Url rewriting causes Magento admin to become inaccessible - php

Question

I have magento in a subdirectory in the root and if I set the secure base url and secure base url link to the correct shared ssl url to enable secure pages I have no problem in the FRONTEND. The pages displays as they should. However when I try to access the admin with the secure link below I cannot gain admittance.
For instance in the frontend: http://mydomain.com/shop becomes http://mydomain.com - which is correct.
https://mydomain.sharedssl.com/shop/customer/account/login/ becomes
https://mydomain.sharedssl.com/customer/account/login/ - which is correct.
But then I can access admin with neither https://mydomain.com/shop/index.php/admin/ nor https://mydomain.com//index.php/admin/
In the root directory I have this in my htaccess:
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_URI} !^/shop(.*)
RewriteRule (.*) /shop/$1 [L]
and in the shop (Magento) I have the following:
############################################
## uncomment these lines for CGI mode
## make sure to specify the correct cgi php binary file name
## it might be /cgi-bin/php-cgi
# Action php5-cgi /cgi-bin/php5-cgi
# AddHandler php5-cgi .php
############################################
## GoDaddy specific options
# Options -MultiViews
## you might also need to add this line to php.ini
## cgi.fix_pathinfo = 1
## if it still doesn't work, rename php.ini to php5.ini
############################################
## this line is specific for 1and1 hosting
#AddType x-mapp-php5 .php
#AddHandler x-mapp-php5 .php
############################################
## default index file
DirectoryIndex index.php
<IfModule mod_php5.c>
############################################
## adjust memory limit
# php_value memory_limit 64M
php_value memory_limit 128M
php_value max_execution_time 18000
############################################
## disable magic quotes for php request vars
php_flag magic_quotes_gpc off
############################################
## disable automatic session start
## before autoload was initialized
php_flag session.auto_start off
############################################
## enable resulting html compression
#php_flag zlib.output_compression on
###########################################
# disable user agent verification to not break multiple image upload
php_flag suhosin.session.cryptua off
###########################################
# turn off compatibility with PHP4 when dealing with objects
php_flag zend.ze1_compatibility_mode Off
</IfModule>
<IfModule mod_security.c>
###########################################
# disable POST processing to not break multiple image upload
SecFilterEngine Off
SecFilterScanPOST Off
</IfModule>
<IfModule mod_deflate.c>
############################################
## enable apache served files compression
## http://developer.yahoo.com/performance/rules.html#gzip
# Insert filter on all content
###SetOutputFilter DEFLATE
# Insert filter on selected content types only
#AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css text/javascript
# Netscape 4.x has some problems...
#BrowserMatch ^Mozilla/4 gzip-only-text/html
# Netscape 4.06-4.08 have some more problems
#BrowserMatch ^Mozilla/4\.0[678] no-gzip
# MSIE masquerades as Netscape, but it is fine
#BrowserMatch \bMSIE !no-gzip !gzip-only-text/html
# Don't compress images
#SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip dont-vary
# Make sure proxies don't deliver the wrong content
#Header append Vary User-Agent env=!dont-vary
</IfModule>
<IfModule mod_ssl.c>
############################################
## make HTTPS env vars available for CGI mode
#SSLOptions StdEnvVars
</IfModule>
<IfModule mod_rewrite.c>
############################################
## enable rewrites
Options +FollowSymLinks
RewriteEngine on
############################################
## you can put here your magento root folder
## path relative to web root
RewriteBase /
############################################
## workaround for HTTP authorization
## in CGI environment
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
############################################
## always send 404 on missing files in these folders
RewriteCond %{REQUEST_URI} !^/(media|skin|js)/
############################################
## never rewrite for existing files, directories and links
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-l
############################################
## rewrite everything else to index.php
RewriteRule ^(.*)$ /shop/index.php [L]
</IfModule>
############################################
## Prevent character encoding issues from server overrides
## If you still have problems, use the second line instead
AddDefaultCharset Off
#AddDefaultCharset UTF-8
<IfModule mod_expires.c>
############################################
## Add default Expires header
## http://developer.yahoo.com/performance/rules.html#expires
ExpiresDefault "access plus 1 year"
</IfModule>
############################################
## By default allow all access
Order allow,deny
Allow from all
############################################
## If running in cluster environment, uncomment this
## http://developer.yahoo.com/performance/rules.html#etags
#FileETag none
Could someone lend some assistance to getting this to work in the Magento backend?

Answer 1

The problem is in getting of REQUEST_URI environment variable value and checking it with SCRIPT_FILENAME and SCRIPT_NAME environment variables values. In your case REQUEST_URI is /index.php/stddadmin/ and SCRIPT_FILENAME with SCRIPT_NAME are equals to /shop/index.php and Magento unable to retrieve path info for controllers matching. So a cause of the problem is in adding of /index.php/ prefix to the request path and the Magento url generation has this value hardcoded for admin.
There are only two solutions to your problem:
Override method called _updatePathUseRewrites in Mage_Core_Model_Store model like in the following example:
class Your_CustomModule_Model_Store extends Mage_Core_Model_Store
{
protected _updatePathUseRewrites($url)
{
return $url; // Return passed variable without adding index.php as prefix
}
}
In this case your admin panel will be available at /admin/ url, like usual frontend page.
Reorganize project structure for placing Magento in root folder or add symbolic links on each its file and folder in root.

Answer 2

You can also use the "Admin Rewrites" extension to get rid of "index.php" in backend URLs:
http://www.magentocommerce.com/magento-connect/clockworkgeek/extension/3692/clockworkgeek_adminrewrites
It enables URL rewrites in the backend and it works fine. The only con is that it is marked as "Beta", because it overrides "Mage_Core_Model_Store".