/*
* 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.pig.piggybank.evaluation.util;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.pig.EvalFunc;
import org.apache.pig.FuncSpec;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.data.DataType;
import org.apache.pig.data.Tuple;
import org.apache.pig.impl.logicalLayer.FrontendException;
import org.apache.pig.impl.logicalLayer.schema.Schema;
/**
* This small UDF takes a search engine URL (Google/Yahoo/AOL/Live) containing
* the search query and extracts it. The URL is assumed to be encoded. The query
* is normalized, converting it to lower-case, removing punctuations, removing
* extra spaces.
*/
public class SearchQuery extends EvalFunc<String> {
private static Pattern queryPattern = Pattern
.compile("(?<=([\\&\\?](as_)?[pq]=)).*?(\\z|(?=[\\&\\\"]))");
@Override
public String exec(Tuple tuple) throws IOException {
if (tuple == null || tuple.size() < 1) {
return null;
}
try {
String refURL = (String) tuple.get(0);
return extractQuery(refURL);
} catch (ExecException ee) {
throw new IOException(ee);
}
}
private String extractQuery(String url) {
try {
String refURL = url;
if (refURL == null || refURL.isEmpty())
return refURL;
String query = null;
refURL = refURL.toLowerCase().trim();
Matcher matcher = queryPattern.matcher(refURL);
if (matcher.find()) {
query = matcher.group();
query = URLDecoder.decode(query, "UTF-8"); // decode query
query = query.replaceAll("[\\p{Punct}]+", ""); // remove punctuation
query = query.trim().replaceAll("[\\s]+", " "); // remove extra spaces
query = (query.length() > 80) ? query.substring(0, 80) : query;
}
return query;
} catch (UnsupportedEncodingException ignore) { // should never happen
}
return null;
}
/* (non-Javadoc)
* @see org.apache.pig.EvalFunc#getArgToFuncMapping()
*/
@Override
public List<FuncSpec> getArgToFuncMapping() throws FrontendException {
List<FuncSpec> funcList = new ArrayList<FuncSpec>();
funcList.add(new FuncSpec(this.getClass().getName(), new Schema(new Schema.FieldSchema(null, DataType.CHARARRAY))));
return funcList;
}
@Override
public Schema outputSchema(Schema input) {
try {
Schema s = new Schema();
s.add(new Schema.FieldSchema("query", DataType.CHARARRAY));
return s;
} catch (Exception e) {
return null;
}
}
}