/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.stanbol.enhancer.engines.zemanta.impl;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
import java.util.EnumMap;
import java.util.Map;
import org.apache.clerezza.rdf.core.Graph;
import org.apache.clerezza.rdf.core.MGraph;
import org.apache.clerezza.rdf.core.impl.SimpleMGraph;
import org.apache.clerezza.rdf.core.serializedform.SupportedFormat;
import org.apache.clerezza.rdf.jena.parser.JenaParserProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* This class wraps the Zemanta API into one method.
* Zemanta is able to return RDF-XML so parsing the response into
* a Graph object is simple.
*
* @author michaelmarth
* @author westei (Rupert Westenthaler)
*/
public class ZemantaAPIWrapper {
private static final Logger log = LoggerFactory.getLogger(ZemantaEnhancementEngine.class);
private static String apiKey;
private static final String URL = "http://api.zemanta.com/services/rest/0.0/";
public ZemantaAPIWrapper(String key) {
apiKey = key;
}
public Graph enhance(String textToAnalyze) throws IOException {
InputStream is = sendRequest(textToAnalyze);
Graph zemantaResponseGraph = parseResponse(is);
return zemantaResponseGraph;
}
private InputStream sendRequest(String textToAnalyze) throws IOException {
try {
URL url = new URL(URL);
HttpURLConnection httpURLConnection = (HttpURLConnection) url
.openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(true);
Map<ZemantaPropertyEnum,String> requestProperties = new EnumMap<ZemantaPropertyEnum, String>(ZemantaPropertyEnum.class);
requestProperties.put(ZemantaPropertyEnum.api_key, apiKey);
requestProperties.put(ZemantaPropertyEnum.text, URLEncoder.encode(textToAnalyze, "UTF8"));
//added an method that adds the default parameters
StringBuilder data = getRequestData(requestProperties);
// StringBuilder data = new StringBuilder();
// data.append("method=zemanta.suggest&").append("api_key=").append(
// apiKey).append("&").append("format=rdfxml&").append(
// "freebase=1").append("&text=").append(
// URLEncoder.encode(textToAnalyze, "UTF8"));
httpURLConnection.addRequestProperty("Content-Length", Integer
.toString(data.length()));
log.info("sending data to Zemanta: " + data);
DataOutputStream dataOutputStream = new DataOutputStream(
httpURLConnection.getOutputStream());
dataOutputStream.write(data.toString().getBytes());
dataOutputStream.close();
InputStream is = httpURLConnection.getInputStream();
return is;
} catch (UnsupportedEncodingException e) {
log.error(e.getMessage(),e);
} catch (MalformedURLException e) {
log.error(e.getMessage(),e);
}
return null;
}
private StringBuilder getRequestData(Map<ZemantaPropertyEnum,String> requestProperties){
StringBuilder data = new StringBuilder();
boolean first = true;
for (ZemantaPropertyEnum property : ZemantaPropertyEnum.values()){
String value = requestProperties.get(property);
if (value == null && property.hasDefault()) {
value = property.defaultValue();
}
//NOTE: value == null may still be OK
if (property.allowedValue(value)) {
//NOTE: also this may still say that NULL is OK
if (value != null) {
if (!first) {
data.append('&');
} else {
first = false;
}
data.append(property.name());
data.append('=');
data.append(value);
} //else property is not present
} else {
//Illegal parameter
log.warn("Value "+value+" is not valied for property "+property);
}
}
return data;
}
private Graph parseResponse(InputStream is) {
JenaParserProvider jenaParserProvider = new JenaParserProvider();
//NOTE(rw): the new third parameter is the base URI used to resolve relative paths
MGraph g = new SimpleMGraph();
jenaParserProvider.parse(g,is, SupportedFormat.RDF_XML,null);
log.debug("graph: " + g.toString());
return g.getGraph();
}
}