instaweb: support for Ruby's WEBrick server

running the webrick server with git requires Ruby and Ruby's YAML and
Webrick libraries (both of which come standard with Ruby). nice for
single-user standalone invocations.

the --httpd=webrick option generates a ruby script on the fly to read
httpd.conf options and invoke the web server via library call. this
script is placed in the .git/gitweb directory. it also generates a
shell script in a feeble attempt to invoke ruby in a portable manner,
which assumes that 'ruby' is in the user's $PATH.

Signed-off-by: Mike Dalessio <mike@csa.net>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Documentation/git-instaweb.txt

@@ -27,7 +27,7 @@ OPTIONS
 	The HTTP daemon command-line that will be executed.
 	Command-line options may be specified here, and the
 	configuration file will be added at the end of the command-line.
-	Currently, lighttpd and apache2 are the only supported servers.
+	Currently lighttpd, apache2 and webrick are supported.
 	(Default: lighttpd)
 
 -m|--module-path::

git-instaweb.sh

@@ -139,6 +139,43 @@ GIT_DIR="$fqgitdir"
 export GIT_EXEC_PATH GIT_DIR
 
 
+webrick_conf () {
+	# generate a standalone server script in $fqgitdir/gitweb.
+	cat >"$fqgitdir/gitweb/$httpd.rb" <<EOF
+require 'webrick'
+require 'yaml'
+options = YAML::load_file(ARGV[0])
+options[:StartCallback] = proc do
+  File.open(options[:PidFile],"w") do |f|
+    f.puts Process.pid
+  end
+end
+options[:ServerType] = WEBrick::Daemon
+server = WEBrick::HTTPServer.new(options)
+['INT', 'TERM'].each do |signal|
+  trap(signal) {server.shutdown}
+end
+server.start
+EOF
+	# generate a shell script to invoke the above ruby script,
+	# which assumes _ruby_ is in the user's $PATH. that's _one_
+	# portable way to run ruby, which could be installed anywhere,
+	# really.
+	cat >"$fqgitdir/gitweb/$httpd" <<EOF
+#!/bin/sh
+exec ruby "$fqgitdir/gitweb/$httpd.rb" \$*
+EOF
+	chmod +x "$fqgitdir/gitweb/$httpd"
+
+	cat >"$conf" <<EOF
+:Port: $port
+:DocumentRoot: "$fqgitdir/gitweb"
+:DirectoryIndex: ["gitweb.cgi"]
+:PidFile: "$fqgitdir/pid"
+EOF
+	test "$local" = true && echo ':BindAddress: "127.0.0.1"' >> "$conf"
+}
+
 lighttpd_conf () {
 	cat > "$conf" <<EOF
 server.document-root = "$fqgitdir/gitweb"
@@ -239,6 +276,9 @@ case "$httpd" in
 *apache2*)
 	apache2_conf
 	;;
+webrick)
+	webrick_conf
+	;;
 *)
 	echo "Unknown httpd specified: $httpd"
 	exit 1