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Thursday, 5 April 2012

Htaccess File Explained


Htaccess File Explained

Intro



Hypertext Access, commonly shortened to htaccess, is a configuration file which controls the directory it is placed in and all the subdirectories underneath it. It’s an incredibly useful feature which allows webmasters to control how many aspects of their website works. You can redirect pages, change the extensions of pages, password protect directories and much much more.
In this htaccess guide I will show you some of the basic tricks and tips which will help you with your website.

So what is htaccess?

The htaccess file is a configuration file which is used on Apache based web servers to control many features of the server. The file itself is just a small basic text file and can be edited via your hosts file manager or alternatively you can download the file, edit it and reupload it.
If you have installed a script before then chances are you have had to edit the .htaccess file at one point or another. The .htaccess file gives you a lot of control and lets you easily redirect pages, password protect directories and much more. Before I go through some tutorials which show you how to use htaccess, I think it is necessary to show you how you edit the file.

Where is the .htaccess file?
The first thing you need to do is find out if your host actually lets you edit htaccess files. Because of security problems which can arise, many hosts stop their customers from editing it the .htaccess file. Therefore you should check the Frequently Asked Questions area of your host to see if you have permission to edit the file (failing that, email them).
Some operating systems may not show the .htaccess file on your computer so you may need to make sure settings show hidden files as well. Likewise some FTP Clients will not show the .htaccess file when you connect to your host so you need to make sure that your FTP is set up to show hidden files too (I personally use FileZilla and that shows .htaccess by default).
Better safe than sorry

The .htaccess gives you a lot of control over what happens on your site but accidents do happen so make sure you keep a backup or best create a copy of the htacess file of the last working .htaccess file you used before attempting to modify it in anyway. This way you can recover quickly from a site crash!
Htaccess is also extremely sensitive. A missing semi colon, incorrect letter or an extra backslash can mess everything up so you need to make sure that what you enter is correct 100%. Don’t let this scare you off though, as long as you take your time and make sure everything is input correctly you can enter just a few lines to htaccess to achieve things which most php scripts take a page to do.
To learn more about htaccess simply click on one of the articles at the right hand side. Good luck :)

How do you edit the .htaccess file?


Before you upload an .htaccess file to your server, make sure there is not already one there. Your host panel or perhaps a script you have uploaded may have already changed the htaccess for some reason so you don’t want to overwrite it as doing so could change something important on your site. For example, in cpanel, you can setup 301 redirects very easily but this tool is simply a script which changes the .htaccess for you. So even though you may not realise it, when you use the redirect script via cpanel, it updates your .htaccess file for you and it’s the .htaccess file which controls the redirect for you (the redirect tool just makes it easier for those who are not familar with .htaccess).
So if there is an .htaccess file there already, you want to download that and edit it before reuploading. This will ensure that nothing you have setup previously is changed.
If there is no .htaccess file there then you need to create one. Thankfully, this is very easy to do. All you need to do is open a text editor and save a blank document as .htaccess. Save the file exactly as it is stated there in bold ie. there is no writing before the extension. You need to save it as .htaccessand not htaccess.txt or document1.htaccess or whatever.
When uploading you should always :
·             Upload in ASCII mode, not binary
·             CHMOD the file to 644 (this isn’t absolutely necessary per say but it’s advisable, it means your server can access it but it can’t be seen via a browser).
Also, after editing your .htaccess file serveral times it may look a little complicated so I recommend adding a comment above the longer parts of code so that you know what each section is for when you look at the file again at a later date. To add a comment to the file you simply start the line with #, any code written after the # in the line will not be executed and is simply a reference for you in the future (and anyone else who may be working on your website ie. co-admin or whatever).

 

Htaccess Supersession


The most common place to upload an .htaccess file is the root ie. the home page of your website. This is because so many things can be controlled from the top level. However, there are many occasions when you will need to upload an .htaccess file to a sub directory. For example, if you want to password protect a directory you need to place the .htaccess file in the directory you want to protect.
The important thing to remember is that any code in a subdirectory .htaccess file supercedes the one in the directory above. However, it only supercedes it when there is a clash. I’ll explain this with an example.
Lets say your root .htaccess and your subdirectory .htaccess file both state how a 404 error should be treated. If someone tries to view a page which has been deleted within the subdirectory then the user will be redirected according to the rule stated in the subdirectory .htaccess file ie. it supercedes the htaccess on the home page. If, however, the user tries to view an incorrect url in the root directory, the root .htaccess file will dictate what will happen.

How to stop someone looking at your htaccess file

One of the first things you want to do is make sure no one tries to look at your .htaccess file. This is actually very easy to do, all you need to do is make use of the Files option.
Just enter the code below to block people seeing your .htaccess file.

# Block people seeing the htaccess file
<Files .htaccess>
order deny,allow
deny from all
</Files>

How to redirect your 404 error to a custom page


A 404 error message is the standard HTTP standard response code which is returned when the visitor cannot communicate with the server. This is a very common error on the web and it occurs when you are trying to visit a page which has either been deleted or has been moved somewhere else. For example, if you change the structure of your website and move a certain directory to a different part of your site, anyone trying to visit the old page url will get a 404 error message.
A 404 error message usually looks something like this :
Not Found
The requested URL /index.php was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.9 (Unix) mod_ssl/2.2.9 OpenSSL/0.9.7a mod_bwlimited/1.4 PHP/5.2.6 Server at yourwebsite.com Port 80

If a visitor comes to your site and sees a standard 404 error message it’s unlikely they will make the effort to see any part of your site. Therefore it is very important to create a 404 page on your site and redirect traffic from incorrect urls.
Thankfully, htaccess makes this very easy. First of all you need to create a 404 error page. So for example, you would create a page at http://www.yoursite.com/404.php which says something like :

It appears you are looking for something which isn’t there. Either you have entered an incorrect URL or we have messed up. Why not visit our home page or alternatively, search for what you are looking for in the search box below.

Whilst a 404 error page does not send the visitor to the exact page they want, it does point them in the right direction and it means they are more likely to stay on your site.
Once you have your 404 page setup, all you need to do is send visitors to incorrect url’s to this page. To do this just add the following line to your .htaccess file :

ErrorDocument 404 /404.php

You can place the 404 error template anywhere you want. For example you could place all error messages in a folder called errormessages

ErrorDocument 404 /errormessages/404.php

 

How to setup a 301 Redirect


A 301 HTTP response status code is a way of telling search engines that a page, pages, directory or entire website has been permanently moved to another place on the web. This is very useful if you have changed the structure of your websites url’s or if you have moved domain. You can also redirect your entire site.
Whereas a 301 code tells search engines that something has been permanently moved, a 302 code tells search engines that something has been temporarily moved. This is useful if you only want to redirect a page for a short period of time. To do a 302 redirect simply change the 301 part to 302.
You can also use 303, which is means ’seeother’ and the page has been replaced by something else. Again, to do this simply substitute 301 with 303 in the tutorials below.

How to setup a 301 Redirect

The basic code for redirecting is :

Redirect 301 old_location new_location

The old location of the file has to be the absolute path from the root of your server. The new location should use http. So for example, if you want to move a file called productreview.html from the root of your site to a subdirectory called products you would use :

Redirect 301 /productreview.html http://www.yoursite.com/products/productreview.html

How to setup a 301 Redirect

If you have moved your domain to another site you may want to redirect the whole site. To so this you simply use the following code :

Redirect 301 / http://www.newdomainname.com/

 

Change the Default Directory Page

When you load a directory on the web, for example www.yoursite.com or www.yoursite.com/articles/, the apache server usually looks for the index.html file. If it can’t find that it will look for index.php or index.cgi. Index.html is usually the page with the highest priority and the one which is loaded first.
It is possible to change the default directory index page. Say, for example, you wanted visitors to go to notice.html instead of index.html. All you have to add to your .htaccess file is

DirectoryIndex notice.html

This can be extended so that the server looks for other files if it cannot find the first one.

DirectoryIndex notice.html index.cgi index.php index.html

Priority goes from left to right. So the server would look for notice.html. If that file is not there it will look for index.cgi, then index.php and then index.html.
You can do to this within any directory on your site. Simply upload an .htaccess file with the above code. Remember, this will supercede the .htaccess file at the root of your domain.

 

Force users to use the WWW or Non-

WWW version of your domain

To avoid duplicate content in search engines you can force users to use either the www or the non-www version of your website domain. This avoids search engines such as Google indexing two versions of your domain, something which is quite common because people link to both www and on-www versions of a domain (known as the www/non-www canonical issue).
It really doesn’t matter if you use www.yoursite.com or yoursite.com. I personally use www on most sites I own however many people prefer to drop it, it’s really up to you.

Force users to use http://www.yoursite.com

To force users to use the www version of your domain all you have to do is add the following code to your .htaccess file (just replace yoursite.com with your domain name).

# Redirect non-www urls to www
RewriteEngine on
RewriteCond %{HTTP_HOST} !^www\.yoursite\.com
RewriteRule (.*) http://www.yoursite.com/$1 [R=301,L]

Alternatively you can use :

# Redirect non-www urls to www
RewriteEngine on
RewriteCond %{HTTP_HOST} ^example\.com [NC]
RewriteRule (.*) http://www.example.com/$1 [R=301,L]

Force users to use http://yoursite.com
To force users to use the non www version of your domain all you have to do is add the following code to your .htaccess file (just replace yoursite.com with your domain name).

# Redirect www urls to non-www
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.yoursite\.com [NC]
RewriteRule (.*) http://yoursite.com/$1 [R=301,L]

Alternatively you can use :

# Redirect www urls to non-www
RewriteEngine on
RewriteCond %{HTTP_HOST} !^example\.com
RewriteRule (.*) http://example.com/$1 [R=301,L]


Notes about this technique

Many popular scripts, particular content management systems (CMS’s) edit the .htaccess file and add their own redirection so you may not have to add any of the code noted above. Infact, by adding the redirection code noted above you could actually mess things up.
For example, the popular blogging script WordPress adds redirection to the .htaccess file. You simply chose the correct domain name in the admin panel and it takes care of everything else. And if you do add the code to the .htaccess file it messes things up a little. It does still redirect non-www to www (and vice versa) but it just redirects the visitor to the home page (ie. http://yoursite.com/folder1/page1 would redirect to http://yoursite.com/ instead of http://www.yoursite.com/folder1/page1).
If this sounds a little confusing, don’t worry. Just remember that certain scripts already apply a redirection and so trying to add a redirection code to the .htaccess file can mess things up, at the very least it will unlikely work the way you want it to.

 

Deny a user by IP Address


There may come a time when you unfortunately need to ban someone from visiting your website completely. This is very easy to do using htaccess and can be useful if there is a spammer or disgruntled member attacking your site (something which unfortunately happens a lot to forum and blog owners).
To ban someone completely all you need to do is add the following code to your .htaccess file. Simply replace the ip address below with the ip of the person you want to ban

#ban users from visiting the site
order allow,deny
deny from 123.45.6.7
allow from all

If you want to ban more people you simply add more lines, like this :

#ban users from visiting the site
order allow,deny
deny from 123.45.6.7
deny from 987.65.4.3
deny from 56.45.34.456
allow from all

 

How to Stop Directory Listing


If you have a lot of files in a directory but there is no index file, your server will list all the files in that server. This can cause a lot of problems. For example, one of the most common directories which webmasters forget to hide is the images folder. This allows everyone to view all the images in their images folder. This isn’t usually a major problem though you may have more important files in a directory, perhaps important documents or software.
You can stop this from occurring from using the following code :

IndexIgnore *

The * is a wildcard and stops the server from listing any type of file. You can of course only stop certain files or file types from being listed.
For example :

IndexIgnore *.gif *.jpg *.png accounts.doc

The above code would stop all gif, jpg and png graphics files from being listed. The accounts.doc document would be blocked too however all other .doc files would be shown. Basically the IndexIgnorecommand lets you decide what files in a directory visitors can see.
You can upload an .htaccess file for every directory you want to stop people viewing but it’s more practical to place everything in your main .htaccess file (ie. your root .htaccess). To do this all you need to do is include the path to the folder(s) you want to protect.
So to block people viewing the files at www.yoursite.com/images/ and www.yoursite.com/banners/ you would the following code to your .htaccess
:
IndexIgnore /images/*
IndexIgnore /banners/*

 

Password Protect a Directory


Password protecting a directory is easy to do, all you have to do is :
1.           Add some code to your .htaccess file
2.           Create a file called .htpasswd
3.           Select a username and generate an encrypted password and then add them to your .htpasswd file
Code to add to your Htaccess
You need to add the following code to your .htaccessfile.

AuthType Basic
AuthName "Name of your secure area”
AuthUserFile /fullpath/to/your/directory/.htpasswd
require valid-user

You need to edit the file accordingly.
·             Name of your secure area = You can call this anything you want ie. Secure Area or Members Area or whatever.
·             Full Path To Your Directory = This is the absolute path to the directory where your .htpasswd file is saved.
Here’s an example :

AuthType Basic
AuthName "Private Area"
AuthUserFile /home/mysite/.htpasswd
require valid-user

Create a file called .htpasswd

You create a .htpasswd file the same way you created the .htaccess file. All you need to do is create a blank document and save it as .htpasswd.
For security reasons, it is best to place this file above the root of your domain ie. place it in something like /home/mysite/ instead of /home/mysite/public_html.

Create a username and password

The username and password added to your .htpasswd file is in the format :
username:encryptedpassword
So my generated password might be something like
Kevin:nDh54k4Nc.C5c
So how do I encrypt my password in this way? Well there are a number of ways but the quickest and easiest is to use one of the many encryption sites on the web. Just use any of the scripts below to generate your encrypted password.
·             htpasswd encryption
·             .htpasswd Content Generator
Once you have your username and password, simply add the line to your .htaccess file. Now go and test it out and see if your directory is now password protected :)
Some things to note :
·             To give additional users access to a directory simply add another line with a username and encrypted password
·             Only the password is encrypted, the username is not encryped


~ w4r-b0y


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This post was written by: w4r-b0y

w4r-b0y . Add me on Facebook

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