D-Net

package eu.dnetlib.functionality.modular.ui.oai;

import com.google.common.base.Joiner;

import eu.dnetlib.functionality.modular.ui.oai.objects.OaiRequest;

import eu.dnetlib.functionality.modular.ui.oai.objects.ResponseDetails;

import eu.dnetlib.miscutils.datetime.DateUtils;

import org.apache.commons.lang.math.NumberUtils;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.apache.http.HttpStatus;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.impl.client.HttpClients;

import org.dom4j.Document;

import org.dom4j.Node;

import org.dom4j.io.SAXReader;

import org.springframework.core.io.ClassPathResource;

import org.springframework.core.io.Resource;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestBody;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.ResponseBody;

import javax.xml.transform.Transformer;

import javax.xml.transform.TransformerFactory;

import javax.xml.transform.stream.StreamResult;

import javax.xml.transform.stream.StreamSource;

import java.io.StringWriter;

@Controller

public class OaiExplorerInternalController {

	private final static Resource oaiXslt = new ClassPathResource("/eu/dnetlib/functionality/modular/ui/xslt/oai.xslt");

	private static final Log log = LogFactory.getLog(OaiExplorerInternalController.class);

	@RequestMapping("/ui/oai_verb")

	public @ResponseBody String oaiVerb(@RequestBody(required=true) OaiRequest req) throws Exception {

		return callOaiVerb(req);

	}

	@RequestMapping("/ui/test_oai_verb")

	public @ResponseBody ResponseDetails testOaiVerb(@RequestBody final OaiRequest req) throws Exception {

		final ResponseDetails response = new ResponseDetails();

		final Document doc = callOaiVerb(req, response);

		if (response.isValid() && doc != null) {

			final OaiRequest nextCall = new OaiRequest();

			nextCall.setBaseUrl(req.getBaseUrl());

			if ("Identify".equals(req.getVerb())) {

				nextCall.setVerb("ListSets");

			} else if ("ListSets".equals(req.getVerb())) {

				nextCall.setVerb("ListMetadataFormats");

			} else if ("ListMetadataFormats".equals(req.getVerb())) {

				nextCall.setVerb("ListRecords");

				if (doc.selectSingleNode("//*[local-name()='metadataPrefix' and text()='oai_dc']") != null) {

					nextCall.setMdf("oai_dc");

				} else {

					nextCall.setMdf(doc.selectSingleNode("//*[local-name()='metadataPrefix']").getText());

				}

			} else if ("ListRecords".equals(req.getVerb())) {

				nextCall.setVerb("ListIdentifiers");

				nextCall.setMdf(req.getMdf());

			} else if ("ListIdentifiers".equals(req.getVerb())) {

				nextCall.setVerb("GetRecord");

				nextCall.setMdf(req.getMdf());

				nextCall.setId(doc.selectSingleNode("//*[local-name()='identifier']").getText());

			} else if ("GetRecord".equals(req.getVerb())) {

				// NOTHING

			}

			response.setNextCall(nextCall);

		}

		return response;

	}

	@RequestMapping("/ui/test_harvesting")

	public @ResponseBody ResponseDetails testHarvesting(@RequestBody final OaiRequest req) throws Exception {

		final ResponseDetails response = new ResponseDetails();

		final Document doc = callOaiVerb(req, response);

		if (response.isValid() && doc != null) {

			final Node node = doc.selectSingleNode("//*[local-name() = 'resumptionToken']");

			if (node != null) {

				response.setSize(doc.selectNodes("//*[local-name()='" + req.getVerb() + "']/*[local-name() != 'resumptionToken']").size());

				response.setCursor(NumberUtils.toInt(node.valueOf("@cursor"), -1));

				response.setTotal(NumberUtils.toInt(node.valueOf("@completeListSize"), -1));

				final OaiRequest nextCall = new OaiRequest();

				nextCall.setBaseUrl(req.getBaseUrl());

				nextCall.setVerb(req.getVerb());

				nextCall.setToken(node.getText());

				response.setNextCall(nextCall);

			}

		}

		return response;

	}

	private String callOaiVerb(final OaiRequest req) throws Exception {

		final HttpGet method = new HttpGet(!req.toQueryParams().isEmpty() ? req.getBaseUrl() + "?" + Joiner.on("&").join(req.toQueryParams()) : req.getBaseUrl());

		method.addHeader("Content-type", "text/xml; charset=UTF-8");

		try(CloseableHttpResponse response = HttpClients.createDefault().execute(method)) {

			int responseCode = response.getStatusLine().getStatusCode();

			if (HttpStatus.SC_OK != responseCode) {

				log.error("Error downloading from baseUrl: " + req.getBaseUrl());

				throw new RuntimeException("Error: " + responseCode);

			}

			final TransformerFactory tfactory = TransformerFactory.newInstance();

			final Transformer transformer = tfactory.newTransformer(new StreamSource(oaiXslt.getInputStream()));

			final StringWriter output = new StringWriter();

			transformer.transform(new StreamSource(response.getEntity().getContent()), new StreamResult(output));

			return output.toString();

		}

	}

	private Document callOaiVerb(final OaiRequest req, final ResponseDetails details) {

		final HttpGet method = new HttpGet(!req.toQueryParams().isEmpty() ? req.getBaseUrl() + "?" + Joiner.on("&").join(req.toQueryParams()) : req.getBaseUrl());

		method.addHeader("Content-type", "text/xml; charset=UTF-8");

		Document doc = null;

		final long start = DateUtils.now();

		try(CloseableHttpResponse response = HttpClients.createDefault().execute(method)) {

			int responseCode = response.getStatusLine().getStatusCode();

			details.setHttpCode(responseCode);

			details.setValid(HttpStatus.SC_OK == responseCode);

			if (HttpStatus.SC_OK == responseCode) {

				try {

					doc = new SAXReader().read(response.getEntity().getContent());

				} catch (Exception e) {

					details.setValid(false);

					details.setError(e.getMessage());

				}

			}

		} catch (Exception e) {

			details.setValid(false);

			details.setError(e.getMessage());

		}

		details.setTime(DateUtils.now() - start);

		details.setVerb(req.getVerb());

		return doc;

	}

}