ca.carleton.gcrc.couch.export.ExportServlet Maven / Gradle / Ivy
package ca.carleton.gcrc.couch.export;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.Date;
import java.util.List;
import java.util.Vector;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.json.JSONArray;
import org.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import ca.carleton.gcrc.couch.export.ExportUtils.Filter;
import ca.carleton.gcrc.couch.export.ExportUtils.Format;
import ca.carleton.gcrc.couch.export.ExportUtils.Method;
import ca.carleton.gcrc.couch.export.impl.DocumentFilterGeometryType;
import ca.carleton.gcrc.couch.export.impl.DocumentRetrievalFiltered;
import ca.carleton.gcrc.couch.export.impl.DocumentRetrievalId;
import ca.carleton.gcrc.couch.export.impl.DocumentRetrievalLayer;
import ca.carleton.gcrc.couch.export.impl.DocumentRetrievalSchema;
import ca.carleton.gcrc.couch.export.impl.ExportFormatCSV;
import ca.carleton.gcrc.couch.export.impl.ExportFormatGeoJson;
import ca.carleton.gcrc.couch.export.impl.SchemaCacheCouchDb;
@SuppressWarnings("serial")
public class ExportServlet extends HttpServlet {
final protected Logger logger = LoggerFactory.getLogger(this.getClass());
private ExportConfiguration configuration;
public ExportServlet() {
}
public void init(ServletConfig config) throws ServletException {
super.init(config);
// Pick up configuration
Object configurationObj = config.getServletContext().getAttribute(ExportConfiguration.CONFIGURATION_KEY);
if( null == configurationObj ) {
throw new ServletException("Can not find configuration object");
}
if( configurationObj instanceof ExportConfiguration ){
configuration = (ExportConfiguration)configurationObj;
} else {
throw new ServletException("Invalid class for configuration: "+configurationObj.getClass().getName());
}
}
public void destroy() {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String paths[] = request.getRequestURI().split("/");
String path = paths[ paths.length - 1 ];
if( "welcome".equalsIgnoreCase(path) ) {
doGetWelcome(request, response);
} else if( "test".equalsIgnoreCase(path) ) {
doGetTest(request, response);
} else {
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Unknown request");
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// Ignore path. Allows client to set any download file name
// Parse format
Format format = null;
{
String formatStr = request.getParameter("format");
if( null == formatStr ) {
format = Format.GEOJSON;
} else {
for(Format f : Format.values()){
if( f.matches(formatStr) ){
format = f;
}
}
}
if( null == format ) {
Exception e = new Exception("Unknown format");
reportError(response,HttpServletResponse.SC_INTERNAL_SERVER_ERROR,e);
return;
}
logger.debug("Export Format: "+format.name());
}
// Parse filter
Filter filter = null;
{
String filterStr = request.getParameter("filter");
if( null != filterStr ) {
for(Filter f : Filter.values()){
if( f.matches(filterStr) ){
filter = f;
}
}
}
if( null != filter ) {
logger.debug("Export Filter: "+filter.name());
}
}
// Parse method
Method method = null;
{
String methodStr = request.getParameter("method");
if( null != methodStr ) {
for(Method m : Method.values()){
if( m.matches(methodStr) ){
method = m;
}
}
}
if( null == method ) {
Exception e = new Exception("Unknown method");
reportError(response,HttpServletResponse.SC_INTERNAL_SERVER_ERROR,e);
return;
}
logger.debug("Export Method: "+method.name());
}
// Parse identifier
String identifier = null;
List identifiers = new Vector();
{
String[] ids = request.getParameterValues("name");
if( null != ids ) {
for(String id : ids){
identifiers.add(id);
}
}
if( identifiers.size() > 0 ) {
identifier = identifiers.get(0);
}
if( null == identifier ) {
Exception e = new Exception("Unknown name");
reportError(response,HttpServletResponse.SC_INTERNAL_SERVER_ERROR,e);
return;
}
logger.debug("Export Name: "+identifier);
}
// Parse contentType
String contentType = null;
{
String[] contentTypes = request.getParameterValues("contentType");
if( null != contentTypes ) {
for(String t : contentTypes){
contentType = t;
}
}
if( null != contentType ) {
logger.debug("Content-Type: "+contentType);
}
}
// Build doc retrieval based on method
DocumentRetrieval docRetrieval = null;
if( Method.LAYER == method ) {
try {
docRetrieval = DocumentRetrievalLayer.create(configuration.getCouchDb(), identifier);
} catch (Exception e) {
throw new ServletException("Problem retrieving documents from layer: "+identifier,e);
}
} else if( Method.SCHEMA == method ) {
try {
docRetrieval = DocumentRetrievalSchema.create(configuration.getCouchDb(), identifier);
} catch (Exception e) {
throw new ServletException("Problem retrieving documents from schema: "+identifier,e);
}
} else if( Method.DOC_ID == method ) {
try {
docRetrieval = DocumentRetrievalId.create(configuration.getCouchDb(), identifiers);
} catch (Exception e) {
throw new ServletException("Problem retrieving documents from doc ids: "+identifiers,e);
}
} else {
throw new ServletException("Do not know how to handle method: "+method.name());
}
// Build document filter based on filter type
if( null != filter ){
DocumentFilter docFilter = new DocumentFilterGeometryType(filter);
DocumentRetrievalFiltered filteredRetrieval =
new DocumentRetrievalFiltered(docRetrieval, docFilter);
docRetrieval = filteredRetrieval;
}
ExportFormat outputFormat = null;
if( Format.GEOJSON == format ) {
try {
SchemaCache schemaCache = new SchemaCacheCouchDb(configuration.getCouchDb());
outputFormat = new ExportFormatGeoJson(schemaCache, docRetrieval);
} catch (Exception e) {
throw new ServletException("Problem setting up format: "+format.name(),e);
}
} else if( Format.CSV == format ) {
try {
SchemaCache schemaCache = new SchemaCacheCouchDb(configuration.getCouchDb());
outputFormat = new ExportFormatCSV(schemaCache, docRetrieval);
} catch (Exception e) {
throw new ServletException("Problem setting up format: "+format.name(),e);
}
} else {
throw new ServletException("Do not know how to handle format: "+format.name());
}
String charEncoding = outputFormat.getCharacterEncoding();
if( null != charEncoding ) {
response.setCharacterEncoding( charEncoding );
}
if( null == contentType ) {
contentType = outputFormat.getMimeType();
}
if( null != contentType ) {
response.setContentType(contentType);
}
response.setHeader("Cache-Control", "no-cache,must-revalidate");
response.setDateHeader("Expires", (new Date()).getTime());
OutputStream os = response.getOutputStream();
try {
outputFormat.outputExport(os);
} catch (Exception e) {
throw new ServletException("Error during export process",e);
}
os.flush();
}
private void doGetWelcome(HttpServletRequest request, HttpServletResponse response) throws IOException {
try {
// Return JSON object to acknowledge the welcome
{
JSONObject obj = new JSONObject();
obj.put("ok", true);
obj.put("message", "export service");
// Formats
{
JSONArray formats = new JSONArray();
for(Format f : Format.values()){
formats.put(f.getLabel());
}
obj.put("formats", formats);
}
// Filters
{
JSONArray filters = new JSONArray();
for(Filter f : Filter.values()){
filters.put(f.getLabel());
}
obj.put("filters", filters);
}
// Methods
{
JSONArray methods = new JSONArray();
for(Method f : Method.values()){
methods.put(f.getLabel());
}
obj.put("methods", methods);
}
response.setCharacterEncoding("utf-8");
response.setContentType("text/plain");
response.setHeader("Cache-Control", "no-cache,must-revalidate");
response.setDateHeader("Expires", (new Date()).getTime());
OutputStreamWriter osw = new OutputStreamWriter(response.getOutputStream(),"UTF-8");
obj.write(osw);
osw.flush();
}
} catch (Exception e) {
reportError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e);
}
}
private void doGetTest(HttpServletRequest request, HttpServletResponse response) throws IOException {
try {
response.setCharacterEncoding("utf-8");
response.setContentType("text/html");
response.setHeader("Cache-Control", "no-cache,must-revalidate");
response.setDateHeader("Expires", (new Date()).getTime());
OutputStreamWriter osw = new OutputStreamWriter(response.getOutputStream(),"UTF-8");
PrintWriter pw = new PrintWriter(osw);
pw.println("Export Test Page ");
pw.println("");
pw.println("");
osw.flush();
} catch (Exception e) {
reportError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e);
}
}
private void reportError(HttpServletResponse response, int code, Throwable error) throws IOException {
if( null != error ) {
response.sendError(code, error.getMessage());
} else {
response.sendError(code);
}
}
}
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