# Nginx host configuration for demosite. 
#
# Attempts to serve a page from memcache, falling
# back to Django if it's not available. 
# This example version also skips trying to get pages 
# from memcache if the page was accessed over SSL.

upstream gunicorn_demosite {
    server 127.0.0.1:8003 fail_timeout=0;
}

server {
    listen 80 default_server;

    # Listen for all server names - lots of sites will be CNAMED
    # to this server, and we won't know what/which.

    # We listen on 80 because, behind ELB, everything is non-SSL
    # and anything that was SSL has the X-Forwarded-Proto: HTTPS
    # header appended to the request, which we'll look for.

    server_name _;

    access_log /var/log/nginx/demosite.access.log;
    error_log /var/log/nginx/demosite.error.log;

    # temporary logging during development
    log_format hashedgeneratedkey $hash_key;
    log_format realkey $memcached_key;
    access_log  /var/log/nginx/keys.log  hashedgeneratedkey;
    access_log  /var/log/nginx/keys.log  realkey;
    # are we getting the HTTPS header?
    log_format http_x_forwarded_proto $http_x_forwarded_proto;
    access_log  /var/log/nginx/keys.log  http_x_forwarded_proto;

    location /static/ {
            root /usr/local/django/demosite/;
    }

    location /media/ {
            root /usr/local/django/virtualenvs/demosite/lib/python2.7/site-packages/django/contrib/admin/;
    }

    location @gunicorn {
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Host $http_host;
            proxy_redirect off;

        proxy_pass http://gunicorn_demosite;

            client_max_body_size 10m;
    }

    location @cache_miss {
            # Pass on the request to gunicorn, creating
            # a URI with the hostname as well as the path                                                                                                  
            # See the docs if $is_args$args is confusing

            set $caught_uri $http_host$uri$is_args$args;
            try_files $caught_uri @gunicorn;
    }

    location @memcache_check {

            # Otherwise, see if we can serve things from memcache.

            # Extract cache key args and cache key. 
            if ($http_cookie ~* "pv=([^;]+)(?:;|$)") {
                set $page_version $1;
            }

            # If you are running multiple sites off the same server, 
            # the cache key to include the domain, too, which nginx
            # doesn't consider part of the $uri. (SJ: it ought to do, but doesn't)

            set_md5 $hash_key $http_host$uri&pv=$page_version;
            # make sure that this matches the CACHE_PREFIX in project settings
            set $django_cache_prefix ps;
            set $django_cache_version 1;
            set $memcached_key $django_cache_prefix:$django_cache_version:$hash_key;

            recursive_error_pages on;

            set $fallthrough_uri null;

            # Hit memcache, to see if the page is there 

            default_type       text/html;
            memcached_pass     127.0.0.1:11211;

            # We hand off all of these to @cache_miss and its descendent handlers.
            # The = means the handlers determine the error code, which is a Good Thing     

            error_page         401 = @cache_miss;
            error_page         403 = @cache_miss;
            error_page         404 = @cache_miss;
            error_page         405 = @cache_miss;
            error_page         502 = @cache_miss;

            # Note that it is not permitted to have a try_files in the same
            # location block as a memcache_pass
    }

    location / {

            recursive_error_pages on;

            set $caught_uri $http_host$uri$is_args$args;

            # Default is to try memcache
            set $destination_block @memcache_check; 

            # If we've got proof that it was an SSL cert, just 
            # short-cut to @gunicorn via the @cache_miss location
            # (ELB sets X-Forwarded-Proto: HTTPS for instance )
            if ($http_x_forwarded_proto = HTTPS){
                set $destination_block @cache_miss;
            }

            # hand off to whichever block was appropriate  
            try_files $caught_uri $destination_block;

            # SJ: not entirely sure about this - needs more 
            # testing as it shouldn't, to my mind, be needed

            error_page         401 = $destination_block;
            error_page         403 = $destination_block;
            error_page         404 = $destination_block;
            error_page         405 = $destination_block;

    }

# install all dependencies
sudo aptitude install libc6 libpcre3 libpcre3-dev libpcrecpp0 libssl0.9.8 libssl-dev zlib1g zlib1g-dev lsb-base

# download nginx
wget http://nginx.org/download/nginx-1.0.11.tar.gz
tar -zxf nginx-1.0.11.tar.gz
rm nginx-1.0.11.tar.gz
cd nginx-1.0.11/

# download modules
wget https://github.com/simpl/ngx_devel_kit/zipball/v0.2.17 -O ngx_devel_kit.zip
unzip ngx_devel_kit.zip
wget https://github.com/agentzh/set-misc-nginx-module/zipball/v0.22rc4 -O set-misc-nginx-module.zip
unzip set-misc-nginx-module.zip
wget https://github.com/agentzh/echo-nginx-module/zipball/v0.37rc7 -O echo-nginx-module.zip
unzip echo-nginx-module.zip

# configure and install
./configure \
    --add-module=simpl-ngx_devel_kit-bc97eea \
    --add-module=agentzh-set-misc-nginx-module-290d6cb \
    --add-module=agentzh-echo-nginx-module-b7ea185 \
    --prefix=/usr \
    --pid-path=/var/run/nginx.pid \
    --lock-path=/var/lock/nginx.lock \
    --http-log-path=/var/log/nginx/access.log \
    --error-log-path=/var/log/nginx/error.log \
    --http-client-body-temp-path=/var/lib/nginx/body \
    --conf-path=/etc/nginx/nginx.conf \
    --with-http_flv_module \
    --with-http_ssl_module \
    --with-http_gzip_static_module \
    --http-proxy-temp-path=/var/lib/nginx/proxy \
    --with-http_stub_status_module \
    --http-fastcgi-temp-path=/var/lib/nginx/fastcgi \
    --http-uwsgi-temp-path=/var/lib/nginx/uwsgi \
    --http-scgi-temp-path=/var/lib/nginx/scgi
make
sudo make install

# Done, now configure your nginx.

from nginx_memcache.decorators import cache_page_nginx

@cache_page_nginx
def my_view(request):
    ...

// JS code
$.ajax({
    url: // your csrf url,
    type: 'GET',
    data: {type: 'login'},  // only if you need a session id for cookie login
    dataType: 'json',
    success: function(data) {
        $('form').each(function() {
            $(this).append(
                '<input type=hidden name=csrfmiddlewaretoken ' +
                    ' value="' + data.token + '">');
        });
    }
});

// Django code
# views.py, don't forget to add to urls.py
def get_csrf(request):
    if request.GET.get('type') == 'login':
        request.session.set_test_cookie()
    return JSONResponse({
        'status': 1,
        'token': getattr(request, 'csrf_token', 'NOTPROVIDED')
    })

python manage.py test nginx_memcache