){

          url=url+(url.length==0?'':',')+'doi:'+dois[i];

        }

        url = OpenaireProperties.getSearchCrossrefAPIURL()+'?filter='+url;

        let key = url;

         return this.http.get( (OpenaireProperties.isCacheEnabled())? (OpenaireProperties.getCacheUrl()+encodeURIComponent(url)): url)

                         .map(request => <any> request.json().message)

                         .do(items => console.log("Crossref Results: total results = "+items['total-results']));

                         //.catch(this.handleError);

        }

  private handleError (error: Response) {

    // in a real world app, we may send the error to some remote logging infrastructure

    // instead of just logging it to the console

    console.log(error);

    return Observable.throw(error  || 'Server error');

  }

}