src/org/cacert/gigi/output/Form.java

   1 package org.cacert.gigi.output;
   2
   3 import java.io.PrintWriter;
   4 import java.util.Map;
   5
   6 import javax.servlet.ServletRequest;
   7 import javax.servlet.http.HttpServletRequest;
   8 import javax.servlet.http.HttpSession;
   9
  10 import org.cacert.gigi.Language;
  11 import org.cacert.gigi.pages.Page;
  12 import org.cacert.gigi.util.RandomToken;
  13
  14 public abstract class Form implements Outputable {
  15         String csrf;
  16
  17         public Form(HttpServletRequest hsr) {
  18                 csrf = RandomToken.generateToken(32);
  19                 HttpSession hs = hsr.getSession();
  20                 hs.setAttribute("form/" + getClass().getName() + "/" + csrf, this);
  21
  22         }
  23
  24         public abstract boolean submit(PrintWriter out, HttpServletRequest req);
  25
  26         @Override
  27         public final void output(PrintWriter out, Language l, Map<String, Object> vars) {
  28                 out.println("<form method='POST' autocomplete='off'>");
  29                 outputContent(out, l, vars);
  30                 out.print("<input type='hidden' name='csrf' value='");
  31                 out.print(getCSRFToken());
  32                 out.println("'></form>");
  33         }
  34
  35         protected abstract void outputContent(PrintWriter out, Language l, Map<String, Object> vars);
  36
  37         protected void outputError(PrintWriter out, ServletRequest req, String text) {
  38                 out.print("<div>");
  39                 out.print(Page.translate(req, text));
  40                 out.println("</div>");
  41         }
  42
  43         protected String getCSRFToken() {
  44                 return csrf;
  45         }
  46
  47         protected void checkCSRF(HttpServletRequest req) {
  48                 if (!csrf.equals(req.getParameter("csrf"))) {
  49                         throw new CSRFError();
  50                 }
  51         }
  52
  53         public static <T extends Form> T getForm(HttpServletRequest req, Class<T> target) {
  54                 String csrf = req.getParameter("csrf");
  55                 if (csrf == null) {
  56                         throw new CSRFError();
  57                 }
  58                 HttpSession hs = req.getSession();
  59                 if (hs == null) {
  60                         throw new CSRFError();
  61                 }
  62                 Form f = (Form) hs.getAttribute("form/" + target.getName() + "/" + csrf);
  63                 if (f == null) {
  64                         throw new CSRFError();
  65                 }
  66                 return (T) f;
  67         }
  68
  69         public static class CSRFError extends Error {
  70
  71         }
  72 }