Redirect folder to subdomain

Question

I want to have 2 Ruby on Rails applications on a domain.

The first one is running at example.com; I have done that with .htaccess (with RewriteRule to example.com:12001)

I want the other one to be in a subdomain, like blog.example.com. So I created a subdomain, and in the file .htaccess I redirect to example.com:12002.

Everything is working fine, but if I go to address example.com/blog, I am not redirected, and I see in browser the contents of blog folder in public_html:

Index of /blog

    Parent Directory

I would like to go to the second application(blog.example.com) when the url is example.com/blog. How could I do that?

Answer 1

the solution depends on how your hosting provider implements multi-subdomain mapping. Some offer a control panel so that you can register your subdomains and point each to a separate subdirectory in your file space. Some will just map *.yourdomain.zzz to the document root for yourdomain.zzz, and from your description, this is what is happening for you. In this case you need to decode the HTTP_HOST variable and route on that. But you also need to stop your rewrite rule looping so that sub1.yourdomain.zzz doesn't get mapped to yourDocRoot/sub1/sub1/sub1...`

If you wanted to process sub1 and sub2 subdomains, then you would do this with a rule in you top level like this:

RewriteBase  /
RewriteCond  %{ENV:REDIRECT_INSUB} !=1
RewriteCond  %{HTTP_HOST}          (sub1|sub2)\.yourdomain\.zzz
ReweriteRule ^(.*)                 %1/$1         [L,E=INSUB:1]

Search for [.htaccess] HTTP_HOST to see lots of variants of this.

Answer 2

first of all, you must replace http://blog.example.com/whatever_or_empty to http://www.example.com/blog/whatever_or_empty in your HTML hrefs.

blog.example.com although a sub domain, is a different URL. i.e. when a RewriteRule does a rewrite to another URL an external redirect will occur. This will reflect in the browser. Be a temporary redirect(302(the default)) or permanent redirect(301).

So, using url rewriting to change the link http://blog.example.com/ to http://www.example.com/blog/ is useless.

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Although, you can achieve this using Apache Module mod_proxy.

The Apache Proxy Modules has these:

• mod_proxy: The core module deals with proxy infrastructure and configuration and managing a proxy request.
• mod_proxy_http: This handles fetching documents with HTTP and HTTPS.
• mod_proxy_ftp: This handles fetching documents with FTP.
• mod_proxy_connect: This handles the CONNECT method for secure (SSL) tunneling.
• mod_proxy_ajp: This handles the AJP protocol for Tomcat and similar backend servers.
• mod_proxy_balancer implements clustering and load-balancing over multiple backends.
• mod_cache, mod_disk_cache, mod_mem_cache: These deal with managing a document cache. To enable caching requires mod_cache and one or both of disk_cache and mem_cache.
• mod_proxy_html: This rewrites HTML links into a proxy's address space.
• mod_xml2enc: This supports internationalisation (i18n) on behalf of mod_proxy_html and other markup-filtering modules. space.
• mod_headers: This modifies HTTP request and response headers.
• mod_deflate: Negotiates compression with clients and backends.

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You need at-least mod_proxy and mod_proxy_http modules enabled for the proxy to work:

you should have lines similar to these in your apache's conf file:

LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule proxy_module modules/mod_proxy.so

use this in your Virtualhost of http://www.example.com

ProxyPass /blog http://blog.example.com
ProxyPassReverse /blog http://blog.example.com
ProxyRequests On
ProxyVia On

<Proxy *>
Order allow,deny
Allow from all
</Proxy>

Definitions:

• ProxyPass ^{Apache Docs}.
• ProxyPassReverse ^{Apache Docs}.
• ProxyRequests ^{Apache Docs}.
• Proxyvia ^{Apache Docs}.

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You can also use a cache with mod_cache: mod_cache.
For more on caching, refer here: mod_cache ^{Apache Docs}.

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Also disable index views indexes by setting this:

options -indexes

Add a index to the folder blog.