FAQ: mod_rewrite, 301 redirects, and optimizing Apache.

Can you please explain, whats the use of

RewriteBase /

Code (markup):

Thanks in advance..

 

I really don't understand how the section ([^.]+) can possibly work for anyone.

When you see [^X] it means "NOT X". If you have [^/] it means "NOT /". The caret as the first symbol in a character class indicates negation.

A single dot on it's own means "anything", a dot with a backslash in front means a literal dot, but without the backslash it will match anything. That's why (.*) matches the whole string.

A plus means "one or more of the preceding character class". A star means "zero or more of the preceding character class". So (.+) means "match one or more of any character" and (.*) means "match zero or more of any character"

Putting it all together, the section ([^.]+) means "one or more of not anything" which doesn't make any sense. I'm happy if this has worked for you but it's probably not working the way you think it is working. Maybe Apache is simply ignoring that section because it's impossible to match anything or maybe it's just ignoring the caret and using the dot on it's own. Apache is quite smart after all.

mod_rewrite is not quite as voodoo-ish as most people think. (It IS still voodoo. Damn cool voodoo, but voodoo none the less.) Most of the confusion stems from a misunderstanding of how regular expressions work.

I'm considering writing a definitive guide to regular expressions which (I hope) will dispel some of the confusion.

 

thanks Nintendo

 

Hello

I would like to share some informations I have collected from net.



Regular Expression Syntax
^ Start of string
$ End of string
. Any single character
(a|b) a or b
(...) Group section
[abc] Item in range (a or b or c)
[^abc] Not in range (not a or b or c)
a? Zero or one of a
a* Zero or more of a
a+ One or more of a
a{3} Exactly 3 of a
a{3,} 3 or more of a
a{3,6} Between 3 and 6 of a
!(pattern) "Not" prefix. Apply rule when URL does not match pattern
RewriteRule FLAGS

I'm going to go a little deeper in this list than what the cheat sheet does as I tend to need a little more of a description on what each flag does (all descriptions are lifted without remorse from Apache.org)...not just the short definition.
R[=code] Redirect to new URL, with optional code (see below). Prefix Substitution with http://thishost[:thisport]/ (which makes the new URL a URI) to force a external redirection. If no code is given a HTTP response of 302 (MOVED TEMPORARILY) is used. If you want to use other response codes in the range 300-400 just specify them as a number or use one of the following symbolic names: temp (default), permanent, seeother. Use it for rules which should canonicalize the URL and give it back to the client, e.g., translate ``/~'' into ``/u/'' or always append a slash to /u/user, etc.

Note: When you use this flag, make sure that the substitution field is a valid URL! If not, you are redirecting to an invalid location! And remember that this flag itself only prefixes the URL with http://thishost[:thisport]/, rewriting continues. Usually you also want to stop and do the redirection immediately. To stop the rewriting you also have to provide the 'L' flag.
F Forbidden (sends 403 header) This forces the current URL to be forbidden, i.e., it immediately sends back a HTTP response of 403 (FORBIDDEN). Use this flag in conjunction with appropriate RewriteConds to conditionally block some URLs.
G Gone (no longer exists) This forces the current URL to be gone, i.e., it immediately sends back a HTTP response of 410 (GONE). Use this flag to mark pages which no longer exist as gone.
P Proxy This flag forces the substitution part to be internally forced as a proxy request and immediately (i.e., rewriting rule processing stops here) put through the proxy module. You have to make sure that the substitution string is a valid URI (e.g., typically starting with http://hostname) which can be handled by the Apache proxy module. If not you get an error from the proxy module. Use this flag to achieve a more powerful implementation of the ProxyPass directive, to map some remote stuff into the namespace of the local server.

Notice: To use this functionality make sure you have the proxy module compiled into your Apache server program. If you don't know please check whether mod_proxy.c is part of the ``httpd -l'' output. If yes, this functionality is available to mod_rewrite. If not, then you first have to rebuild the ``httpd'' program with mod_proxy enabled.
L Last Rule Stop the rewriting process here and don't apply any more rewriting rules. This corresponds to the Perl last command or the break command from the C language. Use this flag to prevent the currently rewritten URL from being rewritten further by following rules. For example, use it to rewrite the root-path URL ('/') to a real one, e.g., '/e/www/'.
N Next (i.e. restart rules) Re-run the rewriting process (starting again with the first rewriting rule). Here the URL to match is again not the original URL but the URL from the last rewriting rule. This corresponds to the Perl next command or the continue command from the C language. Use this flag to restart the rewriting process, i.e., to immediately go to the top of the loop.

But be careful not to create an infinite loop!
C Chain This flag chains the current rule with the next rule (which itself can be chained with the following rule, etc.). This has the following effect: if a rule matches, then processing continues as usual, i.e., the flag has no effect. If the rule does not match, then all following chained rules are skipped. For instance, use it to remove the ``.www'' part inside a per-directory rule set when you let an external redirect happen (where the ``.www'' part should not to occur!).
T=mime-type Set Mime Type Force the MIME-type of the target file to be MIME-type. For instance, this can be used to simulate the mod_alias directive ScriptAlias which internally forces all files inside the mapped directory to have a MIME type of ``application/x-httpd-cgi''.
NS Skip if internal sub-request This flag forces the rewriting engine to skip a rewriting rule if the current request is an internal sub-request. For instance, sub-requests occur internally in Apache when mod_include tries to find out information about possible directory default files (index.xxx). On sub-requests it is not always useful and even sometimes causes a failure to if the complete set of rules are applied. Use this flag to exclude some rules.

Use the following rule for your decision: whenever you prefix some URLs with CGI-scripts to force them to be processed by the CGI-script, the chance is high that you will run into problems (or even overhead) on sub-requests. In these cases, use this flag.
NC Case insensitive This makes the Pattern case-insensitive, i.e., there is no difference between 'A-Z' and 'a-z' when Pattern is matched against the current URL.
QSA Append query string This flag forces the rewriting engine to append a query string part in the substitution string to the existing one instead of replacing it. Use this when you want to add more data to the query string via a rewrite rule.
NE Do not escape output This flag keeps mod_rewrite from applying the usual URI escaping rules to the result of a rewrite. Ordinarily, special characters (such as '%', '$', ';', and so on) will be escaped into their hexcode equivalents ('%25', '%24', and '%3B', respectively); this flag prevents this from being done. This allows percent symbols to appear in the output, as in

RewriteRule /foo/(.*) /bar?arg=P1\%3d$1 [R,NE]

which would turn '/foo/zed' into a safe request for '/bar?arg=P1=zed'.
PT Pass through This flag forces the rewriting engine to set the uri field of the internal request_rec structure to the value of the filename field. This flag is just a hack to be able to post-process the output of RewriteRule directives by Alias, ScriptAlias, Redirect, etc. directives from other URI-to-filename translators. A trivial example to show the semantics: If you want to rewrite /abc to /def via the rewriting engine of mod_rewrite and then /def to /ghi with mod_alias:

RewriteRule ^/abc(.*) /def$1 [PT]
Alias /def /ghi

If you omit the PT flag then mod_rewrite will do its job fine, i.e., it rewrites uri=/abc/... to filename=/def/... as a full API-compliant URI-to-filename translator should do. Then mod_alias comes and tries to do a URI-to-filename transition which will not work.

Note: You have to use this flag if you want to intermix directives of different modules which contain URL-to-filename translators. The typical example is the use of mod_alias and mod_rewrite..
S=x Skip next x rules This flag forces the rewriting engine to skip the next num rules in sequence when the current rule matches. Use this to make pseudo if-then-else constructs: The last rule of the then-clause becomes skip=N where N is the number of rules in the else-clause. (This is not the same as the 'chain|C' flag!)
E=var:value Set environment variable "var" to "value" This forces an environment variable named VAR to be set to the value VAL, where VAL can contain regexp backreferences $N and %N which will be expanded. You can use this flag more than once to set more than one variable. The variables can be later dereferenced in many situations, but usually from within XSSI (via ) or CGI (e.g. $ENV{'VAR'}). Additionally you can dereference it in a following RewriteCond pattern via %{ENV:VAR}. Use this to strip but remember information from URLs.
RewriteCond FLAGS
NC Case insensitive
OR Allows a rule to apply if one of a series of conditions are true.
Redirection Header Codes
301 Moved permanently
302 Moved temporarily
403 Forbidden
404 Not found
410 Gone
Server Variables
Format
%{NAME_OF_VAR}
HTTP Headers
HTTP_USER_AGENT
HTTP_REFERER
HTTP_COOKIE
HTTP_FORWARDED
HTTP_HOST
HTTP_PROXY_CONNECTION
HTTP_ACCEPT
Request
REMOTE_ADDR
REMOTE_HOST
REMOTE_USER
REMOTE_IDENT
REQUEST_METHOD
SCRIPT_FILENAME
PATH_INFO
QUERY_STRING
AUTH_TYPE
Server
DOCUMENT_ROOT
SERVER_ADMIN
SERVER_NAME
SERVER_ADDR
SERVER_PORT
SERVER_PROTOCOL
SERVER_SOFTWARE
Time
TIME_YEAR
TIME_MON
TIME_DAY
TIME_HOUR
TIME_MIN
TIME_SEC
TIME_WDAY
TIME
Special
API_VERSION
THE_REQUEST
REQUEST_URI
REQUEST_FILENAME
IS_SUBREQ
Directives
RewriteEngine
RewriteOptions
RewriteLog
RewriteLogLevel
RewriteLock
RewriteMap
RewriteBase
RewriteCond
RewriteRule
Example Rules
PLAIN TEXT
CODE:

1.
# Site has permanently moved to new domain
2.
# domain.com to domain2.com
3.
RewriteCond %{HTTP_HOST} ^www.domain.com$ [NC]
4.
RewriteRule ^(.*)$ http://www.domain2.com/$1 [R=301,L]

PLAIN TEXT
CODE:

1.
# Page has moved temporarily
2.
# domain.com/page.html to domain.com/new_page.html
3.
RewriteRule ^page.html$ new_page.html [R,NC,L]

PLAIN TEXT
CODE:

1.
# Nice looking URLs (no query string)
2.
# domain.com/category-name-1/ to domain.com/categories.php?name=category-name-1
3.
RewriteRule ^([A-Za-z0-9-]+)/?$ categories.php?name=$1 [L]

PLAIN TEXT
CODE:

1.
# Nice looking URLs (no query string) with pagination
2.
# domain.com/articles/title/5 to domain.com/article.php?name=title&page=5
3.
RewriteRule ^articles/([A-Za-z0-9-]+)/([0-9]+)/?$ article.php?name=$1&page=$2 [L]

PLAIN TEXT
CODE:

1.
# Block referrer spam
2.
RewriteCond %{HTTP_REFERRER} (weight) [NC,OR]
3.
RewriteCond %{HTTP_REFERRER} (drugs) [NC]
4.
RewriteRule .* - [F]

 

Do you want to hide your exact url of your page ?

Here is it

Open .htaccess

Type this

RewriteEngine On
RewriteRule ^([A-Za-z0-9-]+)/?$ go.php?id=$1 [L]

Code (markup):

What this code will do it ,
when you type
www.yoursite.com/contact

then the header will goto
www.yoursite.com/go.php?id=contact

You can define , id = contact.php in that go.php file

demo, www.suntexhosting.com/contact
is opening www.suntexhosting.com/go.php?contact

 

Trying to rewrite home page to the below page.

Problem is after rewriting the % are converted to %25. Is there anyway to make this type of rewrite work:

RewriteRule ^/?$ http://mysite.com/search少妇 [R=301,L]

Appreciate any help. Thx

 

Hi there,

Please help me to solve this problem. Thanks.

This is my testing...

In main.php:
<html>
<head><title></title></head>
<body>
<? include("new.php") ?>
<? include("detail.php") ?>
</body>
</html>


In new.php:
<?
echo "<a href=\"test/artist/paul\">Paul</a><br>";
echo "<a href=\"test/teacher/kurt\">Kurt</a><br>";
echo "<a href=\"test/racer/mike\">Mike</a><br>";
?>


In detail.php:
<?
if(a == "artist"){
if(b == "paul"){ echo "Yes, Paul."; }
else if(b == "kurt"){ echo "Yes, Kurt."; }
else if(b == "mike"){ echo "Yes, Mike."; }
else{ echo "Nobody here."; }
}
else{ echo "Not artist."; }
?>


In .htaccess:
Options +FollowSymLinks
RewriteEngine on
RewriteRule ^test/(.[^\/]*)/(.[^\/]*)$ main.php?a=$1&b=$2 [L]


Now, my problem is:

I hover to any links of the new.php, the links are shown in correct way:
e.g. Link of Paul shown in status bar is:
http://www.my_site.com/test/artist/paul
e.g. Link of Kurt shown in status bar is:
http://www.my_site.com/test/teacher/kurt
e.g. Link of Mike shown in status bar is:
http://www.my_site.com/test/racer/mike

After I click on the link:
e.g. http://www.my_site.com/band/artist/paul
And the output is correct:
Yes, Paul.

And I hover to the links in new.php again, the links are shown in INCORRECT way:
e.g. Link of Paul shown in status bar is:
http://www.my_site.com/test/artist/test/artist/paul
e.g. Link of Kurt shown in status bar is:
http://www.my_site.com/test/artist/test/teacher/kurt
e.g. Link of Mike shown in status bar is:
http://www.my_site.com/test/artist/test/racer/mike

I can't solve this problem and I hope you will tell me what is the mistake. Thanks you.

 

<a href=\"test/artist/paul\">Paul</a><br>
to
<a href=\"/test/artist/paul\">Paul</a><br>
or
<a href=\"http//3w.domain.com/test/artist/paul\">Paul</a><br>

it has to be as if the mod_rewrite URLs are the real URLs. The browser has no idea they are fake URLs.

 

Thanks a lot, it Work!!!

 

I am using the following rule to convert

/game.php?category=pc&item=2 to /pc/2/game-title.html

The rule is :


Rewriterule ^(.*)/([0-9]+)/(.*).html game.php?category=$1&item=$2 [L]

It works great most of the time, meaning there are certain URL's which have problems, for example this one: /pc/6232/D%2FGeneration.html

The server says the page was not found on the server.

Could you advice me in what needs to be changed in the .htaccess file ?

Later edit: I realize now that %2F is "/" and then the rule may not be correct, but the question still remains, can I make the rule in such a way that it would allow the / character in that title ?

I have fixed the pages by replacing the "/" with "_" and doing a permanent redirect to those pages but I'd still like to find out if some solution exists for this.

 

Good tutorial, but have been working on the opposite of one of the examples...going from a query to a subdomain instead of a subdomain to a directory...

http://www.domain.com/viewall.php?cat=1
to
http://subdomain1.domain.com/viewall.php


...and there would be more categories...

http://www.domain.com/viewall.php?cat=2
to
http://subdomain2.domain.com/viewall.php

http://www.domain.com/viewall.php?cat=3
to
http://subdomain3.domain.com/viewall.php

Any ideas???

 

RewriteBase /

RewriteCond %{QUERY_STRING} ^cat=([0-9]+)$
RewriteCond %{HTTP_HOST} ^(www\.)?domain\.com$
RewriteRule ^viewall\.php$ http://subdomain%1.domain.com/viewall.php [R=301,L]

RewriteCond %{QUERY_STRING} ^$
RewriteCond %{HTTP_HOST} ^subdomain([0-9]+)\.domain\.com$
RewriteRule ^viewall.php$ viewall.php?cat=%1 [L]

The first rule redirects the request to the optimised URL, the second is an internal rewrite to make it compatible with the script.

 

How are you dealing with your css files for example?
When you rewrite
http://forums.digitalpoint.com/showthread.php?t=23044
to
http://forums.digitalpoint.com/thread./23044-FAQ_mod_rewrite
Then apache thinks the page is in a separate folder, so it can't find the ../style.css anymore
Is this rewriteable aswell?

 

Dear how can we configure wamp or phptriad for mod_write at localhost.
I have both of them Installed but they didn’t works…

Can you tell me how can we configure it…

 

I need to redirect

http://anything.domain.com/path/to/content

to

http://www.domain.com/content-type/anything/path/to/content

Code (markup):

I have WildCard enabled in both my DNS Server and Apache Configuration. Please tell me the mod_rewrite stuff to do this.

 

Hi:

I'm currently moving a blog from its current home - a proprietary php cms to wordpress - and I'd like to do a 301 redirect from each of the old urls to the new ones in Wordpress.

I've tried reading one or two articles, but I'm not really getting anywhere. Any help would be very much appreciated.

 

Options +FollowSymLinks +Indexes
RewriteEngine on
RewriteBase /
RewriteRule ^wordpress-directory/([^.]+)_([^.]+)\.html$ folder/read-blog.php?article_id=$1&title=$2 [L]

Though odds are, you won't get it to work, since it's WordPress.

 

Thanks for the swift response.

You're right, it doesn't appear to be working.

It's a shame it isn't WP to WP as that's a doddle. What would be the cutest way to do what I'm looking to do so I can explain it to our developer?

Thanks.

 

All this is for apache and PHP...
Is all this is same for tomcat and JSP too...
If yess then how can we configure tomcat for mod_rewrite....

Thanks

 

@ pawoodster:

The ugliest way to do this would be to put a single rewrite rule for each of the old URLs manually mapping to the new URLs in one monolithic .htaccess file.

The cutest way would be to have a single rewrite rule that seamlessly mapped them all using a simple regular expression even your boss could understand. Unfortunately I don't think anything that cute is possible.

The most pragmatic way is to write a rule that will catch all of the old-style URLs and silently map them to a PHP file which will do a lookup in the database and match the old URL to the equivalent new URL and then send an HTTP header telling them where to go.