Ask Ben: Forward ColdFusion Requests To Another Domain
Posted August 21, 2007 at 6:02 PM
I just read your post on Exploring Path Info. I think it is pretty much exactly what I was looking for BUT I am not much of a programmer so I can't implement it. I have to change the domain of a site and need to 301 redirect all the URLs to the new domain... It is not a matter of just forwarding the old domain to the new - I need to forward literally every old URL to every new URL. This all has to do with maintain the search engine rankings in Google. All totaled there are well over 300,000 URLs that need to be redirected.
NOTE: Made one change to the code where query string was returning NULL.
There are a lot of variables that go into this. Things like URL Rewriting and 404 error handling can make this stuff much more complicated and need to be addressed individually. For this demo, I am going to assume that we are dealing with straight-up URLs and that no crazy URL magic is going on.
That being said, all we have to do for this is get the currently requested page URL and then swap out the old domain value for the new domain value using simple string manipulation. There are a few different ways to get the URL parts such as the ColdFusion CGI scope; however, I have been told that those are unreliable going from server to server, so for ease of use, I am going to use the URL String Buffer returned by the underlying ColdFusion Request object. Actually, this is doubly-nice since the StringBuffer already takes care of things like protocol, credentials, and port, so we don't even have to worry about HOW to string together all the URL parts.
Now, we just need a centralized place in the site so that all incoming ColdFusion URLs are redirected. NOTE that I say ColdFusion requests since Image and other File requests are not handled through the ColdFusion application server. I only know this aspect (the ColdFusion aspect). The Application.cfc or Application.cfm file serves as the easiest place to put this code:
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- <!--- Get the request object for the current page. --->
- <cfset objRequest = GetPageContext().GetRequest() />
-
- <!---
- Get the requested URL string buffer (this will NOT
- contain the query string).
- --->
- <cfset objURLBuffer = objRequest.GetRequestURL() />
-
- <!--- Get the query string for the current request. --->
- <cfset strQueryString = objRequest.GetQueryString() />
-
-
- <!---
- Append the query string to the URL buffer if one exists
- for the current request. If no query string was present,
- the GetQueryString() method call will return NULL.
- --->
- <cfif StructKeyExists( VARIABLES, "strQueryString" )>
-
- <cfset objURLBuffer.Append( "?" & strQueryString ) />
-
- </cfif>
-
-
- <!---
- ASSERT: At this point, our URL string buffer holds the
- full URL of the page that is currently being requested.
- Now that we have that, we need to forward users to
- another domain.
- --->
-
-
- <!--- Convert the URL buffer to a string. --->
- <cfset strURL = objURLBuffer.ToString() />
-
- <!---
- Instead of just blindly replacing domain values, make
- sure that it exists (if for some reason, something goes
- wrong, you might create an infinite loop of forwarding
- (if the domain never changes).
-
- CAUTION: I am using a regular expression here in case
- you want to hanlde thinks like www or what not. If you
- don't care about that, just use FindNoCase() and remove
- the \b constructs.
- --->
- <cfif REFindNoCase( "\bOLD_DOMAIN\b", strURL )>
-
- <!---
- We found the OLD domain in the current URL. Now,
- let's replace it with the NEW domain.
-
- CAUTION: I am using regular expression here in case
- you want to handle things differently. If you don't
- care about RegEx, just use a ReplaceNoCase() instead.
- --->
- <cfset strNewURL = strURL.ReplaceFirst(
- "\bswoop\b",
- "NEW_DOMAIN"
- ) />
-
- <!--- Return the permanent redirect to new URL. --->
- <cfheader
- statuscode="301"
- statustext="Moved Permanently"
- />
-
- <!--- Return new URL. --->
- <cfheader
- name="Location"
- value="#strNewURL#"
- />
-
-
- <cfelse>
-
-
- <!---
- Something went wrong with our code and we are not
- finding the old domain. Return a 500 error.
- --->
- <cfheader
- statuscode="500"
- statustext="Internal Server Error"
- />
-
- <!--- Clear the content buffer and return HTML. --->
- <cfcontent
- type="text/html"
- reset="true"
- />
-
- <!---
- Even though something went wrong, provide the user
- with a fail-safe so that they can at least get to
- the new domain.
- --->
- <p>
- There was an error with the current page request.
- Please access our new site
- <a href="http://NEW_DOMAIN_HOME_PAGE">here</a>.
- </p>
-
- </cfif>
-
- <!--- Abort out of page. --->
- <cfabort />
You will notice that in my redirect code, I am not just blindly swapping domain values and returning the headers; first I am checking to see if the domain is found. Once you get your code up and running, this shouldn't be a problem, but, at least for testing, this will help prevent and infinite redirect loop from occurring.
Also, just incase something does go wrong, I am returning a 500 error and giving the user a last-chance link to get to the new site. Hope this helps a bit.
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Reader Comments
Alternative and in my opinion preferred way is to use mod_rewrite if using Apache. Couple fo lines in .htaccess will take care of whole thing (including images and other files)
RewriteEngine On
RewriteRule ^(.*)$ http://www.new.com/$1 [R=301,L]
IIS has something similar, I don't know exact solution for it.
@Tero,
That looks pretty nice. Unfortunately, I don't have access to any rewriting filters where I host / test, so I can't go this route. In your example, maybe I am just not seeing it, but where are you matching the old domain name? It appears as if the current domain name isn't even part of the URL that is exposed to MOD Rewrite? Also, will $1 start with a forward slash?
That would go to .htaccess in your webroot; only requests for that domain will be served there and thus matching is done earlier by Apache virtual hosts setup.
If your host allows you to use .htaccess and they have mod_rewrite enabled this would work for you - I would think that's quite common but it has been ages since I last used anything but dedicated servers one way or another.
I think you are right about forward slash, I just googled for example and copied what they had (http://www.tamingthebeast.net/articles3/changing-domain-names.htm)
Ben, I'd be surprised if your current host does not allow .htaccess. I think that almost all hosts allow it. I know plenty of people who use it to help set up they blogs address string in wordpress. It has become a quite common feature with most webhosting.
@Dave,
To be honest, I know nothing about htaccess files. In general, other than a 404 handler, I don't know much about anything that requires additional CFAdmin or IIS setup. I don't have access to that stuff, so I find ways of doing stuff without it.
You're using a very commendable process to go about this. Scanning for the site first, etc. I can imagine the nightmare the original asker of the question must have gone through trying to do everything one by one like that. Surely there must be an easier way! You do have to assume, though, that no URL magic is going on - so, you still need to probably at least check one by one.
