From b2abacfa63ecd9cb5765a9887e72f7687528f77d Mon Sep 17 00:00:00 2001
From: James Moger <james.moger@gitblit.com>
Date: Fri, 23 Mar 2012 16:22:09 -0400
Subject: [PATCH] Implemented SessionlessForm to workaround Wicket's stateful nature
---
src/com/gitblit/wicket/SessionlessForm.java | 148 +++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 148 insertions(+), 0 deletions(-)
diff --git a/src/com/gitblit/wicket/SessionlessForm.java b/src/com/gitblit/wicket/SessionlessForm.java
new file mode 100644
index 0000000..484e85e
--- /dev/null
+++ b/src/com/gitblit/wicket/SessionlessForm.java
@@ -0,0 +1,148 @@
+/*
+ * Copyright 2012 gitblit.com.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.gitblit.wicket;
+
+import java.text.MessageFormat;
+
+import org.apache.wicket.Component;
+import org.apache.wicket.PageParameters;
+import org.apache.wicket.markup.ComponentTag;
+import org.apache.wicket.markup.MarkupStream;
+import org.apache.wicket.markup.html.form.StatelessForm;
+import org.apache.wicket.protocol.http.WicketURLDecoder;
+import org.apache.wicket.protocol.http.request.WebRequestCodingStrategy;
+import org.apache.wicket.util.string.AppendingStringBuffer;
+import org.apache.wicket.util.string.Strings;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.gitblit.wicket.pages.BasePage;
+
+/**
+ * This class is used to create a stateless form that can POST or GET to a
+ * bookmarkable page regardless of the pagemap and even after session expiration
+ * or a server restart.
+ *
+ * The trick is to embed "wicket:bookmarkablePage" as a hidden field of the form.
+ * Wicket already has logic to extract this parameter when it is trying
+ * to determine which page should receive the request.
+ *
+ * The parameters of the containing page can optionally be included as hidden
+ * fields in this form. Note that if a page parameter's name collides with any
+ * child's wicket:id in this form then the page parameter is excluded.
+ *
+ * @author James Moger
+ *
+ */
+public class SessionlessForm<T> extends StatelessForm<T> {
+
+ private static final long serialVersionUID = 1L;
+
+ private static final String HIDDEN_DIV_START = "<div style=\"width:0px;height:0px;position:absolute;left:-100px;top:-100px;overflow:hidden\">";
+
+ private final Class<? extends BasePage> pageClass;
+
+ private final PageParameters pageParameters;
+
+ private final Logger log = LoggerFactory.getLogger(SessionlessForm.class);
+
+ /**
+ * Sessionless forms must have a bookmarkable page class. A bookmarkable
+ * page is defined as a page that has only a default and/or a PageParameter
+ * constructor.
+ *
+ * @param id
+ * @param bookmarkablePageClass
+ */
+ public SessionlessForm(String id, Class<? extends BasePage> bookmarkablePageClass) {
+ this(id, bookmarkablePageClass, null);
+ }
+
+ /**
+ * Sessionless forms must have a bookmarkable page class. A bookmarkable
+ * page is defined as a page that has only a default and/or a PageParameter
+ * constructor.
+ *
+ * @param id
+ * @param bookmarkablePageClass
+ * @param pageParameters
+ */
+ public SessionlessForm(String id, Class<? extends BasePage> bookmarkablePageClass,
+ PageParameters pageParameters) {
+ super(id);
+ this.pageClass = bookmarkablePageClass;
+ this.pageParameters = pageParameters;
+ }
+
+
+ /**
+ * Append an additional hidden input tag that forces Wicket to correctly
+ * determine the destination page class even after a session expiration or
+ * a server restart.
+ *
+ * @param markupStream
+ * The markup stream
+ * @param openTag
+ * The open tag for the body
+ */
+ @Override
+ protected void onComponentTagBody(final MarkupStream markupStream, final ComponentTag openTag)
+ {
+ // render the hidden bookmarkable page field
+ AppendingStringBuffer buffer = new AppendingStringBuffer(HIDDEN_DIV_START);
+ buffer.append("<input type=\"hidden\" name=\"")
+ .append(WebRequestCodingStrategy.BOOKMARKABLE_PAGE_PARAMETER_NAME)
+ .append("\" value=\":")
+ .append(pageClass.getName())
+ .append("\" />");
+
+ // insert the page parameters, if any, as hidden fields as long as they
+ // do not collide with any child wicket:id of the form.
+ if (pageParameters != null) {
+ for (String key : pageParameters.keySet()) {
+ Component c = get(key);
+ if (c != null) {
+ // this form has a field id which matches the
+ // parameter name, skip embedding a hidden value
+ log.warn(MessageFormat.format("Skipping page parameter \"{0}\" from sessionless form hidden fields because it collides with a form child wicket:id", key));
+ continue;
+ }
+ String value = pageParameters.getString(key);
+ buffer.append("<input type=\"hidden\" name=\"")
+ .append(recode(key))
+ .append("\" value=\"")
+ .append(recode(value))
+ .append("\" />");
+ }
+ }
+
+ buffer.append("</div>");
+ getResponse().write(buffer);
+ super.onComponentTagBody(markupStream, openTag);
+ }
+
+ /**
+ * Take URL-encoded query string value, unencode it and return HTML-escaped version
+ *
+ * @param s
+ * value to reencode
+ * @return reencoded value
+ */
+ private String recode(String s) {
+ String un = WicketURLDecoder.QUERY_INSTANCE.decode(s);
+ return Strings.escapeMarkup(un).toString();
+ }
+}
--
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