D-Net

import {of, throwError as observableThrowError} from 'rxjs';

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

import {HttpClient} from '@angular/common/http';

import {EnvProperties} from '../../../utils/properties/env-properties';

import {ClaimEntity, ClaimResult} from '../claimHelper.class';

import {catchError, map} from 'rxjs/operators';

@Injectable()

export class SearchDataciteService {

  constructor(private http: HttpClient ) {}

  searchDataciteResults(term: string, size: number, page: number, properties: EnvProperties, parse: boolean = false): any {

    //console.info("In search datacite results "+term+ " "+properties.searchDataciteAPIURL);

    let url = properties.searchDataciteAPIURL + '?query=' + term + '&page[size]=' + size + '&page[number]=' + page;

    let key = url;

    return this.http.get((properties.useCache) ? (properties.cacheUrl + encodeURIComponent(url)) : url)

      .pipe(map(request => [request["meta"]["total"], (parse ? SearchDataciteService.parse(request["data"]) : request)]));

    //.catch(this.handleError);

  }

  getDataciteResultByDOI(doi: string, properties: EnvProperties, parse: boolean = false): any {

    let url = properties.searchDataciteAPIURL + '/' + doi;

    let key = url;

    return this.http.get((properties.useCache) ? (properties.cacheUrl + encodeURIComponent(url)) : url)

      .pipe(map(request =>  (parse ? SearchDataciteService.parse([request["data"]])[0] : request)), catchError(err => of(null)));

  }

  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 observableThrowError(error  || 'Server error');

  }

  private extractData(res: any) {

    if (res.status < 200 || res.status >= 300) {

      throw new Error('Bad response status: ' + res.status);

    }

    let body = res.json();

    return body.data || {};

  }

  static parse(response): ClaimEntity[] {

    const results: ClaimEntity[] = [];

    console.log(response);

    for (let i = 0; i < response.length; i++) {

      const item = response[i];

      const entity: ClaimEntity = new ClaimEntity();

      entity.result = new ClaimResult();

      entity.result.publisher = null;

      entity.result.journal = null;

      entity.result.DOI = item.attributes.doi;

      entity.id = item.attributes.doi;

      entity.title = item.attributes.title;

      entity.result.url = 'http://dx.doi.org/' + item.attributes.doi;

      entity.result.source = 'datacite';

      entity.type = 'dataset';

      entity.result.date = item.attributes.published;

      entity.result.accessRights = "OPEN";

      entity.result.publisher = item.attributes['container-title'];

      entity.result.journal = null;

      entity.result.record = item;

      if (item.attributes.author) {

        entity.result.authors = [];

        for (let j = 0; j < item.attributes.author.length; j++) {

          const author = item.attributes.author[j];

          entity.result.authors.push((author.family) ? author.family + ', ' + author.given : author.literal);

        }

      }

      results.push(entity);

    }

    return results;

  }

}