/*
* 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.solr.response;
import java.io.IOException;
import java.io.Writer;
import java.util.Iterator;
import java.util.List;
import org.apache.lucene.index.IndexableField;
import org.apache.solr.common.SolrDocument;
import org.apache.solr.common.SolrDocumentList;
import org.apache.solr.common.SolrException;
import org.apache.solr.common.SolrException.ErrorCode;
import org.apache.solr.common.params.CommonParams;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.response.transform.WriteableGeoJSON;
import org.apache.solr.schema.AbstractSpatialFieldType;
import org.apache.solr.schema.SchemaField;
import org.apache.solr.search.ReturnFields;
import org.locationtech.spatial4j.context.SpatialContext;
import org.locationtech.spatial4j.io.ShapeWriter;
import org.locationtech.spatial4j.io.SupportedFormats;
import org.locationtech.spatial4j.shape.Shape;
/**
* Extend the standard JSONResponseWriter to support GeoJSON. This writes
* a {@link SolrDocumentList} with a 'FeatureCollection', following the
* specification in <a href="http://geojson.org/">geojson.org</a>
*/
public class GeoJSONResponseWriter extends JSONResponseWriter {
public static final String FIELD = "geojson.field";
@Override
public void write(Writer writer, SolrQueryRequest req, SolrQueryResponse rsp) throws IOException {
String geofield = req.getParams().get(FIELD, null);
if(geofield==null || geofield.length()==0) {
throw new SolrException(ErrorCode.BAD_REQUEST, "GeoJSON. Missing parameter: '"+FIELD+"'");
}
SchemaField sf = req.getSchema().getFieldOrNull(geofield);
if(sf==null) {
throw new SolrException(ErrorCode.BAD_REQUEST, "GeoJSON. Unknown field: '"+FIELD+"'="+geofield);
}
SupportedFormats formats = null;
if(sf.getType() instanceof AbstractSpatialFieldType) {
SpatialContext ctx = ((AbstractSpatialFieldType)sf.getType()).getSpatialContext();
formats = ctx.getFormats();
}
JSONWriter w = new GeoJSONWriter(writer, req, rsp,
geofield,
formats);
try {
w.writeResponse();
} finally {
w.close();
}
}
}
class GeoJSONWriter extends JSONWriter {
final SupportedFormats formats;
final ShapeWriter geowriter;
final String geofield;
public GeoJSONWriter(Writer writer, SolrQueryRequest req, SolrQueryResponse rsp,
String geofield, SupportedFormats formats) {
super(writer, req, rsp);
this.geofield = geofield;
this.formats = formats;
if(formats==null) {
this.geowriter = null;
}
else {
this.geowriter = formats.getGeoJsonWriter();
}
}
@Override
public void writeResponse() throws IOException {
if(req.getParams().getBool(CommonParams.OMIT_HEADER, false)) {
if(wrapperFunction!=null) {
writer.write(wrapperFunction + "(");
}
rsp.removeResponseHeader();
NamedList<Object> vals = rsp.getValues();
Object response = vals.remove("response");
if(vals.size()==0) {
writeVal(null, response);
}
else {
throw new SolrException(ErrorCode.BAD_REQUEST,
"GeoJSON with "+CommonParams.OMIT_HEADER +
" can not return more than a result set");
}
if(wrapperFunction!=null) {
writer.write(')');
}
writer.write('\n'); // ending with a newline looks much better from the command line
}
else {
super.writeResponse();
}
}
@Override
public void writeSolrDocument(String name, SolrDocument doc, ReturnFields returnFields, int idx) throws IOException {
if( idx > 0 ) {
writeArraySeparator();
}
indent();
writeMapOpener(-1);
incLevel();
writeKey("type", false);
writeVal(null, "Feature");
Object val = doc.getFieldValue(geofield);
if(val != null) {
writeFeatureGeometry(val);
}
boolean first=true;
for (String fname : doc.getFieldNames()) {
if (fname.equals(geofield) || ((returnFields!= null && !returnFields.wantsField(fname)))) {
continue;
}
writeMapSeparator();
if (first) {
indent();
writeKey("properties", false);
writeMapOpener(-1);
incLevel();
first=false;
}
indent();
writeKey(fname, true);
val = doc.getFieldValue(fname);
// SolrDocument will now have multiValued fields represented as a Collection,
// even if only a single value is returned for this document.
if (val instanceof List) {
// shortcut this common case instead of going through writeVal again
writeArray(name,((Iterable)val).iterator());
} else {
writeVal(fname, val);
}
}
// GeoJSON does not really support nested FeatureCollections
if(doc.hasChildDocuments()) {
if(first == false) {
writeMapSeparator();
indent();
}
writeKey("_childDocuments_", true);
writeArrayOpener(doc.getChildDocumentCount());
List<SolrDocument> childDocs = doc.getChildDocuments();
for(int i=0; i<childDocs.size(); i++) {
writeSolrDocument(null, childDocs.get(i), null, i);
}
writeArrayCloser();
}
// check that we added any properties
if(!first) {
decLevel();
writeMapCloser();
}
decLevel();
writeMapCloser();
}
protected void writeFeatureGeometry(Object geo) throws IOException
{
// Support multi-valued geometries
if(geo instanceof Iterable) {
Iterator iter = ((Iterable)geo).iterator();
if(!iter.hasNext()) {
return; // empty list
}
else {
geo = iter.next();
// More than value
if(iter.hasNext()) {
writeMapSeparator();
indent();
writeKey("geometry", false);
incLevel();
// TODO: in the future, we can be smart and try to make this the appropriate MULTI* value
// if all the values are the same
// { "type": "GeometryCollection",
// "geometries": [
writeMapOpener(-1);
writeKey("type",false);
writeStr(null, "GeometryCollection", false);
writeMapSeparator();
writeKey("geometries", false);
writeArrayOpener(-1); // no trivial way to determine array size
incLevel();
// The first one
indent();
writeGeo(geo);
while(iter.hasNext()) {
// Each element in the array
writeArraySeparator();
indent();
writeGeo(iter.next());
}
decLevel();
writeArrayCloser();
writeMapCloser();
decLevel();
return;
}
}
}
// Single Value
if(geo!=null) {
writeMapSeparator();
indent();
writeKey("geometry", false);
writeGeo(geo);
}
}
protected void writeGeo(Object geo) throws IOException {
Shape shape = null;
String str = null;
if(geo instanceof Shape) {
shape = (Shape)geo;
}
else if(geo instanceof IndexableField) {
str = ((IndexableField)geo).stringValue();
}
else if(geo instanceof WriteableGeoJSON) {
shape = ((WriteableGeoJSON)geo).shape;
}
else {
str = geo.toString();
}
if(str !=null) {
// Assume it is well formed JSON
if(str.startsWith("{") && str.endsWith("}")) {
writer.write(str);
return;
}
if(formats==null) {
// The check is here and not in the constructor because we do not know if the
// *stored* values for the field look like JSON until we actually try to read them
throw new SolrException(ErrorCode.BAD_REQUEST,
"GeoJSON unable to write field: '&"+ GeoJSONResponseWriter.FIELD +"="+geofield+"' ("+str+")");
}
shape = formats.read(str);
}
if(geowriter==null) {
throw new SolrException(ErrorCode.BAD_REQUEST,
"GeoJSON unable to write field: '&"+ GeoJSONResponseWriter.FIELD +"="+geofield+"'");
}
if(shape!=null) {
geowriter.write(writer, shape);
}
}
@Override
public void writeStartDocumentList(String name,
long start, int size, long numFound, Float maxScore) throws IOException
{
writeMapOpener((maxScore==null) ? 3 : 4);
incLevel();
writeKey("type",false);
writeStr(null, "FeatureCollection", false);
writeMapSeparator();
writeKey("numFound",false);
writeLong(null,numFound);
writeMapSeparator();
writeKey("start",false);
writeLong(null,start);
if (maxScore!=null) {
writeMapSeparator();
writeKey("maxScore",false);
writeFloat(null,maxScore);
}
writeMapSeparator();
// if can we get bbox of all results, we should write it here
// indent();
writeKey("features",false);
writeArrayOpener(size);
incLevel();
}
@Override
public void writeEndDocumentList() throws IOException
{
decLevel();
writeArrayCloser();
decLevel();
indent();
writeMapCloser();
}
}