Apache + CGI with ooRexx

This skill serves ooRexx scripts over CGI, using the rexx interpreter and REXX_PATH so that scripts can load their external routines through Call or ::Requires.

Prerequisite: ooRexx installed and runnable (rexx -v). See the oorexx-run skill if you need to install it.

Environment note. The paths below (/path/to/cgi, /path/to/bin, etc.) are placeholders — substitute the actual locations on your machine. The commands assume a Debian/Ubuntu Apache layout (apt, a2enmod, /var/log/apache2/); adapt for other distros.

Installation

apt-get update -qq && apt-get install -y -qq apache2
a2enmod cgid actions

Verification

Check that Apache starts and answers before configuring anything further:

service apache2 start
curl -s http://localhost/

Once your CGI is configured (below), request one of those URLs instead, e.g. curl -s http://localhost/cgi-bin/foo.rex. Errors go to /var/log/apache2/error.log.

Apache configuration

Two example setups, illustrating different patterns. They can coexist (the second overrides the handler for .md files only).

Serving CGI scripts directly

The standard CGI pattern: a request for /cgi-bin/foo.rex runs that script and returns its output.

ScriptAlias /cgi-bin/ /path/to/cgi/
<Directory /path/to/cgi>
    Options +ExecCGI
    AllowOverride None
    Require all granted
    SetHandler cgi-script
</Directory>

Serving .md files through a Rexx handler

A different pattern: instead of executing a requested .rex, every .md file is fed through a Rexx CGI that processes it and returns the result. This is how a Markdown file gets rendered on the fly rather than served raw.

Action Markdown /cgi-bin/markdown_processor.rex
<FilesMatch "\.md$">
    SetHandler Markdown
</FilesMatch>

Shell wrapper (for CRLF shebangs)

A shell wrapper is useful when the .rex CGI scripts are edited on Windows: a #!/usr/local/bin/rexx shebang saved with CRLF line endings leaves a trailing \r glued to the interpreter path, so the kernel looks for /usr/local/bin/rexx\r, fails to find it, and the script dies with not found (exit 127). Because Apache invokes the wrapper through Action/ScriptAlias rather than through the script's own shebang line, the wrapper's clean shebang is what runs, and its exec rexx ... launches the real script regardless of the broken shebang inside it.

cat > /path/to/cgi-wrapper.sh << 'WRAPPER'
#!/bin/bash
export REXX_PATH="/path/to/cgi:/path/to/bin"
exec rexx /path/to/CGI-script.rex "$@"
WRAPPER
chmod +x /path/to/cgi-wrapper.sh
chmod +x /path/to/CGI-script.rex

If your scripts have clean LF shebangs (or you run them with SetHandler cgi-script directly), you don't need the wrapper — set REXX_PATH with SetEnv in the <Directory> block instead.

Case sensitivity on Linux

::Requires and CALL must reference filenames that match what is on disk exactly. On Windows it doesn't matter; on Linux, HTTP.Request.cls ≠ http.request.cls.