Allow manual specification of a base URL.

From: Michael Smith <msmith@cbnco.com>

includes/header.jsp uses org.opennms.web.Util.calculateUrlBase() to
come up with an HTML base tag. By default this queries the request
to come up with a URL, but now you can override it if it gets it wrong.
You can also put in substitutions (scheme, host, port, context path)
from the real URL. I needed this to get Jetty working behind an Apache/SSL
reverse proxy. (OK, you don't need the variable substitutions just for that.
You only need them if you use SSH port forwards to get to your Apache/SSL
vhost. Then you can't hardcode the base URL.)

opennms-webapp/src/main/webapp/tiles/mainLayout.jsp had its own
code to set the base tag. I have changed it to use calculateUrlBase()
but I can't test it.
---

 .../src/main/filtered/etc/opennms.properties       |   17 +++++
 .../src/main/java/org/opennms/web/Util.java        |   86 +++++++++++++++--------
 .../web-filtered/WEB-INF/configuration.properties  |    9 ++
 .../src/main/webapp/tiles/mainLayout.jsp           |    3 -
 4 files changed, 84 insertions(+), 31 deletions(-)


diff --git a/opennms-daemon/src/main/filtered/etc/opennms.properties b/opennms-daemon/src/main/filtered/etc/opennms.properties
index e5dea69..cc9b876 100644
--- a/opennms-daemon/src/main/filtered/etc/opennms.properties
+++ b/opennms-daemon/src/main/filtered/etc/opennms.properties
@@ -110,3 +110,20 @@ org.opennms.netmgt.jetty.port = 8980
 # bind address here. If you set this to a value other than 127.0.0.1,
 # you will need to update the rtc-client and map-client URLs above.
 #org.opennms.netmgt.jetty.host = 127.0.0.1
+
+# If OpenNMS is setting an incorrect HTML <base> tag, you can override
+# its idea of the local URL here. The URL must end with a '/'. The following
+# substitutions are available:
+# %s: scheme (http, https)
+# %h, %p: host and port from the Host: header
+# %x: host and port from the X-Forwarded-Host, X-Host or Host header
+# %c: context path (without trailing slash)
+#
+# You can use this to get Jetty working behind an Apache/SSL proxy.
+# Set the base-url to https://%x%c/ and include in your Apache SSL vhost:
+#     <Location /opennms>
+#         ProxyPass http://127.0.0.1:8980/opennms
+#         ProxyPassReverse http://127.0.0.1:8980/opennms
+#     </Location>
+#
+#opennms.web.base-url = https://%x%c/
diff --git a/opennms-webapp/src/main/java/org/opennms/web/Util.java b/opennms-webapp/src/main/java/org/opennms/web/Util.java
index 406b037..2686aab 100644
--- a/opennms-webapp/src/main/java/org/opennms/web/Util.java
+++ b/opennms-webapp/src/main/java/org/opennms/web/Util.java
@@ -66,11 +66,6 @@ import org.opennms.web.element.NetworkElementFactory;
 public abstract class Util extends Object {
 
     /**
-     * Internal flag used to cache a servlet context parameter
-     */
-    protected static Boolean usePortInBaseUrls;
-
-    /**
      * Return a string that represents the fully qualified URL for our servlet
      * context, suitable for use in the HTML <em>base</em> tag.
      * 
@@ -79,6 +74,12 @@ public abstract class Util extends Object {
      * from port 80, and your web application name was "opennms," then this
      * method would return: <code>http://www.mycompany.com:80/opennms/</code>
      * </p>
+     *
+     * <p>
+     * If this guess is wrong, you can override it by setting the property
+     * <code>opennms.web.base-url</code> in opennms.properties
+     * (for embedded Jetty) or WEB-INF/configuration.properties (for Tomcat).
+     * </p>
      * 
      * @param request
      *            the servlet request you are servicing
@@ -88,33 +89,60 @@ public abstract class Util extends Object {
             throw new IllegalArgumentException("Cannot take null parameters.");
         }
 
-        // get what the web browser thinks is the URL
-        StringBuffer buffer = request.getRequestURL();
-
-        // get a string version of the buffer so we can search in it
-        String string = buffer.toString();
-
-        // find the "//" in something like "http://host"
-        int schemeSlashesIndex = string.indexOf("//");
-
-        // find the "/" at the end of "http://host:port/"
-        int schemeHostPortIndex = string.indexOf("/", schemeSlashesIndex + 2);
-
-        // truncate everything after the base scheme, host, and port values
-        buffer.setLength(schemeHostPortIndex);
-
-        String context = request.getContextPath();
-
-        // if the context is not the root context
-        if (!context.equals("")) {
-            // context will always start with a slash
-            buffer.append(context);
+        String tmpl = Vault.getProperty("opennms.web.base-url");
+        if (tmpl == null) {
+            tmpl = "%s://%x%c/";
         }
+        return substituteUrl(request, tmpl);
+    }
 
-        // add a trailing slash
-        buffer.append("/");
+    protected static final char[] substKeywords = { 's', 'h', 'p', 'x', 'c' };
+
+    protected static String substituteUrl(HttpServletRequest request,
+                                          String tmpl) {
+        String[] replacements = {
+            request.getScheme(),                        // %s
+            request.getServerName(),                    // %h
+            Integer.toString(request.getServerPort()),  // %p
+            getHostHeader(request),                     // %x
+            request.getContextPath()                    // %c
+        };
+
+        StringBuffer out = new StringBuffer(48);
+        for (int i = 0; i < tmpl.length();) {
+            char c = tmpl.charAt(i++);
+            if (c == '%' && i < tmpl.length()) {
+                char d = tmpl.charAt(i++);
+                for (int key = 0; key < substKeywords.length; ++key) {
+                    if (d == substKeywords[key]) {
+                        out.append(replacements[key]);
+                        break;
+                    }
+                }
+            }
+            else {
+                out.append(c);
+            }
+        }
+        return out.toString();
+    }
 
-        return buffer.toString();
+    protected static final String[] hostHeaders = {
+        "X-Forwarded-Host",     // Apache ProxyPass
+        "X-Host",               // lighttpd
+        "Host"                  // unproxied
+    };
+
+    /** Obtains the host and port used by the end user. */
+    public static String getHostHeader(HttpServletRequest request) {
+        for (int i = 0; i < hostHeaders.length; ++i) {
+            String ret = request.getHeader(hostHeaders[i]);
+            if (ret != null) {
+                return ret;
+            }
+        }
+        return request.getServerName() + ":"
+                + Integer.toString(request.getServerPort());
     }
 
     /**
diff --git a/opennms-webapp/src/main/web-filtered/WEB-INF/configuration.properties b/opennms-webapp/src/main/web-filtered/WEB-INF/configuration.properties
index 0ec5398..911452f 100644
--- a/opennms-webapp/src/main/web-filtered/WEB-INF/configuration.properties
+++ b/opennms-webapp/src/main/web-filtered/WEB-INF/configuration.properties
@@ -53,3 +53,12 @@ org.opennms.rrd.storeByGroup=false
 # The password the Map System uses when authenticating itself in an HTTP POST.
 #opennms.map-client.http-post.password = map
 
+# If OpenNMS is setting an incorrect HTML <base> tag, you can override
+# its idea of the local URL here. The URL must end with a '/'. The following
+# substitutions are available:
+# %s: scheme (http, https)
+# %h, %p: host and port from the Host: header
+# %x: host and port from the X-Forwarded-Host, X-Host or Host header
+# %c: context path (without trailing slash)
+#
+#opennms.web.base-url = https://%x%c/
diff --git a/opennms-webapp/src/main/webapp/tiles/mainLayout.jsp b/opennms-webapp/src/main/webapp/tiles/mainLayout.jsp
index 51a2374..3a19b90 100644
--- a/opennms-webapp/src/main/webapp/tiles/mainLayout.jsp
+++ b/opennms-webapp/src/main/webapp/tiles/mainLayout.jsp
@@ -46,11 +46,10 @@
 <html>
 	<head>
 		<title><tiles:getAsString name="title"/></title>
+		<base href="<%=org.opennms.web.Util.calculateUrlBase( request )%>" />
 		<link rel="stylesheet" type="text/css" href="css/styles.css" />
   		<script src="javascripts/prototype.js" type="text/javascript"></script>
 		<script src="javascripts/scriptaculous.js" type="text/javascript"></script>
-		<base href="<%= request.getScheme() + "://" + request.getServerName() + ":" +
-   			  	request.getServerPort() + request.getContextPath() + "/" %>"/>
 	</head>
 
 	<body>