## HOWTO: Compile and Install

Unix, install in home directory:

    $ ./configure --prefix=$HOME/local --enable-so --enable-mods-shared=most
  
Note: without <tt>--enable-mods-shared=XXX</tt> none of the modules get
compiled!

Unix, install in default (system) location:
  
    $ ./configure --enable-layout=Darwin --enable-so --enable-mods-shared=most

SunOS:

Apache installed into <tt>$HOME</tt>:

    $ lconfigure --with-apxs2=$LOCAL/bin/apxs --with-xsl=$LOCAL \
      --with-libxml-dir=$LOCAL
    
(May need to adjust the paths in the "LoadModule" commands by hand,
though they may only get broken if installing PHP at the same.)

(See php.txt for how to install PHP.)

## HOWTO: Install on Windows.

1.  Use the installer, select the "custom" mode.

2.  To install into e.g. <tt>c:\server\apache-2.2.4</tt> (where
    <tt>httpd.exe</tt> is
    <tt>c:\server\apache-2.2.4\bin\httpd.exe</tt>), choose
    <tt>c:\server\apache-2.2.4</tt> for the "Install to" (root)
    directory.  (This used to be a lot more non-intuitive and
    complicated, but this seems to just work now.)

(See php.txt for how to install PHP.)

## HOWTO: Rewrite URLs Based on Query String

If you want to redirect:

    http://foo.com/foo/bar?name=quux
  
to:

    http://foo.com/new/quux

Use:

    RewriteCond %{REQUEST_URI} ^/foo/bar$
    RewriteCond %{QUERY_STRING} ^name=(.+)$
    RewriteRule .* /new/%1? [R]

or

    RewriteCond %{QUERY_STRING} ^name=(.+)$
    RewriteRule ^/foo/bar$ /new/%1? [R]
  
The final question mark prevents the original query string from being
appended, which otherwise happens via default.  See the [mod_rewrite documentation](http://httpd.apache.org/docs/2.2/mod/mod_rewrite.html#rewriterule).

(See the QSA option for more query string manipulation options.)

## HOWTO: Ensure Some URLs are Delivered via <tt>https</tt>

    # Rewrite https:// URLs that shouldn't be https (most of them) 
    # to the http:// equivalent.  If modifying this, remember images!
    # (The pattern on the second line has to match every URL that
    # is of content type text/html.)

    RewriteCond %{HTTPS} ^on$
    RewriteCond %{REQUEST_URI} (\.html$|\/$)
    RewriteRule !(^join/join.html|^supportus/donate.html) http://%{SERVER_NAME}%{REQUEST_URI} [R]

    # Rewrite http:// URLs that should be https to the https://
    # equivalent.  (If running on www.artfund.org only.)

    RewriteCond %{HTTPS} ^off$
    RewriteCond %{SERVER_NAME} ^www.artfund.org$
    RewriteRule (^join/join.html|^supportus/donate.html) https://%{SERVER_NAME}%{REQUEST_URI} [R]

## GOTCHA: Can't Rewrite Encoded Question Marks or Slashes

If you're having trouble rewriting characters like %3F (encoded
question mark) or an encoded slash, you've hit a bug; see [the bug report](http://issues.apache.org/bugzilla/show_bug.cgi?id=34602#c16)
for a workaround and associated discussion.

## HOWTO: Canonical Hostnames

[Canonical host documentation](http://httpd.apache.org/docs/2.2/rewrite/rewrite_guide.html#canonicalhost)

## GOTCHA: mod_rewrite log File Isn't Written

Even if you're editing the main httpd.conf, the RewriteLogLevel
command needs to be issued from within a VirtualHost (or similar)
directive.

## TIP: Directive are merged in which order?

[Merge order documentation](http://httpd.apache.org/docs/2.2/sections.html#mergin)

## ERROR: "Cannot get media type"

If the types specified in your Action and AddType lines don't actually
look like MIME types, Apache will generate this error:

    # WRONG

    Action php-fastcgi /bin/test.fcgi
    AddType php-fastcgi php

    # RIGHT
  
    Action text/php-fastcgi /bin/test.fcgi
    AddType text/php-fastcgi php

## ERROR: "Negotiation: discovered file(s) matching request: ... (None could be negotiated)."

This probably means you have MultiViews turned on accidentally via
<tt>httpd.conf</tt> or <tt>.htaccess</tt>.  Disable it.

## TIP: Userful environment variables when running PHP, mod_rewrite

Suppose the following URL is requested:

    http://example.com/foo?name=Michael
  
which is matched and rewritten via:

    RewriteRule ^foo$ /quux.php/baz?email=mjs@beebo.org [QSA]

then the following are set based on the original request:

    SCRIPT_URL       /foo
    SCRIPT_URI       http://example.com/foo
    REQUEST_URI      /foo?bar=quux
    SERVER_NAME      example.com - from Apache
    HTTP_HOST        example.com - from PHP

and the following are set based on the rewritten request:

    PATH_INFO        /baz
    QUERY_STRING     name=Michael&email=mjs@beebo.org
    SCRIPT_NAME      /quux.php - filesystem path (relative to docroot)
    SCRIPT_FILENAME  /www/quux.php - filesystem path (absolute)
    PHP_SELF         /quux.php/baz - filesystem path (relative to docroot)

More information:

* [http://hoohoo.ncsa.uiuc.edu/cgi/env.html](http://hoohoo.ncsa.uiuc.edu/cgi/env.html)
* [http://httpd.apache.org/docs/2.2/mod/mod_rewrite.html#EnvVar](http://httpd.apache.org/docs/2.2/mod/mod_rewrite.html#EnvVar)
* [http://httpd.apache.org/docs/2.2/mod/mod_rewrite.html#rewritecond](http://httpd.apache.org/docs/2.2/mod/mod_rewrite.html#rewritecond)
* [http://php.net/manual/reserved.variables.html#reserved.variables.server](http://php.net/manual/reserved.variables.html#reserved.variables.server)

## ERROR: "Could not reliably determine the server's fully qualified domain name"

Add a ServerName directive somewhere at the top level of your
<tt>httpd.conf</tt>.  i.e. <em>not</em> within a &lt;VirtualHost&gt; section.

## HOWTO: Proxy requests to/from another server

For proxying to work, you need to have both the `mod_proxy_http` and
`mod_proxy` modules loaded.

Single URL:

    RewriteRule ^feedback/ http://example.com%{REQUEST_URI} [P]
    
This transparently proxies all requests for URLs that begin with
`/feedback/` to the `example.com` server.  HTTP authentication, cookies,
etc. all work.

Entire site:

    <VirtualHost *:80>

        ServerName wikileaks.beebo.org
        RewriteEngine On
        RewriteRule ^ http://88.80.13.160%{REQUEST_URI} [P]
        <Location />
          Allow from all
        </Location>

    </VirtualHost>

## ERROR: "NameVirtualHost *:80 has no VirtualHosts"

This is pretty much as described; you get this error if, for example, you have:

    NameVirtualHost *:80
    
with no corresponding:

    <VirtualHost *:80>
    </VirtualHost>

Note that the rogue `NameVirtualHost` statement can appear in a file you're
not expecting, like `/etc/apache2/ports.conf`.

## TIP: Virtual host configuration

About virtual hosts:

  1. The
     [`Listen`](http://httpd.apache.org/docs/2.2/mod/mpm_common.html#listen) directive controls what addresses and ports Apache will
     receive connections on.  You probably want `Listen *:80`.
  1. The
     [`NameVirtualHost`](http://httpd.apache.org/docs/2.2/mod/core.html#namevirtualhost)
     directive controls what addresses and ports
     Apache will use for virtual hosts.  (A subset of whatever addresses and
     ports Apache is listening on.)  You probably want `NameVirtualHost *`.
  1. The argument to the `<VirtualHost>` block must exactly match the
     argument to `NameVirtualHost`.  You probably want `<VirtualHost
     *>`.  There must also be a `ServerName` directive within the block.
  
You should make sure that all hostnames that map to the current server are
explicitly mentioned in a `ServerName` or `ServerAlias` line.  If not,
clients will get the site defined by the first <VirtualHost> section, which
may not be the one you expect if Includes, etc. are being used.

    Listen 80

    NameVirtualHost *:80
    
    <VirtualHost *:80>
    
        # If an IP address maps to this server, and it
        # *doesn't* match a ServerName or a ServerAlias,
        # the first <VirtualHost> section is used.
    
        ServerName beebo.org
        ServerAlias www.beebo.org
        
        # Redirect to canonical hostname.
        
        RewriteEngine On
        RewriteCond %{HTTP_HOST} !^beebo\.org [NC]
        RewriteCond %{HTTP_HOST} !^$
        RewriteRule ^/(.*)       http://beebo.org/$1 [L,R]

    </VirtualHost>
    
    <VirtualHost *:80>
    
        ServerName dev.beebo.org
        
        # Redirect to canonical hostname.
        
        RewriteEngine On
        RewriteCond %{HTTP_HOST} !^dev\.beebo\.org [NC]
        RewriteCond %{HTTP_HOST} !^$
        RewriteRule ^/(.*)       http://dev.beebo.org/$1 [L,R]

    </VirtualHost>

## FAQ: Why does my `Alias` or `ScriptAlias` command not work?

Try with and without trailing slashes; there are [some complicated rules
that make them signification](http://httpd.apache.org/docs/2.2/mod/mod_alias.html).

## ERROR: "client denied by server configuration"

A common cause of this error is Apache not being given explicit permission
to server files from the directory in question.  This can be fixed as follows:

    <Directory /Users/mjs/workspace/beebo/bin>
      Order allow,deny
      Allow from all
    </Directory>

You may also get this error in conjunction with `RewriteRule`.  If you're
rewriting to something like `/bin/foo.php`, then even if loading
`http://localhost/bin/foo.php` works, a rewrite to exactly the same file may
not.  I'm not sure if this is a bug or not, but it can be fixed by
specifying the full path to the rewrite target.  i.e. change:

    RewriteRule .? /bin/simple.php [L]

to

    RewriteRule .? %{DOCUMENT_ROOT}/bin/simple.php [L]

(It [seems that](http://discuss.joyent.com/viewtopic.php?id=14452) Apache
checks to see if `/bin` on the filesystem exists, discovers that it does and
then notices that you aren't allowed to access it.) 

(You may encounter this error if moving rules from a `.htaccess` to
`httpd.conf`--the first works in the context of a `.htaccess`, but for some
reason fails in `httpd.conf`.)

## ERROR: Address already in use: make_sock: could not bind to address 0.0.0.0:443

This can happen if another program is already listening on the port (use
`sudo netstat -lp --numeric-ports` or `sudo lsof -i tcp:443` to see if this
is the case), but it can also happen if your Apache configuration contains
the same `Listen 443` line twice.

## FAQ: Having problems with `RewriteRule` and `REQUEST_FILENAME` in
conjunction with `VirtualDocumentRoot` 

There seem to be some problems when using `RewriteRule` on
`REQUEST_FILENAME` in conjunction with `VirtualDocumentRoot`.  In
particular, the the `REQUEST_FILENAME` appears to change, from one
internal subrequest to another, you might be experiencing this problem.

For example, if you see something like
   
    RewriteCond: input='/mnt/hgfs/workspace/kookai/mnt' pattern='!-f' => matched

in the log where you were expecting something like

    RewriteCond: input='/mnt/hgfs/workspace/kookai/index.php' pattern='!-f' => matched

Then the solution may be to change the `RewriteRule` from

    RewriteRule .* index.php [L]

to 

    RewriteRule .* /index.php [L]

(I came across this problem when using Magento with rewrites turned
on, in a `VirtualDocumentRoot` environment.)