A Web Server Written in Sed

The sed script translates HTTP protocol into shell commands that return files. It implements the GET method as defined in RFC 2618. Mostly: absolute URIs are not supported, so the Host header is required.

Quick Start

1. Create a named pipe; this will connect the shell that executes the output of the httpd.sed script with the server process:

    mkfifo /tmp/httpd.sed.fifo
   

2. Change to the directory containing the files you want to serve:

    cd /path/to/my/doc/root
   

3. Start a shell that takes its input from the named pipe created in step 1; Start nc in listen mode on a port (e.g. 8080) and send its output to httpd.sed; close the loop by sending the output of http.sed to the named pipe:

    sh < /tmp/httpd.sed.fifo | nc -k -l 8080 | sed -u -n -f httpd.sed > /tmp/httpd.sed.fifo
   

4. Any files in the docroot are now available via HTTP.

httpd.sed will translate GET requests into shell commands that determine content length and type (via stat and file); and attempt to send that file to the client (via cat). httpd.sed will convert URIs that reference directories by appending "index.html" to the end of the URI.

Access logs are sent to the standard error of the shell process and are formatted in the Common Log Format

Any method other than GET will result in a 405 (Method Not Allowed) response; Any attempt to use a version of HTTP other than 1.1 will result in 505 (HTTP Version Not Supported).

Note: httpd.sed requires GNU sed (gsed on a Mac). Little or no input validation is performed beyond basic URL decoding. Use at your own risk.