301 Redirect Issues in Apache Virtual Host

Question

I've got a site with SSL (Certbot) enabled and so I've setup my 301 redirects in the /etc/apache2/sites-available/example.com-le-ssl.conf file. I did it this way since the non-ssl virtual host (:80) redirects everything to :443 as far as I understand it.

Some of the redirects work, but if the URL fragment is the same (except moved into a parent URL slug) then I get a redirect loop. Also, blog posts with a GET parameter aren't being picked up at all.

Like so:

# This works
Redirect 301 /foobar https://www.example.com/slug/foo-bar/

# This loops
Redirect 301 /foo-bar https://www.example.com/slug/foo-bar/

# This doesn't seem to redirect at all
Redirect 301 /article.cfm?blogid=9 https://www.example.com/blog/pretty-name/

I can guess that the looping one redirects properly the first time, but then also sees /foo-bar at the end of the new URL and attempts another redirect. I end up with a URL in the browser bar that looks like:

https://www.example.com/slug/foo-bar///////

Until I get an error from Chrome about redirect loops.

So, I thought that the leading / right after Redirect 301 only picked up the URL fragment starting from immediately after the base of the FQDN?

And is there any reason why a 301 with a GET parameter (e.g. /article.cfm?blogid=9) doesn't work either?

I Googled around but so much of what I found is just about moving non-www to www or non-ssl to ssl. I also find the documentation a bit obtuse.

EDIT: These directives are directly inside of the <VirtualHost> and not inside of a <Directory> block. From the non-ssl config, 3 different domains are being redirected to the new, canonical domain. Rather than having a non-canonical domain redirect to https and then to the canonical, I changed the RewriteRule to direct all to the https version of the canonical. I also removed the trailing slashes from the 301 redirect lines in the ssl config file.

Answer 1

# This loops
Redirect 301 /foo-bar https://www.example.com/slug/foo-bar/

I can guess that the looping one redirects properly the first time, but then also sees /foo-bar at the end of the new URL and attempts another redirect.

Nope, by itself this would not cause a loop. The mod_alias Redirect directive is prefix-matching - it matches the start of the URL, not the "end of the URL".

Either...

• You are seeing a cached redirect (since you are testing with 301 permanent redirects). Unless you are careful to disable the browser cache whilst testing, you should test with 302 (temporary) redirects until you have confirmed it works as expected.
• There is a conflict with other directives.
• You've not restarted the web server, after making these changes to the server config.

However, since you have omitted the trailing slash on the source URL-path (ie. /foo-bar), but you have included the trailing slash on the target URL then if you were to request /foo-bar/ (with a trailing slash) then this would result in a redirect to https://www.example.com/slug/foo-bar// (double trailing slash), but still no loop. This is because with the Redirect directive, everything after the initial match is appended to the end of the target URL.

You would see a redirect loop like the following:

https://www.example.com/slug/foo-bar///////

If you had a directive like:

Redirect 301 /slug/foo-bar https://www.example.com/slug/foo-bar/

And requested /slug/foo-bar/ (with a trailing slash). If you want a one-to-one redirect then you need to use RedirectMatch or use mod_rewrite instead.

So, I thought that the leading / right after Redirect 301 only picked up the URL fragment starting from immediately after the base of the FQDN?

Yes, that is correct.

# This doesn't seem to redirect at all
Redirect 301 /article.cfm?blogid=9 https://www.example.com/blog/pretty-name/

And is there any reason why a 301 with a GET parameter (e.g. /article.cfm?blogid=9) doesn't work either?

Yes. You can't match the query string with the Redirect directive. The Redirect directive matches against the URL-path only, which excludes the query string.

If you want to match against the query string then you need to use mod_rewrite and check against the QUERY_STRING server variable. For example:

RewriteEngine On
RewriteCond %{QUERY_STRING} ^blogid=9
RewriteRule ^/?article\.cfm https://www.example.com/blog/pretty-name/ [R,L]

"pretty-name" - However, you'll need to be careful of redirect loops, since you are presumably rewritting the "pretty-name" later in the request. (?) If this is the case, then this redirect is not strictly necessary, unless these URLs have already been indexed or linked to by external third parties.

Note also, that once you start using mod_rewrite for some redirects/rewrites then it is advisable to convert all your mod_alias redirects (Redirect and RedirectMatch) to use mod_rewrite (RewriteRule) in order to avoid unexpected conflicts. Different modules execute at different times during the request, despite their apparent order in the config file (mod_rewrite executes first).