package edu.stanford.nlp.pipeline.webapp;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.function.Consumer;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import edu.stanford.nlp.io.RuntimeIOException;
import edu.stanford.nlp.pipeline.AnnotationOutputter;
import nu.xom.Builder;
import nu.xom.Document;
import nu.xom.Nodes;
import nu.xom.xslt.XSLTransform;
import org.apache.commons.lang3.StringEscapeUtils;
import edu.stanford.nlp.pipeline.Annotation;
import edu.stanford.nlp.pipeline.StanfordCoreNLP;
import edu.stanford.nlp.pipeline.XMLOutputter;
public class CoreNLPServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private StanfordCoreNLP pipeline;
private XSLTransform corenlpTransformer;
private String defaultFormat = "pretty";
private static final int MAXIMUM_QUERY_LENGTH = 4096;
public void init()
throws ServletException
{
pipeline = new StanfordCoreNLP();
String xslPath = getServletContext().
getRealPath("/WEB-INF/data/CoreNLP-to-HTML.xsl");
try {
Builder builder = new Builder();
Document stylesheet = builder.build(new File(xslPath));
corenlpTransformer = new XSLTransform(stylesheet);
} catch (Exception e) {
throw new ServletException(e);
}
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
if (request.getCharacterEncoding() == null) {
request.setCharacterEncoding("utf-8");
}
response.setContentType("text/html; charset=UTF-8");
this.getServletContext().getRequestDispatcher("/header.jsp").
include(request, response);
addResults(request, response);
this.getServletContext().getRequestDispatcher("/footer.jsp").
include(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
doGet(request, response);
}
public void addResults(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException
{
String input = request.getParameter("input");
if (input == null) {
return;
}
input = input.trim();
if (input.equals("")) {
return;
}
PrintWriter out = response.getWriter();
if (input.length() > MAXIMUM_QUERY_LENGTH) {
out.print("<div>This query is too long. If you want to run very long queries, please download and use our <a href=\"http://nlp.stanford.edu/software/corenlp.shtml\">publicly released distribution</a>.</div>");
return;
}
Annotation annotation = new Annotation(input);
pipeline.annotate(annotation);
String outputFormat = request.getParameter("outputFormat");
if (outputFormat == null || outputFormat.trim().equals("")) {
outputFormat = this.defaultFormat;
}
switch (outputFormat) {
case "xml":
outputXml(out, annotation);
break;
case "json":
outputJson(out, annotation);
break;
case "conll":
outputCoNLL(out, annotation);
break;
case "pretty":
outputPretty(out, annotation);
break;
default:
outputVisualise(out, annotation);
break;
}
}
public void outputVisualise(PrintWriter out, Annotation annotation)
throws ServletException, IOException
{
// Note: A lot of the HTML generation in this method could/should be
// done at a templating level, but as-of-yet I am not entirely sure how
// this should be done in jsp. Also, a lot of the HTML is unnecessary
// for the other outputs such as pretty print and XML.
// Div for potential error messages when fetching the configuration.
out.println("<div id=\"config_error\">");
out.println("</div>");
// Insert divs that will be used for each visualisation type.
final int visualiserDivPxWidth = 700;
Map<String, String> nameByAbbrv = new LinkedHashMap<String, String>();
nameByAbbrv.put("pos", "Part-of-Speech");
nameByAbbrv.put("ner", "Named Entity Recognition");
nameByAbbrv.put("coref", "Coreference");
nameByAbbrv.put("basic_dep", "Basic dependencies");
nameByAbbrv.put("collapsed_dep", "Collapsed dependencies");
nameByAbbrv.put("collapsed_ccproc_dep",
"Collapsed CC-processed dependencies");
for (Map.Entry<String, String> entry : nameByAbbrv.entrySet()) {
out.println("<h2>" + entry.getValue() + ":</h2>");
out.println("<div id=\"" + entry.getKey() + "\" style=\"width:"
+ visualiserDivPxWidth + "px\">");
out.println(" <div id=\"" + entry.getKey() + "_loading\">");
out.println(" <p>Loading...</p>");
out.println(" </div>");
out.println("</div>");
out.println("");
}
// Time to get the XML data into HTML.
StringWriter xmlOutput = new StringWriter();
pipeline.xmlPrint(annotation, xmlOutput);
xmlOutput.flush();
// Escape the XML to be embeddable into a Javascript string.
String escapedXml = xmlOutput.toString().replaceAll("\\r\\n|\\r|\\n", ""
).replace("\"", "\\\"");
// Inject the XML results into the HTML to be retrieved by the Javascript.
out.println("<script type=\"text/javascript\">");
out.println("// <![CDATA[");
out.println(" stanfordXML = \"" + escapedXml + "\";");
out.println("// ]]>");
out.println("</script>");
// Relative brat installation location to CoreNLP.
final String bratLocation = "../brat";
// Inject the location variable, we need it in Javascript mode.
out.println("<script type=\"text/javascript\">");
out.println("// <![CDATA[");
out.println(" bratLocation = \"" + bratLocation + "\";");
out.println("// ]]>");
out.println("</script>");
// Inject the brat stylesheet (removing this line breaks visualisation).
out.println("<link rel=\"stylesheet\" type=\"text/css\" href=\"" +
bratLocation + "/style-vis.css\"/>");
// Include the Javascript libraries necessary to run brat.
out.println("<script type=\"text/javascript\" src=\"" + bratLocation +
"/client/lib/head.load.min.js\"></script>");
// Main Javascript that hooks into all that we have introduced so far.
out.println("<script type=\"text/javascript\" src=\"brat.js\"></script>");
// Link to brat, I hope this is okay to have here...
out.println("<h>Visualisation provided using the " +
"<a href=\"http://brat.nlplab.org/\">brat " +
"visualisation/annotation software</a>.</h>");
out.println("<br/>");
}
public void outputPretty(PrintWriter out, Annotation annotation)
throws ServletException
{
try {
Document input = XMLOutputter.annotationToDoc(annotation, pipeline);
Nodes output = corenlpTransformer.transform(input);
for (int i = 0; i < output.size(); i++) {
out.print(output.get(i).toXML());
}
} catch (RuntimeException e) {
throw e;
} catch (Exception e) {
throw new ServletException(e);
}
}
public void outputByWriter(Consumer<StringWriter> printer,
PrintWriter out) throws IOException {
StringWriter output = new StringWriter();
printer.accept(output);
output.flush();
String escapedXml = StringEscapeUtils.escapeHtml4(output.toString());
String[] lines = escapedXml.split("\n");
out.print("<div>");
for (String line : lines) {
int numSpaces = 0;
while (numSpaces < line.length() && line.charAt(numSpaces) == ' ') {
out.print(" ");
++numSpaces;
}
out.print(line.substring(numSpaces));
out.print("<br>\n");
}
out.print("</div>");
}
public void outputXml(PrintWriter out, Annotation annotation) throws IOException {
outputByWriter(writer -> {
try {
pipeline.xmlPrint(annotation, writer);
} catch (IOException e) {
throw new RuntimeIOException(e);
}
}, out);
}
public void outputJson(PrintWriter out, Annotation annotation) throws IOException {
outputByWriter(writer -> {
try {
pipeline.jsonPrint(annotation, writer);
} catch (IOException e) {
throw new RuntimeIOException(e);
}
}, out);
}
public void outputCoNLL(PrintWriter out, Annotation annotation) throws IOException {
outputByWriter(writer -> {
try {
pipeline.conllPrint(annotation, writer);
} catch (IOException e) {
throw new RuntimeIOException(e);
}
}, out);
}
}