/**
* Make sure a gem is available
*
* @param $gem string - the name of the gem to install
* @param $version string - the specific version to install
* @param $tryupdating bool - if the gem is present, check for update? (hits the internet, so slow)
*
* @return null | string - an error string on error, nothing on success
*/
public static function require_gem($gem, $version = null, $tryupdating = false)
{
// Check that ruby exists
if (self::$ruby_ok === null) {
self::$ruby_ok = (bool) `which ruby`;
}
if (!self::$ruby_ok) {
return 'Ruby isn\'t present. The "ruby" command needs to be in the webserver\'s path';
}
// Check that rubygems exists and is a good enough version
if (self::$gem_version_ok === null) {
$code = self::_run('gem environment version', $ver, $err);
if ($code !== 0) {
return 'Ruby is present, but there was a problem accessing the \\
current rubygems version - is rubygems available? The "gem" \\
command needs to be in the webserver\'s path.';
}
$vers = explode('.', $ver);
self::$gem_version_ok = ($vers[0] >= 1 && $vers[1] >= 2 or $vers[0] >= 2);
}
if (!self::$gem_version_ok) {
return "Rubygems is too old. You have version {$ver}, but we need at \\\n\t\t\t\tleast version 1.2. Please upgrade.";
}
$veropt = $version ? "-v '{$version}'" : '';
// See if the gem exists. If not, try adding it
self::_run("gem list -i {$gem} {$veropt}", $out, $err);
if (trim($out) != 'true' || $tryupdating) {
$code = self::_run("gem install {$gem} {$veropt} --no-rdoc --no-ri", $out, $err);
if ($code !== 0) {
return "Could not install required gem {$gem}. Either manually \\\n\t\t\t\t\tinstall, or repair error. Error message was: {$err}";
}
}
}
