Merecat started out as a pun at Mongoose, but is now useful for actual web serving purposes. It is however not a real Meerkat, merely yet another copycat, forked from the great thttpd created by Jef Poskanzer.
Merecat expands a lot on the features originally offered by thttpd, but still has a very limited feature set:
- Virtual hosts
- Basic
.htpassd
and.htaccess
support - URL-traffic-based throttling
- CGI/1.1
- HTTP/1.1 Keep-alive
- Built-in gzip deflate using zlib
- HTTPS support using OpenSSL/LibreSSL
The resulting footprint (~100 kiB) makes it quick and suitable for small and embedded systems, even those smaller than a Raspberry Pi!
Merecat is available as free/open source software under the simplified
2-clause BSD license. For more information, see the manual
page merecat(8)
, or the FAQ.
Try out Docker Merecat safely isolated from the rest of the system, with easy deployment.
To protect a directory in your ~USERNAME/public_html/
, create the file
.htpasswd
using the included htpasswd
tool:
user@example:~/> cd public_html/Downloads
user@example:~/public_html/Downloads/> htpasswd -c .htpasswd friend
Changing password for user friend
New password: *****
Re-type new password: *****
Enable this feature, and user home directories, with the configure
script. See more on this in the Features section below.
Setting up virtual hosts on a server can be a bit of a hassle with other web servers. With Merecat you simply create directories for each host in the web server root:
/var/www/
|-- icons/
|-- cgi-bin/
|-- errors/
| `-- err404.html
|-- ftp.example.com/
`- www.example.com/
Edit /etc/merecat.conf
:
virtual-host = true
cgi-pattern = /cgi-bin/*|**.cgi
Now the web server root, /var/www/
, no longer serves files, only
virtual host directories do, execpt for the shared files in icons/
,
cgi-bin/
, and errors/
.
On Linux bind mounts can be used to set up FTP and web access to the
same files. Example /etc/fstab
:
/srv/ftp /var/www/ftp.example.com none defaults,bind 0 0
There are many tricks to optimizing the performance of your web server.
One of the most important ones is browser caching. Merecat supports
both ETag:
and Cache-Control:
, however to enable the latter you need
to define the max-age
setting in /etc/merecat.conf
:
max-age = 3600 # One hour
The value is completely site dependent. For an embedded system you might want to set it to the maximum value, whereas for other scenarios you will likely want something else. By default this is disabled (0).
Another trick is to employ gzip
compression. Merecat has built-in
support for serving HTML, CSS, and other text/*
files if there is a
.gz
version of the same file. Here is an example of how to compress
relevant files:
root@example:~/> cd /var/www/
root@example:/var/www/> for file in `find . -name '*.html' -o -name '*.css'`; do \
gzip -c $file > $file.gz; done
This approach is more CPU friendly than letting Merecat "deflate" files on the fly, which it otherwise does.
If the configure
script finds OpenSSL installed HTTPS support will be
enabled by default, this can be disabled using --without-ssl
.
The HTTPS support has SSLv2, SSLv3, and TLSv1 disabled (hard coded) by default. Only TLSv2 and later will be enabled and negotiated on a per client basis.
To set up Merecat for HTTPS the following /etc/merecat.conf
settings
must be enabled:
port = 443
ssl = true
dhfile = certs/dhparm.pem
certfile = certs/cert.pem
keyfile = private/key.pem
To create a self signed certificate and enable perfect forward secrecy,
PFS, i.e. Diffie-Helman paramters (optional), use the openssl
tool as
shown below. Notice the use of a sub-shell with openssl.cnf
where
most of the certificate settings are, and more importantly notice the
use of subjectAltName
, or SAN. The latter is required by most
browsers today.
root@example:/var/www/> mkdir private certs
root@example:/var/www/> openssl req -x509 -newkey rsa:4096 -nodes \
-keyout private/server.key -new -out certs/server.pem \
-subj /CN=www.acme.com -reqexts SAN -extensions SAN \
-sha256 -days 3650 -config <(cat /etc/ssl/openssl.cnf \
<(printf '[SAN]\nsubjectAltName=DNS:www.acme.com'))
root@example:/var/www/> openssl dhparam -out certs/dhparm.pem 4096
NOTE: Currently, virtual hosts are not supported when HTTPS is enabled. A wildcard certificate may work, although this has not been tested yet pending native Let's Encrypt support.
Merecat depends on a few external libraries, if enabled, e.g. OpenSSL,
zlib, and libConfuse which,
when built from source, defaults to an install prefix of /usr/local
.
Non Debian/Ubuntu systems rarely support this GNU standard, so here is
how you reference it for the Merecat configure
script:
user@example:~/merecat/> PKG_CONFIG_LIBDIR=/usr/local/lib/pkgconfig ./configure
To build Merecat without support for /etc/merecat.conf
:
user@example:~/merecat/> ./configure --without-config
If you build from GIT sources and not a released tarball, then remember:
user@example:~/merecat/> ./autogen.sh
To install httpd
into /usr/sbin/
, default index and icons into
/var/www
, and config file to /etc/merecat.conf
:
user@example:~/merecat/> ./configure --prefix=/usr --localstatedir=/var --sysconfdir=/etc
user@example:~/merecat/> make
user@example:~/merecat/> sudo make install
Merecat consists of a front-end, merecat.c
, and a standalone HTTP
library, libhttpd.c
, which can be tweaked in various ways and used
for embedding a web server in another application if needed.
The most common options are available from the merecat
command line
and the merecat.conf
configuration file. Other, less common options,
can be enabled using the configure
script:
--enable-builtin-icons Enable built-in icons for dir listings
--enable-htaccess Enable .htaccess files for access control
--enable-htpasswd Enable .htpasswd files for authentication
--enable-public-html Enable $HOME/public_html as ~USERNAME/
--enable-msie-padding Add padding to error messages for Internet Explorer
--disable-dirlisting Disable directory listings when no index file is found
--without-config Disable /etc/merecat.conf support using libConfuse
--without-ssl Disable HTTPS support, default: enabled
--without-symlinks Disable httpd and in.httpd symlinks to merecat
--without-zlib Disable mod_deflate (gzip) using zlib
The source file merecat.h
has even more features that can be tweaked,
some of those are mentioned in the man page, but the header file has
very useful comments as well.
Merecat is a stiched up fork of sthttpd with lots of lost patches found lying around the web. The sthttpd project in turn is a fork from the original thttpd -- the tiny/turbo/throttling HTTP server.
- thttpd was created by Jef Poskanzer mailto:[email protected]
- sthttpd was spawned by Anthony G. Basile mailto:[email protected]
- Merecat is maintained by Joachim Nilsson mailto:[email protected]