From ec24568f14ee38b264c86133ce8ebcc35a39034b Mon Sep 17 00:00:00 2001
From: David Ostrovsky <david@ostrovsky.org>
Date: Mon, 10 Mar 2014 01:50:49 +0100
Subject: [PATCH] Add http request filter extension point

To allow for integration of 3rd party server monitoring solutions,
Gitblit needs to expose an extension point for collecting http data.
---
 src/main/java/WEB-INF/web.xml                 | 11 ++-
 .../java/com/gitblit/dagger/DaggerFilter.java |  4 +-
 .../gitblit/extensions/HttpRequestFilter.java | 49 ++++++++++++
 .../servlet/AccessRestrictionFilter.java      |  5 +-
 .../gitblit/servlet/AuthenticationFilter.java |  3 +-
 .../servlet/EnforceAuthenticationFilter.java  |  3 +-
 .../java/com/gitblit/servlet/GitFilter.java   |  5 +-
 .../java/com/gitblit/servlet/ProxyFilter.java | 76 +++++++++++++++++++
 .../java/com/gitblit/servlet/RpcFilter.java   |  5 +-
 .../gitblit/servlet/SyndicationFilter.java    |  5 +-
 src/site/plugins_extensions.mkd               | 20 +++++
 11 files changed, 173 insertions(+), 13 deletions(-)
 create mode 100644 src/main/java/com/gitblit/extensions/HttpRequestFilter.java
 create mode 100644 src/main/java/com/gitblit/servlet/ProxyFilter.java

diff --git a/src/main/java/WEB-INF/web.xml b/src/main/java/WEB-INF/web.xml
index cb483af4..3a6c4490 100644
--- a/src/main/java/WEB-INF/web.xml
+++ b/src/main/java/WEB-INF/web.xml
@@ -214,6 +214,15 @@
 		<url-pattern>/robots.txt</url-pattern>
 	</servlet-mapping>
 
+    <filter>
+		<filter-name>ProxyFilter</filter-name>
+		<filter-class>com.gitblit.servlet.ProxyFilter</filter-class>
+	</filter>
+	<filter-mapping>
+		<filter-name>ProxyFilter</filter-name>
+		<url-pattern>/*</url-pattern>
+	</filter-mapping>
+	
 	<!-- Git Access Restriction Filter
 		 <url-pattern> MUST match: 
 			* GitServlet
@@ -353,4 +362,4 @@
         <url-pattern>/*</url-pattern>
     </filter-mapping>
     
-</web-app>
+</web-app>
\ No newline at end of file
diff --git a/src/main/java/com/gitblit/dagger/DaggerFilter.java b/src/main/java/com/gitblit/dagger/DaggerFilter.java
index 1c73d4b7..01c07a4a 100644
--- a/src/main/java/com/gitblit/dagger/DaggerFilter.java
+++ b/src/main/java/com/gitblit/dagger/DaggerFilter.java
@@ -36,10 +36,10 @@ public abstract class DaggerFilter implements Filter {
 	public final void init(FilterConfig filterConfig) throws ServletException {
 		ServletContext context = filterConfig.getServletContext();
 		ObjectGraph objectGraph = (ObjectGraph) context.getAttribute(DaggerContext.INJECTOR_NAME);
-		inject(objectGraph);
+		inject(objectGraph, filterConfig);
 	}
 
-	protected abstract void inject(ObjectGraph dagger);
+	protected abstract void inject(ObjectGraph dagger, FilterConfig filterConfig) throws ServletException;
 
 	@Override
 	public void destroy() {
diff --git a/src/main/java/com/gitblit/extensions/HttpRequestFilter.java b/src/main/java/com/gitblit/extensions/HttpRequestFilter.java
new file mode 100644
index 00000000..e3e330cb
--- /dev/null
+++ b/src/main/java/com/gitblit/extensions/HttpRequestFilter.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2014 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.extensions;
+
+import java.io.IOException;
+
+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 ro.fortsoft.pf4j.ExtensionPoint;
+
+/**
+ * Extension point to intercept HTTP requests passing through the server.
+ *
+ * @author David Ostrovsky
+ * @since 1.6.0
+ *
+ */
+public abstract class HttpRequestFilter implements Filter, ExtensionPoint {
+
+	@Override
+	public void init(FilterConfig config) throws ServletException {
+	}
+
+	@Override
+	public void destroy() {
+	}
+
+	@Override
+	public abstract void doFilter(ServletRequest request, ServletResponse response,
+			FilterChain chain) throws IOException, ServletException;
+}
diff --git a/src/main/java/com/gitblit/servlet/AccessRestrictionFilter.java b/src/main/java/com/gitblit/servlet/AccessRestrictionFilter.java
index e6a0169c..0e6d323d 100644
--- a/src/main/java/com/gitblit/servlet/AccessRestrictionFilter.java
+++ b/src/main/java/com/gitblit/servlet/AccessRestrictionFilter.java
@@ -19,6 +19,7 @@ import java.io.IOException;
 import java.text.MessageFormat;
 
 import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
 import javax.servlet.ServletException;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
@@ -54,8 +55,8 @@ public abstract class AccessRestrictionFilter extends AuthenticationFilter {
 	protected IRepositoryManager repositoryManager;
 
 	@Override
-	protected void inject(ObjectGraph dagger) {
-		super.inject(dagger);
+	protected void inject(ObjectGraph dagger, FilterConfig filterConfig) {
+		super.inject(dagger, filterConfig);
 		this.runtimeManager = dagger.get(IRuntimeManager.class);
 		this.repositoryManager = dagger.get(IRepositoryManager.class);
 	}
diff --git a/src/main/java/com/gitblit/servlet/AuthenticationFilter.java b/src/main/java/com/gitblit/servlet/AuthenticationFilter.java
index dd821ac7..5710a4af 100644
--- a/src/main/java/com/gitblit/servlet/AuthenticationFilter.java
+++ b/src/main/java/com/gitblit/servlet/AuthenticationFilter.java
@@ -24,6 +24,7 @@ import java.util.HashMap;
 import java.util.Map;
 
 import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
 import javax.servlet.ServletException;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
@@ -64,7 +65,7 @@ public abstract class AuthenticationFilter extends DaggerFilter {
 	protected IAuthenticationManager authenticationManager;
 
 	@Override
-	protected void inject(ObjectGraph dagger) {
+	protected void inject(ObjectGraph dagger, FilterConfig filterConfig) {
 		this.authenticationManager = dagger.get(IAuthenticationManager.class);
 	}
 
diff --git a/src/main/java/com/gitblit/servlet/EnforceAuthenticationFilter.java b/src/main/java/com/gitblit/servlet/EnforceAuthenticationFilter.java
index 5fdccb71..c015021d 100644
--- a/src/main/java/com/gitblit/servlet/EnforceAuthenticationFilter.java
+++ b/src/main/java/com/gitblit/servlet/EnforceAuthenticationFilter.java
@@ -19,6 +19,7 @@ import java.io.IOException;
 import java.text.MessageFormat;
 
 import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
 import javax.servlet.ServletException;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
@@ -53,7 +54,7 @@ public class EnforceAuthenticationFilter extends DaggerFilter {
 	private IAuthenticationManager authenticationManager;
 
 	@Override
-	protected void inject(ObjectGraph dagger) {
+	protected void inject(ObjectGraph dagger, FilterConfig filterConfig) {
 		this.settings = dagger.get(IStoredSettings.class);
 		this.authenticationManager = dagger.get(IAuthenticationManager.class);
 	}
diff --git a/src/main/java/com/gitblit/servlet/GitFilter.java b/src/main/java/com/gitblit/servlet/GitFilter.java
index f9c062d2..bb3d3216 100644
--- a/src/main/java/com/gitblit/servlet/GitFilter.java
+++ b/src/main/java/com/gitblit/servlet/GitFilter.java
@@ -17,6 +17,7 @@ package com.gitblit.servlet;
 
 import java.text.MessageFormat;
 
+import javax.servlet.FilterConfig;
 import javax.servlet.http.HttpServletRequest;
 
 import com.gitblit.Constants.AccessRestrictionType;
@@ -53,8 +54,8 @@ public class GitFilter extends AccessRestrictionFilter {
 	private IFederationManager federationManager;
 
 	@Override
-	protected void inject(ObjectGraph dagger) {
-		super.inject(dagger);
+	protected void inject(ObjectGraph dagger, FilterConfig filterConfig) {
+		super.inject(dagger, filterConfig);
 		this.settings = dagger.get(IStoredSettings.class);
 		this.federationManager = dagger.get(IFederationManager.class);
 	}
diff --git a/src/main/java/com/gitblit/servlet/ProxyFilter.java b/src/main/java/com/gitblit/servlet/ProxyFilter.java
new file mode 100644
index 00000000..bfdc87f3
--- /dev/null
+++ b/src/main/java/com/gitblit/servlet/ProxyFilter.java
@@ -0,0 +1,76 @@
+/*
+ * Copyright 2014 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.servlet;
+
+import java.io.IOException;
+import java.util.Iterator;
+import java.util.List;
+
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+
+import com.gitblit.dagger.DaggerFilter;
+import com.gitblit.extensions.HttpRequestFilter;
+import com.gitblit.manager.IPluginManager;
+
+import dagger.ObjectGraph;
+
+/**
+ * A request filter than allows regsitered extension request filters to access
+ * request data.  The intended purpose is for server monitoring plugins.
+ *
+ * @author David Ostrovsky
+ * @since 1.6.0
+ */
+public class ProxyFilter extends DaggerFilter {
+	private List<HttpRequestFilter> filters;
+
+	@Override
+	protected void inject(ObjectGraph dagger, FilterConfig filterConfig) throws ServletException {
+		IPluginManager pluginManager = dagger.get(IPluginManager.class);
+		filters = pluginManager.getExtensions(HttpRequestFilter.class);
+		for (HttpRequestFilter f : filters) {
+			f.init(filterConfig);
+		}
+	}
+
+	@Override
+	public void doFilter(ServletRequest req, ServletResponse res, final FilterChain last)
+			throws IOException, ServletException {
+		final Iterator<HttpRequestFilter> itr = filters.iterator();
+		new FilterChain() {
+			@Override
+			public void doFilter(ServletRequest req, ServletResponse res) throws IOException,
+					ServletException {
+				if (itr.hasNext()) {
+					itr.next().doFilter(req, res, this);
+				} else {
+					last.doFilter(req, res);
+				}
+			}
+		}.doFilter(req, res);
+	}
+
+	@Override
+	public void destroy() {
+		for (HttpRequestFilter f : filters) {
+			f.destroy();
+		}
+	}
+}
diff --git a/src/main/java/com/gitblit/servlet/RpcFilter.java b/src/main/java/com/gitblit/servlet/RpcFilter.java
index e0b1a233..23bf956e 100644
--- a/src/main/java/com/gitblit/servlet/RpcFilter.java
+++ b/src/main/java/com/gitblit/servlet/RpcFilter.java
@@ -19,6 +19,7 @@ import java.io.IOException;
 import java.text.MessageFormat;
 
 import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
 import javax.servlet.ServletException;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
@@ -53,8 +54,8 @@ public class RpcFilter extends AuthenticationFilter {
 	private IRuntimeManager runtimeManager;
 
 	@Override
-	protected void inject(ObjectGraph dagger) {
-		super.inject(dagger);
+	protected void inject(ObjectGraph dagger, FilterConfig filterConfig) {
+		super.inject(dagger, filterConfig);
 		this.settings = dagger.get(IStoredSettings.class);
 		this.runtimeManager = dagger.get(IRuntimeManager.class);
 	}
diff --git a/src/main/java/com/gitblit/servlet/SyndicationFilter.java b/src/main/java/com/gitblit/servlet/SyndicationFilter.java
index 67a845ea..78da47e9 100644
--- a/src/main/java/com/gitblit/servlet/SyndicationFilter.java
+++ b/src/main/java/com/gitblit/servlet/SyndicationFilter.java
@@ -19,6 +19,7 @@ import java.io.IOException;
 import java.text.MessageFormat;
 
 import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
 import javax.servlet.ServletException;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
@@ -50,8 +51,8 @@ public class SyndicationFilter extends AuthenticationFilter {
 	private IProjectManager projectManager;
 
 	@Override
-	protected void inject(ObjectGraph dagger) {
-		super.inject(dagger);
+	protected void inject(ObjectGraph dagger, FilterConfig filterConfig) {
+		super.inject(dagger, filterConfig);
 		this.runtimeManager = dagger.get(IRuntimeManager.class);
 		this.repositoryManager = dagger.get(IRepositoryManager.class);
 		this.projectManager = dagger.get(IProjectManager.class);
diff --git a/src/site/plugins_extensions.mkd b/src/site/plugins_extensions.mkd
index 60f8b47d..e8b53d11 100644
--- a/src/site/plugins_extensions.mkd
+++ b/src/site/plugins_extensions.mkd
@@ -185,3 +185,23 @@ public class MyTicketHook extends TicketHook {
 }
 ```
 
+### Request Filter
+
+*SINCE 1.6.0*
+
+You can provide your own custom request filter by subclassing the *HttpRequestFilter* class.
+
+```java
+import com.gitblit.extensions.HttpRequestFilter;
+import ro.fortsoft.pf4j.Extension;
+
+@Extension
+public class MyRequestFilter extends HttpRequestFilter {
+
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response,
+            FilterChain chain) throws IOException, ServletException {
+    }
+}
+```
+
-- 
2.39.5