> It’s sad to see that a very common and simple task like this, to be so
complex to implement.
It is only a few lines of XQuery in eXist.
On Wed, Jul 2, 2014 at 11:09 AM, William Velasquez <
[email protected]> wrote:
> It’s sad to see that a very common and simple task like this, to be so
> complex to implement.
>
>
>
> Maybe REST is popular these days, but server implementations are still far
> from being easy for us, not only on Java.
>
>
>
> *De:* Stephen Cameron [mailto:[email protected]]
> *Enviado el:* miércoles, 02 de julio de 2014 2:16 a. m.
> *Para:* XSLTForms xsltforms
> *Asunto:* [Xsltforms-support] XSLTForms Caching Servlet Filter
>
>
>
> I imagine there might be some other interested in this perhaps. Here is a
> first cut.
>
> It needs the format=html query parameter to give you the cached translated
> form.
>
> So, a URL will be something like
>
> http://thedomain.org/appcontext/forms/form.xml
>
> or
>
> http://thedomain.org/appcontext/forms/form.xml?format=html
>
> The later being what I wanted to avoid for obvious reasons, but I cannot
> get around it and have the behaviour that I'm seeking.
>
> The web.xml follows the Java code. The SimpleRESTServlet can be replaced
> with whatever you use to persist the raw XML forms.
>
> It needs more work, use at own risk, comments welcomed.
>
> Steve Cameron
>
>
>
>
> package net.sourceforge.schema2xforms;
>
> import java.io.ByteArrayOutputStream;
> import java.io.CharArrayWriter;
> import java.io.File;
> import java.io.IOException;
> import java.io.PrintWriter;
> import java.io.StringReader;
> import java.util.Enumeration;
>
> import javax.servlet.Filter;
> import javax.servlet.FilterChain;
> import javax.servlet.FilterConfig;
> import javax.servlet.ServletException;
> import javax.servlet.ServletOutputStream;
> import javax.servlet.ServletRequest;
> import javax.servlet.ServletResponse;
> import javax.servlet.ServletResponseWrapper;
> import javax.servlet.UnavailableException;
> import javax.servlet.http.HttpServletRequest;
> import javax.servlet.http.HttpServletResponse;
> import javax.servlet.http.HttpServletResponseWrapper;
> import javax.xml.transform.ErrorListener;
> import javax.xml.transform.Source;
> import javax.xml.transform.Templates;
> import javax.xml.transform.Transformer;
> import javax.xml.transform.TransformerConfigurationException;
> import javax.xml.transform.TransformerException;
> import javax.xml.transform.TransformerFactory;
> import javax.xml.transform.stream.StreamResult;
> import javax.xml.transform.stream.StreamSource;
>
> public final class XSLTFormsTransformerCachingServletFilter implements
> Filter {
>
> private FilterConfig filterConfig = null;
> private Templates templates;
> private static FormCache cache = new FormCache();
>
> public void init(FilterConfig config) throws UnavailableException,
> ServletException {
> this.filterConfig = config;
> String factory = config
>
> .getInitParameter("javax.xml.transform.TransformerFactory");
> System.out.println(factory);
> if (factory != null) {
> System.setProperty("javax.xml.transform.TransformerFactory",
> factory);
> }
> Enumeration<String> initParams = config.getInitParameterNames();
> for (int i = 0; initParams.hasMoreElements(); i++) {
> System.out.println("param " + i + ": " +
> initParams.nextElement());
> }
> if (config.getInitParameter("xsltforms_dir") == null) {
> throw new UnavailableException("xsltforms_dir init-param not
> found");
> }
> if (config.getInitParameter("xsltforms_baseurl") == null) {
> throw new UnavailableException(
> "xsltforms_baseurl init-param not found");
> }
> // create the XSLTforms Transformer
> TransformerFactory transFactory = TransformerFactory.newInstance();
> String xmlStylesheet = null;
> try {
> String path = config.getServletContext()
> .getRealPath(
> config.getInitParameter("xsltforms_dir")
> + "/xsltforms.xsl");
> File stylesheet = new File(path);
> if (!stylesheet.exists()) {
> throw new UnavailableException(
> "XSLTForms stylesheet not found at: " + path);
> }
> this.templates = transFactory.newTemplates(new StreamSource(
> stylesheet));
> } catch (TransformerConfigurationException tce) {
> tce.printStackTrace();
> throw new UnavailableException("Unable to compile stylesheet");
> }
> }
>
> public void destroy() {
> this.filterConfig = null;
> this.templates = null;
> }
>
> public void doFilter(ServletRequest request, ServletResponse response,
> FilterChain chain) throws IOException, ServletException {
> String formName = ((HttpServletRequest) request).getRequestURI();
> formName = formName.substring(formName.lastIndexOf("/") + 1);
> String format = ((HttpServletRequest)
> request).getParameter("format");
> if (format == null)
> format = "raw";
> System.out.println("form=" + formName);
> System.out.println("format=" + format);
> if (format != null && !format.matches("((raw)|(html))")) {
> throw new ServletException(
> "expecting format parameter to be raw or html");
> } else {
> String method = ((HttpServletRequest) request).getMethod();
> if (method.matches("(?i:(PUT)|(POST)|(DELETE))")) {
> // invalidate the cached version
> cache.remove(formName);
> chain.doFilter(request, response);
> } else if (method.matches("(?i:(GET))")) {
> // check if the raw xml is required
> if (format == "raw") {
> // pass on the request
> response.setContentType("text/xml");
> chain.doFilter(request, response);
> } else {
> // check if there is a cached version
> if (cache.containsKey(formName)) {
> String formHTML = cache.get(formName);
> response.setContentType("text/html");
> response.setContentLength(formHTML.length());
> response.getWriter().write(formHTML);
> } else {
> BufferedHttpServletResponseWrapper responseWrapper
> = new BufferedHttpServletResponseWrapper(
> (HttpServletResponse) response);
> chain.doFilter(request, responseWrapper);
> byte[] bytes = responseWrapper.toByteArray();
> //System.out.println("RESPONSE -> " + new
> String(bytes));
> // do the transform
> try {
> Transformer trans = templates.newTransformer();
> ErrorListener listener = new
> ErrorListenerImpl();
> trans.setErrorListener(listener);
> trans.setParameter("baseuri", filterConfig
>
> .getInitParameter("xsltforms_baseurl"));
> CharArrayWriter caw = new CharArrayWriter();
> trans.transform(new StreamSource(new
> StringReader(
> new String(bytes))), new
> StreamResult(caw));
> String formHTML = caw.toString();
> response.setContentType("text/html");
> response.setContentLength(formHTML.length());
>
> response.getOutputStream().write(formHTML.getBytes("UTF-8"));
> cache.put(formName, formHTML);
> } catch (TransformerException e) {
> throw new ServletException(e);
> }
> }
> }
> } else { // not GET|POST|PUT|DELETE HTTP method
> chain.doFilter(request, response);
> }
> }
> }
>
> private static class ByteArrayServletStream extends
> ServletOutputStream {
>
> ByteArrayOutputStream baos;
>
> ByteArrayServletStream(ByteArrayOutputStream baos) {
> this.baos = baos;
> }
>
> public void write(int param) throws IOException {
> baos.write(param);
> }
> }
>
> private class BufferedHttpServletResponseWrapper extends
> HttpServletResponseWrapper {
>
> private ByteArrayOutputStream baos = new ByteArrayOutputStream();
>
> private PrintWriter pw = new PrintWriter(baos);
>
> private ServletOutputStream sos = new ByteArrayServletStream(baos);
>
> private boolean isWriter = false;
> private boolean isStream = false;
>
> public BufferedHttpServletResponseWrapper(HttpServletResponse
> response) {
> super(response);
> }
>
> @Override
> public String toString() {
> if (isWriter) {
> return pw.toString();
> } else if (isStream) {
> return sos.toString();
> } else {
> return "";
> }
> }
>
> @Override
> public PrintWriter getWriter() {
> isWriter = true;
> return pw;
> }
>
> @Override
> public ServletOutputStream getOutputStream() throws IOException {
> isStream = true;
> return sos;
> }
>
> byte[] toByteArray() {
> return baos.toByteArray();
> }
> }
> }
>
> <?xml version="1.0" encoding="UTF-8"?>
> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; xmlns="
> http://java.sun.com/xml/ns/javaee"; xmlns:web="
> http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd";
> xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
> http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"; id="WebApp_ID"
> version="3.0">
>
> <display-name>XForms</display-name>
>
> <context-param>
> <param-name>javax.xml.transform.TransformerFactory</param-name>
> <param-value>net.sf.saxon.TransformerFactoryImpl</param-value>
> </context-param>
>
> <servlet>
> <servlet-name>XSLTFormsServlet</servlet-name>
>
> <servlet-class>net.sourceforge.schema2xforms.XSLTFormsTransformerServlet</servlet-class>
> <init-param>
> <description></description>
> <param-name>xsltforms_dir</param-name>
> <param-value>/xsltforms</param-value>
> </init-param>
> <init-param>
> <description></description>
> <param-name>xsltforms_baseurl</param-name>
> <param-value>http://localhost:8080/XForms/xsltforms/
> </param-value>
> </init-param>
> <load-on-startup>1</load-on-startup>
> </servlet>
>
> <servlet>
> <servlet-name>SimpleRESTServlet</servlet-name>
>
> <servlet-class>net.sourceforge.schema2xforms.SimpleRESTServlet</servlet-class>
> <load-on-startup>1</load-on-startup>
> </servlet>
>
> <filter>
> <filter-name>XSLTFormsCachingFilter</filter-name>
>
> <filter-class>net.sourceforge.schema2xforms.XSLTFormsTransformerCachingServletFilter</filter-class>
> <init-param>
> <param-name>xsltforms_dir</param-name>
> <param-value>/xsltforms</param-value>
> </init-param>
> <init-param>
> <param-name>xsltforms_baseurl</param-name>
> <param-value>http://localhost:8080/XForms/xsltforms/
> </param-value>
> </init-param>
> </filter>
>
> <filter-mapping>
> <filter-name>XSLTFormsCachingFilter</filter-name>
> <url-pattern>/forms/*</url-pattern>
> </filter-mapping>
>
> <servlet-mapping>
> <servlet-name>SimpleRESTServlet</servlet-name>
> <url-pattern>/forms/*</url-pattern>
> </servlet-mapping>
>
> </web-app>
>
>
> ------------------------------------------------------------------------------
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> Turn processes into business applications with Bonita BPM Community Edition
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> _______________________________________________
> Xsltforms-support mailing list
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>
>
--
Dan McCreary
http://danmccreary.com
Co-author: Making Sense of NoSQL <http://manning.com/mccreary>
office: (952) 931-9198
cell: (612) 986-1552
skype: dmccreary47
------------------------------------------------------------------------------
Open source business process management suite built on Java and Eclipse
Turn processes into business applications with Bonita BPM Community Edition
Quickly connect people, data, and systems into organized workflows
Winner of BOSSIE, CODIE, OW2 and Gartner awards
http://p.sf.net/sfu/Bonitasoft
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