github に push すると、Webhooks 経由で、ウェブサーバ側が自動で git pull して、jekyll build して、rsync する感じのあれ

hook.php

<?php
header('Content-Type: application/json');
$secret = 'パスワード';
$repo = 'リポジトリの名前';

function generate_response($code) {
    $response = array(
                      '200' => array(
                                     'status' => 'success',
                                     'errors' => null
                                     ),
                      '400' => array(
                                     'status' => 'fail',
                                     'errors' => array(
                                                       'code' => '400',
                                                       'message' => 'Invalid request.'
                                                       )),
                      '401' => array(
                                     'status' => 'fail',
                                     'errors' => array(
                                                       'code' => '401',
                                                       'message' => 'Could not authenticate.'
                                                       )),
                      '500' => array(
                                     'status' => 'fail',
                                     'errors' => array(
                                                       'code' => '500',
                                                       'message' => 'Internal Server Error.'
                                                       ))
                      );

    return json_encode($response[$code]);
}


function cmd ($cmd) {
    exec($cmd, $arr, $res);
    if ($res === 0) return true;
    else return false;
}

function publish () {
    $HOME = '/home/ユーザ名';
    if(chdir($HOME.'/git/ほげほげ')
       and cmd('export GIT_SSH_COMMAND="ssh -i '.$HOME.'/.ssh/id_rsa -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no";'.
               'git pull')
       and cmd("export RUBYLIB=${HOME}/local/lib/ruby/site_ruby/1.9.3:${HOME}/local/lib/ruby;".
               "export GEM_HOME=${HOME}/local/lib/ruby/gems;".
               "export NODE_PATH=${HOME}/local/lib/node_modules;".
               "export NODE_MODULES=${HOME}/local/bin/node;".
               "export LD_LIBRARY_PATH=${HOME}/local/lib;".
               "export LD_RUN_PATH=${HOME}/local/lib;".
               "PATH=${HOME}/local/bin:${HOME}/local/lib/ruby/gems/bin:${PATH};".
               "jekyll build --config __config.yml")
       and cmd("rsync -rv _public/ ${HOME}/www")
       ) return true;
    else return false;
}


if (!isset($_SERVER['HTTP_X_HUB_SIGNATURE'])) {
    header('HTTP/1.1 400 Bad Request');
    print generate_response(400);
    error_log(__FILE__.' : '.__LINE__ .': HTTP/1.1 400 Bad Request');
    die();
}

$json_str = file_get_contents('php://input');
$json_obj = json_decode($json_str);
$signature = substr($_SERVER['HTTP_X_HUB_SIGNATURE'], 5);
$hash = hash_hmac('sha1', $json_str, $secret);

if (($hash !== $signature) || ($json_obj->repository->name !== $repo)) {
    header('HTTP/1.1 401 Unauthorized');
    print generate_response(401);
    error_log(__FILE__.' : '.__LINE__ .': HTTP/1.1 401 Unauthorized');
    die();
} elseif (! publish()){
    header('HTTP/1.1 500 Internal Server Error');
    print generate_response(500);
    error_log(__FILE__.' : '.__LINE__ .': HTTP/1.1 500 Internal Server Error');
    die();
} else {
    print generate_response(200);
    die();
}