78 lines
2.9 KiB
Java
78 lines
2.9 KiB
Java
package eu.dnetlib.data.collector.plugins.ariadneplus.ehri;
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import java.io.IOException;
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import java.io.InputStreamReader;
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import java.net.URI;
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import java.net.URISyntaxException;
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import java.util.Iterator;
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import com.google.common.collect.Iterables;
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import com.google.common.collect.Lists;
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import com.google.gson.JsonArray;
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import com.google.gson.JsonObject;
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import com.google.gson.JsonParser;
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import eu.dnetlib.rmi.data.CollectorServiceException;
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import org.apache.commons.logging.Log;
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import org.apache.commons.logging.LogFactory;
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import org.apache.http.HttpEntity;
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import org.apache.http.client.methods.CloseableHttpResponse;
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import org.apache.http.client.methods.HttpPost;
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import org.apache.http.entity.StringEntity;
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import org.apache.http.impl.client.CloseableHttpClient;
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import org.apache.http.impl.client.HttpClients;
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import org.apache.http.util.EntityUtils;
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/**
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* IDs of units are retrieved from the EHRI GraphQL API, see docs at https://portal.ehri-project.eu/api/graphql
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*
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* Created by Alessia Bardi on 19/04/2017.
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*
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* @author Alessia Bardi
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*/
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public class EHRIGraphQLClient {
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private static final Log log = LogFactory.getLog(EHRIGraphQLClient.class);
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public Iterator<String> collect(final String baseURL, final String graphQLQuery) throws URISyntaxException, IOException, CollectorServiceException {
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/*
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The curl equivalent:
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curl --header X-Stream:true \
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--header Content-type:application/json \
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https://portal.ehri-project.eu/api/graphql \
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--data-binary '{"query":"{topLevelDocumentaryUnits{items{id}}}"}'
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*/
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CloseableHttpClient httpClient = HttpClients.createDefault();
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URI baseURI = new URI(baseURL);
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HttpPost httpPost = new HttpPost();
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httpPost.setURI(baseURI);
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httpPost.setHeader("X-Stream", "true");
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httpPost.setHeader("Content-type", "application/json" );
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log.info(graphQLQuery);
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StringEntity postQuery = new StringEntity(graphQLQuery);
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httpPost.setEntity(postQuery);
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HttpEntity entity = null;
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try(CloseableHttpResponse response = httpClient.execute(httpPost)) {
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switch(response.getStatusLine().getStatusCode()){
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case 200:
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entity = response.getEntity();
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InputStreamReader reader = new InputStreamReader(entity.getContent());
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return getIdentifiers(reader);
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default:
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log.error(httpPost);
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log.error(response.getStatusLine());
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throw new CollectorServiceException(response.getStatusLine().toString());
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}
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} finally {
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if(entity != null) EntityUtils.consume(entity);
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}
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}
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protected Iterator<String> getIdentifiers(final InputStreamReader input){
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JsonObject jsonObject = new JsonParser().parse(input).getAsJsonObject();
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JsonArray items = jsonObject.getAsJsonObject("data").getAsJsonObject("topLevelDocumentaryUnits").getAsJsonArray("items");
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log.debug(items);
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return Lists.newArrayList(Iterables.transform(items, jelem -> jelem.getAsJsonObject().get("id").getAsString())).iterator();
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}
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}
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