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 file changed, 148 insertions(+)
 create mode 100644 src/com/gitblit/wicket/SessionlessForm.java

diff --git a/src/com/gitblit/wicket/SessionlessForm.java b/src/com/gitblit/wicket/SessionlessForm.java
new file mode 100644
index 00000000..484e85e3
--- /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();
+	}
+}
-- 
2.39.5