http://code.google.com/p/phusion-passenger/issues/detail?id=30&colspec=ID%20Type%20Status%20Priority%20Milestone%20Stars%20Summary
http://code.google.com/p/phusion-passenger/issues/detail?id=136&colspec=ID%20Type%20Status%20Priority%20Milestone%20Stars%20Summary

Problem: The problem with RailsBaseURI is that it expects Rails directory
to be in virtualhost's documentroot. If it does'nt then you have to create
symlink to use rails application outside of document root.

Fix: Instead of creating symlinks there could be second optional argument
for RailsBaseURI which specifies full path to Rails application's public
directory.

For example, instead of creating symlink /var/www/somehost/railsapp1 ->
/home/user/railsapp1/public and:
<virtualhost *>
DocumentRoot /var/www/somehost
RailsBaseURI /railsapp1
</virtualhost>

we skip the symlink and specify the full path in apache conf:
<virtualhost *>
DocumentRoot /var/www/somehost
RailsBaseURI /railsapp1 /home/user/railsapp1/public
</virtualhost>

The patch (for 2.0.3) that does the thing is attached (patches also
RackBaseURI).

The combined patch:

1) Aliases and rewrite rules now apply when translating RailsBaseURI into
physical path. Resolved paths are cached.
2) Current behaviour remains: DocumentRoot+RailsBaseURI works also
3) If RailsBaseURI or RackBaseURI has second argument then this second argument
is used as physical path to rails public directory. This eliminates the need
for extra lookup using Apache subrequest and the overhead caused by it.

diff -wur ext/apache2/Configuration.cpp ext/apache2/Configuration.cpp
--- ext/apache2/Configuration.cpp	2008-08-09 15:19:15.000000000 +0300
+++ ext/apache2/Configuration.cpp	2008-09-23 22:06:15.000000000 +0300
@@ -75,11 +75,11 @@
 	DirConfig *add = (DirConfig *) addv;
 	
 	config->railsBaseURIs = base->railsBaseURIs;
-	for (set<string>::const_iterator it(add->railsBaseURIs.begin()); it != add->railsBaseURIs.end(); it++) {
+	for (set<BaseURIConfig*>::const_iterator it(add->railsBaseURIs.begin()); it != add->railsBaseURIs.end(); it++) {
 		config->railsBaseURIs.insert(*it);
 	}
 	config->rackBaseURIs = base->rackBaseURIs;
-	for (set<string>::const_iterator it(add->rackBaseURIs.begin()); it != add->rackBaseURIs.end(); it++) {
+	for (set<BaseURIConfig*>::const_iterator it(add->rackBaseURIs.begin()); it != add->rackBaseURIs.end(); it++) {
 		config->rackBaseURIs.insert(*it);
 	}
 	
@@ -275,18 +275,27 @@
  *************************************************/
 
 static const char *
-cmd_rails_base_uri(cmd_parms *cmd, void *pcfg, const char *arg) {
+cmd_rails_base_uri(cmd_parms *cmd, void *pcfg, const char *arg, const char *arg2) {
 	DirConfig *config = (DirConfig *) pcfg;
+	BaseURIConfig *bConfig = new BaseURIConfig;
 	if (strlen(arg) == 0) {
 		return "RailsBaseURI may not be set to the empty string";
 	} else if (arg[0] != '/') {
 		return "RailsBaseURI must start with a slash (/)";
 	} else if (strlen(arg) > 1 && arg[strlen(arg) - 1] == '/') {
 		return "RailsBaseURI must not end with a slash (/)";
-	} else {
-		config->railsBaseURIs.insert(arg);
-		return NULL;
 	}
+
+	apr_pool_cleanup_register(cmd->pool, bConfig, destroy_config_struct<BaseURIConfig>, apr_pool_cleanup_null);
+
+	bConfig->baseURI = arg;
+
+	if (arg2) {
+	    bConfig->publicDirectory = arg2;
+	}
+
+	config->railsBaseURIs.insert(bConfig);
+	return NULL;
 }
 
 static const char *
@@ -321,18 +331,26 @@
  *************************************************/
 
 static const char *
-cmd_rack_base_uri(cmd_parms *cmd, void *pcfg, const char *arg) {
+cmd_rack_base_uri(cmd_parms *cmd, void *pcfg, const char *arg, const char *arg2) {
 	DirConfig *config = (DirConfig *) pcfg;
+	BaseURIConfig *bConfig = new BaseURIConfig;
 	if (strlen(arg) == 0) {
 		return "RackBaseURI may not be set to the empty string";
 	} else if (arg[0] != '/') {
 		return "RackBaseURI must start with a slash (/)";
 	} else if (strlen(arg) > 1 && arg[strlen(arg) - 1] == '/') {
 		return "RackBaseURI must not end with a slash (/)";
-	} else {
-		config->rackBaseURIs.insert(arg);
-		return NULL;
 	}
+
+	apr_pool_cleanup_register(cmd->pool, bConfig, destroy_config_struct<BaseURIConfig>, apr_pool_cleanup_null);
+
+	bConfig->baseURI = arg;
+
+	if (arg2)  {
+		bConfig->publicDirectory = arg2;
+	}
+	config->rackBaseURIs.insert(bConfig);
+ 	return NULL;
 }
 
 static const char *
@@ -414,7 +433,7 @@
 		"The user that Rails/Rack applications must run as when user switching fails or is disabled."),
 
 	// Rails-specific settings.
-	AP_INIT_TAKE1("RailsBaseURI",
+	AP_INIT_TAKE12("RailsBaseURI",
 		(Take1Func) cmd_rails_base_uri,
 		NULL,
 		RSRC_CONF,
@@ -441,7 +460,7 @@
 		"The spawn method to use."),
 	
 	// Rack-specific settings.
-	AP_INIT_TAKE1("RackBaseURI",
+	AP_INIT_TAKE12("RackBaseURI",
 		(Take1Func) cmd_rack_base_uri,
 		NULL,
 		RSRC_CONF,
diff -wur ext/apache2/Configuration.hpp ext/apache2/Configuration.hpp
--- ext/apache2/Configuration.hpp	2008-08-09 15:19:33.000000000 +0300
+++ ext/apache2/Configuration.hpp	2008-09-23 22:06:15.000000000 +0300
@@ -41,21 +41,25 @@
 
 using namespace std;
 
+struct BaseURIConfig {
+	std::string baseURI;
+	std::string publicDirectory;
+};
 	
 /**
  * Per-directory configuration information.
  *
  * Use the getter methods to query information, because those will return
  * the default value if the value is not specified.
  */
 struct DirConfig {
 	enum Threeway { ENABLED, DISABLED, UNSET };
 	enum SpawnMethod { SM_UNSET, SM_SMART, SM_SMART_LV2, SM_CONSERVATIVE };
 	
 	Threeway enabled;
 	
-	std::set<std::string> railsBaseURIs;
-	std::set<std::string> rackBaseURIs;
+	std::set<BaseURIConfig*> railsBaseURIs;
+	std::set<BaseURIConfig*> rackBaseURIs;
 	
 	/** Whether to autodetect Rails applications. */
 	Threeway autoDetectRails;
diff -wur ext/apache2/DirectoryMapper.h ext/apache2/DirectoryMapper.h
--- ext/apache2/DirectoryMapper.h	2008-08-09 15:19:15.000000000 +0300
+++ ext/apache2/DirectoryMapper.h	2008-09-23 22:13:36.000000000 +0300
@@ -39,6 +39,7 @@
 // compilation will fail on OpenBSD.
 #include <httpd.h>
 #include <http_core.h>
+#include <http_request.h>
 
 namespace Passenger {
 
@@ -87,6 +87,7 @@
 	request_rec *r;
 	bool baseURIKnown;
 	const char *baseURI;
+	BaseURIConfig *bConfig;
 	ApplicationType appType;
 	
 	inline bool shouldAutoDetectRails() {
@@ -114,6 +115,7 @@
 		appType = NONE;
 		baseURIKnown = false;
 		baseURI = NULL;
+		bConfig = NULL;
 	}
 	
 	/**
@@ -136,7 +138,7 @@
 			return baseURI;
 		}
 		
-		set<string>::const_iterator it;
+		set<BaseURIConfig *>::const_iterator it;
 		const char *uri = r->uri;
 		size_t uri_len = strlen(uri);
 		
@@ -146,7 +148,8 @@
 		}
 		
 		for (it = config->railsBaseURIs.begin(); it != config->railsBaseURIs.end(); it++) {
-			const string &base(*it);
+			BaseURIConfig * bc = (*it);
+			const string base = bc->baseURI;
 			if (  base == "/"
 			 || ( uri_len == base.size() && memcmp(uri, base.c_str(), uri_len) == 0 )
 			 || ( uri_len  > base.size() && memcmp(uri, base.c_str(), base.size()) == 0
@@ -155,13 +158,15 @@
 				baseURIKnown = true;
 				baseURI = base.c_str();
 				appType = RAILS;
+				this->bConfig = bc;
 				return baseURI;
 			}
 		}
 		
 		UPDATE_TRACE_POINT();
 		for (it = config->rackBaseURIs.begin(); it != config->rackBaseURIs.end(); it++) {
-			const string &base(*it);
+			BaseURIConfig * bc = (*it);
+			const string base = bc->baseURI;
 			if (  base == "/"
 			 || ( uri_len == base.size() && memcmp(uri, base.c_str(), uri_len) == 0 )
 			 || ( uri_len  > base.size() && memcmp(uri, base.c_str(), base.size()) == 0
@@ -169,6 +174,7 @@
 				baseURIKnown = true;
 				baseURI = base.c_str();
 				appType = RACK;
+				this->bConfig = bc;
 				return baseURI;
 			}
 		}
@@ -213,26 +219,14 @@
 			return "";
 		}
 		
-		const char *docRoot = ap_document_root(r);
-		size_t len = strlen(docRoot);
-		if (len > 0) {
-			string path;
-			if (docRoot[len - 1] == '/') {
-				path.assign(docRoot, len - 1);
-			} else {
-				path.assign(docRoot, len);
-			}
-			if (strcmp(baseURI, "/") != 0) {
-				/* Application is deployed in a sub-URI.
-				 * This is probably a symlink, so let's resolve it.
-				 */
-				path.append(baseURI);
-				path = resolveSymlink(path);
-			}
-			return path;
-		} else {
-			return "";
+		if (this->bConfig->publicDirectory.empty ()) {
+			request_rec *sub_req;
+			sub_req = ap_sub_req_lookup_uri(baseURI, r, NULL);
+
+			this->bConfig->publicDirectory = resolveSymlink(sub_req->filename);
 		}
+
+		return this->bConfig->publicDirectory;
 	}
 	
 	/**