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.apache.log4j.Logger;
import org.json.JSONObject;
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.DocumentRetrievalId;
import ca.carleton.gcrc.couch.export.impl.DocumentRetrievalLayer;
import ca.carleton.gcrc.couch.export.impl.DocumentRetrievalSchema;
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 = Logger.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 ) {
filter = Filter.ALL;
} else {
for(Filter f : Filter.values()){
if( f.matches(filterStr) ){
filter = f;
}
}
}
if( null == filter ) {
Exception e = new Exception("Unknown filter");
reportError(response,HttpServletResponse.SC_INTERNAL_SERVER_ERROR,e);
return;
}
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<String> identifiers = new Vector<String>();
{
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);
}
// 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
DocumentFilter docFilter = null;
{
docFilter = new DocumentFilterGeometryType(filter);
}
ExportFormat outputFormat = null;
if( Format.GEOJSON == format ) {
try {
SchemaCache schemaCache = new SchemaCacheCouchDb(configuration.getCouchDb());
outputFormat = new ExportFormatGeoJson(schemaCache, docRetrieval, docFilter);
} 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 );
}
String 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");
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("<html><head><title>Export Test Page</title></head><body>");
pw.println("<form action=\"export\" method=\"POST\">");
pw.println("<label for=\"format\">Format: </label>");
pw.println("<select id=\"format\" name=\"format\">");
pw.println("<option value=\"geojson\">GEOJson</option>");
pw.println("<option value=\"invalid\">Invalid Format</option>");
pw.println("</select>");
pw.println("<br/>");
pw.println("<label for=\"filter\">Filter: </label>");
pw.println("<select id=\"filter\" name=\"filter\">");
pw.println("<option value=\"all\">All Documents</option>");
pw.println("<option value=\"points\">Only Point Geometries</option>");
pw.println("<option value=\"lines\">Only Line Geometries</option>");
pw.println("<option value=\"polygons\">Only Polygon Geometries</option>");
pw.println("</select>");
pw.println("<br/>");
pw.println("<label for=\"method\">Method: </label>");
pw.println("<select id=\"method\" name=\"method\">");
pw.println("<option value=\"layer\">Features from a Layer</option>");
pw.println("<option value=\"schema\">Documents with a schema type</option>");
pw.println("<option value=\"doc-id\">Document with identifier</option>");
pw.println("</select>");
pw.println("<br/>");
pw.println("<label for=\"name\">Name: </label>");
pw.println("<input id=\"name\" type=\"text\" name=\"name\"/>");
pw.println("<br/>");
pw.println("<input type=\"submit\" value=\"OK\"/>");
pw.println("</form>");
pw.println("</body></html>");
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);
}
}
}