What is RewriteRule

RewriteRule directive is used to rewite/redirect URLs on Apache server. To convert a longer URL path into shorter one we use RewriteRule directive which is part of Apache mod-rewite (Rewrite Module) .
The following is the basic syntax of RewriteRule directive:

RewriteRule newPath oldPath [flags]

Redirect directive

Redirect directive is part of Apache core module which is mainly used for URL redirection on Apache server. Redirect directive is used to redirect URL path from one location to the other for example /this to /that .

Syntax of Redirect directive:

Redirect  /newPath oldPath 

I often see users posting questions on stackoverflow about URL redirection. in their initial attempts to redirect the URLs they either try a mixture of RewriteRule and Redirect directives or misorder the directives which produces an unexpected result.

RewriteRule and Redirect are directives of two different apache modules. Although both the directives are used for URL redirection but due to their different run time behavior you can use them together in a single rule block.
RewriteRule directive takes precedence over Redirect directive. No matter where you place the Redirect if there is a RewriteRule directive with the same pattern as Redirect Apache server will check the RewriteRule first even if your Redirect line is at the top of your htaccess or server.config.

To better understand the runtime difference between these two directives, let’s see some real world code examples now .

RewriteRule vs Redirect

The main difference between these two directives is ther runtime behavior. Both directives run on different time. Apache server often reads RewriteRule first.

Here is a basic htaccess code example to better understand the behavior :

Redirect /demo.php /location.php
RewriteRule ^demo.php$ /location.php [L,R]

The both lines above does the same thing as they redirect /demo.php to /location.php . As you can see the RewriteRule directive is placed bellow the Redirect in the above code, you would expect the Redirect to trigger first but The apache server will read the RewriteRule line first as this directive takes precedence over Redirect.

Intermixing RewriteRule with Redirect

Some people who are new to URL rewriting world often mix RewriteRule with Redirect. They use both directives together in htaccess hoping that the redirect will work normally this way but it doesn’t. Why ? Because these two directives are part of two different apache modules.

Redirect /file.php /file1.php
RewriteRule ^file /file2.php [L,R]

In the above code we used Redirect directive to redirect /file.php to /file1.php and RewriteRule to redirect /file to /file2.php .

Since the pattern of above RewriteRule matches anything after file this will also match the /file.php request path so in the above code example our Redirect will never be triggered as the RewriteRule runs first and redirects any path starting with /file.

I often see users struggling with their RewriteRule to redirect fragment URLs.

Fragment is something that the server doesn’t receive meaning that a URL containing #path  can not be redirected using htaccess or any other server side redirection methods.

Fragment usually appers at the end of the URL and starts with a “#” character.

Anything that comes after # in URL is part of URL fragment.

A fregment is handled client side ( by web browser) and used as jump to navigation link in a web page. 

When  a fragment URL is typed in browser address bar your web browser makes it so that the page automatically  scrolls to the fragment href section on the requested page .

The following is an example  of fragment URL:

http://example.com/file.php#foobar

In the above URL , /file.php is URL path and #foobar is a fragment.

Your web server only receives the URL path  as request header string and the remaining part (#foobar) is trimmed or not sent. Since the fragment is manipulated client side , your webserver doesn’t get such URL segment and there is no way to handle it server side.
You can redirect fragment URLs using JavaScript or other client side redirect logic. In the last paragraph bellow I will show you how we redirect fragment URLs client-side  with some code examples.

Redirect to a Fragment URL using RewriteRule

It is quite possible to redirect your original URL path to a fragment URL . For example example.com/thispath can be redirected to example.com/#thispath using NE  and R (NoEscape and Redirect) flags in RewriteRule directive. 

But
example.com/#thispath can not be redirected to example.com/thispath because the requested URL contains # path and its is not manipulated server-side. 

You can’t redirect fragment using htaccess RewriteRule

As I already mentioned fragment is manipulated by web browser and not by server . All you can do to redirect your fragment URL is JavaScript redirect.  I often see users posting questions on stackoverflow regarding #path where they want to redirect fragment URLs to a custom path . For example /path/#foobar to /newpathWithoutFregment and the RewriteRule they try is something like :

The rule above will never work because of the following two reasons :

1. # is a special character in mod-rewite as it is used to add comments in RewriteRule.
2. # is a fragment which is maintained by browser  and its not sent to the server.

The rewiteRule above won’t work even if you escape the # character as its not even sent to the server. 

The following Rewriterule works  perfectly fine

.

You can redirect your URL path to fragment using NE and R flag.

Here is a RewriteRule example to redirect /foobar to /#foobar :

The above example works because here you are redirecting your NonFregmentPath to a FragmentPath. You type the path /foobar into your browser, your browser then sends the path to server , server receives the path , reads htaccess rules and then issues a Redirect (/foobar => /#foobar) to your webbrowser . And finally your web browser makes the hash redirection.

The NE flag is important in the rule above.  Without NE the # gets encoded to its hex value which may end up in an incorrect or not found path.

JavaScript based solution to redirect fragment URLs

Since JavaScript is a client scripting language and works on web browser, you can easily redirect your fragment URLs using JS window.location.assign() property . The following is a simple one liner code to redirect /#foobar to http://example.com/#foobar .

The window.location.hash() property returns the current page hash ie #foobar in this example.

You can learn more about JS location pproperties on the official Mozilla site here .

I hope the post was helpful. Thank you so much for reading.

Time based URL rewriting on Apache

With mod-rewite you can rewite or redirect your URLs based on server date and time logic. You can redirect your visitors to a specific page or URL destination using this date/time logic.
In this post, we will learn how to apply date/time conditions to RewriteRule directive with some code examples of basic to advance Time based URLrewriting.

Let’s first have a look at available mod-rewite date/time variables

Mod-rewite date and time variables

The following are the pre-defined apache mod-rewite variables to work with server date and time . The date and time Alpanumbric values these variables contain depend on the timezone set on your server.

You can set server timezone using server.config file.

• %{TIME}

• %{TIME_YEAR}

• %{TIME_DAY}

• %{TIME_MON}

• %{TIME_HOUR}

• %{TIME_WDAY}

• %{TIME_MIN}

• %{TIME_SEC}

%{TIME} variable is used to match against the current time in the number of seconds since the Unix Epoch (January 1 1970 00:00:00 GMT).

%{TIME_YEAR} represents the current year ie 2019. This variables contains year value in YYYY format (4digits).

%{TIME_DAY} variable is used to match against the current Date ie (date of the day from 1 to 31)

%{TIME_MON} is used to match against the current month of the year ie 1 to 12.

%{TIME_HOUR} represents the current hour for example 1 if the time is between 1:00 and 1:59 .

%{TIME_WDAY} week day. This variable is used to match against the current day of the week in numeric format . For example 6 if the day is Saturday.

%{TIME_MIN} is used to match against current minute starting from 00. This variable returns number of minutes from 00 to 59.

%{TIME_SEC} used to match against current secind starting from 00. This variable returns number of seconds from 00 to 59.

To test these variables on your server, create a demo.php in your public_html folder and add the following php code :

<?php
echo $_GET["myvar"];
?>

Next add the following RewriteRule to your htaccess file :

RewriteEngine on
RewriteRule ^test /demo.php?myvar=%{TIME} [L]

Now visit yoursite.com/test you will see the content of demo.php file. Your demo.php file will show you the value of whatever variable was requested. You can manually change the variable in the RewriteRule’s destination ( /demo.php?myvar=%{TIME} ).

Time based URL rewriting examples

Suppose you have a website that is updated or maintenanced every friday and you want to redirect your website visitors to specific page ie under-construction.php on this day of week. The rewrite logic you will need for this will be read as :

If the day is Friday
Redirect all visitors to under-construction.php.

here is the RewriteRule:

RewriteEngine on
RewriteCond %{TIME_WDAY} ^5$
RewriteRule (.*) /under-construction.php [L,R]

The rule above redirects all of your website URLs to a single page under-construction.php if the condition is met ie (%{TIME_WDAY} is == 5) . 5 is number of weekday for friday.

This rule above redirects all of your site URLs including the target page url under-construction.php to itself which can cause a Redirect loop error on your server , to fix this error you will need to exclude the target URL from your RewriteRule regex so it can not match the target.

The following is the perfect version of the above rule :

RewriteEngine on
RewriteCond %{TIME_WDAY} ^5$
RewriteCond %{REQUEST_URI} !/under-construction.php [NC]
RewriteRule (.*) /under-construction.php [L,R]

More examples

To redirect your website URLs to a different location at 8PM , you can use the following Rule :

The rule above redirects your website visiters to /location.php if the server time hour is 20 which means 8PM . The rule will be applied from 20:00 to 20:59 .

Redirect all website traffic to example.com at 8:30PM

RewriteEngine on
RewriteCond %{TIME_HOUR}:%{TIME_MIN} ^20:30$
RewriteRule (.*) http://example.com/ [L,R]

The rule above will redirect your website visitors to example.com exactly at 8:30PM.

We used two variables in the RewriteCond test string %{TIME_HOUR} and %{TIME_MIN} separated by a colon : to test the server time using a regex based pattern ^20:30$ .

Hope you liked the post. Thank you for reading!

How to check whether mod-rewite is enabled on Apache server

mod-rewite is a URL rewriting module provided by Apache. We use this module to rewite or beautify our site URLs.

Although all web hosting service providers have pre-installed this module but in some cases you must enable it yourself in order to use RewriteRules in htaccess.

In this post , I will show how you can know whether mod-rewite ( URL rewiting module ) is activated on your apache web server and how you to activate it yourself if its not already activated.

Keep on reading!!

How to know whether mod rewite is active ?

One of the simplest ways to check mod-rewrite is PHP’s function php_info() .

With php you can easily get informations about all installed/active modules on your server.
Checking mod-rewite by php

PHP’s php_info() function returns a list of all active modules on apache server. Create a file test.php in your web directory with the following code and save it.

Now open the file in your web browser. You will see a list of all available modules on your webserver. The test.php will show you contents something like the following:
mod-mime

mod-core
mod-rewrite
mod-ssl..etc

All module that your server is using will be printed. Read the file from top to bottom , if you don’t see mod-rewite that means the module isn’t installed.

Check mod-rewite by htaccess

You can also check whether mod-rewite is enabled on your server by htaccess.

Create an htaccess file in your web root directory and put the following code

Now visit : yoursite.com/foo . If mod-rewite is enabled Then the htaccess rule will redirect you to http://example.com else you will get an internal server error with 500 status code.

How to enable mod-rewite on Apache?

You can enable this module easily by editing your server.config file. Open your server configuration file and put the following line to enable the module :

This line tells server to read rewrite rules from htaccess file rather then reading server.config.

If your webhost doesn’t allow you to edit server.config file then contact your hosting service to enable it for you.

Hope this helps. Thanks for reading!

With a RewriteRule directive you can deny access to a specific IP address or multiple ip addresses at the same time. If you need to deny access to a visitor IP address you can use a RewriteRule directive in htaccess file that checks the visitor IP address and blocks access to that address.
Blocking IP addressess using RewriteRule is as simple as ABC. You don’t need to do anything except using a RewriteRule in an htaccess file. In this post I will show you three RewriteRule examples that deny access according to visitors IP addresses.

Deny access to a specific IP address

To deny access to a single IP address you can use the following Rule in htaccess:

This will deny access to this specific ip address. Visitors having this ip addresses will get a forbidden error. You can also replace F with R=403 its same as F .

Deny access to multiple ip addresses

It is possible to deny access to multiple ip addresses at once using a single RewriteRule directive. If you have more then one ip addresses to deny access to, you can use a regex based pattern to match against those ip addresses, the following is a basic regex pattern to exclude 3 ip addresses, you can manully add more ip addresses to the pattern :

The pattern (.*) applies to the entire site including all files and folders , if you want deny access to a specific file path , say /user.php repace the (.*) with ^user.php$ or if the user.php file is located in /foo folder then use ^foo/user.php$ .

Block access to a specific path

To deny ip based access to a specific path you can use :

This will forbid access to /thispath for a specific ip address matching the pattern 1.2.3.4.5 .

Hope this helps. Thanks for reading!

It is quite possible to redirect http and non www requests to https and www with one single redirect using a RewriteRule in htaccess.
Assuming, you want your site visitors to always redirect to https://www version of your site regardless of they come by http or non-www you can use a single redirect Rule that can both non-https and non-www. The benifit using a single redirect is that your site URLs will load faster as the one single rule is triggered when your visitors visit the http or non www version of your site.

writing a single redirect rule

You need to use a combination of RewriteCond directives and an OR flag between them so that the rule can run if one of the conditions is true.
In the following example we will use two conditions to match against HOST and HTTPS header we use [OR] flag to make the rule run when either HTTP_HOST or HTTPS condition is matched.

Explanations :
The first condition matches against the host header ie example.com. Replace it with your non-www domain name.
The second condition matches against HTTPS variable . The off represents http non-ssl. This condition is met when the URL scheme is http.
You can use RewriteRule directive just bellow the condition to redirect your non-ssl and non-www urls to https://www.

The following is the complete htaccess rule to enforce ssl and www in a single redirect

http to https www generic rule

If you have more then one domain to redirect, then instead of using multiple above codes , you can just use one dynamic rule :