Apache Web Server

Apache runs as the httpd service (package httpd):

-> yum install httpd httpd-tools httpd-manual
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-> systemctl start httpd.service
-> systemctl enable httpd.service
ln -s '/usr/lib/systemd/system/httpd.service' '/etc/systemd/system/multi-user.target.wants/httpd.service'

The base URL is http://localhost, which looks to the document root /var/www/html for content. Until this directory gets a proper home page, Apache displays the "Fedora Test Page" (cf. conf.d/welcome.conf).

The error and access logs reside under /var/log/httpd.

Optional package httpd-manual installs documentation to /usr/share/httpd/manual as HTML files. The manual can be browsed through URL http://localhost/manual (cf. conf.d/manual.conf).

To see the list of modules:

-> httpd -M
Loaded Modules:
 core_module (static)
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Apache loads modules as instructed by the configuration files in directory conf.modules.d. It looks to directory conf.d for modules' run-time configuration.

To add support for running PHP, install package php and restart Apache. Installation adds configuration file conf.modules.d/10-php.conf that tells Apache to load the PHP-handling module, and it also adds file conf.d/php.conf that tells Apache to use the module when it encounters a PHP page. The modules resides under /usr/lib64/httpd/modules.

To optionally test or inspect, create file /var/www/html/phpinfo.php like this:

-> echo '<?php phpinfo(); ?>' > /var/www/html/phpinfo.php

Then open URL http://localhost/phpinfo.php in a browser.

Under Security-Enhanced Linux (SELinux), Apache's httpd process runs under the httpd_t SELinux type:

-> ps -eZ | grep httpd_t
system_u:system_r:httpd_t:s0     5073 ?        00:00:00 /usr/sbin/httpd

system_u:system_r:httpd_t:s0     5999 ?        00:00:00 /usr/sbin/httpd

To have a running Apache server reload its (modified) configuration files:

-> apachectl graceful

The examples below implicitly assume this step.

After you edit a configuration file, let apachectl make sure you did not mess up:

-> apachectl configtest
AH00526: Syntax error on line 119 of /etc/httpd/conf/httpd.conf:
DocumentRoot must be a directory
-> emacs /etc/httpd/conf/httpd.conf
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->  apachectl configtest
Syntax OK

• Directive Quick Reference

DirectoryIndex determines what file Apache seeks when a client requests a directory (e.g., http://localhost/). By default, Apache looks for file index.html in that directory (e.g., http://localhost/index.html):

-> grep DirectoryIndex /etc/httpd/conf/httpd.conf
    DirectoryIndex index.html

You can adjust DirectoryIndex to suit your tastes. For example, this website uses home.html as a directory's response:

<IfModule dir_module>
    DirectoryIndex home.html
</IfModule>

This next website prefers home.html but lets index.html do the job in the absence of the former:

DirectoryIndex home.html index.html

Order counts here: Apache will seek index.html only if it does not find home.html first.

• Directory Listing Configuration

Apache's root document directory is set by directive DocumentRoot in httpd.conf:

-> grep DocumentRoot /etc/httpd/conf/httpd.conf | grep --invert-match '#'
DocumentRoot "/var/www/html"

You can relocate the document root by editing the new path into httpd.conf. Remember to make the new directory and its contents world-executable (e.g., directories) and world-readable (e.g., directories and files) as appropriate. And under SELinux, you may also need to adjust the security context of the new location (type httpd_sys_content_t).

As an example, here's how to put the document root under /home/www/html (as a safeguard against overwriting /var when installing a new version of Fedora). First, in httpd.conf, replace string /var/www/html with string /home/www/html. Then:

-> cd /home/www
-> mkdir html
-> chcon --type httpd_sys_content_t html
-> ls --context
unconfined_u:object_r:httpd_sys_content_t:s0 html/
-> cd html
-> echo 'Hello World!' > hello.txt
-> ls --context hello.txt 
unconfined_u:object_r:httpd_sys_content_t:s0 hello.txt

After you restart Apache (as root), you can use curl or lynx or similar to make a quick and easy test:

-> curl http://localhost/hello.txt
Hello World!
-> lynx -dump http://localhost/hello.txt
Hello World!

Apache's scripts directory is set by directive ScriptAlias in httpd.conf:

 -> grep ScriptAlias /etc/httpd/conf/httpd.conf | grep --invert-match '#'
    ScriptAlias /cgi-bin/ "/var/www/cgi-bin/"

You can allow per-user web directories wherein URL http://localhost/~username maps to /home/username/public_html for each user on the system. First, adjust SELinux and file permissions:

-> setsebool -P httpd_enable_homedirs 1
-> chmod 711 /home/*

Next, modify /etc/httpd/conf.d/userdir.conf to enable user directories and to set the source directory:

<IfModule mod_userdir.c>
    UserDir enabled
    UserDir public_html
</IfModule>

Each user's public_html directory must be listable to other, and its (public) contents must be readable to other:

-> cd ~
-> chmod o+x public_html
-> ls -dog public_html
drwxr-xr-x. 2 4096 Aug  3 15:01 public_html/
-> chmod -R o+r public_html

This directory can be added to /etc/skel with the required permissions so that useradd creates it for new accounts.

To have Apache look for file home.html when an URL ends in a directory, add this name to DirectoryIndex in /etc/httpd/conf/httpd.conf. For example:

<IfModule dir_module>
    DirectoryIndex home.html index.html 
</IfModule>

To allow access to directory /home/ray/notebook via URL /notebook, for example, create configuration file /etc/httpd/conf.d/notebook.conf with the following sort of contents:

Alias /notebook /home/ray/notebook
<Directory /home/ray/notebook>
     <RequireAny>
       Require ip 127.0.0.1
       Require ip ::1
       Require ip 192.168.1
     </RequireAny>
</Directory>

The filename is not significant to Apache. The location and extension, however, ensure that the IncludeOptional directive ending httpd.conf loads this file.