towards the bottom of the page:
...
I'm using HtmlUnit as the headless browser, and it doesn't work. Why not?
If "doesn't work" means that HtmlUnit does not return the snapshot you
were expecting to see, it's very likely that the culprit is that you
didn't give it enough time to execute the JavaScript and/or XHR
requests. To fix this, try any or all of the following:
- Use NicelyResynchronizingAjaxController. This will cause HtmlUnit
to wait for any outstanding XHR calls.
- Bump up the wait time for waitForBackgroundJavaScript and/or
waitForBackgroundJavaScriptStartingBefore.
On Fri, Mar 30, 2012 at 12:37 PM, Ovidiu Mihaescu <gandacu@gmail.com> wrote:
> Does your existing app's URLs conform to the spec at
> https://developers.google.com/webmasters/ajax-crawling/docs/specification
> ? More specifically, do all your history tokens start with an
> exclamation mark?
>
> On Fri, Mar 30, 2012 at 9:31 AM, erebrus <erebrus@gmail.com> wrote:
>> Hi all,
>> I was reading https://developers.google.com/webmasters/ajax-crawling/
>> on how to make ajax apps (consequently gwt apps) crawlable.
>> I took the code from google (summarized in point 3 of "How to create
>> an HTML snapshot?" to create a filter (that returns html from ajax
>> using HtmlUnit) and changed the web.xml accordingly. I created a new
>> GWT project with example code and applied the filter and the web.xml
>> there. It worked directly.
>> However, I did exactly the same on the gwt app I want to make
>> searchable and it doesn't work. For some reason, the only requests the
>> filter gets are the ones to the ones for the rpc.
>> I think I must be missing a terribly simple detail, but I'm a bit lost
>> on where to go from here.
>>
>>
>> Following you can see the code for the filter (CrawlServlet) and the
>> web.xml
>>
>> package crawltest.server;
>>
>> import com.gargoylesoftware.htmlunit.BrowserVersion;
>> import com.gargoylesoftware.htmlunit.WebClient;
>> import com.gargoylesoftware.htmlunit.html.HtmlPage;
>>
>> import java.io.IOException;
>> import java.io.PrintWriter;
>> import java.io.UnsupportedEncodingException;
>> import java.net.URLDecoder;
>> import java.util.logging.Logger;
>>
>> import javax.servlet.Filter;
>> import javax.servlet.FilterChain;
>> import javax.servlet.FilterConfig;
>> import javax.servlet.ServletException;
>> import javax.servlet.ServletRequest;
>> import javax.servlet.ServletResponse;
>> import javax.servlet.http.HttpServletRequest;
>> import javax.servlet.http.HttpServletResponse;
>>
>> /**
>> * Servlet that makes this application crawlable
>> */
>> public final class CrawlServlet implements Filter {
>>
>> private static final Logger logger =
>> Logger.getLogger(CrawlServlet.class
>> .getName());
>> private static String rewriteQueryString(String queryString) throws
>> UnsupportedEncodingException {
>> StringBuilder queryStringSb = new StringBuilder(queryString);
>> int i = queryStringSb.indexOf("&_escaped_fragment_");
>> if (i != -1) {
>> StringBuilder tmpSb = new
>> StringBuilder(queryStringSb.substring(0, i));
>> tmpSb.append("#!");
>> tmpSb.append(URLDecoder.decode(queryStringSb.substring(i + 20,
>> queryStringSb.length()),"UTF-8"));
>> queryStringSb = tmpSb;
>> }
>>
>> i = queryStringSb.indexOf("_escaped_fragment_");
>> if (i != -1) {
>> StringBuilder tmpSb = new
>> StringBuilder(queryStringSb.substring(0, i));
>> tmpSb.append("#!");
>> tmpSb.append(URLDecoder.decode(queryStringSb.substring(i + 19,
>> queryStringSb.length()), "UTF-8"));
>> queryStringSb = tmpSb;
>> }
>> if (queryStringSb.indexOf("#!") != 0) {
>> queryStringSb.insert(0, '?');
>> }
>> queryString = queryStringSb.toString();
>>
>>
>>
>> return queryString;
>> }
>>
>> private FilterConfig filterConfig = null;
>>
>> /**
>> * Destroys the filter configuration
>> */
>> public void destroy() {
>> this.filterConfig = null;
>> }
>>
>> /**
>> * Filters all requests and invokes headless browser if necessary
>> */
>> public void doFilter(ServletRequest request, ServletResponse
>> response,
>> FilterChain chain) throws IOException {
>> System.out.println("crawl");
>> if (filterConfig == null) {
>> return;
>> }
>> System.out.println("crawl");
>> HttpServletRequest req = (HttpServletRequest) request;
>> HttpServletResponse res = (HttpServletResponse) response;
>> String queryString = req.getQueryString();
>> System.out.println("query:"+queryString);
>> System.out.println("param:"+req.getParameterMap().toString());
>> System.out.println("req:"+req);
>> if ((queryString != null) &&
>> (queryString.contains("_escaped_fragment_"))) {
>> System.out.println("in!!");
>> StringBuilder pageNameSb = new StringBuilder("http://");
>> pageNameSb.append(req.getServerName());
>> if (req.getServerPort() != 0) {
>> pageNameSb.append(":");
>> pageNameSb.append(req.getServerPort());
>> }
>> pageNameSb.append(req.getRequestURI());
>> queryString = rewriteQueryString(queryString);
>> pageNameSb.append(queryString);
>>
>> final WebClient webClient = new
>> WebClient(BrowserVersion.FIREFOX_3);
>> webClient.setJavaScriptEnabled(true);
>> String pageName = pageNameSb.toString();
>> HtmlPage page = webClient.getPage(pageName);
>> webClient.waitForBackgroundJavaScriptStartingBefore(2000);
>>
>> res.setContentType("text/html;charset=UTF-8");
>> PrintWriter out = res.getWriter();
>> out.println("<hr>");
>> out.println("<center><h3>You are viewing a non-interactive page
>> that is intended for the crawler. You probably want to see this page:
>> <a href=\""
>> + pageName + "\">" + pageName + "</a></h3></center>");
>> out.println("<hr>");
>>
>> out.println(page.asXml());
>> webClient.closeAllWindows();
>> out.close();
>>
>> } else {
>> try {
>> chain.doFilter(request, response);
>> } catch (ServletException e) {
>> e.printStackTrace();
>> }
>> }
>> }
>>
>> /**
>> * Initializes the filter configuration
>> */
>> public void init(FilterConfig filterConfig) {
>> this.filterConfig = filterConfig;
>> }
>>
>> }
>>
>>
>> web-xml:
>>
>> <?xml version="1.0" encoding="UTF-8"?>
>> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>> xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
>> http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
>> version="2.5" xmlns="http://java.sun.com/xml/ns/javaee">
>>
>> <filter>
>> <filter-name>CrawlServlet</filter-name>
>> <filter-class>crawltest.server.CrawlServlet</filter-class>
>> </filter>
>>
>> <filter-mapping>
>> <filter-name>CrawlServlet</filter-name>
>> <url-pattern>/*</url-pattern>
>> </filter-mapping>
>>
>> <!-- Servlets -->
>>
>> <!-- Default page to serve -->
>> <welcome-file-list>
>> <welcome-file>CrawlTest.html</welcome-file>
>> </welcome-file-list>
>>
>> </web-app>
>>
>>
>>
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