import java.io.IOException;
import java.io.PrintWriter;
+import java.util.HashMap;
import java.util.Map;
-import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.cacert.gigi.GigiApiException;
import org.cacert.gigi.pages.Page;
import org.cacert.gigi.util.RandomToken;
+/**
+ * A generic HTML-form that handles CSRF-token creation.
+ */
public abstract class Form implements Outputable {
+ public static class PermamentFormException extends RuntimeException {
+
+ public PermamentFormException(GigiApiException cause) {
+ super(cause);
+ }
+
+ @Override
+ public synchronized GigiApiException getCause() {
+ return (GigiApiException) super.getCause();
+ }
+ }
+
+ /**
+ * Encapsulates a (non-failure) outcome of a form.
+ */
+ public static abstract class SubmissionResult {
+
+ public abstract boolean endsForm();
+ }
+
+ /**
+ * The form has finished and the user should see the successful completion
+ * on a regular page.
+ */
+ public static class RedirectResult extends SubmissionResult {
+
+ private final String target;
+
+ public RedirectResult(String target) {
+ this.target = target;
+ }
+
+ @Override
+ public boolean endsForm() {
+ return true;
+ }
+
+ }
+
+ /**
+ * The form has not finished and should be re-emitted, however no error
+ * occurred.
+ */
+ public static class FormContinue extends SubmissionResult {
+
+ @Override
+ public boolean endsForm() {
+ return false;
+ }
+ }
+
+ /**
+ * The form has successfully finished and a message should be emitted on a
+ * stateful page.
+ */
+ public static class SuccessMessageResult extends SubmissionResult {
+
+ private final Outputable message;
+
+ public SuccessMessageResult(Outputable message) {
+ this.message = message;
+ }
+
+ @Override
+ public boolean endsForm() {
+ return true;
+ }
+ }
+
public static final String CSRF_FIELD = "csrf";
+ public static final String SUBMIT_RESULT = "form-submit-result";
+
private final String csrf;
private final String action;
+ /**
+ * Creates a new {@link Form}.
+ *
+ * @param hsr
+ * the request to register the form against.
+ */
public Form(HttpServletRequest hsr) {
this(hsr, null);
}
+ /**
+ * Creates a new {@link Form}.
+ *
+ * @param hsr
+ * the request to register the form against.
+ * @param action
+ * the target path where the form should be submitted.
+ */
public Form(HttpServletRequest hsr, String action) {
csrf = RandomToken.generateToken(32);
this.action = action;
hs.setAttribute("form/" + getClass().getName() + "/" + csrf, this);
}
- public abstract boolean submit(PrintWriter out, HttpServletRequest req) throws GigiApiException;
+ /**
+ * Update the forms internal state based on submitted data.
+ *
+ * @param req
+ * the request to take the initial data from.
+ * @return true, iff the form succeeded and the user should be redirected.
+ * @throws GigiApiException
+ * if form data had problems or operations went wrong.
+ */
+ public abstract SubmissionResult submit(HttpServletRequest req) throws GigiApiException;
+
+ public boolean submitExceptionProtected(HttpServletRequest req, HttpServletResponse resp) throws IOException {
+ try {
+ SubmissionResult res = submit(req);
+ req.setAttribute(SUBMIT_RESULT, res);
+ if (res instanceof RedirectResult) {
+ resp.sendRedirect(((RedirectResult) res).target);
+ return true;
+ }
+ if (res.endsForm()) {
+ HttpSession hs = req.getSession();
+ hs.removeAttribute("form/" + getClass().getName() + "/" + csrf);
+ }
+ return false;
+ } catch (PermamentFormException e) {
+ req.setAttribute(SUBMIT_RESULT, e);
+ return false;
+ } catch (GigiApiException e) {
+ req.setAttribute(SUBMIT_RESULT, e);
+ return false;
+ }
+ }
+
+ /**
+ * Prints any errors in any form submits on this request.
+ *
+ * @param req
+ * The request to extract the errors from.
+ * @param out
+ * the output stream to the user to write the errors to.
+ * @return true if no permanent errors occurred and the form should be
+ * reprinted (and it has not already been successfully submitted)
+ */
+ public static boolean printFormErrors(HttpServletRequest req, PrintWriter out) {
+ Object o = req.getAttribute(SUBMIT_RESULT);
+ if (o != null && (o instanceof PermamentFormException)) {
+ ((PermamentFormException) o).getCause().format(out, Page.getLanguage(req));
+ return false;
+ }
+ if (o != null && (o instanceof GigiApiException)) {
+ ((GigiApiException) o).format(out, Page.getLanguage(req));
+ return true;
+ }
+ if (o != null && (o instanceof FormContinue)) {
+ return true;
+ }
+ if (o != null && (o instanceof SuccessMessageResult)) {
+ Outputable message = ((SuccessMessageResult) o).message;
+ if (message != null) {
+ out.println("<div class='alert alert-success'>");
+ message.output(out, Page.getLanguage(req), new HashMap<String, Object>());
+ out.println("</div>");
+ }
+ return false;
+ }
+ return true;
+ }
protected String getCsrfFieldName() {
return CSRF_FIELD;
} else {
out.println("<form method='POST' action='" + action + "'>");
}
- failed = false;
outputContent(out, l, vars);
out.print("<input type='hidden' name='" + CSRF_FIELD + "' value='");
out.print(getCSRFToken());
out.println("'></form>");
}
+ /**
+ * Outputs the forms contents.
+ *
+ * @param out
+ * Stream to the user.
+ * @param l
+ * {@link Language} to translate text to.
+ * @param vars
+ * Variables supplied from the outside.
+ */
protected abstract void outputContent(PrintWriter out, Language l, Map<String, Object> vars);
- boolean failed;
-
- protected void outputError(PrintWriter out, ServletRequest req, String text, Object... contents) {
- if ( !failed) {
- failed = true;
- out.println("<div class='formError'>");
- }
- out.print("<div>");
- if (contents.length == 0) {
- out.print(Page.translate(req, text));
- } else {
- out.print(String.format(Page.translate(req, text), contents));
- }
- out.println("</div>");
- }
-
- protected void outputErrorPlain(PrintWriter out, String text) {
- if ( !failed) {
- failed = true;
- out.println("<div class='formError'>");
- }
- out.print("<div>");
- out.print(text);
- out.println("</div>");
- }
-
- public boolean isFailed(PrintWriter out) {
- if (failed) {
- out.println("</div>");
- }
- return failed;
- }
-
protected String getCSRFToken() {
return csrf;
}
+ /**
+ * Re-fetches a form e.g. when a Post-request is received.
+ *
+ * @param req
+ * the request that is directed to the form.
+ * @param target
+ * the {@link Class} of the expected form.
+ * @return the form where this request is directed to.
+ * @throws CSRFException
+ * if no CSRF-token is found or the token is wrong.
+ */
+ @SuppressWarnings("unchecked")
public static <T extends Form> T getForm(HttpServletRequest req, Class<T> target) throws CSRFException {
String csrf = req.getParameter(CSRF_FIELD);
if (csrf == null) {
if (hs == null) {
throw new CSRFException();
}
- Form f = (Form) hs.getAttribute("form/" + target.getName() + "/" + csrf);
+ Object f = hs.getAttribute("form/" + target.getName() + "/" + csrf);
if (f == null) {
throw new CSRFException();
}
+ if ( !(f instanceof Form)) {
+ throw new CSRFException();
+ }
+ if ( !target.isInstance(f)) {
+ throw new CSRFException();
+ }
+ // Dynamic Cast checked by previous if statement
return (T) f;
}