Popular techniques to debug .htaccess - apache

I'm a self-taught coder and I like to debug by echoing suspicious variables and commenting out code.
Lately, I've had to learn more about the .htaccess file. I need it to do things like interpret php scripts as php5, url rewriting, limit file upload size etc.... I have a lot of trouble debugging a .htaccess file. I often have to migrate PHP applications from one shared hosting environment to another. Sometimes this breaks the .htaccess file (or instead, something in the .htaccess file breaks the site). I check to make sure domain names are updated.
Are there popular techniques for debugging a .htaccess file? Is it just look in the apache logs? Anything else?

Looking in the apache logs is the easiest way to debug .htaccess imho (adding rewriteLog Directive if necessary)
About migrating: if you are not using any physical file paths inside .htaccess (i.e. /var/www/site/script.php) they should be working without problems. If this is not the case, first try to remove all options and leave only redirect directives, in this mode you can see if it's problem with server configuration which denies rewriting of default settings.
Some reference

Related

How to avoid displaying directory path in url?

I set up a little Apache2 server on a Raspberry PI4. Now I’m looking for a way to hide the real directory path displayed in the URL. I read around that you should deal with a file called .htaccess but, I don’t even know what to actually look for on the internet. How can I display an arbitrary url in the address bar of the browser, Hiding file extension like .php and file path?
You make rewrite rules in an Apache config file, a .htaccess file for example. One way you could achieve this is to create re-write rules in a .htaccess file. Use to below link to test your rewrite rules, then once you have that part working implement on your live apache installation.
https://htaccess.madewithlove.be/

Is there any way in Apache to specify a single .htaccess file?

My hosting allows use of .htaccess files as the configuration files are not available.
I'm aware of the performance hit that override files incur though - so I was thinking - If Apache provided a mode for having a single .htaccess file - wouldn't that be faster than having to check for multiple .htaccess files whilst still maintaining the convenience?
If Apache provided a mode for having a single .htaccess file
Well, not a "mode" as such, but you could achieve this by allowing .htaccess for the parent directory (root directory or even one above the document root) and disable the use of .htaccess files in all subdirectories. The .htaccess file in the parent directory will still apply.
Realistically (if indeed this is at all "realistic"), you would probably need to enable .htaccess for the directory "above the document root" and disable .htaccess in the document root and below, rather than enabling .htaccess for the document root. Otherwise, if you enable .htaccess for the document root, you will have to disable .htaccess for each subdirectory individually. And if you add more subdirectories, the server config will need to be updated accordingly. (Since, the AllowOverride directive is only allowed in <Directory> containers without regex, not <DirectoryMatch> containers.) However, this might not be possible on some shared hosting environments (there might not be an "above the document root") and it could impact the installation of some CMSs.
Note that you obviously need access to the server config (or VirtualHost) in order to implement this, so it is hypothetical in this instance.
wouldn't that be faster than having to check for multiple .htaccess files
Possibly. But you are only talking about a micro-optimsation at best in real terms. On most sites, even enabling .htaccess files at all will hardly be noticeable - if at all. The "performance hit" you speak of is not as big as you might think. To put it another way, if you are finding that .htaccess is proving to be a bottle neck then you've either done something wrong, or you have far more serious problems to address.
Note, however, that you are generally only using .htaccess files on smaller sites anyway. On larger / high traffic sites you will have your own VPS / Server and access to the server config, so there wouldn't be any need to use .htaccess (or, importantly, have it enabled).
whilst still maintaining the convenience?
Not exactly. Part of the "convenience" is being able to put the .htaccess file in any directory you like, overriding parent directives and have it apply to just that directory tree. (It is the userland equivalent of the <Directory> container in the server config.)

How to avoid .htaccess constant seek?

Are there any options in Apache 2.4 that enable the .htaccess to be cached, and not having the web server looking for it at each request?
I know that using the AllowOverride None, will do this, but then, for most popular scripts this will need the required settings to be made in the vhosts file for each folder.
If somehow we could just tell Apache to remember the htaccess files that it has already accessed since previous restart, this would be a great tool for speed improvement.
A script that reads the base content recursively for all htaccess, and builds a vhosts file, would not be a bad idea as well, anyone uses this approach?

Prevent Non-Existent Directories From Loading Wildcard Files

I am looking to prevent URLs for directories that don't exist from loading files with the same basename. For example http://domain.com/test/ is loading test.php. The test directory does not exist, but the file test.php does. I can see how this would be useful in most cases, but I am looking to disable it for my project.
I am on an Apache server. Is there a way to disable this option through an .htaccess file?
If there is an actual name for this type of feature, maybe "wildcard filename helper" or something like that, I'd like to know the official term too. Thanks!
This happens because MultiViews is enabled on the server.
If the apache configuration allows you to do so, you should be able to disable it by putting the following in .htaccess:
Options -MultiViews

Apache serving files that should not be served

Today I discovered that my fresh installation of Apache HTTP Server is able to serve files from my C:\uploads\ directory.
I have two folders in C:\uploads:
C:\uploads\templates
C:\uploads\sites
Both folders contain testimage.jpg.
I found that Apache will serve the files from the templates folder if I request:
http://localhost/templates/testimage.jpg
However, http://localhost/sites/testimage.jpg 404's!
OMG - firstly, why does Apache serve the templates folder in the first place? Is it special?
Secondly, by what arbitrary set of rules does apache disallow access to other folders such the sites?
I'm so confused. Perhaps I've taken a wrong turn somewhere during the installation.
Did you look through your httpd.conf file to see what rules are in place for what is being served? Alternatively, are there .htaccess files that may be changing what is being served? You might have templates exposed in one or the other, but not sites... that's the first thing that comes to mind.
I would suggest going through these configuration files with a fine toothed comb to see what may cause the behavior you see.